What gearbox choices do mid drives have?

[chriswfoster]

I'm thinking of adopting an older 125 or moped frame, as a base, and building on that.
I have a mid drive kit that I'm taking off of a bike. Do I have any gearbox options for this? That are reasonably priced?

Or any alternatives/hacks anyone has come up with?

 

[AngryBob]

You have the gear cluster on the rear wheel or you can use a good quality IGH, are you looking for something other than what normally mounts on a bicycle? If so, then not too many at all as the existing options seem to work for most.

 

[chriswfoster]

I broke 3 different Sturmey Archer IGHs on the rear of my cyclone kit bike. I wasn't doing anything too extreme. In my opinion at least...

I thought about going with a cassette but I figured it'd be a hacky solution on a moped frame.

Is single speed for mid drive the main option?

 

[PRW]

what power are you planning on running? That may guide the choice

 

[AngryBob]

There are specific models of Alfine and Nuvinci hubs that are recommended, and apparently most Rohloff hubs, these are well out of my price range. Some newer models are actually warranted for electric drives. For the vast majority, the warranty is void if used with a motor.

Chris, which model of Sturmey-Archer did you use? RXK-5? Also, what wattage of Cyclone?

Bicycle-grade components are just not going to last long when you push thru them 10 times, or more, the power level they were designed for. This is the dirty little secret of crank drives.

 

[chriswfoster]

They were all 3 spd SA IGHs. All 3 were different models.

1 (from an ofo bike) was an XRD3 with an internal brake, another was an rk3, and I can't remember the older model that I got off ebay but people online said it was supposedly one of the stronger 3spd models ever made.

My cyclone is 3kw. I'm putting under 3kw into it now, but also looking to up the amperage and go with an 80amp controller sold by Luna.
So heavier frame (if I go moped/dirtbike frame), heavier battery (2 batteries in parallel), probably close to 4kw (more amps same 52v though).

I did jump some golf course hills a little bit with those IGHs, but I didn't do it every night. Again, I've seen how some people ride their bike, so I don't think I was too hard on my IGHs.
I always ease into my acceleration, never full throttle, etc etc.

Luckily none of the IGHs flat out broke. They all just started skipping teeth, but I could still get home. Sometimes ~20 miles away from home. When I got the XRD3 home that night, I held the front brake and twisted the throttle a little, and it was on its last tooth... It stripped out completely right in front of my house. I bike at night so there's no calling the wife to come pick me up 20 miles from home

 

[John in CR]

A mid-drive kit for an electric bicycle is not sufficient to run something the weight of a 125cc dirtbike.

As far as gearboxes go, just get an appropriately sized motor for your vehicle and you'll have no need for multiple gears. That's just for smoke belchers because their torque band is too narrow. Except for those doing homebuilt electric cars who don't know any better, electric cars like Tesla's and all the others don't have multi-speed gearboxes, because the torque band of electric motors is nice and wide, with maximum torque available at 0rpm. Plus they can go in reverse with just a flip of the switch. Don't let the makers of severely under-powered systems that need multiple gears just to move cloud your view.

 

[DtiK]

I run cyclone 3000w at single speed. There is no need for gears.

I had 8-speed shimano hubgears, but always find myself just one gear (5 or 6) . Removed it as heavy and its useless.

Cycle analyst softens launches so there isn't huge torque in sprockets from standing acceleration. Highly recommend...