Gear shifting problem
Discussion
Rear mech on my gravel bike has decided it doesn't like going into the two, sometimes three, smallest gears on the cassette. Nothing on the mech has been touched regarding indexing or movement, though the indexing is also now a bit out.
Shifters and mech are 7000 series 105 11-sp and have caused no probs at all over the past four years. I don't have time to tinker and play at the mo, so just trying to figure out if its cables or mech or shifters. Any pointers?
Shifters and mech are 7000 series 105 11-sp and have caused no probs at all over the past four years. I don't have time to tinker and play at the mo, so just trying to figure out if its cables or mech or shifters. Any pointers?
Easy enough to check.
if you can, put the bike into a stand or at least be able to have the rear wheel off the ground.
Chage down to lowest gear and observe whats happening, if it won't move down, carefully, assist the derailleur with your hand.
If it then moves, its friction in the system, not the limit screws - as you've said, they haven't been adjusted.
Then it's simple elimination, cables as highlighted, ensuring the derailleur main pring and pivots are loose and lubricated - quick WD40 squirt, then shifters themselves.
I'd go with cables though, replacing inners and outers. Also good to make sure they're well lubed internally when you do refit them.
if you can, put the bike into a stand or at least be able to have the rear wheel off the ground.
Chage down to lowest gear and observe whats happening, if it won't move down, carefully, assist the derailleur with your hand.
If it then moves, its friction in the system, not the limit screws - as you've said, they haven't been adjusted.
Then it's simple elimination, cables as highlighted, ensuring the derailleur main pring and pivots are loose and lubricated - quick WD40 squirt, then shifters themselves.
I'd go with cables though, replacing inners and outers. Also good to make sure they're well lubed internally when you do refit them.
The thing I always try to remember is that if the limit screws are set correctly, then the only thing that stops a derailleur putting you into the highest gear/smallest cog is the cable and indexing.
It's why going up the cassette tends to always work, as you're overcoming any friction with your own power, going down the cassette is purely on the strength of the spring in the derailleur and you operating, in essence, a ratchet. Releasing the index, releases just enough cable for the next gear etc. The actual motion of the derailleur is self powered.
Hence, any friction in the system slows it down, but is less noticeable when going up the cassette.
It's why going up the cassette tends to always work, as you're overcoming any friction with your own power, going down the cassette is purely on the strength of the spring in the derailleur and you operating, in essence, a ratchet. Releasing the index, releases just enough cable for the next gear etc. The actual motion of the derailleur is self powered.
Hence, any friction in the system slows it down, but is less noticeable when going up the cassette.
The internal cable guides were duff on my Planet-X CX bike, with too many sharp corners. It was fine with freshly-fitted, clean cables, but the slightest bit of extra friction and the total resistance became too much for the spring in the rear mech to deal with, resulting in slow shifts down the cassette and a failure to reach the 11-tooth cog altogether.
I've also had the rear mech moving all the way to the limit stops but still not shifting gear: that seemed to come on during the course of a single ride and was down to worn-out teeth on the jockey wheels. The symptoms were weird, but essentially it wouldn't shift away from the middle three cogs on the cassette in either direction.
I've also had the rear mech moving all the way to the limit stops but still not shifting gear: that seemed to come on during the course of a single ride and was down to worn-out teeth on the jockey wheels. The symptoms were weird, but essentially it wouldn't shift away from the middle three cogs on the cassette in either direction.
Right, little update...
Went through the range of tests to check it could all work, kept riding it for a bit then got completely fed up with only being able to use about 6/11 gears. So, having no time to phaff, booked it into the LBS for new cables, and to check the rear hub kept working loose.
Result is that the problem was being caused by lots of things, and with new cables, new freehub body, new bar tape and lots of tweaking by people who know what they're doing rather than just making guesses, it rides like a new bike again. For the princely sum of AU$200. That counts as a bargain in this place.
Riding tomorrow!
Went through the range of tests to check it could all work, kept riding it for a bit then got completely fed up with only being able to use about 6/11 gears. So, having no time to phaff, booked it into the LBS for new cables, and to check the rear hub kept working loose.
Result is that the problem was being caused by lots of things, and with new cables, new freehub body, new bar tape and lots of tweaking by people who know what they're doing rather than just making guesses, it rides like a new bike again. For the princely sum of AU$200. That counts as a bargain in this place.
Riding tomorrow!
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