Rear derailleur adjustment problem with Paul's Thumbies
Has anyone had a problem with being unable to properly adjust the rear derailleur and cable with Paul's Thumbies? I have a new bike, with dura ace bar end shifters (mounted with the thumbies), an XTR rear derailleur and the XT 11-34 cassette (9-speed).
With the bike on the rack, I cannot adjust the cable tension to cleanly shift through all of the gears, even with the bike on the rack. Its as if the shifter is not compatible with the derailleur (I have the same setup on another bike, but without the thumbies, and I can properly adjust the cable tension on that bike). I was going to take off the thumbies, and try it with the shifters attached to the bar ends, but before I do that I was looking for any other suggestions.
You have 2 different adjusters, one on the rear mech , and one on the Thumbie mount,
you may be operating at cross purposes with the one on the bar , not being able to see What it'd doing to the cable tension.
Did it work OK before changing to the Thumbie mounted lever. ??
or is it an issue of all the other things that are required to make SIS stuff work,
like starting with the Frame's dropout hanger being in accurate parallel plane to the Wheel rim, and so centerline of the frame ?
Rear derailleurs take a hit and bend the frame. Bike shops have a dropout eyelet alignment tool to quickly bend that frame portion into proper alignment.
Thanks for the response. There is no adjuster at the deraileur. As this is a new bike, I did not have the shifters mounted without the thumbies. The bike has not been damaged or hit, and the deraileur seems to be straight and true.
check hanger alignment. hangers on new bikes are not aligned properly
That's what I think too. whenever I encounter a rear shifting problem that doesn't respond to normal tuneing the first thing that I do is to check the derailleur hanger alignment. Most of the time - that's it.
Originally Posted by reptilezs
Thanks for the input. I'll have the LBS check the alignment and report back.
I got the Park Derailleur Alignment Gauge tool and found out that my new bike's derailleur was significantly out of alignment - despite the fact that the bike was new and expensive. I aligned the derailleur, and the shifting is smooth. Thanks for your help.
It's very common for derailleur hangers to get bent during shipping while the bike is in the box. If there's any sizable impact on the right side of the box the derailleur and hanger seem to get pushed in a bit.
Not with reference to your current problem, but to give you a heads up about using Paul's Thumbies: it's not uncommon for the screw that holds down the right side shifter to work loose. This causes poor shifting (acts just like cable drag due to slop at the shifter) and can damage the Thumbie at the mount. I put Pauls Thumbies on my girlfriend's touring bike and had this happen a year later (unfortunately, she has a high tolerance for a poor shifting bike, and didn't make me aware of the problem for quite a while which is how I know that this can damage the Thumbie). The fix for this is to either use Locktite Blue on assembly, or if you want to make really certain that it doesn't come loose, use a longer shifter mounting bold and put a locknut on the underside of the Thumbie, which is what we did.