northerntier

I'm riding with rivendell's SOS (silver-on-soma) thumb shifters (https://www.rivbike.com/product-p/sh5.htm). I love the feel and placement, but I have to re-tighten each shifter after each 5-10 shifts, which is kind of ridiculous. Is there some trick to setting up friction shifters?

HillRider

The shifters should not come out of adjustment anywhere near that frequently, if ever. Some of Campy's older dt shifters tended to loosen spontaneously but most other makes did not. I'd contact Rivendell directly about this problem. One obvious fix is a mild thread locker on the center bolt.

FBinNY 

In a friction shifter the top plate (directly under the wing nut) is keyed to the shaft by some means so it can't rotate. If it's not keyed securely it'll rotate slightly with each shift and work the wingnut loose over time, sometimes a very short time.

I don't know your shifter, but watch the top plate for any sign of movement as you move the lever. If you see any take the wingnut off and remove the top plate and see if there's a way to bind it tighter to the shaft. You can also reduce the torque on it, by making sure it's well greased, and letting the lever get more friction (comparatively) from the bottom.

If all else fails, remove the wingnut, clean the threads of it and the hole in the shaft with acetone, then paint the wingnut threads with rubber cement, and assemble it. This will slow the process down, but the only real cure is stabilizing the top plate.

onespeedbiker

If you have Campy bosses, your SOS shifters will need an additional .8mm spacer between the back plate washer and the washer behind the shifter; Campy bosses have a longer area prior to the lands so the shifters need to be spaced out farther or they will bottom out on the boss. This was explained with the the Suntour Sprint levers that the SOS were modeled after (the Sprint levers came with needed spacers) but Rivendell seemed clueless when I called them.

Rest_assured

I had this problem, the previous owner greased the shifters. Took them apart and soaked in metho, fixed it for me. Just make note of the order of the washers...

northerntier

Very helpful diagram, thanks.

Brian from Rivendell responded that springs are much stronger these days than when these shifters were designed (I totally believe this). He suggests beeswax on the bolt threads, as a light loc-tite, and possibly a "nord lock washer" under the D-ring but over the nylon washer below it. The nord would be less rough on the nylon washer.

I have beeswax, but the local ACE hardware has never heard of nord lock washers. Packs of 20-50 can be found online, plus shipping. Any other place I could find these, hopefully just a few?

Thanks,
pete

onespeedbiker

Okay my bad, I see you are using the thumbshifters not down tube shifters. If Brian from Rivendell is correct then their shifters are obsolete and should not be sold as the nord washer will grind on the plastic washer (steel on plastic) every time you shift to a smaller cog; what rear derailleur are you using? At the very least, with the exception of the mounting boss, I would clean all the mating surfaces and washers of any grease. Also make sure the oblong raised portion on the back of the plastic washer is properly inserted into the oblong cutout in the center of the shifter.

fietsbob

maybe a flat washer to cover the plastic, to not get chewed, and then a split ring spring washer under the bolt?

northerntier

Why would this matter?

The derailleur is a Deore M592 SGS Shadow Long Cage. Hmm...google reveals the following quote:

• Low profile Shadow design features direct cable routing and a stronger guide spring.

FWIW, I'm using the shadow derailleur on a disc LHT because I'm using at 12-36 cassette. Shimano says you should only use this cassette w/ a shadow derailleur.

The front shifter doesn't have a problem.

northerntier

Would a little loctite on the bolt be a terrible idea? I'd be able to "break" it if I just use a little.

onespeedbiker

It would matter because you are not attaching the lever to the boss that is brazed to the frame (these bosses come in many flavors, some not compatible with your shifters), but a boss that comes with the bracket that comes with the shifter itself.

onespeedbiker

The loctite may work but I would still want to address the cause. I used the same levers attached to down tube and after solving the Campy boss issue, they did not loosen up at all.

northerntier

The "boss" in this case is the bolt that comes in from underneath. The D-ring bolt screws into the lower bolt. The lower bolt is prevented from rotating by a square recess in the clamp the whole thing is mounted on. So if the D-ring can be prevented from rotating with respect to the lower bolt (the boss), then I think I'm good.

It seems my options are either to:
- ensure that the two bolts won't rotate with respect to each other, or
- change the derailleur, or the derailleur's spring

The latter seems a big much.

onespeedbiker

Also make sure the plastic washer under the D-ring is not moving. BTW, the end result of a stronger derailleur spring would be you would have to tighten the D ring more. The ratchet system works by isolating and holding the outer keyed or oblong half of the inner workings, so the inner half can ratchet; the D-ring tightens to preload the lever with enough friction to hold the shifter lever against he derailleur spring. Again, the plastic washer under the D ring is the key to stopping the lever from loosing up. Here is a video showing the installation of the downtube version of your shifter; note the issue of getting the plastic washer lined up with the shifter.