Why Have my Gear Shifts Gone Auto?

Iwasgoodonce

Old School Grand Master
My last few rides have all been a bit messed up by the rear gears changing by themselves. The bike didn't do this prior to being put away for a time during the cold weather we had for a while. The gears were left small/small during this time.
To me, the shifter feels quite easy (too easy) to push. The gears always change themselves to a higher gear. Falling down the cassette then. I have done the screw up as tight as it will go.
Shifters are old Shimano downtube shifters in friction mode. Nothing has changed. I haven't worked on the shifters for a long while.

Before I start searching for a new set, is there anything I can try or check?
 

Jonny69

Senior Retro Guru
Take the shift lever off and degrease all the bits. There will be a stack of washers, spring washers and maybe a fibre friction washer in there. Just check they’re all in good enough condition to do their job. Usually, if you tighten it right up you will be able to make it too tight to operate; so it sounds like something has either got too greasy or worn a bit.
 

jim haseltine

Devout Dirtbag
Conversely, it could be that the grease has dried out. Friction levers need a small amount of grease to equalise the friction across the whole range of the lever movement to avoid a lever being too tight at some points but too loose at others due to manufacturing tolerances.
 

Iwasgoodonce

Old School Grand Master
I thought I had fixed it. The lever felt a lot better but after a few miles the auto shift returned. I had to ride all the uphill bits holding the lever in place. It was on the final climb that I decided life is too short and the shifters have now been sacked off. This set looked bargaintastic:


Looking at the expected post arrival time, I think SJS must be delivering them by hand via the very top of Scotland whilst only being allowed to crawl. Luckily, to tide me over until that distant date, I found these in the stash:

image.jpeg

I really like the look of these shifters but don't want to use them permanently as I want to return my Alan to more or less the build I first got it in.
 
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