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Chain jumping - changed everything!

Discussion in 'Bicycle Mechanics and Repairs' started by theoriginaldus, 28 Feb 2008.

  1. theoriginaldus

    theoriginaldus New Member

    Hi guys,

    I recently changed my chain and rear derailleur, this caused the chain to jump due to wear on the cassette, so I also changed that out but the chain is still jumping when applying too much pressure. Seated peddling is fine, but standing to take off from a stand for instance causes the chain to jump. Here's a bit more detail but I'm really at loss as to why this is still happening tbh, any thoughts appreciated.....

    New chain, new rear derailleur, new cassette. Chainset looks to my eye fine and doesn't have enough wear to need changing out. I haven't replaced the rear hub but have overhauled it and replaced the bearings (racers look fine, the spindle isn't bent etc). The old cassette was off road but the new one I have fitted is a road cassette, however the rear derailleur has a long cage. Now I went into my local bike shop and they suggested that maybe I needed a short cage but tbh I'm not entirely convinced, I've already taken a couple of links out of the new chain and thoroughly checked for stiff links so I don't think its a tension thing Also the chainset is still an off road triple, so surely I need to have the long cage to take up the slack for that? (not that I use the inner ring at all and only rarely the middle).

    One thing, the frame did get slightly bent meaning the derallieur was not straight and pointed in towards the wheel, so I straightened the little lip you screw the derallieur into and reinstalled it. With the derallieur exactly vertical, the chain was catching on the frame when on the smallest cassette ring so I ended up having the bend the lip out very slightly more, so the derallieur is pointing a little outwards away from the wheel, this is only very slight (a couple of degrees max), but might have some significance?

    Oh yes and its not a shifting issue, the derallieur is lined up and reliably shifting between cassette cogs (I changed the cable here) and isn't between cogs or anything like that.

    I'm by no means an expert on all this so there might well be something I've missed, I just wanted to get some more thoughts before I spend any more of my hard earned cash :becool: Any ideas?

    Cheers

    Jon
     
  2. Tynan

    Tynan Veteran

    Location:
    e4
    I know nothing about this sort of thing but is the chain the right type for the cassette, speed wise?
     
  3. OP
    OP
    theoriginaldus

    theoriginaldus New Member

    I bought it for a 9 speed which is right for my cassette but tbh I wasn't aware that the link distance in a chain could be variable? If you are meaning length wise I'm pretty confident this is ok although I haven't measured the actual tension of the chain, is this worth doing? (I judged the tension by the angle of the cage, was initially obviously too lose)
     
  4. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    Don't buy anything else yet!!

    Does it slip in both front chainrings?
    it could be one of your chainrings is very worn and this will cause slip in most cases.
    Does it slip in some gears more than others?
    new components sometimes slip ion the smaller cassette gears, don't aske me why, they just do.
    Has the chain got a stiff link?
    this will cause chain to jump. is it the right chain for the speed you got?
    Is it your freehub slipping?
    Have you tried a different wheel with the new cassette? A slipping freehub can be really hard to identify, as they only really slip under pressure, which you can't replicate off the bike. A different wheel will not slip if its the freehub on the first wheel
     
  5. Tynan

    Tynan Veteran

    Location:
    e4
    a proper answer

    I was almost sure last night that the free hub slipped a couple of times, kinda like the crank went round on it's own and didn't pull the wheel, very odd feeling and momentary

    gawd, I didn't even know that could happen
     
  6. OP
    OP
    theoriginaldus

    theoriginaldus New Member

    Hi Steve thanks for the thoughts, here are my answers:

    Well the cassette is new, as is the chain and the derailleur. The chainset isn't but it doesnt look warn enough to cause a slip to me - no shark teeth or anything here. I should check on the middle ring tho as this will definitely have seen less use than the outer ring - if the slipping stops then it must be wear on the chainset right? (ugghhh, my wallet)

    This is kind of hard to tell to be honest. Its slipping when I start off ie the larger cassette cogs, and I haven't had it slip in the smaller, but it's hard to apply equivalent pressure on the smaller cogs compared to when taking off from a stand on the larger. I'm also pretty reluctant to give a really good push when at speed on the smaller cogs as it has caused the chain to actually come off in one case and I don't really want to stack it in the middle of the road at speed :wacko:

    I've had a really thorough check through the chain for stiff links and it all looks good. However when I bought the chain I don't remember specifically asking for a 9 speed but I'm sure I must have done... Could the wrong speed chain cause this kind of effect? Is there any difference between the distance between links or is it just that the overall length of the chain is different ie links may need to be removed on different speed chains?

    I don't think so. If the hub was slipping would it not be the case that the chain would stay in contact with the cogs? If so, the chain definitely feels and sounds like it's leaving the cogs not just slipping but staying engaged, and that fact it caused the chain to come off the chainset in one case perhaps supports this? Unfortunately I don't really have spare wheel to test this out with...

    So you think I'm ok using a long cage on a road cassette with off road triple chainset?
     
  7. Rosser

    Rosser New Member

    Had the same problem and just sorted it this week. Chain started slipping - so changed chain. Slipping became worse - so changed cassette. Slipping continued so changed chainset (cheaper than buying individual rings, what is that all about). Success.

    moral: if you do not first succeed throw more money at the problem.
     
  8. OP
    OP
    theoriginaldus

    theoriginaldus New Member

    Did the old chainset look warn to you or did it 'look' ok? Mine looks ok tbh but maybe that is the answer afterall.
     
  9. squeaker

    squeaker Über Member

    Location:
    Steyning
    Recently fitted a new 8-spd Wippermann chain to my recumbent and found it was jumping on the smaller rear cogs due to one of the quick links being 'the wrong way around' (Wippermann quick links are somewhat asymmetric). Reversing the link fixed it - Wierd :~
     
  10. bianco

    bianco New Member

    does your hub require a spacer, is it possible the cassette has side to side movement?
     
  11. OP
    OP
    theoriginaldus

    theoriginaldus New Member

    I don't think so bianco, its the same hub from before I changed any parts, I just overhauled it and replaced the bearings. I'm going to try some tests peddling on the middle chainset rings this weekend, I'll just have to bite the bullet and get another chainset if that solves it...
     
  12. bianco

    bianco New Member

    Is it the same model cassette, some hubs require spacers with different cassettes.
     
  13. OP
    OP
    theoriginaldus

    theoriginaldus New Member

    Ughh, no its not the same model, the original cassette was the one that came with the bike, I believe it was something along the lines of deore xt (tho I cant remember exactly tbh), the new cassette is ultegra. The lockring looks to be screwing in at the correct point and everything, is there anything I can look out for to try and determine if the spacers are needed?
     
  14. fossyant

    fossyant Ride It Like You Stole It!

    Location:
    South Manchester
    Shimano road and MTB are inter-changeable. As a cheap option, try a different chain.

    What chain have you got ?
     
  15. Dormouse

    Dormouse New Member

    For what it's worth I had a similar problem a few years ago, I changed the cassette and chain but that had no effect. I took it to the LBS and they diagnosed a bent derailleur, they replaced it and that cured it.