Yes, many good mechanics know how to trouble shoot friction shifters that wont hold gears under hard effort
My thoughts are that there is one of two things going on: Either you are never getting it tight enough, or it is loosening itself up. The reason you may not be able to get it tight enough is that the bolt that threads into the downtube shifter boss is bottoming out at the bottom of the threaded hole. It feels tight in your hand, because it's bottoming out, but it's not actually squeezing the friction bits any harder. To test this, tighten it to confirm whether it is possible to make it too-tight. Can you tighten it to a point where the friction is clearly too firm? If so, then this is not what is going on. Alternatively remove the shifter entirely and install only the bolt and observe how far in you can thread it before it bottoms out. See what that looks like and what it feels like. If you determine the bolt is bottoming out, carefully file 0.5mm off the end and you should be good. If you can get it tight enough, and it transitions from 'tight enough' to 'not tight enough' over a few shifts, then the bolt is loosening itself. Consider using a not-too-permanent threadlocker. I'd start with blue Loctite. Also decide if you have parts that don't fit well on the shifter boss that are free to wobble somewhat, and that wobbling helps auto-extract the bolt. If the judgement calls are difficult, find a good mechanic you trust to put their eyes on it. One other contributor can be excessive friction on the cable at the BB. Your hard efforts cause the cable to very slightly tighten and loosen as you flex the frame. The friction between the cable and the housing or guides at the BB can 'win' in the tug-of-war with the shifter. The last thing is to question whether the return spring on your rear derailler is just too strong. If you are using an RD that is clearly intended for index-only operation, or one with a known super-burly spring, you just may have a poor combo of parts. These are the things I'd go through if the bike(s) were in my stand Bill Lindsay El Cerrito CA On Thursday, August 20, 2020 at 7:14:40 AM UTC-7 Sam Perez wrote: > does any one know how to trouble shoot friction shifters that wont hold > gears under hard effort, i have riv silver shifters and 9speed dura ace > down tube shifters that slip on friction mode. > > I have done the following only to have the lever loose grip after a few > shifts. (lots of hills) > -tightened the bolt (done) > -tightened the D ring (done) > -adjusted the rear deralure (done) > > any thoughts? > > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/1bf8cf26-66e7-4afe-8c15-a0fe2050209an%40googlegroups.com.
