My situation explained

[Solcar]

Hi, the situation is that I have about a 200' rise in about 3000' riding run. I need to get up that with only light pedaling, because that's all I can do. My legs are too old after all these tough 57 years.

I was working on a friction drive project that might have worked but these hills are steeper than I was considering when I was building that, and I don't have my big electronics room and loads of parts stocks anymore to finish that friction drive project.

Even if it's just a 5mph rate going up the side of the road, that's ok. The cost of getting this done needs to be low and that's the main thing. I figure I just need about a theoretical 15wh to make the round trip of lifting 200lb, 200', plus some extra to account for system losses.

Thanks if you can help

 

[MadRhino]

3000 ft is a very short ride, even with 200 ft climb. I bet you can do it with a drill as a friction drive. Cheap enough? Bring a spare battery, just in case. :wink:

 

[Solcar]

Cool. Earlier I was thinking of getting a Ryobi brushless drill to try to do it with. Your input adds impetus to that idea I was considering using a drill as the basis of a friction drive.

 

[MadRhino]

You just need to make a mounting bracket, then find the proper roller size to climb the hill. I would do it in a day, with one of the drills in my shop and the ‘no parking’ sign that the city just planted on my lawn.

 

[Solcar]

Lol. I was liking the way a moderately hard rubber roller was doing when I did some preliminary testing on that last friction drive project.

 

[markz]

Why bother with friction drive at all, why not go with a hub motor kit from YESCOMUSA as they are pretty cheap. Then deal with battery and charger.

One step down from that is a Unite Motor, they usually start off with a model # starting with MY####

On par with that are the ezip that are placed near the rear axle, not much wattage power from those.

Friction drive, eats through your tire, then when the rain comes, or the mud you get more slipping. Not the best ideal setup, but there are people that will use RC outrunning motors, an ESC and maybe 6S Lipo, all from Hobbyking, then deal with the throttle linkage. Using drills, circular saws, tread mill motors, dryer motors, starters, alternator, generators off old cars just too much work, when you can just buy a hub motor kit, and a battery from another place; BMSBattery.com, maybe a small 500W geared laced in whatever wheel size you want.

 

[Balmorhea]

Hi, the situation is that I have about a 200' rise in about 3000' riding run.
[...]
Even if it's just a 5mph rate going up the side of the road, that's ok.

I reckon how I'd do it is with a little geared hub motor (like Q128 48V 201rpm) run at lower than specified voltage, but full current. At 36V, you'd cruise up a 7% grade easily at a modest speed. You can run it with power to spare on two 4.4Ah hoverboard packs in parallel. When you don't need it, the reasonable extra weight and negligible drag wouldn't bum you out. A 36V 20A controller is a very cheap commodity item, and small.

Friction drives have their place, but hill climbing isn't their strong suit.

 

[Solcar]

Markz,

I was thinking about a hub motor kit. The hub might be too wide for the rear dropouts. The bike has an aluminum frame which indicates counter to spreading the dropouts. It would be important for me to have a 20" wheel with a geared hub motor in it that has the freewheel cluster and that fits in the dropouts. It appears pretty uncertain to come together.

I like the plug in, unplug of the battery between the drill and the charger with the drill idea. I wouldn't be using it on the bike very much and would have the dual purpose of a decent drill when needed.

I've looked into usual-type ebike batteries and the cost is relatively high for me, and they need special care to operate and charge like balancing and discharge low voltage protection. With the drill, that's solved with just the drill and the charger that comes with it. I recall the pretty involved nature on ES here of people working on their battery systems.

I thought about the Curry Pro Drive type set-up that uses the Unite-type gear motor, but then it should have a freewheel on the opposite side of the back hub from the pedal-drive sprocket freewheel.

The thought presently tends toward to make a removable mount for the drill itself to be attached over the front wheel.

 

[Solcar]

Hi, the situation is that I have about a 200' rise in about 3000' riding run.
[...]
Even if it's just a 5mph rate going up the side of the road, that's ok.

I reckon how I'd do it is with a little geared hub motor (like Q128 48V 201rpm) run at lower than specified voltage, but full current. At 36V, you'd cruise up a 7% grade easily at a modest speed. You can run it with power to spare on two 4.4Ah hoverboard packs in parallel. When you don't need it, the reasonable extra weight and negligible drag wouldn't bum you out. A 36V 20A controller is a very cheap commodity item, and small.

Friction drives have their place, but hill climbing isn't their strong suit.

I figure the grade hits 15% in at least one spot. Friction drive wasn't my preference, yet I see a lot of ifs concerning whether a hub drive system will be able to work on the bike, and the cost level of the entire project, though the freewheeling of a geared hub motor is something I'd like. I don't plan to try to have a hub motor placed in the stock wheel. It's a Tern aluminum folding type bike. Good about the idea of the hoverboard pack and the 36V 20A controller. Yet would still need a throttle, unless it comes with the controller.

