Chicken... meet egg. My trike quandary

[bcsteeve]

Hi there. First time poster. I've never had an e-bike and I have very little experience with bikes in general. However, I've been reading a TON to try to get me up to speed, and I'm pretty sure I have all the basics. Still... there are gaps.

This is likely to be a long post. I'm putting headings and by all means skip what you want. This is just as much to get my thoughts down as it is looking for answers, and I'm not asking anyone to provide me all the answers (though they are welcome!).

About me: Hi. I'm Steve. I live in Beautiful British Columbia (they put that on our license plates so I guess I'm obliged to say that) in a small-ish mountain/valley town. I have a background in electronics, though I've never done anything related to motors (I get the basic gist though). I consider myself mechanically inclined, but that comes with the caveat that I have pretty much no fabrication abilities. I don't know how to weld, I don't have a grinder, etc. But I've taken apart several cars and put them back together to develop automotive electronic products. A few years ago, my house burned down after a hobby-grade LiPO pack caught fire in my basement. I lost my office and equipment, so I went and got a regular job and for the last 2-3 years I've been working in auto insurance/legal (quite the change, but I enjoy it!). The hard times continued though, and last November I was out for a walk and was struck by a truck and I've been recovering since. A couple of weeks ago, the specialist suggested I lose weight. I've gained (gasp) 30 pounds since November. My injuries are to my foot and my back. My foot makes walking difficult and my back makes sitting upright very painful. He advised I get a recumbent bike. Now, I'm sure he meant stationary... but that sounds mind-numbingly boring, so I started to expand my search.

Physical needs: Recumbent seating, 300lbs (297 and hopefully dropping), 6'4" with 48" x-seam. I'm thinking tadpole style trike makes the most sense, probably with fat tires.

Geographical concerns: Two fold. 1) availability. A lot of what I find on the Internet won't (or reasonably won't) ship to Canada. I need stuff available here. If COVID restrictions are lifted in short order, I don't mind picking up from a shipping address in WA state. 2) terrain. What I envision being where I'd want to ride the most, is in the mountain bike trails very near my home. I'm 2 minutes walk to the nearly/locally-famous "Feel the love" trails. Many of the trails are far too narrow for a trike, but there's a lot that are wider too and used for horses and hikers. Still, it gets really steep (short 40% grade slopes, sustained 15%) and bumpy. I'm not saying I need to go on every trail, but I want something capable of getting out into that. Am I asking too much? Youtube videos of "off-road trikes" almost all lead to Utah Trikes and they show them on gentle grass slopes.

Desired characteristics: Besides handling my weight and terrain, I'm not picky when it comes to things like speed or range. I suppose I don't want to be limited to walking speed, but I'm not out to win speed contests either. For range, 40km sounds like double what I'd ever need... but at the same time, I don't want to be unnecessarily limited and I know from experience with electric cars that I would likely want the largest battery that fits the frame and budget. I don't have a particular opinion w.r.t wheel size and am open to advice.

Budget: In Canadian dollars, I'd say $10k is my soft limit, but the closer I can get that to $5k, the healthier my marriage will be. Within reason, I don't want to be budget-constrained. I want to get what works. If that means $10k-$12k, then it is what it is.

Where I'm leaning after doing research:
Trike: all roads keep pointing to the Sun Seeker Fat Tad. It has a 300lb weight limit and x-seam range that I would fit. It is marketed as "off road". It is available here. Cattrike tops out at 275lb. Does that really matter? Is it like so many things where the rating is being cautiously safe? Or should I respect that as an absolute limit? I'm by no means married to the Sun Seeker and totally open to suggestions.
Motor: "most" roads point to the Bafang 1000W BBSHD. So many, that I almost take that as a given. Almost. Then someone points me to nearly-local Grin Technologies (ebikes.ca) and their "all-axle" hub motor, which makes a pretty good case. It acknowledges that for off-road/high load applications that the traditional wisdom is to go mid-drive, but challenges that thinking and suggests their hub motors are suitable. I have to say... the lower maintenance, higher reliability, and (if I understand) certain drive characteristics of a hub design have me WANTING to go hub-mount. But Grin's offering is more expensive and virtually everything but them says mid is the way to go. Thoughts? I've asked Grin if it would fit on the Sun Seeker and they were entirely non-committal, saying I'd have to figure that out on my own. I'm unclear on what the determining factors are. They suggest Cattrike (see weight limit issues) or Terratrike (haven't successfully found a dealer) or Greenspeed (still looking) or, generically, "DIY" but again don't provide the necessary details to know if any given trike would work. What really piques my interest is the possibility to do a 2WD setup! On the other hand, maybe 1 Bafang is superior to 2 Grins... I really have no way of knowing.
"Gears": here's where my brain really farts. I'm just not familiar enough with bike components. I'm not even sure if "gears" is the right word. Utah Trikes come with a Nuvi N380 and a very expensive upgrade option to a Rohloff 14. I've read about these and others, but it is all Greek to me, unfortunately. I'm really hoping to get advice on what I'd need in this regard. Now, another benefit (I think) of the Grin motors is that it is independent of this. So I suppose I could go with whatever comes on the trike I order, and upgrade that later if necessary? I can't say I fully understand, but I gather that if I go Bafang I'm more limited here?

The chicken v. egg or cart v. horse problem:I'm starting to think I need the trike before I can really decide on e-components. But then, I don't want to drop $2-3k on a trike to find out it doesn't work with X. I don't really know what I need in terms of e-power until I try it, but I can't try it without buying it! So I'm hoping your wise advice can fill in the blanks better than my entirely inexperienced brain.

