How much beating can a hub take?

Pedrodemio · Dec 30, 2019

Hey guys, for a long time I've been thinking if switching my bike to a low power hub motor like the G310, I don't need much power, currently I run a friction drive with RC motors, but due to a bunch of factors the low speed torque is bad

What worries me is if they can take the way I ride, I like to make my commute fun by jumping wherever possible, take shortcuts through stairs and other obstacles that the city can offer, no massive jumps or anything too extreme

But I worry I would break the hub in little time, and to make it worse my bike ir a hard tail

What experience can you guys share?

Thanks

amberwolf · Dec 30, 2019

In theory, the bearings on the axle should take the loading between hub cover and axle, but some people have discussed breakage of plastic gears inside geared hubs, or of teh clutch itself.

I'm not certain that's directly from the impact, but might rather be from the motor / wheel spinning really fast while in the air, then suddenly slamming to a near-stop upon impact, placing a lot of shear loading on the gear teeth and/or the clutch parts.

Sometimes motor axles are crappily made of crappy metals, and break from impacts. I've definitely had this happen at least once, I think it's contributed to at least one other such failure I had. Both of these were on a very heavy trike's rear wheels (both on the right side, which sees most of the potholes), and were from pothole impacts rather than jumps, but the effect is essentially the same as hard long jumps.

I expect that if you're not doing anything extreme, it's probably going to be ok with good quality (relatively) hubmotors, but I don't think there can be any guarantees.

john61ct · Dec 30, 2019

Talk to Justin @ Grin

Mcdabber · Dec 31, 2019

I ride my hub motor (qs205) pretty hard and so far its held up great. I mainly built my stealth clone to do wheelies but i have takin it off of a 3 foot high jump before and landing onto concrete. I also like to find as many jumps as possible around the city.

https://www.instagram.com/p/B5RRV4eJWQP/?utm_source=ig_web_copy_link

dogman dan · Dec 31, 2019

A direct drive hub can take some severe beating, but big hucks are not really advisable. Meaning over 4 foot drops, particularly to flat landings. The danger is mostly to spokes and rim though, with a big DD motor like McDabber has.

With the smaller internal planetary gear hubs you have to be a bit more careful. When landing those, don't have the throttle on. landing with the throttle one puts a lot of shear on the cotter key that attaches the motor assembly to the shaft, and you can shear the key, or tear up gears themselves if the key doesn't fail first. With the throttle off, landing does not cause the shear, it should freewheel. It can be a hard motorcycle habit to break, landing with power on.

But yeah, small pops, stairs, they can be ok provided you don't ride around with broken or loose spokes. And yeah, shit can break anyway, like the alloy hub itself, where the spoke holes are, or the freewheel screws on. But often those failures do reveal a casting defect. I rode a trail once so rough, I loosened a lot of cover screws on the motor, and the derailleur fell off the bike. The motor overheated and got damaged wiring, but no problem with the spokes, rim, or motor itself.

Punx0r · Jan 2, 2020

The tyre/tube and rim seem to give out first. With a heavy hub the wheel hits bumps harder and it's more difficult to pop the rear wheel over them.

Pedrodemio · Jan 3, 2020

amberwolf said:
In theory, the bearings on the axle should take the loading between hub cover and axle, but some people have discussed breakage of plastic gears inside geared hubs, or of teh clutch itself.

I'm not certain that's directly from the impact, but might rather be from the motor / wheel spinning really fast while in the air, then suddenly slamming to a near-stop upon impact, placing a lot of shear loading on the gear teeth and/or the clutch parts.

Sometimes motor axles are crappily made of crappy metals, and break from impacts. I've definitely had this happen at least once, I think it's contributed to at least one other such failure I had. Both of these were on a very heavy trike's rear wheels (both on the right side, which sees most of the potholes), and were from pothole impacts rather than jumps, but the effect is essentially the same as hard long jumps.

I expect that if you're not doing anything extreme, it's probably going to be ok with good quality (relatively) hubmotors, but I don't think there can be any guarantees.

It makes sense, in the way I ride it would be difficult to landing with the motor powered to happen

But the fact that there is an unknown and that if it broke would be expensive to fix makes me think that I should continue to pursue my RC motors based mid drive

john61ct said:
Talk to Justin @ Grin

Will definitely send a message to them, but I expected to hear that isn't recommended since they are the ones selling

Mcdabber said:
I ride my hub motor (qs205) pretty hard and so far its held up great. I mainly built my stealth clone to do wheelies but i have takin it off of a 3 foot high jump before and landing onto concrete. I also like to find as many jumps as possible around the city.

https://www.instagram.com/p/B5RRV4eJWQP/?utm_source=ig_web_copy_link

This bike looks nice, I think having a rear suspension really helps to soften the load a bit

dogman dan said:
A direct drive hub can take some severe beating, but big hucks are not really advisable. Meaning over 4 foot drops, particularly to flat landings. The danger is mostly to spokes and rim though, with a big DD motor like McDabber has.

With the smaller internal planetary gear hubs you have to be a bit more careful. When landing those, don't have the throttle on. landing with the throttle one puts a lot of shear on the cotter key that attaches the motor assembly to the shaft, and you can shear the key, or tear up gears themselves if the key doesn't fail first. With the throttle off, landing does not cause the shear, it should freewheel. It can be a hard motorcycle habit to break, landing with power on.

But yeah, small pops, stairs, they can be ok provided you don't ride around with broken or loose spokes. And yeah, shit can break anyway, like the alloy hub itself, where the spoke holes are, or the freewheel screws on. But often those failures do reveal a casting defect. I rode a trail once so rough, I loosened a lot of cover screws on the motor, and the derailleur fell off the bike. The motor overheated and got damaged wiring, but no problem with the spokes, rim, or motor itself.

Thanks for the tips, I really feel I should go to another drive system. I always check my spokes, but to be honest I've been riding for the past months with one spoke less since it broke in the middle of a trail and I always forget to get it repaired

Punx0r said:
The tyre/tube and rim seem to give out first. With a heavy hub the wheel hits bumps harder and it's more difficult to pop the rear wheel over them.

This is a concern, the weight making it way less maneuverable for climbing curbs and small stairs, I've never tried to jump a hub ebike since the ones I've ridden wasn't mine

j bjork · Jan 5, 2020

Mcdabber said:
I ride my hub motor (qs205) pretty hard and so far its held up great. I mainly built my stealth clone to do wheelies but i have takin it off of a 3 foot high jump before and landing onto concrete. I also like to find as many jumps as possible around the city.

https://www.instagram.com/p/B5RRV4eJWQP/?utm_source=ig_web_copy_link

Yes, they can take more than the Chinese rims.

It may be good for reference, but it was not those hubs that were in question here.

How much beating can a hub take?

Pedrodemio

100 W

amberwolf

Administrator

john61ct

1 TW

Mcdabber

1 µW

dogman dan

1 PW

Punx0r

1 GW

Pedrodemio

100 W

j bjork

100 kW

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