 

[MikeSSS]

My gas bike uses a Straton friction drive, with a Subaru Robin engine. The roller is 1" knurled steel, the Performance Gotham 26" x 1.75" tire showed little wear after a year of riding. When not using motor assist a quick release raises the drive unit off the tire. Point is, a friction drive can work. In the rain it did slip though. All force against the tire is carried by a bearing on each side of the roller, the engine does not carry any side load. Drills aren't made for side load, the roller has to carry the load against the tire. Edit to add, a friction drive provides miles per hour at the roller and tire contact. For this reason, tire size, 20", 26", doesn't change the speed or thrust of a friction drive system.

An inexpensive hub motor, from Amazon or WalMart online, would be more practical, and less work. Front or rear drive makes little difference when riding. Geared hub motors are smaller and lighter and don't have much drag when not under power. Direct drive hubs just last and last. Steel dropouts or thick and strong steel torque arms on aluminum dropouts is important when using a hub motor. Grin makes great torque arms.

Electric assist will change your riding in ways that are surprising: you will probably pedal just as hard, but an 8 mph average becomes a 12 mph average. A 4 mile ride average becomes a 16 mile ride average. Because the e rides are longer, you will get warmed up and feel really good when pedaling hard. Electric assist leads to better physical conditioning, not worse. Whoda thunkit?

 

[dogman dan]

Actually, the best solution for you may well be the old school Currie drive system. I think you can still buy them somewhere.

https://electricscooterparts.com/curriebicyclekits.html

Brushed,( or used to be) so not so great for long rides. yours aint long.

Noisy, so not so great for long rides, yours aint long.

But cheap, sometimes 24v, opening up use of drill batteries or similarly cheap batteries.

And they climb hills like mad. That's the one thing those old curries did really good.

A bit more than I thought for that kit, but it included a battery.

Another option would be from the same place, a scooter motor and controller with a chain sprocket on it, then attach a left side chain sprocket on the bike. That doesn't freewheel though.

 

[John in CR]

If you go with one of the cheapie recommended above solutions (a drill, a Unite motor, a Currie drive), you better gear it quite low or a steep climb over half a mile long will melt them quickly. I melted one of those Unites in about that distance with a lot less increase in altitude on my very first ebike.

Also, no one asked your weight. The all up load any system has to haul up steep climbs is a critical factor in determining what is needed. Just about anything works on level streets, but hills are a completely different ball of wax.

 

[Solcar]

MikeSSS,

For lessening the side load I was thinking that the side of the friction roller shaft opposite of the drill could have a bearing, or a seperate roller shaft supported by bearings on both sides that the output shaft of drill turns, similar to that Stanton. I don't plan on using the drive system much and avoid riding when the street has water on it.

Dogman Dan,

I've gotten things from ElectricScooterParts in the past, so that would be a plus. That system you linked to looks like a possibility except for it being for a 26" wheel, whereas mine is 20". I like how it's a complete kit including battery.

The other day I was looking at the possibility of making a friction drive using a scooter wheel from them that included a freewheel and a pneumatic tire that would be the friction roller.

John in CR,

I was wondering about the motor overheating possibility. I've also seen it mentioned with regard to geared hub motors to some extent. I'm pretty light at 130lb and might be riding with something like 20lb of purchases, mostly food. The bike weighs about 25lb.

 

[MadRhino]

Yep. There are many cheap solutions. That is about how cheap is cheap. I suggested the drill because it is hard to beat for cheap and easy. The roller, I would do with wood with a piece of 16 grit sandpaper glued on. This had proved to be efficient and reliable. The mount on a pivot, spring loaded with on or off positions. Then you can wire the drill variable trigger switch to your handlebar. I have many old cordless drills in my shop that would be suitable, dirty drills that were used to mix pals of mortar or ceramic adhesives. If you don’t have any, I guess you could find one very cheap at a pawn shop. I have no doubt this solution works, cheapest and fastest to realize.

If you have the budget, a cheap kit will do. But never as cheap as a drill, and likely much longer to get and build to have the bike running. If you don’t like it, you still have a drill and can wait for a kit, that will maybe require the drill to install anyway. :wink:

 

[LeftieBiker]

The problem with the Currie Drive is that to climb steep hills well, you need an 8 tooth motor gear - and those were never actually made. So you have to over-volt it a bit, but only the early controllers handle overvolting...

 

[Solcar]

MadRhino,

A lot of those thoughts were like mine. I can do the drill idea, and if I don't like it I'll have a tool that I can use for other things. I kind of plan to have the drill be removable from the bike for when I don't have to ride on the big hill.

I like the way the drive roller can pivot to engage the tire deeper as it applies more rotational force. That was what that last but incomplete friction drive I was working on did. It was appearing to work well during tests connecting it to the bench power supply that I had at the time. I might someday be able to add the missing components to a system using it. It used a moderately hard rubber drive wheel, but soft enough to give grip against the tire.