Cheers!

 

[goatman]

if i try and go up a steep gravel path on the trike, back tire spins out i lock up the front brakes and start sliding backwards and have to put feet down to stop while the pedal cranks are spinning backward, not much fun. on my sons normal trike with front hub if his front wheel spins he pedals and rear wheels turn, 2wd and up he goes. you have the budget to go with 2 Grin motors on the front and can still assist by pedalling, 3 wheel drive, nothing would stop you

 

[amberwolf]

Some thoughts about various things, and some "pointed questions" on things you may not have thought about below, after various quoted bits of your post. If I didn't respond to a particular part of the post, it just means I didn't have any relevant info.

Physical needs: Recumbent seating, 300lbs (297 and hopefully dropping), 6'4" with 48" x-seam. I'm thinking tadpole style trike makes the most sense, probably with fat tires.

A typical tadpole is VERY low to the ground. Can you climb down into and up out of that kind of seat that far down?

I can't, which is one reason I use semi-recumbent seating at basically regular chair-height (like an average car seat). I built my bike and trikes, but you can buy them this way. (Sun Trikes, etc) My trikes have only been delta, mostly because building the steering interconnects for tadpole is complex, and I didn't want to deal with that. This can limit the turning speed and radius depending on trike design and rider experience, vs tadpole.

My SB Cruiser trike is the most successful so far, and has evolved to the point I am designing it's successor around it's best points.

Another issue with typical, non-leaning, trikes is crowned roads. If your roads have radically tall / rounded crowns, then unless you're near the center on that crown, you'll be riding at an angle all the time; hte steeper the crown the worse the angle. Mostly that's just annoying, but it also affects riding / steering as you have to constantly be slightly steering toward the center of the road, whcih also wears your tires out faster.

2) terrain. What I envision being where I'd want to ride the most, is in the mountain bike trails very near my home.
<snip>
Many of the trails are far too narrow for a trike, but there's a lot that are wider too and used for horses and hikers. Still, it gets really steep (short 40% grade slopes, sustained 15%) and bumpy. I'm not saying I need to go on every trail, but I want something capable of getting out into that. Am I asking too much? Youtube videos of "off-road trikes" almost all lead to Utah Trikes and they show them on gentle grass slopes.

Will a trike fit on those trails that you do want to ride on? Not just width, but track width where the tires end up vs where the previous tire paths and horsehoof holes and tracks are, and elevation of each side of the trail vs the center. If the trails aren't very flat, like a paved road (regardless of general hills and slopes), a trike may have trouble navigating those at any speed without bouncing you all over the place (even with typical suspension, and most trikes have no suspension at all), or even actually tipping over.

How fast do you intend to ride those trails?

How much exercise do you actually want to get, vs the electric assist? Do you just want it to help you up the worst hills? Etc.

If there isn't a smooth enough runup to the 40% slopes to let you get speed up enough for momentum to help you up, and you don't have enough torque (thru either gearing or total power), you might end up getting off and walking up those.


If there is anywhere you can rent a trike that's even remotely similar to what you want to use, you should try it out on the paths, roads, and trails you want to ride on. It will give you some idea of what you're facing; it can be very very different to ride that kind of stuff on a trike vs a bike. (you can't exactly stand up on a low-seated trike to let your knees take some of the bumps, for one).

Desired characteristics: Besides handling my weight and terrain, I'm not picky when it comes to things like speed or range. I suppose I don't want to be limited to walking speed, but I'm not out to win speed contests either. For range, 40km sounds like double what I'd ever need... but at the same time, I don't want to be unnecessarily limited and I know from experience with electric cars that I would likely want the largest battery that fits the frame and budget. I don't have a particular opinion w.r.t wheel size and am open to advice.

For your stated needs you will almost certainly have to go with a middrive that drives thru the pedal drivetrain, and gives you a very wide gearing range. Something like the Stokemonkey style that drives the lefthand side of the pedal crank, so that you still have all of the righthand gears to shift thru (which you wont have with any of the crank-mounted drives, so you lose either significant speed ranges or significant torque ranges).

I'm not sure who still sells the SM drives; it might require fabrication to make one that fits whichever trike (or bike) you get.

The problem with anything that goes thru the pedal drivetrain on a low tadpole is that you have a really really long chainline, and you are expecting bumpy conditions, which is an easy way to derail one if it's not setup right, and a derailment under motor power can quickly destroy the chain and/or sprockets. (you can feel it quickly under pedal power, and stop cranking, but the motor won't do that).

Also, power thru the chain and sprockets will be higher for longer periods than just pedaling, and will wear out the sprockets and chains faster, so you have to replace the whole drivetrain more often.

Another issue with any middrive thru pedal drivetrain is that you have a single-point-of-failure (several actually) that leaves you stranded, walking, when that point breaks. The freewheel (or freehub), any of the sprockets, chainlinks, etc., can fail and then you have no pedals and no motor.

A hubmotor generally makes a redundant drive system; if it fails to work you still have pedals, and if pedals fail, you still have that (as long as your control system doesn't require pedals to operate fully).

Also, with a rear pedal drive and front hubmotor drive, you have 2WD minimum, and 3WD if both wheels on that end of the trike are driven (from either motor or pedals, whichever kind of trike it is). That could be helpful on hills with poor traction.

Budget: In Canadian dollars, I'd say $10k is my soft limit, but the closer I can get that to $5k, the healthier my marriage will be. Within reason, I don't want to be budget-constrained. I want to get what works. If that means $10k-$12k, then it is what it is.

Unless you have to have something custom-built for you for the trike itself, I'm sure you can get in under that $5k budget.

