Need advice on leaf 1500w motor build

[Atommeat]

Hello

This is my first time posting on here. I have done a fair bit of research and I am wanting to build a ebike on a steel track frame Surly Steamroller the dropouts are spaced at 120mm on this bike I have spoken to my local bike builder and he’s says it’s fine to coldset this frame to 135mm to take the leaf 1500w motor but he thinks that the power of the motor will bend the rear triangle? If I install 2 strong torque arms do you think the steamrollers dropouts and rear triangle will be strong enough to support me running this motor 4-5kw? Also will I have any chain line issues? Planning on lacing the hub in a 650b 27.5 wheel with 48 tyres

Thanks guys

 

[Atommeat]

Or maybe would I be better with a omnium cxc that already comes with 135mm spacing. Would these frames hold up to leaf motor running at 5-6kw

 

[spinningmagnets]

If you use two very solid torque-arms, you will be fine. At those watt levels, a Leafbike motor will need ferro fluid.

 

[E-HP]

It looks like if the dropouts have that curved piece of metal around the axle bolt, your torque arm options may be limited. You may need to make custom ones.


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[Atommeat]

Thanks for your response I think I am going to use the Omnium CXC frame as it is already spaced 135mm and has the track bike geometry I am looking for. Was the bike builder just chatting shit saying the power of the motor will bend the steel rear triangle? I have heard of motors snapping alu frames....I know the rear steel tubes are very thin but..?