6X10 Mid Drive Trike

[Rassy]

Put the freewheels on, so now there is the original freewheel at the hub (part of the 8-speed internal gear system), a freewheel on the motor itself, and a freewheel at the crank.

There was not enough clearance for the freewheel at the crank. The proper fix would be a BB Cartridge with a slightly longer axle, but I used an angle grinder to remove the tabs on the freewheel instead. These were the tabs that were there so that you could remove the freewheel. So now I may never be able to take the freewheel off of the crank arm.

Also, there was a very slight bend in the bottom bolt that supports the motor. I took it all apart, but the bend was so slight there was no need to even straighten it out, and I added a pair of braces to share the stress from the motor torque.

Took a nice little ride today, seeking out the biggest hills in the village, one of which is about 20% grade for about 1/2 of its quarter mile. Very light pedaling was needed to maintain 5 MPH or better in low gear. Motor only became slightly warm to the touch.

Checked WOT speeds in each gear, which varied by about 1 1/2 MPH between each gear, from 8 1/2 MPH in low to 20 MPH in 8th. This was on the best flat spot I could find, and was only 1 block long with a stop sign at each end. Couldn't get very good amps readings because it varied quite a bit, and in the higher gears I ran out of space soon after reaching top speed, but in low gear it settled out a little under 3 amps and in 5th gear at about 5 amps.

For me this is the best setup I've had. It's not as quick as several of my hub motor rigs were, because I have to shift through some of the gears to keep from damaging the 8 speed internally geared hub. But I just ride for fun and exercise and need the hill assistance more than anything else. Plus most of my longer rides are with pedal only guys and this will allow me to match their speeds while keeping the motor in its happy RPM range.

I expect the weakest point will be the 8 speed transmission, and maybe the free wheels. Will report problems when/if they occur.

I also expect good efficiency from this motor. I plan to go on the "Ride The Rogue" in September. 68 miles in the Medford/Grants Pass area. In 2008 with a BD36 on the front wheel of a LWB recumbent bicycle I used 19 AH from a 48V 20AH LiFePO4. My goal this year will be 10 AH.

 

[recumpence]

I think you will really love the FW cranks. Admittedly, they are a strange feeling. The FW engages slower than normal because of the very slow cadence compared to the rear wheel. Still, they are a blessing. It does add complexity to the system as a whole. But, that is not a bad thing. If you spend an extra 5 hours setting up FW cranks and any details that go along with it and use them for years, you are way ahead.

Anyway, you should really love them!

Matt

 

[Rassy]

Matt, thanks for the comments on the FW cranks. After reading the Stoke Monkey (Clever Cycles) FAQ on the subject I decided to try doing without the FW cranks.

First, the gearing on my trike allows the motor to spin a little faster than my comfortable cadence so to use this extra speed in any given gear was uncomfortable for me. Sure, I could put a larger chain ring on, but then pedaling without motor assistance would be more difficult.

Also, on every ride I would do something where my pedaling was interrupted while under power, resulting in an abrupt chain pull on the pedals, and a couple of times causing the tensioner to bounce up and the chain coming off an idler. The freewheel crank eliminates these issues.

So if anyone is planning a Stoke Monkey type drive, I recommend you consider a FW crank in your design, budget, etc.

 

[evblazer]

Also, on every ride I would do something where my pedaling was interrupted while under power, resulting in an abrupt chain pull on the pedals, and a couple of times causing the tensioner to bounce up and the chain coming off an idler. The freewheel crank eliminates these issues.

So if anyone is planning a Stoke Monkey type drive, I recommend you consider a FW crank in your design, budget, etc.

I'm glad you found a solution to those issues and it is performing well for you I hope I can get there soon! I'm sorta hoping it was to solve your unique design setup. I have a stokemonkeyish setup I'm working on with a tandem crank. Depending on how that controller works I think the normal strokemonkey setup the motor would continue to pull you around the chain but the tensioner and chain dropping issues won't happen. I guess I'll find out once I get on the road.

 

[recumpence]

I just realized something.............

Are you driving the crank through the left side as the Stoke-Monkey system shows? If so, a freewheeling crank will not do you any good. :?

Matt

 

[evblazer]

The OP is doing so.. Which I haven't seen before and has it's own little unique quirks which it sounds like the freewheel chainring solves.

I'm hoping his solution isn't neccessary for a stokemonkeyish system.

 

[Rassy]

Just a little update. Added another brace to help share the load on the bottom bolt. It is an M8 stainless and it bent a small amount. Took it apart, and the bend was so slight there was no need to do anything about it. Also added a link to the chain so the tension idler could go back and down a little more, which eliminated the need for an idler on the bottom bolt. Did put a piece of tubing above the chain so that it would hit plastic instead of metal if it did slap.

The Eno freewheels on the motor and chainring are working good. Not thrilled with the noise of the Eno, but it's not really too bad. At lower speeds there is more noise when just pedaling than when the motor is running. The freewheels do make everything work smoothly. No more jerks if I pause the pedals while the motor is running, etc.