The most expensive part, depending on your power and range needs, is the battery. That's one thing you dont' want to cheap out on, becuase it has to deliver everything that the motor needs under all possible conditions, from the time you start on a trip to the time you come home, for the life of the trike. You usually want to add at least 25% capability and capacity to what's required, to account for pack ageing over time, and if you may have to have detours, windy conditions, etc., you may want to add at least another 25% to account for those.

Pardon me for using miles vs km in my stuff below; I got lazy and didn't convert back to km for you.

With all the slow riding and hills and whatnot, with the weight, you're probably going to use 30-50wh/mile, average. Might be more, or less, but we'll start there, before busting out the math and calculators.

For 50wh/mile, and a 25 mile minimum range, you'd need 50 x 25 = 1250wh minimum. That's around 15-20lbs of battery (maybe less), depending on the kind and quality, and might generally be available in the larger COTS "shark" type packs, IIRC. (not sure that's the right specific name, but that general style).

If you add in another 50% (for the aging and the worst-case conditions), then you could round up to 2Kwh, and you'd probably need two packs in parallel, if using that type of COTS battery.

You can build your own out of things like used Nissan Leaf cell modules, whcih will probalby last longer than typical ebike batteries even though the Leaf cells would be used, and are very easy to reconfigure or replace problem cells in (where it realistically requires a spotwelder and practice and other materials to do that for COTS ebike packs).

Trike: all roads keep pointing to the Sun Seeker Fat Tad. It has a 300lb weight limit and x-seam range that I would fit. It is marketed as "off road". It is available here. Cattrike tops out at 275lb. Does that really matter? Is it like so many things where the rating is being cautiously safe? Or should I respect that as an absolute limit? I'm by no means married to the Sun Seeker and totally open to suggestions.

The weight limit wouldn't matter as much if you were riding on completely flat perfect roads. The problems happen when you ride on bumpy surfaces, especially ones with jolting holes and whatnot. Each time a wheel drops and hits, or bounces up on a rock or piece of road debris, the whole frame twists, axles bend, etc. with forces created by the weight multiplied by the g-forces involved. It's unlikely anything will break off immediately...but stress damage builds up, and especially with aluminum can being to stress-fracture and eventualy just snap off. (where steel stuff tends to bend first, giving you an easier chance of seeing something is wrong before it breaks).

For certain applications, fat tires help on unsuspended wheels (like the front of that trike), but for uneven track heights especially for things like trails damaged by horses, actual long-travel suspension helps more.

Motor: "most" roads point to the Bafang 1000W BBSHD. So many, that I almost take that as a given. Almost. Then someone points me to nearly-local Grin Technologies (ebikes.ca) and their "all-axle" hub motor, which makes a pretty good case.

The two problems with hubmotor in your application are weight in the wheel causing whatever suspension you do have to not work as well (inertia of the motor mass being MUCH greater than that of the regular bike wheel the suspension was made for), and slow high power climbing, which creates many times the waste heat that regular high power riding at speed would.

The problem with the BBSxx types is that you lose your front shifting ability, and get only one chainring there out to the driving wheel's input sprockets.

One way around this problem is using one of the few IGHs that also supports a freewheel or freehub with multiple gears, so you have more total gears and can shift down far enough for really slow hill stuff, etc., but also stil shift up for faster flatter stuff.


Grin's stuff in general is more expensive, but it is also generally more well-built, and more well-thought out. They are the only ebike retailer I myself trust buying from, though they're not perfect either. The all-axle hub will be more expensive partly because you'll need mounts for it that might have to be made for your particular trike, if the ones they already sell don't fit.

I've asked Grin if it would fit on the Sun Seeker and they were entirely non-committal, saying I'd have to figure that out on my own. I'm unclear on what the determining factors are.

If you look at the mechanics of the wheel attachment points on each tadpole, you'll find they are typically very similar, but not always identical. The hardware Grin has was, AFAICR, developed for a Catrike, based on this thread here:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=88266

There's enough diferent ones out there that I can see why they wouldn't be able to tell you if a particular one would work with their hardware or not. If it does'nt fit the one you want to use, you'd ahve to design and make or have made the hardware to do it. Thankfully the GAA hubs are easy to do that for, compared to what you'd have to do for any other typical hubmotor (disassembling it, pressing out the axle, maybe making custom covers for larger bearings, axle retention, etc etc).

"Gears": here's where my brain really farts. I'm just not familiar enough with bike components. I'm not even sure if "gears" is the right word. Utah Trikes come with a Nuvi N380 and a very expensive upgrade option to a Rohloff 14. I've read about these and others, but it is all Greek to me, unfortunately. I'm really hoping to get advice on what I'd need in this regard. Now, another benefit (I think) of the Grin motors is that it is independent of this. So I suppose I could go with whatever comes on the trike I order, and upgrade that later if necessary? I can't say I fully understand, but I gather that if I go Bafang I'm more limited here?

The rohloff can take a lot more torque than the nuvinci stuff, AFAIK. The NV shifts perfectly smoothly but will probably wear faster if you do that under load due to the way it works inside (balls and fluids instead of gears).

As noted previously, if you go with any crank-mounted middrive I know of (that replaces your crankshaft, or that drives one of the rightside sprockets) you lose the front gearing. (at the least, you lose the lowest gear(s), which are the ones you really need for your purposes).

A hubmotor doesn't lose you any gearing...but since it doens't go thru the gearing, it has a lot more waste heat for the kind of riding you're wanting to do. And it masses a lot more for the same power level, at the wheel itself, affecting suspension performance.