LeftieBiker,

I recall several years ago at least one friend had an ebike that used a Currie type drive. In those days I was using one of the versions of my middrive approach. I made several versions over the years. It turned out, me having my experimental ebike that they could see me benefit from led them to buy their own ebikes.

 

[markz]

The problem with the Currie Drive is that to climb steep hills well, you need an 8 tooth motor gear - and those were never actually made. So you have to over-volt it a bit, but only the early controllers handle overvolting...

8T is getting to the "too small" area where the chain needs more teeth to engage, otherwise the wear is too much, I think the smallest I've seen is a 10T and maybe a 9T in bicycle format. In industrial chain/gear format, 10T.

 

[Balmorhea]

The problem with the Currie Drive is that to climb steep hills well, you need an 8 tooth motor gear - and those were never actually made. So you have to over-volt it a bit, but only the early controllers handle overvolting...

8T is getting to the "too small" area where the chain needs more teeth to engage, otherwise the wear is too much, I think the smallest I've seen is a 10T and maybe a 9T in bicycle format. In industrial chain/gear format, 10T.

Drive smoothness, efficiency, and wear start to get really bad below 13T, with each tooth reduction below that exacting an increasingly large penalty. You can get sprockets as small as 6T, but they’re incredibly noisy and destructive. On the other extreme, tooth counts above 21T don’t give discernible benefits versus 21T (except to the degree that larger sprockets reduce force at the chain).

 

[dogman dan]

Well, the real problem is you need it so cheap.

You can get wheels re laced to 20". but you need the skills, or the money.

You can buy 48v DD kits in 20" wheel, but the really cheap ones are 26"

BEST solution is not cheap, a Bafang mid drive kit.

Your weight does matter a lot.. But you said 200 pounds. No problem for a medium expensive kit. Kind of a problem on the cheap though. 250w tiny front wheel motor won't do it if the grade is much more than 6%, without heavy pedaling.

Back to that bike, is the rear dropout 135 mm wide? If not, you are looking at mid drives, friction drive, or some other bike.

Your funds may be really limited, but brand new, a 7 speed Schwinn beach cruiser is pretty cheap. They make great e bikes with a cheap 1000w rear motor kit on them. 48v battery, not so cheap. And,,, right now, just try to find one.

 

[Solcar]

Dogman Dan, I've been leaning a lot toward the drill-based friction drive. It's not too bad if I spend a couple hundred dollars for everything to have something operational. A thing I like about it is the plug and play battery system.

I think a lot about reliable battery systems and problems that can happen. It's good to have you around on ES after the nightmare you went through. I know how some of us ES old-timers have gone through some real hardship, yours and AW's standing out in my mind as having been particularly bad.

I've been reluctant to go back to middrive after damaging a couple of my bikes by overstressing a chainring, rear cluster, and rear freewheel, and chains.

I'm settling in again after another housing move but the move before this one is when I had to give up decades of tools and materials. I had some huge calipers that could easily measure back dropout width. But all that's here is a tape measure marked in inches. As far as I can tell it's 5 1/4 inches, which converts to 133mm.

This place I live at now is low on space compared to my old place. The smaller 20" wheels on my bike help a lot.

 

[Solcar]

The design is evolving whereas I was considering pivoting the motor assemblies into the wheel tire, not too different from the old EV Warrior way, but now it's looking more like the motor assemblies will be sliding into the tire on a track.

That way looks to be able to get a better grip on the tire. I think it will also enable me to just slide the whole assembly forward off the track to remove it quickly.

EV Todd had some fame with it here on ES. I don't know if he was the original or not. The old mopeds also used the pivot, but maybe a few used the slide.

Something that I've determined is that the rubber wheels built into casters are the best friction rollers to apply torque to the tire for my friction drives. I drill out the pop riveted axle of the caster to get the drive wheel out.

 

[Solcar]

It turned out ok. I ended up going with the pivot approach as being easier.

I made a mini rear platform at the end of the seat I slide back onto to keep the rear wheel on the ground for hard braking. Maybe it will also be able to give better stability by changing the weight distribution when coasting down the problem hill. Don't do this at home, as they say.

The drill slides into position and tightens onto the end of the threaded rod. The throttle is a ziptie around the trigger and body of the drill that I pull with a thin rope. I wasn't able to get pictures to upload, I guess because they're about two MB each. I was going to just video it from various angles but it said it doesn't accept mp4 format. Sorry.

 

[MadRhino]

Took some time but at least you got it done. So, climbing speed? Put a vid on youtube, or resize the pics with a free app.

 

[Solcar]

Thank you. The speed is pretty close to what I wanted, less than 5mph. That's less strain on the drill motor and more drive to the wheel that I need, and I like going slower these days. I'll see if I can do something about images.

 

[MadRhino]

https://picresize.com/