BMX 110m dropout build help

[raveydavey]

Folks,

I've got a nice, old, BMX (a fitbikeco van homan signature from 2010ish). Its a 110m dropout crmo frame so I could cold set it, but I doubt I'd get past 115 safely. UK based.

I'd like to ebike convert it - a 1500 or 2000w hub motor. I've been researching options and virtually every kit I see has two problematic traits: 135mm dropout requirment, and a X speed casette.

I've been considering options and have found:

- A few kits that do fit a 110m dropout with a single speed setup - leafbike and ebikepoweruk. Unsure about Leafbike quality/shipping and ebikepoweruk are out of stock (and have been for a while now)
- using a 100mm front wheel and accepting no chain/pedals.

I'm curious about other options I'm overlooking - other 110m dropout motors, ways to reduce width of a 135mm kit (I dont need a casette), ways to fit a single speed freewheel to a 100mm front hub? My research tells me a mid-mount is a poor fit (though id be hapy to be wrong) for the gearing and I'd like to avoid a front wheel drive.

Help/thoughts appreciated.

 

[albinoe38]

BMX frames with 110mm dropouts can be tricky for ebike hubs since most kits want 135mm. Some folks have managed to cold set the dropouts a bit wider safely, but like you said, 115mm is about the max without risking damage.

 

[Chalo]

There are some narrow spaced single speed hub motors, rare but I've seen some. Nothing like 1500-2000W though. That seems like trouble with a bike as short as a BMX protracted-adolescence, peaked-in-junior-high-school bike, though.

 

[E-HP]

Folks,

I've got a nice, old, BMX (a fitbikeco van homan signature from 2010ish). Its a 110m dropout crmo frame so I could cold set it, but I doubt I'd get past 115 safely. UK based.

I'd like to ebike convert it - a 1500 or 2000w hub motor. I've been researching options and virtually every kit I see has two problematic traits: 135mm dropout requirment, and a X speed casette.

I've been considering options and have found:

- A few kits that do fit a 110m dropout with a single speed setup - leafbike and ebikepoweruk. Unsure about Leafbike quality/shipping and ebikepoweruk are out of stock (and have been for a while now)
- using a 100mm front wheel and accepting no chain/pedals.

I'm curious about other options I'm overlooking - other 110m dropout motors, ways to reduce width of a 135mm kit (I dont need a casette), ways to fit a single speed freewheel to a 100mm front hub? My research tells me a mid-mount is a poor fit (though id be hapy to be wrong) for the gearing and I'd like to avoid a front wheel drive.

Help/thoughts appreciated.

I recall from when I was considering converting a BMX bike, that the axle diameter of 14mm vs most hubs made for a 10mm slotted dropout was another issue requiring some custom dropout fabrication.

 

[neptronix]

The biggest problem you'll have with this build is a lack of suspension. A 3kw rated motor can do 40mph. A bike with 26" wheels starts to get sketchy due to the lack of it at 20mph unless you have huge fat tires on it, chromoly frame, etc.
..and you have smaller wheels than that.
..and you also have a tiny wheelbase so it will be way too squirrely.

You also have an uncommon axle shape that no hub motor is made for, plus probably an uncommon bottom bracket a mid drive won't fit on either.

I wouldn't recommend converting this kind of bike.

 

[Papa]

bmsbattery.com/motor/631-16312-q100h-36v350w-rear-driving-ebike-hub-motor-ebike-kit.html#/213-rpm-201