One thing I would recommend is to use the http://ebikes.ca/tools/simulator.html to see what the hubmotor option would require to do what you want without overheating. First read the whole page so you know whate vertything is and how it works, then setup a basic system with that GAA motor, first just one, and then if that doesn't work out try 2WD with it, then you can try using some smaller motors as middrives (ther'es a checkbox option for that) and see how they perform in the same situation, and "downshifting" using the gear ratio on the middrive option to be appropriate for the terrain in question. There is also a trip simulator linked to the motor simulator, but it doesn't allow for varying the gear ratio AFAIK so it is probably mostly useful for chekcing out the hubmotor options on your specific terrain.

 

[donn]

I need stuff available here. If COVID restrictions are lifted in short order, I don't mind picking up from a shipping address in WA state. 2) terrain.

You might have a look at craigslist. Nothing much on the BC side of the border, but some of your preferred options are to be found less than 100km south of the border, new or used.

You'll see a Burley Limbo in Surrey - a bicycle, but a recumbent bicycle with rear suspension. Looks like a steal. I happen to ride the same, and I like it a lot. Simple matter to put a hub motor on the back - yeah, the suspension isn't designed for that, but I have not had any reason to care. There may be reasons why a bicycle won't work for you, but it's worth a little thought. Because there's no tip-over problem, bicycles can be as tall as you want, and the Limbo is on the tall side for a recumbent; I'm at about average car driver eye level. I'm just a couple inches shorter than you, and over the last half century at that height I've gotten used to having a pretty good view. A bicycle is also a little less unwieldy in a squeeze, easier to park, lighter ... and more fun.

 

[LewTwo]

Between mass and terrain you have managed to combine some of the biggest challenges pushing the envelope for a E-Assist bike/trike. Let me add one more: you mentioned horse trails.You may occasionally note the existence of some 'fresh trail markers' left by previous visitors. You likely will want sufficient control and maneuverability to avoid encountering those directly and spreading them all over the environment (consider your person as part of that environment).

I have two thoughts:

I believe most trikes have a live axle (AmberWolf please correct me if I am mistaken). I seem to remember a thread or a video somewhere of someone adding a secondary drive system with a BLDC motor (think wheelchair) to one side of the trike's live axle chain drive. They also used a 3 speed IGH hub as a intermediate transmission. The 3 speeds IGH are reputed to somewhat more tolerant than their more higher speed siblings. They are also available with drum brakes if one want the option of added stopping power. It did require some custom fabrication but nothing very exotic ... mainly brackets for mounting the components. The biggest challenge was getting a sprocket drilled to be attached to the intermediate hub via the spoke holes (local machine shop). The point is nothing from the trike's normal operation was lost. Either or both drive systems could be used.

The second thought is a bit more outside the box. Our friends in the electric skateboard world have come up with a series of motor controllers specifically designed to drive TWO DC motors at the same speed (Flipsky Dual FSESC 6.6 Plus). These folks are 'hot rodders' so those controllers are designed to be able to push a lot of power as well as being completely programmable. They are expensive ($250 to $500). I am thinking one of those could be combined with a TWO geared hub motors on the front of a tadpole trike. This approach has the advantages of leaving the Tadpoles trike's delicate (did I use that word) intack and doubling the amount of power to the ground. It should also not exhibit the inconvenience of pulling to one side or the other.

I like the concept of a tadpole but on the streets where I live, being below the line of sight of cage operators would be consistent with suicide.

 

[bcsteeve]

if i try and go up a steep gravel path on the trike, back tire spins out i lock up the front brakes and start sliding backwards and have to put feet down to stop while the pedal cranks are spinning backward, not much fun. on my sons normal trike with front hub if his front wheel spins he pedals and rear wheels turn, 2wd and up he goes. you have the budget to go with 2 Grin motors on the front and can still assist by pedalling, 3 wheel drive, nothing would stop you

Thanks for that. Very encouraging. So I presume your take is that 2xGrin > 1x Bafang in terms of overall capability/suitability for my needs?

 

[amberwolf]

I believe most trikes have a live axle (AmberWolf please correct me if I am mistaken).

Many *delta* trikes have a live axle with both rear wheels directly connected to it, and some use a live axle with a differential between them, but I don't know that there is a "most" type, that I've seen. Chalo has probably seen more different kinds of trikes than I have, though.

Other delta trikes connect only one side (often the left) to the pedal drivetrain, and the other is left freewheeling all the time. (the trike kit I started out with to build Delta Tripper and later converted to SB Cruiser is like that).

Some delta trikes use a split axle, with a set of freewheels and chains on a jackshaft between the pedals and the split axles acting as a sort of backwards-working differential; these don't work as well as a straight live axle or a real differential would.

The drive system you describe for a live axle would work (similar things have been used for very heavy pedicabs for instance), but the only trikes I've seen that way are delta (vs the tadpoles that the OP mentioned).


I don't know of any commercial tadpoles with live axles (or drive axles at all), so for those the options are limited to driving the pedal chain, or directly driving the wheels either via chain / belt from non-wheelmounted motors or via hubmotors. (or friction drives, but probably not a great option for dirty potentially muddy trails)

 

[fatty]

Budget: In Canadian dollars, I'd say $10k is my soft limit, but the closer I can get that to $5k, the healthier my marriage will be. Within reason, I don't want to be budget-constrained. I want to get what works. If that means $10k-$12k, then it is what it is.

Unless you have to have something custom-built for you for the trike itself, I'm sure you can get in under that $5k budget.

