Bicycle Mechanics - Thumbie shifter Q

I have an old lugged steel road bike that I want to turn into a flat bar commuter. I had canti posts brazed on and the rear respaced to 130mm and I have an old set of XT indexing thumbies I wanna use. The problem is they are 7 speed and I'd like to use an 8 speed cassette. I have heard that the "ghost position" will let you use these with an 8 speed cassette, and I'm just looking for verification along the lines of "been there, done that, and it worked just fine.". Anyone out there that can say that?

The truth is that it only sort of works.

7-speed and 8-speed cassettes and shifters aren't spaced exactly the same. The difference is close enough that you can get the indexing to kind of work. But it doesn't index perfectly. I'm convinced that the people who will tell you otherwise either haven't ever actually done it themselves or else they just have way lower standards than I do.

I've tried using 8-speed rapid fire and 8-speed STI to shift onto 7-speed cassettes (two different bikes of course). In both of those cases, I could get it to index well in one direction, but it required two shifts to change direction. Then it would index properly until you wanted to shift in the other direction again.

Right now one of my personal bikes uses 7-speed bar cons to shift onto an 8-speed cassette. I can access all 8 cogs (using the "ghost" position), but some shifts require two shifts up and one shift down to access the next cog. Being a retro grouch, I find it more convenient to use friction mode and shift it by feel like we did in the old days.

Pick up some 8 speed shifters on Ebay. They won't cost much.

As Retro Grouch suggested, give friction mode a good, honest trial. You may discover why I always operate the SunTour accushift thumb lever on my mountain bike in friction mode. With the possible exception of Campag. Ergo and Shimano STI on road bike rear derailleurs, indexed shifting is a marketing gimmick with little, if any, real value.

A bit off topic but Paul Components recently came out with these nifty little gizmos which enables you to use your bar end shifters as thumbies on bar tops.

I knew about the Paul's setup, and I may go that route given the advice I have read here. Unless I can get a nice 7 speed cassette that's what I'll do.

What up,

I had an experience much like Retro Grouch's with my 7spd thumbies and an 8-spd cassette. In my case, the experimental vehicle was a mtb, and friction shifting was not a practical solution. In the end I switched to a 7spd cassette with a spacer, and limited the travel on my r.derailleur using the set screws. That set-up worked very nicely until a trailside stick ruined the whole goddam party.

BK