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Strange noise when freewheeling

westy81westy81 Posts: 7
edited May 2012 in Workshop
Hello.

I rode in a sportive this weekend and after 30 miles a strange noise developed. After checking and not finding anything amiss I rode on but kept hearing and feeling a dragging and grinding noise. When this happened I looked down at the drivetrain and realised that the chain was hanging slack and was being pulled across to the small sprocket but the rear mech hadn't moved. Later in the ride when peddling on the flat at a fair pace I noticed that if I dropped off the pace a bit the noise returned...
After speaking to other riders someone suggested the freewheel was on the way out... I kept riding but had to pedal downhill to stop the noise happening constantly. Could this just be the wheel bearings??
Does anyone have any suggestions/solutions and/or advice as to whether it is serviceable.
Thanks in advance.

Andy

Posts

  • smidsysmidsy Posts: 5,273
    If it is the freehub body then some are repairable and some ar'nt.

    If the freehub is going it would generally manifest as freewheel in both directions (i.e loss of drive). If not more likely something else to me.

    You say it was noisy but did the peddaling action seem wierd in any way (slipping, notchy etc.)? If so that would seem more like a chain or gear issue. There are many things that it could be as sometimes the symptom is not a direct consequence of the cause.

    As an example I recently had a strange pedalling issue after changing wheels (same cassette) which was an intermittent slipping, and immediately assumed it was a hub issue on the new wheels. Turns out after hours of trying to decipher (had the freehub apart etc) that one of the side plates on the chain was damaged and catching on the rear mech face plate. Difficult to spot and not an instant item to check given the situation, well in my mind anyway.
    Yellow is the new Black.
  • GrahamNGrahamN Posts: 66
    sound like spring number "2" on the below needs re-greased which is quite easy to remove but slightly more
    tricking to get back together but perfectly feasible as I`ve done it myself on about half a dozen occassions


    good luck


    http://techdocs.shimano.com/media/techd ... 609122.pdf
  • westy81westy81 Posts: 7
    Thanks for the advice and suggestions guys. Spring number 2 is on the rear mech is that correct? There was no slipping or jumping from the gears, they all worked quite well for once! I fitted a new ultegra cassette and dura-ace 10spd chain only 250 miles ago, running on a year old chainset, so would be fairly sure these are ok. The mech worked fine when new cassette fitted, though it is the original and has taken a few knocks.

    Would that spring cause a rubbing noise? I could feel a vibration through the bike when it happened, thats what made me think wheel bearings/freehub. Its as short cage mech running on an 11-28 cassette, does that have any implications?

    Thanks for any help

    Andy
  • smidsysmidsy Posts: 5,273
    How much clearance do you have on your rear mech to the cassette? Is the top jockey wheel touching anything?
    Yellow is the new Black.
  • GrahamNGrahamN Posts: 66
    If the chain`s hanging slack it suggest`s your rear mech isn`t holding the tension in the chain
    as probably that spring has dried up , highly unlikely there`s muck in it as it`s pretty well sealed from road grime
  • westy81westy81 Posts: 7
    The top jockey wheel is clear, by a few mm. Set the b-screw and the gears all work fine, still do, so I reckon I will take a look at that spring, thanks Graham. I will let you know how I get on. Was thinking of replacing the mech with an Ultegra 6700 medium cage to help with clearance.

    I will let you know how it goes, hopefully get it apart tomorrow night.

    Cheers
  • markshaw77markshaw77 Posts: 437
    I had exactly the same as the OP (slack chain, noise/vibration)and it was the freehub on my Mavic Aksiums that was worn/dirty and therefore sticking when trying to freewheel. The pawls, etc were still fine and would engage properly when pedalling, but when coasting the freehub unit would "stick" and cause the upper chain line to go slack and the lower chain line and RD to go tight (as the stuck freewheel would push the chain forward but my feet were keep the chainset from rotating).

    I removed the freehub expecting to replace it, but on inspection, it just needed a good clean and lubrication and since re-fitting I have had no issues whatsoever

    It is a common problems with mavic wheels (just google mavic death squeal :D ) so if adjustment of the derailleur does not help, that might be the next suspect to check.

    HTH
  • p7riderp7rider Posts: 370
    got a similar prob on a tiagra hub the freewheel drags while freewheeling and slows the wheel down rather quickly if you take the chain off and spin the rim then hold the freewheel and is noisy could it just need removing and cleaning?
  • SlackSlack Posts: 326
    Nothing to do with the rear dérailleur. This:

    markshaw77 wrote:
    I had exactly the same as the OP (slack chain, noise/vibration)and it was the freehub on my Mavic Aksiums that was worn/dirty and therefore sticking when trying to freewheel. The pawls, etc were still fine and would engage properly when pedalling, but when coasting the freehub unit would "stick" and cause the upper chain line to go slack and the lower chain line and RD to go tight (as the stuck freewheel would push the chain forward but my feet were keep the chainset from rotating).

    I removed the freehub expecting to replace it, but on inspection, it just needed a good clean and lubrication and since re-fitting I have had no issues whatsoever

    It is a common problems with mavic wheels (just google mavic death squeal :D ) so if adjustment of the derailleur does not help, that might be the next suspect to check.

    HTH
    Plymouthsteve for councillor!!
  • westy81westy81 Posts: 7
    Thanks chaps for the advice. Cleaned everything thoroughly, cassette and rear mech pivots etc, seemed to do the trick. Until I was 50 miles into the Fred Whitton last weekend! I will have another go at the freewheel, though I am thinking of a new set of lighter wheels and keep these as training jobs.
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