Great post, but I'm not so optimistic on under $5k -- ebikes quickly get expensive, and most projects (certainly all of mine) eventually run towards the high end, if not over.

It looks easy with a $2200 complete trike, but you have to realize that like any bike not built with a complete big three groupset, the components are going to be cheap Chinese parts that get enough bikes through warranty to be profitable -- and that's before electrification. At the very least, considering the trike+rider+electrification weight, you're going to want a proper rear coil shock, even just a Marzocchi (Fox) Bomber CR, and proper 200mm hydraulic disc brakes with 4-piston calipers. Eventually, you'll probably want lighter/more-aero wheels, with tires (and therefore rims) to suit your specific riding conditions, and on, and on, and on...

The trike+rider+electrification weight is going to approach motorcycle weight, so you won't want to skimp out on critical suspension and braking components.

 

[bcsteeve]

Some thoughts about various things [...]

firstly, thank you SO much for taking the time to respond as you have. Much appreciated.

A typical tadpole is VERY low to the ground. Can you climb down into and up out of that kind of seat that far down?

Yes, mobility in that way is fine.

Another issue with typical, non-leaning, trikes is crowned roads. If your roads have radically tall / rounded crowns, then unless you're near the center on that crown, you'll be riding at an angle all the time

I don't think our roads are excessively crowned, but regardless I'm not really thinking about road use anyway. I don't think it would be street legal, and after my incident that led to this injury, at least right now I'm not to keen on being around vehicles without airbags But something to think about.

Will a trike fit on those trails that you do want to ride on? Not just width, but track width where the tires end up vs where the previous tire paths and horsehoof holes and tracks are, and elevation of each side of the trail vs the center. If the trails aren't very flat, like a paved road (regardless of general hills and slopes), a trike may have trouble navigating those at any speed without bouncing you all over the place (even with typical suspension, and most trikes have no suspension at all), or even actually tipping over.

Well, see that's what I'm trying to figure out. That's my definition of "off road". Sure, they are true mountain bike trails, and yeah I'm expecting the trike to handle that. That's where some of my confusion comes from, because I see Utah Trikes videos of them "offroading" and they are casually going down gentle slopes of well manicured lawns. On the other hand, there are still photos suggesting some of these things can be genuine rock crawlers.

How fast do you intend to ride those trails?

Hiking speed or better. The point is to replace my daily hikes with daily rides. As I said in my intro, I'm not interested in going fast, but rather getting where I want to go. Of course, the ability to go fast when desired/appropriate would not be shunned.

How much exercise do you actually want to get, vs the electric assist? Do you just want it to help you up the worst hills? Etc.

Exercise. The whole point is exercise. I wouldn't get electric assist, except that I know the terrain (even my driveway) is too steep for my deconditioned body. it would be pointless and discouraging. I think I'll be able to resist the throttle and only use what I need. Afterall, I'm pretty motivated to recovery and get back to where I was. My weight has ballooned because I haven't been able to do my regular activities.

If there isn't a smooth enough runup to the 40% slopes to let you get speed up enough for momentum to help you up, and you don't have enough torque (thru either gearing or total power), you might end up getting off and walking up those.

I hear you. My hope is that I can put together a setup that has enough oomph to tackle those. But if not, worst case is I find another way round. There are hundreds of trails up there and they all intertwine. There's almost always a longer way round.

If there is anywhere you can rent a trike that's even remotely similar to what you want to use, you should try it out on the paths, roads, and trails you want to ride on. It will give you some idea of what you're facing; it can be very very different to ride that kind of stuff on a trike vs a bike. (you can't exactly stand up on a low-seated trike to let your knees take some of the bumps, for one).

Excellent Idea, and at the time I wrote my intro I would have said that's not an option. THEN I FOUND IT! There's a specialty outfit that barely registers on Google that specializes in adventures for disabled people, and they rent their equipment and guess what!?! They have an e-assist TerraTrike and I'm meeting with them tomorrow to check it out! The person on the phone wasn't sure if I could rent it yet, as they don't start rentals until May, but he said I'd be able to at least sit in it. I currently have no way of transporting it though, and I live one town over so I don't think I'd be able to try it on the actual trails... however, where they are located they have some decently off-road options to explore. That being said, I don't know if that particular trike is meant for anything other than road. I'll see soon!

For your stated needs you will almost certainly have to go with a middrive that drives thru the pedal drivetrain, and gives you a very wide gearing range. Something like the Stokemonkey style that drives the lefthand side of the pedal crank, so that you still have all of the righthand gears to shift thru (which you wont have with any of the crank-mounted drives, so you lose either significant speed ranges or significant torque ranges).

I'm not sure who still sells the SM drives; it might require fabrication to make one that fits whichever trike (or bike) you get.

The problem with anything that goes thru the pedal drivetrain on a low tadpole is that you have a really really long chainline, and you are expecting bumpy conditions, which is an easy way to derail one if it's not setup right, and a derailment under motor power can quickly destroy the chain and/or sprockets. (you can feel it quickly under pedal power, and stop cranking, but the motor won't do that).

Also, power thru the chain and sprockets will be higher for longer periods than just pedaling, and will wear out the sprockets and chains faster, so you have to replace the whole drivetrain more often.

Another issue with any middrive thru pedal drivetrain is that you have a single-point-of-failure (several actually) that leaves you stranded, walking, when that point breaks. The freewheel (or freehub), any of the sprockets, chainlinks, etc., can fail and then you have no pedals and no motor.

A hubmotor generally makes a redundant drive system; if it fails to work you still have pedals, and if pedals fail, you still have that (as long as your control system doesn't require pedals to operate fully).

