adlai

I'm looking to convert a recumbent to EV power.

The problem is that the rear dropout is 130mm for some reason. I do have a Bionx hub wheel that is 135mm.

I insist on a hub motor for these reasons: weight distribution on the rear wheel is needed because of wheel slippage problems, it reduces chain wear which is a big deal given the lengthy complex chain of a recumbent, and lastly there is no rear brake installed on the rear wheel of this model of recumbent so regen would add slow down capacity where it wasn't before.

I've looked at CSC hub wheels on amazon because apparently they have regen braking. Where else to look? How to find a 130mm hub motor with regen?

cat0020

Likely will need to “cold set”
yhe frame to accommodate for the regen hub motor.

AFAIK, there is no mid-drive motor with regen function.

https://www.ebay.com/itm/163835785724

Leisesturm

Have you measured the dropouts three times? I'm not accepting that they are 130mm on a first pass assessment. What brand/model of recumbent? There aren't many I don't know anything about. The ones with complex chainpaths are usually highracers or lowracers. Not good candidates for EV. You need torque arms, and they can be hard to fit to recumbent drop-outs. Not impossible, but still. If the regen is set high enough to offer any useful braking, the dynamics of the bike will be most unnatural. People think they need/want regen until they experience it. Does anyone still talk about regen anymore in 2023? Why not? Find some other way to put braking at the rear, because you may want it after finding a motor, if you still insist on motorizing the bent. I wouldn't. I get that that means nothing coming from some random on the Internet.

2old

Direct drive motors can be equipped with regen, but a number of Amazon's, e-Eikelings\'s and YESCOM's don't. Go to ebikesca; they have systems that will support it, and are very responsive to questions. If they're too expensive go to endless sphere and ask for other options.

adlai

Revisiting this thread.

im curious if I could have simply swapped out the freehub to get it narrower. I think the recumbent was from the early 2000’s so at that time it was like the 7 speed era.

fooferdoggie 

a dd drive would really suck on a tandem low end torque is not there and it would need a hell of a battery. though chain wear in a mid drive is not that great. we get 2000 miles from chains.

adlai

I've installed a direct drive bionx onto a recumbent.

I think it works great. My only issue is that sometimes it overheats and shuts itself off. Also long term battery replacement will be a problem. And I do have concerns about torque on that recumbent arm.

Otherwise, it gave a noticable boost, and the extra weight on the wheel increased traction and improved weight distribution. The Regen braking was welcome too because a lot of recumbents don't have brakes on the rear wheel.

Alas, it was also 135mm which didn't fit the older 130mm.

2old

Is the frame steel? If so, it's easy to cold set to 135. I suspect it's aluminum and "moving" it that much could over-stress the system; you might inquire on endless sphere whether cold setting is feasible. Also, some motors possibly have washers that can be removed to reduce their width.

adlai

What I had not considered at the time was maybe the problem was the freewheel and cassette. Maybe the solution was to get a 7 speed cassette and freewheel to fit into the wheel. The bionx was like 9 speed.

2old

Good point; you can get seven-speed freewheels with up to 36 teeth "low" gears which should suffice with a motor. The only other change would be the shifter.

Leisesturm

A freewheel OR cassette. Not freewheel and cassette. A 9sp hub is unlikely to be a freewheel, it will most likely be a cassette. A 7 speed is most likely to be a freewheel. The two types are not interchangeable. The 7 speed freewheel is narrower than the 9 speed cassette but I don't know if it is enough narrower to worry about. There should be room enough in both to monkey around with spacers and locknuts to get them into a 130mm dropout.

Pop N Wood

Boy, not sure I would consider riding a motorized bent with no rear brake. You are a braver man than I.

To echo what others have said in my experience chain life is quite good with recumbents. I would be more concerned about losing gears than chain life, cadence is important to me on the bent.

Last you do realize regen braking really doesn't do much? The numbers just don't add up, who rides their brakes when riding? There simply isn't much energy to recover, especially when considering the losses everytime energy is pumped into or out of a battery. I've read articles claiming any energy recovery from the regen braking is lost due to the inefficiency of needing to use a direct drive motor in the first place. You are better off getting a geared system that allows spinning the motor at a more efficient RPM.

tallbikeman

Only steel frames are candidates for cold setting ie. respacing the rear dropouts. Do not try on carbon or aluminum frames as you will cause major damage to the frames. I run a 2019 RAD City with direct drive hub motor in back with the regen setup. I notice that it generates about 275 watts of braking force as measured by the control panel. Frankly that is not a lot of braking force. However on longer grades I have used it to keep speeds down a bit so it does have some use. To just use regen I pull the brake handle until the brake light switch triggers but before the pads touch the brake disc. I would say that the regen feature does not give back a significant amount of recharge to the battery. I think it probably is a sales point more than anything. I have manual disc brakes. Like all the bicycle disc brakes I have had the pleasure of owning they always start dragging while riding and not in use and require a lot more maintenance than rim brakes for that issue. I love the direct drive for how quiet it is in operation. No gear whine at all.