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embee

Interesting cush drive experiment

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embee

Put a new rear tyre on for my upcoming holiday and noticed the cush drive in the rear wheel had become a bit slack, perhaps a mm or so of rotational free play at the joint between the housing and wheel hub. The cush drive sprocket carrier lifted out with no resistance. The rubbers look fine, no significant deterioration (compared to some I've seen) but are definitely a loose fit now.

 

As an experiment I decided to pack the rubbers to get a tighter fit, removing the free play. I cut some pieces of inner tube rubber and added a few drops of superglue (good with rubbers generally) and fitted them to the inner face of the overrun blocks (the smaller ones of the pairs) working on the basis that the inner tube, while being good quality rubber, is probably not ideal for continuous heavy loading on the drive side.

 

The sprocket carrier was then a good firm push fit into the rubbers installed in the wheel hub and there was no free play.

 

Took the bike out for a run today and there is a marked improvement in refinement especially when it upshifts into 6th at low revs. Generally it feels nicer, it has lost the slight grumble feel when running light at low rpm in the higher gears.

 

It'll be interesting to see how it stands up, but so far it's a definite improvement. I dare say new rubbers would give the same effect, but since they've only done 15k miles that could work out a bit pricey over time. If I can extend the life with some inner tube patches it seems a cost effective farkle..

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Grumpy Meltdown

Hmmm, a job for the next time the rear wheel is out.

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kayz1

I changed my tyres at 2500-ish and mine were the same, i thought with the low miles they must be ok...but i will look again Thanks Embee.

i can't do it Wednesday i have a young lads GasGas to fix for the weekend club meet.

Lyn.

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embee

It'd be very interesting to hear what if anything others find by trying this experiment. If you have the facilities to remove the wheel and have a bit of inner tube laying around (and who doesn't?) there's nothing really to lose by trying it, you can always return it to original.

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steve916s

On my high mileage other bike, the aluminium 'paddles' wore quite early in its life, allowing the sprocket carrier to wobble a bit on the bearing. I resorted to inner tube slices just pushed over the 'paddles'. This has lasted well, I renew the inner tube very occasionally. I think it makes the sprocket carrier bearing last longer too.

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scoot_to_boot

Is that bicycle inner tube? 

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embee

I think mine was motorbike inner tube, but it depends what thickness you need. I have various bits of inner tube in the stores! :lol:  Bicycle inner tube is usually pretty decent stuff.

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wjvh

I recently changed my chain & sprockets so decided to try this mod; have ended up slipping the rubber inserts on the drive side (in error you might say but I ain’t dismantling it all again) and I didn’t bother gluing them in place either but they seemed pretty snug when they went in. Anyway, due to lockdown I’ve only done 2 miles with the new c&s but will report back in due course; of course it will be difficult to differentiate between the effect of the Cush drive mod and the effect of the new c&s. I figure it’s unlikely to make things worse and it might improve things for zero cost. 🤞

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motorbykcourier

In times of 'emergency', I've used either an old inner tube OR cut up a plastic milk bottle to pack out the rubbers - it worked for longer than you might think :blink:

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Andy m

A lot of Yamaha XT's and Tenere's have inner tube pieces used as a permanent fix for some inherrant design fault. Lasts as least as long as a set of tyres so no real hassle. 

 

Andy

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Graham NZ

I did the embee mod and it works very well.

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Graham NZ

I used 1mm Butynol roofing membrane as packers and stuck the pieces to the face of the overrun blocks.  Next time the wheel is out I will fit new blocks because the linking strips between the block pairs has embrittled and likely to crack.  Under 30,000km but the bike is almost six years old, four in my ownership.

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electric_monk

I used bicycle inner tube just last week and it has made a difference.

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