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Ultegra Vibration

Pegasus2Pegasus2 Posts: 18
edited September 2015 in Workshop
Hello

Bit of a problem. I'm getting a vibration issue through the pedals whilst running on the middle chainring. I can't hear anything, just feel it through the drive side pedal, occasionaly the other pedal too.

I'd describe it as a fine high-frequency judder or vibration, between 6 o'clock and 12 o'clock on the 'pull up' part of the pedal stroke. It's on all reachable sprockets for the middle range, so 4,5,6 & 7 on a 10 speed. It's most pronounced around 5,6 whilst running at 88-92 RPM.
    The chain is running straight and not catching the front derailur. It's only whilst under load, not even heavy load but that makes it more prevelant. Nothing on light load or freewheeling. Gear changes are like clockwork right through the full range. There is no noticable play in the crankset and the whole bike has done only 150 miles from new. LBS didn't find anything. I've checked cleats are tight and changed the pedals over for new ones.

Tightening the cassette locker helped *slightly*. It's a brand new Shimano Ultegra groupset with hollowtech 2 chain.

There are moments, occasionly, where the chainset feels as smooth as i'd expect it too but they are few and far between. Changing up to the large chainring almost transforms the feel of the bike.

Any ideas appreciated.

Posts

  • dj58dj58 Posts: 2,161
    Is it Ultegra FC-6703 10sp? Is the Shimano CN-6701 chain fitted in the correct direction? Chainring bolts tight?
  • Pegasus2Pegasus2 Posts: 18
    Is it Ultegra FC-6703 10sp? Is the Shimano CN-6701 chain fitted in the correct direction? Chainring bolts tight?


    Yes, FC-6703 is stamped on the crank arms. The chain is stamped CN6600 and the rings HG-X. After some googling, this is what Shimano reccomends for the tripple set.

    As far as i can tell, the 6600 is symetrical. I'll have a close look at the bolts tomorrow but there isn't any movement in the ring.

    Cheers

    Peg
  • jgsijgsi Posts: 5,027
    Try a different chain - KMC or Wippermann.. it wont go to waste anyway and yo dont have to worry about unidirectional either.
    The middle chainring is the right way about ..?
    Check chain length as well.. it will be very quickly obvious if the chainring ring bolts need nipping up.
    It will be something very simple but be logical about it... the fun of curing snags.
  • dee4life2005dee4life2005 Posts: 773
    The 6600 is symmetrical, that's what I run my 6703 triple 10sp ultegra. This is the recommended combo for that chainset. In the past, I've had similar vibration feel through the pedals, without any associated noise. Can't remember what caused it, but how many miles have you put on the bike?

    I'd be looking at the bottom bracket, or possibly the freewheel ... the bottom bracket is more likely to cause a vibration feel through the pedals, especially if the bearings are excessively worn. Similarly, if it's the freewheel then the roughness may transfer to the chainset through the chain, and feel like a vibration.
  • Pegasus2Pegasus2 Posts: 18
    The 6600 is symmetrical, that's what I run my 6703 triple 10sp ultegra. This is the recommended combo for that chainset. In the past, I've had similar vibration feel through the pedals, without any associated noise. Can't remember what caused it, but how many miles have you put on the bike?

    I'd be looking at the bottom bracket, or possibly the freewheel ... the bottom bracket is more likely to cause a vibration feel through the pedals, especially if the bearings are excessively worn. Similarly, if it's the freewheel then the roughness may transfer to the chainset through the chain, and feel like a vibration.

    I stripped a little bit of oil from the chain (sides and top + bottom) with just a paper tissue, did some cleaning and went for a ride. Chain still well oiled where it needs to be.

    There is now a sound accompanying the vibration and it is definately coming from the chainwheel. Im thinking it's possibly just the chain connecting and leaving the chain wheel with a small mismatch in the tooth profile as that's what the sound seems to be. The crank arms are tight and there is zero play in them, it all feels sturdy.

    The whole set is running a bit rough on the front. Same again with changing up on the large ring, no noise and is acceptably smooth.