Also, with a rear pedal drive and front hubmotor drive, you have 2WD minimum, and 3WD if both wheels on that end of the trike are driven (from either motor or pedals, whichever kind of trike it is). That could be helpful on hills with poor traction.

I'm a little confused on what you're recommending. From my searching, I'd say that the vast majority of these tadpole trikes that are advertised as off-road use the Bafang BBSHD system and I think that's a mid-drive that's at the pedals, right? I've never heard of the Stokemonkey you mention. The alternative seems to be hub motors, but most say that it isn't suitable for my needs because it will burn out. Then there's the Grin hub motors that (at least say) they are a different animal and maybe give the best of both worlds?

Unless you have to have something custom-built for you for the trike itself, I'm sure you can get in under that $5k budget.

That would be nice, but almost everytime I try to price something out (for example, on Utah Trikes) it nets out closer t $10k. Then again, I don't know what options are really necessary. For example, it is like USD$1500 to upgrade to a Rohloff but I don't have any clue if that's necessary or advantageous or even detrimental. The Bafang would be around $1200 (including the battery, which they don't give specs for) and the trike itself starts at $2k so I can see how it can get expensive quickly. The Grin motor setup I think is $3-$4k for one and something like $5k for two, and that doesn't include the Trike. But maybe I'm overshooting?

Pardon me for using miles vs km in my stuff below; I got lazy and didn't convert back to km for you.

I don't mind. I appreciate your battery analysis, but realistically I imagine once I settle on a system (Bafang vs. Grin vs. other) I'd likely go with whatever they recommend to pair it with. They all seem to come as kits. Or is that being lazy?

For certain applications, fat tires help on unsuspended wheels (like the front of that trike), but for uneven track heights especially for things like trails damaged by horses, actual long-travel suspension helps more.

Most of the tad-poles seem to have no front suspension. They all have rear. The Sun Seeker does have front as well.

One way around this problem is using one of the few IGHs that also supports a freewheel or freehub with multiple gears, so you have more total gears and can shift down far enough for really slow hill stuff, etc., but also stil shift up for faster flatter stuff.

so is that where, for example, the Rohloff comes in?

There's enough diferent ones out there that I can see why they wouldn't be able to tell you if a particular one would work with their hardware or not. If it does'nt fit the one you want to use, you'd ahve to design and make or have made the hardware to do it. Thankfully the GAA hubs are easy to do that for, compared to what you'd have to do for any other typical hubmotor (disassembling it, pressing out the axle, maybe making custom covers for larger bearings, axle retention, etc etc).

I'm good at design. So I guess worst case is to design a bracket and have it machined somewhere? I'm a hands-on, visual learner... it probably becomes clear once I have it all in my hands. I'd just hate to drop this coin and find out it isn't possible for some reason.

The rohloff can take a lot more torque than the nuvinci stuff, AFAIK. The NV shifts perfectly smoothly but will probably wear faster if you do that under load due to the way it works inside (balls and fluids instead of gears).

As noted previously, if you go with any crank-mounted middrive I know of (that replaces your crankshaft, or that drives one of the rightside sprockets) you lose the front gearing. (at the least, you lose the lowest gear(s), which are the ones you really need for your purposes).

A hubmotor doesn't lose you any gearing...but since it doens't go thru the gearing, it has a lot more waste heat for the kind of riding you're wanting to do. And it masses a lot more for the same power level, at the wheel itself, affecting suspension performance.

Thanks for that explanation! I feel like I'm getting closer, but my brain still isn't there.

One thing I would recommend is to use the http://ebikes.ca/tools/simulator.html to see what the hubmotor option would require to do what you want without overheating. First read the whole page so you know whate vertything is and how it works, then setup a basic system with that GAA motor, first just one, and then if that doesn't work out try 2WD with it, then you can try using some smaller motors as middrives (ther'es a checkbox option for that) and see how they perform in the same situation, and "downshifting" using the gear ratio on the middrive option to be appropriate for the terrain in question. There is also a trip simulator linked to the motor simulator, but it doesn't allow for varying the gear ratio AFAIK so it is probably mostly useful for chekcing out the hubmotor options on your specific terrain.

I did spend some time on that tool. I could find no combination that never had a burnout risk. 300lbs and 20% is just that harsh, I guess.

Is there some warning when things get overheated? Or it just craps out?


Again, thank you SO much for taking the time here!

 

[bcsteeve]

You'll see a Burley Limbo in Surrey - a bicycle, but a recumbent bicycle with rear suspension. Looks like a steal. I happen to ride the same, and I like it a lot. Simple matter to put a hub motor on the back - yeah, the suspension isn't designed for that, but I have not had any reason to care. There may be reasons why a bicycle won't work for you, but it's worth a little thought. Because there's no tip-over problem, bicycles can be as tall as you want, and the Limbo is on the tall side for a recumbent; I'm at about average car driver eye level. I'm just a couple inches shorter than you, and over the last half century at that height I've gotten used to having a pretty good view. A bicycle is also a little less unwieldy in a squeeze, easier to park, lighter ... and more fun.

I found that listing. $600, right? It certainly doesn't appear to be anything remotely capable of mountain trails though. Am I missing something?

 

[LewTwo]

I don't know of any commercial tadpoles with live axles (or drive axles at all), so for those the options are limited to driving the pedal chain, or directly driving the wheels either via chain / belt from non-wheelmounted motors or via hubmotors. (or friction drives, but probably not a great option for dirty potentially muddy trails)

I should have been more clear with my first thought. It was only supposed to be applicable to Trike with two rear wheels. The concept of a live axle on the front of a tadpole would be somewhat mechanically chalegening.