The old duct tape batteries (they were not from Ping) are starting to lose some of their capacity, in fact one is down to 50%. So I got a new Ping V2.5 48V 10AH. It fits in a nice little trunk bag on the rack so the Playmate cooler has been retired.

 

[dnmun]

since the bolt is really long and unsupported is why it bent? where is the brace you added? way cool ride.

 

[Rassy]

Thanks Dennis. Yes, the bolt is long. I thought about using a shorter bolt and bending the brackets, but that would be difficult for me and then chain clearance becomes an issue. And, I didn't want to modify or weld on the frame.

Anyway, when the seat was raised I made a triangle on each side from the original seat mounts. The additional braces run from the new seat mount to the front motor braces, just behind the chain. The motor seemed to be in a solid position prior to adding the new braces so I don't expect any problems.

It's a nice day here and I have a noon meeting 10 miles out of town so I get to combine museum board business with my regular ride.

Sorry the quality of the picture is so poor, but if you look hard you can see the added brace. edit: Replaced picture, still not great.

 

[Rassy]

I can't say enough times how well I like this setup. Went to Medford and rode with a buddy that has a pedal only trike. We tried an experiment yesterday where I pulled him up a hill with a 5+ % grade. So in low gear with neither one of us pedaling at all our speed varied from 6.2 MPH to 6.5 MPH. We estimated the total weight of both trikes and riders was about 520 pounds. My max speed in low gear on level ground (just me alone) is a little over 7 MPH.

The hill was about 1/8 mile long and the temperature was about 85 degrees F. Everything remained cool to the touch.

 

[buzzfirst]

How is the noise level with the motor so close to you. I'm trying to decide to go inwheel hub or a setup like yours where I can use the gears. Quiet is important to me and I live on flat land so it is a toss up right now. Thanks.

 

[Rassy]

buzzfirst, The noisiest item in the drive train is the eno freewheel, which can only be heard when I pedal without using the motor. The noise from the brushless direct drive motor is normally less than the wind and road noise.

However, on flat to 5% grade I was very happy with all of my hub motor installations. But I have a 15% grade back to my house on every local ride, plus a final 20% on my own driveway. Also encounter hills on most places I ride away from home. So it was the hills that drove me to this current configuration that I like much better than any of the others I did.

On another note, I can get great efficiency with this motor since it can run in its happy zone anywhere from about 5 to 20 MPH. On that last Saturday ride I went over 30 miles on less than 250WH. Of course it was just a leisure ride, but there were plenty of hills and I always used the motor to help me up them, including the one where I pulled my buddy also.

 

[Rassy]

I have tweaked my trike a bit.

Bolted a 56 tooth chain ring directly to the 48 tooth chain ring that has a unique attachment to the freewheel. Now I can keep up with the top speed of the motor.

The best change was on the brakes. I put the front disk brakes on a single dual cable lever on the left side and added a roller brake to the Nexus which is operated by the right side lever. The rear brake is not nearly as strong as the front ones, but I can skid the rear wheel on dry pavement at a slow speed, with a really hard pull on the brake lever. What I really like is using the rear brake on a long steep hill to maintain a comfortable coast speed. I was worried that the front brakes might pull to one side, but they don't, so at higher speeds I can also apply the front brakes without having to continuously balance the pull on the front wheels.

 

[spinningmagnets]

The mid-drive is an intriguing idea, I'm glad you're posting these results. After seeing your thread, I've kept my eye out for various parts to make it easier to assemble one of these (if someone didn't have a welder). A lot depends on the frame being used, but I recently saw these at a farm and ranch supply store. They are steel and they had them in several sizes up to a 12" diameter tire. Maybe larger is available on the web if needed?

 

[torker]

And you fabbed a side cover ! Nice I wish a tadpole would come up on Craigslist Yea that is going to happen..

 

[Rassy]

Thanks Torker, but "fab" is a stretch. Coro-Plast, scissors, and zip ties. The goal was to clean it up a little and make it a little more stealthy. Most didn't see the motor anyway, so it will be interesting to see if it's noticed at all now. Going on an organized metric century ride in a few weeks.

Also forgot to mention the addition of 5X Slime tubes. After I ordered the tubes had two flats on a short 12 mile ride. The other advantage is they don't keep going soft. Haven't added air for the last month, and they are still full. Of course they are a little heavier, but not a problem on the trike.

As far as the Mid-Drive through the gears goes, it is great for my use because of the hills. It is the electric assist I've been looking for for several years. But, if you only have a few little 5% grades a one speed hub is nicer, since you don't have to keep shifting gears. Plus, the Nexus can't take the torque of the motor when its in a high gear at a low speed. I think the pawls on the freewheel slip, so I avoid putting that kind of stress on it. I expect it to hold up the way I use it, but only time will tell.

