Bicycle Mechanics - Can't get chain on all rear cogs by cable

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krushgroove
08-21-08, 12:04 PM
Any ideas why I can't get the RD to access the big AND little sprocket?

I messed around for at least half an hour (again) with cable tension, barrel adjusters and finally settled on the 'big hammer' approach of loosening and tightening the cable at the RD attachment point, holding the cable with locking pliers and using my thumb/eye to gauge the movement of the RD. I have looked from behind the bike and set the stopping points on the RD - the RD CAN get the chain on all the sprockets if the RD is pushed/pulled into position by hand, but the cable won't move it all the way from big to little sprocket. (have just replaced the cables and housings on this bike, it's an old flat bar 700c I use for commuting)

The best I've been able to get it to is start on the smallest sprocket and get it to shift to the second-largest, then adjust the tension with the barrel adjuster so the chain is rubbing quite a lot, but it still wouldn't get on the largest sprocket. At the moment I have it set so that it can't get to the smallest cog, which is OK because with the new cables I can finally access the big gear up front :)

Any ideas would be great. I'm getting more and more comfortable with adjusting the bike so I'll be happy to try just about anything.


treebound
08-21-08, 12:34 PM
(have just replaced the cables and housings on this bike, it's an old flat bar 700c I use for commuting)


How many cogs are on the rear?
Did you recently change the shifter?
Has it ever worked correctly and full range with the current shifter?
Is the shifter indexed and if so does it give an appropriate number of clicks?

DannoXYZ
08-21-08, 12:37 PM
Are you using 9-spd shifters/RD with 10-spd cogset?


Bill Kapaun
08-21-08, 12:38 PM
Sounds like the limit screws need to be backed out a bit. Go slow, like 1/4 turn at a time.
http://www.parktool.com/repair/byregion.asp?catid=53

krushgroove
08-21-08, 01:01 PM
many thanks for the quick replies!


How many cogs are on the rear? 7, should have mentioned this, sorry
Did you recently change the shifter? yes but I (maybe naively) don't think it matters because the RD can be pushed by hand to get the chain on all the cogs
Has it ever worked correctly and full range with the current shifter? no, and not with the old RD either but the old cables were pretty crap
Is the shifter indexed and if so does it give an appropriate number of clicks? yes and yes


Are you using 9-spd shifters/RD with 10-spd cogset?
Nah, it's an old Raleigh with 3 chainrings up front and 7 speeds in the rear


Sounds like the limit screws need to be backed out a bit. Go slow, like 1/4 turn at a time.
http://www.parktool.com/repair/byregion.asp?catid=53
right, I'll give this a try, thanks for the heads up!

edit - got it sorted out, printed the Park FD and RD adjustment guides and went through them step by step this time! I can get to all my gears now! awesome :D thanks for all the replies