 

[bcsteeve]

Between mass and terrain you have managed to combine some of the biggest challenges pushing the envelope for a E-Assist bike/trike. Let me add one more: you mentioned horse trails.You may occasionally note the existence of some 'fresh trail markers' left by previous visitors. You likely will want sufficient control and maneuverability to avoid encountering those directly and spreading them all over the environment (consider your person as part of that environment).

Lol, good point. Most of the horses wear diapers since they also walk them on the streets, but I have seen the odd "trail marker".

I have two thoughts:

Excellent thoughts. I'm not sure I understand "live axle", but it gives me some searching to do, thank you.


[edit]I'm replying to posts in order, and I see there was subsequent discussion on this I can't keep up! lol

 

[goatman]

i wouldnt use anything on the chainline, i snapped my chain 20km's from home but my rear DD hub has enough power to get me home without needing a chain and then i needed to buy 3 bike chains and link them together which was $100 about 4 months ago. i guess you could pack a chain repair kit with you.

i wouldnt be going 4x4ing with a trike

if you did do the 2- all-axle hubs with 2 phaserunners, i dont think there is cogging issues if one died and double regen upfront for braking would be nice, i go through alot of pads because you dont want to use the rear wheel for braking. where as my other bikes are rear DD with regen and i dont use the disc brakes really

 

[bcsteeve]

The trike+rider+electrification weight is going to approach motorcycle weight, so you won't want to skimp out on critical suspension and braking components.

Agreed. When I playing with Utah Trikes' configurations, I always put the brakes and suspension options (if any) to the max, even though I didn't know what they necessarily meant, because I assumed my scenario would want to have as good as possible.

 

[fatty]

Physical needs: Recumbent seating, 300lbs (297 and hopefully dropping), 6'4" with 48" x-seam. I'm thinking tadpole style trike makes the most sense, probably with fat tires.

Health and fitness are my other passions, so just to add a completely different perspective, to get to normal BMI at 6'4", you'd need to get under 205lbm, so you'd optimally want to lose at least another 92lbm. 92lbm * 3500kcal/lbm of fat = 322000kcal / 500kcal deficit/day = 644 perfect no-cheat days
322000kcal / 1000kcal deficit/day = 322 perfect no-cheat days.

Since there's no evidence that ebikes help people lose weight more/faster than regular bikes (and all the reason to expect the contrary), I would suggest that you start with an appropriately-geared conventional trike. Ride it, love it, lose some weight on it, and then reassess your needs. You may find that you never need electrification, and if you do, you'll have a platform you're already experienced with to better inform your conversion.

 

[LewTwo]

Excellent thoughts. I'm not sure I understand "live axle", but it gives me some searching to do, thank you.

[edit]I'm replying to posts in order, and I see there was subsequent discussion on this I can't keep up! lol

Just to clarify:
A "Live Axle" is a single long shaft to which both rear wheels are attached.
The entire assembly rotates as a single entity.

 

[bcsteeve]

i wouldnt be going 4x4ing with a trike

I suppose that's not possible, given that it only has 3 wheels I suppose it would be.. what? 1x3 or 2x3ing depending on the setup. Well, actually I guess human power counts so that would be 2x3 or 3x3ing.

if you did do the 2- all-axle hubs with 2 phaserunners, i dont think there is cogging issues if one died and double regen upfront for braking would be nice, i go through alot of pads because you dont want to use the rear wheel for braking. where as my other bikes are rear DD with regen and i dont use the disc brakes really

Now I have to Google "phaserunner", but I think I get your point. Does regen actually do anything at this kind of weight? I have to electric cars with regen, and after owning electric cars for about 6 years now... I gotta say the regen aspect feels a bit marketing-ish to me. Free energy is great, and I love the braking aspect of it, so don't get me wrong (ie. I totally get your point there), but really it might save a percent or two on a charge. I wouldn't have thought regen on a bike setup would do anything noticeable (in terms of charge).

 

[fatty]

Agreed. When I playing with Utah Trikes' configurations, I always put the brakes and suspension options (if any) to the max, even though I didn't know what they necessarily meant, because I assumed my scenario would want to have as good as possible.

If you are to get deep into this, then the accepted wisdom is to buy the base model, get experienced and comfortable with it, and then upgrade it yourself as your specific needs dictate. If you get in deep either way, you'd likely change the "max" components eventually anyway. Might as well save the up-front cost...

 

[bcsteeve]

Health and fitness are my other passions, so just to add a completely different perspective, to get to normal BMI at 6'4", you'd need to get under 205lbm

No offense intended, but someone passionate about health and fitness has to understand that it isn't that simplistic. There is no world where I could be 205 pounds (or, literally there are probably millions of worlds, but certainly not Earth) and be considered even remotely healthy, if even alive. I can't even imagine how much muscle I'd have to give up to get to 205. I haven't been 205 since I was 16 without a pinch of fat and barely any muscle on me. By 18 I was 225 having gained some athletic muscle, and I suppose that could be my ideal weight if I were still in my 20's and I was looking to win a fitness contest. I'm not, and I'm not. Even then, I'd have to shed muscle to get there, as I'm a lot more powerful now than I was then. 250 is my goal, and I doubt at that point there would be another 10 to lose without some significant compromise.

However...

Since there's no evidence that ebikes help people lose weight, I would suggest that you start with an appropriately-geared conventional trike. Ride it, love it, lose some weight on it, and then reassess your needs. You may find that you never need electrification, and if you do, you'll have a platform you're already experienced with to better inform your conversion.

There's wisdom to that!

But...

