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Rear hub diagnostics

(10 posts)
  • Started 10 years ago by tk
  • Latest reply from tk
  • This topic is not resolved

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  1. tk
    Member

    I mentioned a little of this on the best tyres thread but thought if bring it over here. After changing the tyres I noticed the rear wheel felt stiff in cycling like the tensioned side of the chain was vibrating as it pulled the wheel round which made pedalling seem lumpy. Problem was worse in high gears but I'm guessing that's just because of the number of rear wheel rotations. There is also a horrible clicking sound when driving the wheel round that seems to go when freewheeling - listen here https://www.dropbox.com/s/zrvdeoj6vax7tup/New%20Recording%202.m4a

    - have rebuilt the rear hub replacing the old dry grease in the hubs. The dust caps on the cones had been rubbing a little but seem to be corrected. New grease has the wheel really smooth when spinning in your hand
    - very slight play in bearings how I've set them is removed when the QR is done up
    - Redid the rear indexing but didn't help. There seems to be a little vibration at the jockey wheel and tensioner on the rear derailer when running but nothing of concern. Alignment is good and a small nudge in each direction doesn't correct the sound
    - when freewheeling, putting a finger on the cassette on the largest sprocket you feel a little movement in and out perpendicular to the wheel on each wheel rotation

    Any ideas? This is starting to drive me mad!

    Posted 10 years ago #

  2. allebong
    Member

    The sound is exactly what I'd expect from severely damaged cups and/or cones and also maladjusted gears but you've ruled both those out.

    The wobbling perpendicular movement on the freewheel is normal - I've yet to see one that doesn't do it at all, but cheap freewheels do it much worse than Shimano ones. Sometimes the cog cluster is loose on the freewheel internals which manifests as the cluster wobbling about relative to the hub and axle - there's a whole other set of cup and cone bearings inside the ratchet which can (with considerable difficulty) be adjusted to remove it.

    First thought then is that the freewheel is close to dying. I've seen this happen with a Sunrace branded one. Exactly as you described, there would be an awful grinding/clunking going on when pedalling, this progressed to the looseness and wobbling I described. Final symptom was a scraping/grinding noise that would occur only at certain crank and pedal positions. Shortly after that the ratchet completely mangled itself and left me with freely spinning cogs going forward.

    Second thought completely unrelated to the above is less scary - could be simple chain wear. When the chain gets really worn, and especially if it's worn more or less than a sprocket, you will get that grinding sensation - worse on smaller cogs since there's less teeth to spread the load and the links have to bend more.

    I think you mentioned on the other thread that you use panniers on this wheel. My advice: A quick release freewheel axle is just begging for trouble when put under those loads. Keep a close eye on it and when you come to replace the wheel you'll get a massive improvement with a Shimano freehub model, preferably with 36 spokes. Wheel choice is a whole thread in itself but I do think you're on borrowed time with the problems you've been having.

    Posted 10 years ago #

  3. Cyclops
    Member

    Other potential causes (in no particular order):
    - bent axle/dropouts/QR skewer
    - wear of the wheel axle cones/races
    - chain incorrectly routed through jockey wheel cage

    Does the bike freewheel okay or is there vibration/resistance then as well?

    Posted 10 years ago #

  4. tk
    Member

    I think I can rule out most wear - the bike did a couple of hundred miles then sat for about 6 years (although kept reasonably maintained and clean/dry) as we moved house then I've started commuting again with a new job and put perhaps 500 miles on it. Only issue seems tone some grease dried in hubs and the tyres perished slightly.

    Pretty much ruled out anything chain related - you can even pull the top of the chain an inch with the pedals held (using the tensioners slack) and it feels and sounds the same. Do wonder if perhaps the axle has a slight bend - the rear wheel feels unbalanced when rotating like a bad washing machine. Might need to drop by a bike shop for an opinion and potentially replace the wheel.

    Posted 10 years ago #

  5. tk
    Member

    Freewheeling at speed there is wheel vibration but the noise only arrives with turning the pedals at the same time whether celebrating or just turning enough to prevent freewheeling

    Posted 10 years ago #

  6. allebong
    Member

    Most likely is a bent axle then, possibly the freewheel is also causing trouble by itself. If you wanted a quick fix swap out the hollow qr axle for a solid bolted one (ebay link).

    New wheel is the best solution from the sounds of things though. How many gears do you have on the freewheel? Freehub cassettes start at 7, so if there's that many already the swap should be straightforward - should be the same indexing between a 7 speed freewheel and cassette, though I'm not certain. If it's a 6 speed freewheel you'll need a new shifter as well. Bike shop will keep you right.

    Posted 10 years ago #

  7. I were right about that saddle
    Member

    There are some things that words just can't express, and I think we just demonstrated that bicycle 'grindy noises and odd sensations' fall firmly into that category. It's oddly reminiscent of the Literary Review's Bad Sex in Fiction Awards....

    Posted 10 years ago #

  8. I were right about that saddle
    Member

    I should add - key quote may be 'After changing the tyres...'. Your axle could be bent...but unless you're remarkably ham-fisted I doubt you bent it changing the tyres!

    Posted 10 years ago #

  9. tk
    Member

    The changing the tyres is just the annoyance of it - this may be an excuse for a new bike rather than throwing £70 for a free hub wheel at a bike that like for like would only be about £300 new. I probably wouldn't have bought tyres had I been thinking new bike at the time....

    Next try tonight is to remove the cassette so the freewheel doesn't engage the chain and see if it grinds when in the frame and spinning forwards. Might also completely remove the cones from the axle and see if the axle is fully straight. Looking through the middle seemed ok but rolling on a flat surface might be a better test.

    Evans have the identical freewheel for £20ish and that and a solid axle might get me another few months to think about an upgrade.

    Unless anyone has seen any amazing deals for a flat bar road bike type hybrid with disc brakes and a rack mount......

    Posted 10 years ago #

  10. tk
    Member

    Finally concluded it's the freewheel - with the wheel mounted on its own it's perfectly quiet. I've also noticed the freewheel rattled even when engaging it with the splined removal too and shaking it off the bike. Adding grease with it freewheeling seems to have pulled in enough to help reduce the noise. I think without it engaging smoothly it was also causing the chain to jump a little making it more noisy.

    Posted 10 years ago #

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