 

[docnjoj]

That is a very clean installation of the drive system, rassy! I have thought about a mid drive but I really don't need it where I live. The 9C hub @ 54 volts really offers enought power for any hills around here. Thanks for sharing the info about the side covers as I am doing something similar to cover the batteries and wiring "rats nest" that I have.
otherDoc

 

[tom2slow]

Hi Rassy,

I am very interested in this project, it certainly solves a lot of issues trying to power a Tadpole. I have a Tour that would be perfect to follow in your tracks, how is the single brake lever working. Our Tour does brake steer some, your solution is a great idea to resolve that issue too.

In its entirety I think this project is a very elegant solution to a tricky problem.

Its been a few months, how is everything working, did the rear hub give up the ghost? How is it working out now that it's the wet season up there? Any now add's or advice?

--T

 

[Rassy]

Thanks Tom. I have posted some things elsewhere, but should update this thread anyway to answer your questions.

The 8 speed Nexus IGH is still going strong. Probablly because I purchased insurance. I.e., the original upgrade to the trike for the 8 speed over the stock 3 speed was $500, and you didn't even get to keep the old 3 speed. I found a site where I could purchase the 8 speed complete with shifter for about $200 shipped. Of course it isn't laced into a wheel, but I purchased one and put it on the shelf so I could fix the original when/if it fails.

In september I rode in an organized 100K ride. Probably the only electric assist out of several hundred bikes and trikes. Anyway, it rained the entire day and I had no issues either then or up to now, except my bike computer quit the next day.

I recently added a Veltop to the trike, so expect to use it even more on rainy days. The Veltop isn't too good in 20 MPH+ winds, but works great for regular rain.

Anyway, this through the gears setup is by far the best setup for me, compared to any of my previous straight hub motor rigs. It's not as quick as some of my previous builds, but it does top out just over 20 MPH in 8th gear. The important thing is it will pull any of the hills around here without any complaint, as long as I shift down. On even my best previous builds I avoided hills over 15% grade because even with me pedaling hard the motor would start lugging down.

I am running on a 48V 10AH V2.5 Ping battery. The max Amps is under 23, but I only pull about 15 Amps going up a 15% grade in low gear. Probably pushing the battery a little hard, but when/if it fails prematurly I'll deal with it. On that 100K ride I took an extra battery along and used a total of 17AH. I was riding with a friend on his pedal only tadpole, so average speed was just over 10MPH.

Edit: Missed answering on the single brake lever. I like it much better than having a lever for each wheel. Still don't like going over 25 MPH. Sometimes I feel a slight pull when first applying the brakes, but it is slight and evens out right away and doesn't cause me to swerve. I did add a roller brake to the Nexus, so I have a fully independent brake on the other lever. I sometimes use it just to control speed on a downhill, but it's not near the brake that the front disks are. Of course, you don't want to lock up the rear wheel anyway.

 

[tom2slow]

Hi Rassy,

Thanks for the update, I am glad to hear there have been no gotcha's

I am looking at using a Nuvinci for the rear as I believe it may be a litter tougher. I really am not sure about a hub motor and a screw on 6 or 7 speed freewheel, and an internal gives one the chance of getting away from what I have always felt is a downside of a cassette set up 20 inch rear, in that the rear der, at full extension is only an inch'ish off the ground.

I will be asking more I am sure, I appreciate the update.

--T

 

[zenon]

Hi Rassy,

Very nice setup, i wish your close by and we can go for etrike ride. My friends trike is set up with Eco Speed system and hooked up to a normal 9 speed derailleur works good, the only issue in that set up is the chain pops out on big road bumps. He added an extra chain roller guide and solved the problem.

If you want more speed you can go 5 turn 9C

About your brake issue try to balance the two brake cable so it grab at almost same time. Or upgrade to Avid 185 mm BB7 rotor and caliper it got a built in adjust on both side of the caliper, works great on my trike.

Question how do you find higher set handling now compare to the original seating , is it more tipsy on corners?

Zenon

 

[Rassy]

Thanks Zenon

I am very happy with the speed, which is a little over 20 MPH in 8th gear. My main goal was to be able to go up steep hills, 15% grade or more, without motor issues.

The brakes are working good. I did set both brakes up to engage at the same time, and the dual brake lever does balance the pressure on each brake.

As far as stability, since the seat is set up straighter than most tadpoles I find it easier to lean my upper body into corners. The only time I lifted a front wheel was before the seat was raised. At 70 I just ride the trike for recreation and exercise so I don't ride too fast and don't push it hard on sharp corners.

 

[zenon]

Hi Rassy,

It nice to know your able to climb 15 grade with small input on the pedal, what model is your trike?


Zenon

 

[Rassy]

Zenon, it's a TerraTrike Path. If I was starting now, I'd probably get TerraTrike's new Rover. It is taller, and I like the square main tube. Should be easier to attach motors and idlers to it.

 

[zenon]

Yes, the Rover is roomy simple and have easy to adapt mid drive square tubing, what is the most popular tadpole brand that you've seen in Oregon state, my friend from Portland mentioned that it's very popular ride there.

Zenon