I have a 1990-vintage Trek 1100 that came with 3x7 drive train and Suntour shifters on the downtube (friction left/front and indexed right/rear). I've switched to a modern compact double crank and a freehub/cassette wheel, with seven cogs and a spacer, so I can still use the old shifters. Now I'm ready to upgrade to integrated levers and a 10-speed cassette. I'm confident in my ability to install some Shimano 105 levers and compatible cassette, RD, chain, and cables. As they say, the devil's in the details, so here's my potential hang-up:

I'll obviously need to put some housing stops for both dérailleur cables in place of the current shifters. I see a few different options available for this. As far as I can tell, they're designed to work on old shifter braze-ons that are a simple, hollow, round stud--internally threaded, of course--with a square section near the base. The mechanism inside my Suntour shifters uses splines for anti-rotation effect, rather than the square base. Therefore, on the right side at least (I haven't taken off the left one yet), the stud has splines about halfway down its length. There are six splines, I think, with one wider than the rest to enforce the correct clock angle. Will this make any difference for the housing stops?

If the highly preferable approach mentioned above does not work, I realize I could always go with a clamp-on housing stop, like manufacturers used on millions of bikes with stem mounted shifters. The trouble with this approach is that I have an aluminum frame with oversized downtube. I think it's 36mm, but would have to measure again to confirm that. I'm not sure anyone makes a clamp-on stop that big.

Thoughts?

do you think these Shimano Downtube Barrel Stops in Tree Fort Bikes Cable Stops wouldn't work?


note it's the curve of the tube not the square boss that keeps these aligned

they have a big round hole inside, and are designed for square-section bosses - I bet they'd clear what you have.

Do you have a photo of your DT braze-on?

I would think it has to be similar to the boss (plate holder) for these thumbies, and I think the Shimano barrel stops would clear it

If you buy a new set of integrated levers a set of cable stops will be included in the package.

I mount them without the adjusters and countersink the bolt holes for flat-head cleat bolts for more clearance and a cleaner look...

Some of like redundancy in cable adjusting options. I'd keep the barrel adjusters. Especially for the front as STI levers and current front ders like specific front cable tension. Andy.

"some" May ..
I got some Black plastic ones, long ago ... I use friction Bar end shifters, so didn't need the fine tuning

I do that with the lever on the bars . I Used Button head screws.

+1 on trying these. They're cheap enough and I bet the hole will clear your splined stud. And since they're cheap, you can even try some fabrication like widening the hole if need be without losing any sleep over it.

Bulldog, my shifter is exactly like the one in your picture. The lever itself is a different shape, but the guts are identical. The "plate holder" is the part brazed right to my frame.

Rmfnla, that is a really clean looking installation.

Thanks for the input, everyone. I'm going to buy the shifters and see if they come with housing stops. If not, I'll order something like the ones pictured, or maybe some plastic ones I saw at Bike Recyclery.

Every aftermarket/upgrade set of Shimano brifters came with a pair of those downtube housing stops bulldog1935 pictured so most bike shops will have a bunch of surplus sets. Ask around and you might get a set free or at very low cost.

Right; I forgot that "brifters" do not have shift cable adjusters. I ride flat-bar so my shifters do.

Don't see any need for redundancy, tho...

I appreciate all the help people offered here. I'll post a follow-up just in case someone searches for info on this topic in the future.

For various reasons, I've decided to install bar-end shifters instead of STI. They're on order and should be in my mailbox in a week or so. Obviously, I still need the housing stops.

The shifters do indeed come with cables, housing stops, everything needed for proper installation.

And it turns out my bike has standard shifter bosses/studs brazed onto the downtube. Those funky, splined "plate holder" pieces shown in the picture above were simply pressed on over the studs. A little careful prying with a screwdriver easily freed them.

Now I'm super excited to get the bike all set up how I want. It's a good bike now, and will be even better with the new levers.

thanks for posting the follow-up