Wheel help

lectureral

Esteemed Pedelecer
Apr 30, 2007
397
60
Suva, Fiji
I have a Currie electro-drive kit on a MTB (the motor drives the wheel through a collar which attaches to the spokes of the back wheel). For 18 months it ran fine but then a spoke broke and the wheel eventually died (I did run on it for quite a while). My local bike shop sold me a new wheel but now 2 weeks later it has buckled.

My question is - are there different grades of wheel (I am guessing yes - my new wheel seemed lighter and shinier than the old one - maybe al or an alloy? - it cost about £40) and whether anyone can suggest a particularly strong wheel which would survive the forces better.

The wheel must be the right spoke pattern (I think its defined by each spoke crossing 3 others on the journey to the rim)

Any advice would be wheely appreciated.
 
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Ian

Esteemed Pedelecer
Apr 1, 2007
1,333
0
Leicester LE4, UK.
While there are specialized wheels available the chances are that both the original and replacement are "normal" wheels with an aluminium alloy rim. Stronger wheels are made but their strength lies in their ability to resist shocks to the rim rather than drive forces on the spokes.

I'm not sure now the electrodrive sprocket attaches to the spokes but I would guess the drive forces are concentrated on a few spokes at a time on the "pulled" side of the sprocket which would quickly find any weakness caused by uneven spoke tension or overstressed spokes.

I think the answer is probably a properly hand built wheel that has been properly de-stressed. A good shop could probably rebuild either your present or previous wheel to the required standard depending on which is the higher quality
 

flecc

Member
Oct 25, 2006
52,765
30,351
The Electrodrive attachment is for three cross 36 spoke standard hubs only, derailleur or fixed gear, and they are notorious for breaking spokes. It's essential that the spokes be very evenly tensioned and that the tension is quite high to prevent rotational flexing with each drive take-up, which saws through the spoke ends.

Taking it easy on the throttle application helps, making it smooth and progressive rather then flicking straight open.

It's for these reasons that on the complete bikes they've marketed, the drive transfer has been by other means, not using the spoke engagement block.
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lectureral

Esteemed Pedelecer
Apr 30, 2007
397
60
Suva, Fiji
Thanks Guys - I will have to talk to my bike shop about making up a good strong wheel.