Hub Motor Mounting in forks / frame

[Peter.Bridge]

So for "our" sorts of ebikes (ie with peak input power less than 1000w) is there are rule of thumb as to the material that a hub motor is fitted to

Front Forks Steel	Yes
Front Forks Alloy	No ?
Front Forks Carbon	No
Rear Dropouts Steel	Yes
Rear Dropouts Alloy	Yes
Rear Dropouts Carbon	No ?

 

[Az.]

So for "our" sorts of ebikes (ie with peak input power less than 1000w) is there are rule of thumb as to the material that a hub motor is fitted to

Front Forks Alloy

No ?

Why not? I have two bikes with front wheel hubs and they are just fine.

A lot will depend o how much "meat" you have there and what extra measures are you ready to implement (like torque arm). Also how much power/torque you want would be critical. I guess there is no clear yes/no answer here.

 

[lenny]

Front fork failure

It's worth reading the comments in this thread if you're thinking of fitting a front motor or buying a ready made bike with one, especially one with enough torque to get you up the hills:

www.pedelecs.co.uk

https://www.reddit.com/r/ebikes/comments/13zr27l

 

[saneagle]

So for "our" sorts of ebikes (ie with peak input power less than 1000w) is there are rule of thumb as to the material that a hub motor is fitted to

Front Forks Steel	Yes
Front Forks Alloy	No ?
Front Forks Carbon	No
Rear Dropouts Steel	Yes
Rear Dropouts Alloy	Yes
Rear Dropouts Carbon	No ?

You can't make a rule like that. It depends on how much torque the motor makes and how strong the drop-outs are.

My guidelines would be:

• Running at 36v and 12A or less (450w from battery) strong aluminium forks are probably OK.
• Up to 600w from the battery would require a torque arm or some reinforcement.
• Above that power you need steel forks.
• For a rear motor, most aluminium drop-outs would be OK up to 600w. Above that, up to say 1000w,you need at least one torque arm.
• Above 1000w, you need two torque arms.
• Steel drop-outs are OK up to 1000w. Above that, you need at least one torque arm.

All those powers are from the battery and nothing to do with the rating of the motor.