DT shifter slipping

[p nut]

My bikes have been getting some attention lately.

Working on my bike with Dia Compe DT shifters, which have worked ok overall, but with an annoying issue. They’re friction set up with 3x9 drivetrain.

The right shifter (rear) has worked great. However, the left shifter (front) keeps slipping. When shifting to middle or large chainring, it will hold for a bit then after a few hundred yards, I’ll hear the chain rubbing against the derailer cage and I have to adjust the shifter again.

I’ve tightened the wingnut down pretty tight. And used beeswax in conjunction. Still slips.

Any suggestions in fixing this? Maybe it’s just a bad unit.

I had Riv Silver DT shifters in the past and those were even worse.

[monarchguy]

Is it assembled correctly, with all of the shims/washers present in the correct order? That's usually my problem, when this happens.

Dan

[p nut]

Is it assembled correctly, with all of the shims/washers present in the correct order? That's usually my problem, when this happens.

Dan

I will double check. There was only one way the plastic washer could sit, but if it can be installed incorrectly, it’s a high likelihood I have done just that.

[Hindmost]

Beeswax? The friction points of the shifter should be clean. (Sometimes you have to create more friction at the friction points.) You can lubricate the pivot points.

Check the cable guides under the bottom bracket. The guides should be clean and these can be beeswaxed for a little lubrication.

From below: "The plastic washers tend to compress, then require replacement." Yes, if they are old they will harden and lose some of their pliability and friction.

[p nut]

Beeswax? The friction points of the shifter should be clean. (Sometimes you have to create more friction at the friction points.) You can lubricate the pivot points.

Check the cable guides under the bottom bracket. The guides should be clean and these can be beeswaxed for a little lubrication.

Sorry, to be clear, beeswax on the bolt threads only. Not on the shifter itself. This was to keep the bolt/wingnut from loosening.

[Spaghetti Legs]

Is the bolt loosening?i.e Tighten it down and when you notice it slips, you have to retighten it? In that case, I'd recommend some blue Loctite (242/243) and tighten back down.

If it is slipping when tightened down as tight as you can go, I would add a thin washer somewhere. I don't have experience with these shifters, just old Campy and Simplex friction.

[cmbicycles]

Couple things you can try... carbon paste on the shifter, adjust der. stop out a little, or try loosening cable tension slightly. Been a while since I've used DT shifters, maybe its time to upgrade to electronic. ;)

[Peter P.]

The plastic washers tend to compress, then require replacement.

If you can find shifters with metal washers such as the Mavic Retrofriction shifters, you'll never have that problem.

[jojobos]

I use the same shifter. My right one died and replaced at about 15000 mile. The shifter developed a slight wobble. It was just enough to lose the wire tension slightly after shifting and would catch between gears or drops to a next gear. kind of what you are describing.

Also if you haven't checked, make sure there is a metal washer on the backside of the shifter. The metal washer-shifter body-plastic washer and then the wingnut.

[charliedid]

Cable too tight?

[Ken Robb]

Cable too tight?
Rider too tight? COVID captive humor.

[p nut]

Thanks everyone. Troubleshooting one at a time. I found a thin washer and installed it. I’ll see if that does the trick. Then I’ll go down the list. Hoping I won’t have to buy another shifter.

...maybe its time to upgrade to electronic. ;)

Doesn’t that initiate a self destruct sequence on all Riv’s??

[ultraman6970]

Sound weird but, did you try maybe adding some carbon paste to the plastic washer so the lever has some traction there and gets tad harder to slip?

[Nomadmax]

Best down tube shifters I've ever used (and are still on one of my rides) is Simplex retro-frictions.

[oldpotatoe]

I will double check. There was only one way the plastic washer could sit, but if it can be installed incorrectly, it’s a high likelihood I have done just that.

Is the bolt coming loose? If so, blue loctite. If the bolt is tight and it still gets loose, then something is worn inside. I have a LH Campag DT shifter I'll give you if you don't care about aesthetics..Retrofriction C-Record.

[p nut]

Is the bolt coming loose? If so, blue loctite. If the bolt is tight and it still gets loose, then something is worn inside. I have a LH Campag DT shifter I'll give you if you don't care about aesthetics..Retrofriction C-Record.

It appears maybe it’s a combination of the two? The bolt is pretty tight. When I notice the derailer slip, I can just tighten the wingnut ever so slightly. I don’t think it’s loosened enough to cause the shifter to slip, but I’m not familiar enough with this shifter to know.

I will try blue loctite and carbon paste. If that doesn’t work, I will contact you. Very kind of you!

[p nut]

Well, nothing worked. So Mr. Old Potatoe hooked me up with a Campy DT shifter. No rattles this morning as I rode! No slippage! And I kind of dig the mismatchy look. Thanks OP and everyone else.

[Ken Robb]

Nice bike on an inviting trail! BTW, I put my DT shifters into pods and used them as barends which made my Riv Allrounder easier to manage off-road because I never had to ride one-handed on rough ground.