chain/cassette slippage [edited]
formerlyknownasbonj
Posts: 483
my chain often 'slips' on the cassette when changing gear.
It doesn't skip in the way that it does when using a worn chain with a new cassette, or v.v., it's only when actually changing gear, it feels like the chain is moving about 5 teeth along before engaging on the cassette, which feels like the pedals spinning for a brief moment and is quite disconcerting!
It doesn't do it for long, and it will engage soon, after what feels like about 3-5 links of the chain have 'slipped' straight over the cassette before falling into the teeth.
It does it mainly on changes between 5 and 4, although it also does it on changes between 6 and 5 and 7 and 6. (9 being smallest). And mainly when changing down (i.e. smaller to bigger sprocket), although sometimes up.
Otherwise, the gear changing is spot on - it goes up and down into all the gears perfectly. i.e. the rear mech movement, and cable tension seem absolutely fine. And it doesn't always do this slipping, only about 1 in 5 times.
bit confused as to what's wrong with it, to be honest...a ny ideas much appreciated
It doesn't skip in the way that it does when using a worn chain with a new cassette, or v.v., it's only when actually changing gear, it feels like the chain is moving about 5 teeth along before engaging on the cassette, which feels like the pedals spinning for a brief moment and is quite disconcerting!
It doesn't do it for long, and it will engage soon, after what feels like about 3-5 links of the chain have 'slipped' straight over the cassette before falling into the teeth.
It does it mainly on changes between 5 and 4, although it also does it on changes between 6 and 5 and 7 and 6. (9 being smallest). And mainly when changing down (i.e. smaller to bigger sprocket), although sometimes up.
Otherwise, the gear changing is spot on - it goes up and down into all the gears perfectly. i.e. the rear mech movement, and cable tension seem absolutely fine. And it doesn't always do this slipping, only about 1 in 5 times.
bit confused as to what's wrong with it, to be honest...a ny ideas much appreciated
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Comments
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*bump* (have edited post)0
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It may be a slightly maladjusted indexing. Try turning the cable adjuster on the mech out a 1/4 turn (anti clockwise as you look from the back of the bike). Just go 1/4 turn then test. If it is the same try another 1/4 turn. If this does not cure it then try cleaning the cables as dirt in them can slow the change down causing the chain to ride up the cog for a few teeth before settling into position. The most common places for drag to take place are the rear loop of outer cable and the guide under the BB.0
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yeah, this was the first thing I thought of trying, and it doesn't seem to make any difference.0
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Also, check to make sure the mech cable is not frayed.0
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nah, the cable isn't frayed. Don't think it's anything to do with the cable tension, or the movement of the mech. It goes into every gear, and i have tried it at the upper and lower limit of the cable tension for which that is the case, i.e. it does it with the cable only just tight enough, and with it only just loose enough.
I think it's either the position of the chain relative to the cassette, or the interface of the chain with the cassette.
It's almost as if the relative position of the teeth on one cog compared to the next one is wrong - as could be the case if they were all separate and the splines were radially symmetrical, but only one of the grooves on the circumference of the freehub splines is narrower, to ensure they all go on correctly relative to each other, and anyway the sram cassette is one solid block apart from the smallest sprocket!
I've ordered a shimano cassette. If it works, then i'll send the current one back to sram and tell them it's been manufactuered wrong.0