    With this in mind and having covered 147 miles i'm thinking i'll give it another 100 miles with a better lube (if I can find one) to see if it does wear in a bit more. There certainly isn't anything visibly wrong as far as I can see.

    To be honest I was expecting a lot more from an ultegra chainset after riding somthing that was barely maintained from 1980 for the previous 3 years. It may yet vindicate itself.

    I can post a picture of the teeth on the middle chainring and their wear if that's any use?

    Thanks for the replies.
  • k-dogk-dog Posts: 1,652
    It's more likely to be a setup issue - even if you lubed the chain with sand I wouldn't expect a chainring to be worn after 150 miles.
    I'm left handed, if that matters.
  • dj58dj58 Posts: 2,161
    Unless the middle chainring has a manufacturing fault, e.g. runout or defective teeth profile, it is unlikely to be the source of the problem with only 150mls on the clock. Shift into your lowest gear and unhook the chain from the inner chainring, check that the BB spins freely and that there are no tight spots between 6 and 12 o'clock.

    As suggested above, buy another chain, with a quick link and substitute to eliminate that as the source.
  • svettysvetty Posts: 1,904
    If it only occurs on the middle ring the answer's simple: fit a compact. No middle ring, no problem :lol::lol:
    FFS! Harden up and grow a pair :D
  • Pegasus2Pegasus2 Posts: 18
    Update:

    BB taken out, checked, reseated, regreased.
    Crank arms checked, tightened
    Pedals checked regreased etc etc.
    New KMC chain, replacing shimano CN6600.

    Different chain lube, now wet instead of dry.


    Rode 40 miles today

    Much less noticible now, which is good but the vibration is still there.
  • Pegasus2Pegasus2 Posts: 18
    Hello everyone


    Sorry to bring this back up but this problem is driving me up the wall.

    I've swapped out so many components and each time it's still there.
    I've swapped the rear wheel + cassette/pedals and cleats out and replaced the chain.

    The only things I haven't changed are the rear mech, front mech, BB and chain rings and the last two have been apart and serviced twice. Mech isn't bent and front is at a bit of an angle but clearing everything beyond tollerance, even factoring in frame felx I can't see it catching.

    I can still only describe it as a rubbing/buzzing/vibration once every revolution on the upstroke felt through the pedals with occasional accompanying grindy noise.

    If I change my pedaling technique to horizontal (as opposed to vertical or circular) it exacerbates into a rough judder throughout the whole revolution.

    It's a 10 speed tripple with a push fit BB.

    Any ideas?

    Even though the LBS can't find anything wrong with the BB i'm thinking of just replacing the entire BB?

    Thanks for help.
  • have you checked the rear mech hanger for alignment or if bent?
  • dj58dj58 Posts: 2,161
    Press fit BB's are not designed to be removed and refitted, that is not to say you cannot do it, just that you may have damaged the bearings during the process, which will lead to premature failure, so for the cost you may as well fit a new one to eliminate that as the problem.
  • deswellerdesweller Posts: 5,271
    Is there too much axial load in the bottom bracket? Release the crank arm clamp screws and back the preload screw off 1/4 turn and see how it feels.
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  • I'm experiencing the exact same issue with Ultegra double 53/39 on my hi-mod synapse which has the si-sl spider chainring and BB30 bottom bracket. Bike has done about 1000 miles this year, is well maintained with weekly degrease/lube of the chain. Tried many of the same things as you to solve the problem but still getting it!
  • I'm experiencing the exact same issue with Ultegra double 53/39 on my hi-mod synapse which has the si-sl spider chainring and BB30 bottom bracket. Bike has done about 1000 miles this year, is well maintained with weekly degrease/lube of the chain. Tried many of the same things as you to solve the problem but still getting it!

    I never got to the bottom of it. I swapped out all the components with the LBS one by one until everything had been replaced in the end and still it persisted. The LBS spent over two hours on it and were defeated, they said it was quite bad vibration but couldn't track it down.

    The bike went back to the manufacturer (which is abroad) about two weeks ago, haven't heard from them yet. Not very happy.

    If they find anything I'll post back.
  • Sounds pretty serious! What frame was it by the way?
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