ub_ben

I am doing a build on an old trek that is set up with 7 speed cassette and the levers on the tube. I am on a tight budget so, the idea is to change to bar end shifters and work with the other parts. The issue is the shifter sets I am finding are 8 or 9 speed. I have never tried to mismatch parts like this. What issues will I face?

Hocam

Friction bar-end/down tube shifters work with anything. Dura-Ace bar ends can do either and work really nicely (I have a pair).

Ask the mechanics forum about indexing issues, I'm not sure about 7/8 speed compatibility.

SSRI

Shimano 8 speed sti will work with 7 speed cassettes.

Hocam

Good to know.

ub_ben

Thanks for the feedback.

CrimsonKarter21

Actually, I just heard of Suntour's answer to Shimano's STI system. Apparently there's a really fast rider around here who had a hole in his heart his whole life that was blocked for 50some years by a blood clot, but when the clot moved he had a stroke. Now he can only use the right side of his body. my coach rigged him up a bike with this Suntour piece and a barend, kind of cool. I wish I could remember the name, but he said he liked it better than the STI's.

vpiuva

The difference in spacing is 0.2mm per cog, so to set this up for best results use the middle cog to line up your RD with the cassette. This way your max misalignment (on the smallest and largest cogs) = 3*0.2mm = 0.6mm.

And a DA 8s shifter will not work

ultraman6970

if the down tube shifters are set in friction mode, you can even used them with a 10 sp wheel and it will work fine... still dont know why people uses index systems... are so boring

nites..

Winter76

There's a screw on the rear derailleur that you can set to stop it from shifting to your non-existant 8th gear.
This page talks about it: https://www.utahmountainbiking.com/fix/rshf-tun.htm