I could be selling myself short, but I seriously think I would never get anywhere without e-assist. It is just too hilly around here, particularly right where I live. Even if I abandon my thoughts of trail riding and stick to the streets, I don't think I could get out of my cul-de-sac. I'm on the bottom of a ~12 degree hill and I'm just not conditioned to get up it. Even if I could manage that... on the other end of that is a 15 degree hill that I can surely go down but I'll never make it back up. If I had a truck (and I don't, nor do I have any plans for one) then I could take it to places where I could ride.

Realistically, if losing weight were my only concern, I'd get a stationary. But I've been there, done that and eventually that's just a lousy room decoration. it is just TOO bloody boring. Before getting hit, I was walking/hiking 1 to 1.5 hours ever single evening. I was on one such walk when I got nailed. I was also playing rec and competitive volleyball 4 times a week pre-COVID. That's all been taken away from me. I'm told probably permanently. Cycling seems like a possible replacement. Or so I hope, anyway.

 

[bcsteeve]

If you get in deep either way, you'd likely change the "max" components eventually anyway. Might as well save the up-front cost...

Fair.

I suppose I was thinking it was saving on the up-front costs by upgrading. Getting a $300 component for $200 because they are swapping out the $100 seems like a deal if eventually I need the $300. Even if I need to replace that later, at that point I'm in for $500 instead of $600. If the stock ($100 in this imaginary example) component is useful though... that changes things. I was (ignorantly?) presuming the stock brakes/suspension were a waste.

 

[LewTwo]

Does regen actually do anything at this kind of weight? I have to electric cars with regen, and after owning electric cars for about 6 years now... I gotta say the regen aspect feels a bit marketing-ish to me. Free energy is great, and I love the braking aspect of it, so don't get me wrong (ie. I totally get your point there), but really it might save a percent or two on a charge. I wouldn't have thought regen on a bike setup would do anything noticeable (in terms of charge).

When I drove a Honda Insight (the first model) I found energy recovery worked well in hilly environments where energy was expended going up one side and recovered going downhill afterwards. In more flat environments with few stops I rarely recovered any energy. I should think the same applies to ebikes. Currently I live in the "flats". A hill is a bridge over a drainage canal so I prefer the lighter freewheel geared hubs.

I will note that the more mass involved the higher the potential for recovering inertial energy.

 

[bcsteeve]

When I drove a Honda Insight (the first model) I found energy recovery worked well in hilly environments where energy was expended going up one side and recovered going downhill afterwards. In more flat environments with few stops I rarely recovered any energy. I should think the same applies to ebikes. Currently I live in the "flats". A hill is a bridge over a drainage canal so I prefer the lighter freewheel geared hubs.

I will note that the more mass involved the higher the potential for recovering inertial energy.

I live in the mountains, so regen is maximized in my scenario... and it seems over-rated to me. I hear people say (lie?) about how they drive up The Connector (that's a high-speed mountain freeway here) in their Nissan Leaf and gain it all back on the way down, when they're trying to sell their friends on the idea of going electric. That's definitely not my experience! I'll go from 90% to about 65% climbing that damn thing and I'll be at 71% when I get back down. I'm not saying gaining 6% is something to scoff at! But to get that 6% I had to spend 25%.

Anyway, if it weren't for regen I'd burn through brakes a lot more and I love "one pedal driving", so I'm not complaining, I was just imagining that regen on a bike would be practically nil in terms of charging the battery. Happy to learn that's wrong!

Ps. I remember trying so hard to buy that first model Insight (wow, that was TWENTY years ago!). Back then, the local Honda dealer made it impossible. I didn't understand the politics behind it at the time. I just remember thinking how stupid it was that they're saying things like, "you're the 100th person to ask about it, but no we can't get them". So glad those days are behind us.

PPs. I guess a car doesn't benefit from the human pedaling! With that in mind, I can see how a bike would get a much more balanced up vs. down hill wattage scenario.

 

[fatty]

No offense intended, but someone passionate about health and fitness has to understand that it isn't that simplistic... 250 is my goal, and I doubt at that point there would be another 10 to lose without some significant compromise.

Sure -- I just like to illustrate the scale of the challenge. Most people don't realize what losing weight takes.

Doctors don't care about power since the mass needed to get there is still a liability. I was assuming they preferred you get down to normal weight for medical reasons -- especially orthopedics.

 

[fatty]

Fair.

I suppose I was thinking it was saving on the up-front costs by upgrading. Getting a $300 component for $200 because they are swapping out the $100 seems like a deal if eventually I need the $300. Even if I need to replace that later, at that point I'm in for $500 instead of $600. If the stock ($100 in this imaginary example) component is useful though... that changes things. I was (ignorantly?) presuming the stock brakes/suspension were a waste.

It might look that way, but base components have almost negligible cost -- they have to, to hit the base price point. And
max components usually have max markup too.
The stock parts are enough to get you rolling, and to get a better idea of what you really need.

Agree that the stock brakes/shock are a waste. Just a question of paying highest markup for something that probably isn't quite perfect or what you would choose, or actually choosing it yourself..

 

[goatman]

i dont pedal and lost 30lbs just because it gets you out the door :wink:
phaserunner is the controller from grin

all axle motors i think are 32 hole spoke count not the usual 36 hole
grin built my wheel with dual gauge sapim spokes and they sell rims

basically they could build their motor into a fat tire rim and pre-program the phaserunners to the motor with the PAS so its plug and play out of the box for you

if you do the math in Canadian pesos youll be at or a little under $10k

guy had a like new/used trike (fat tad full suspension) on the island just before xmas for $1200