STI shifter problem
 

I have a set of old Shimano Sora 9-speed shifters that I used on a bike project I just got done putting together and I'm having trouble getting the right one to index properly. When shifting from high gear (small cog) to low gear (large cog) the shifter doesn't want to move the derailleur enough on each shift to line the derailleur pulleys up with each cog, except for the last shift which all of a sudden brings the derailleur to where it should be. Then shifting the other way (low gear to high gear) it does just the opposite - it moves the derailleur too much with each shift.

I've worked and worked with the cable tension adjustment and the derailleur adjustments, as well as spraying a bunch of WD-40 in the shifter mechanism in case something is gummed up, but I still get the same result. It's as if there is a return spring in the ratcheting mechanism that has lost its tension and so the shifting up and down isn't balanced.

I've read that Shimano 9-speed STI's aren't very reliable and that's why the people who rebuild STI's won't even mess with them, and that STI's in general are not very long lasting compared with non-ratcheting types of shifters. Is this this STI kaput or can it be saved? The left one isn't in the greatest of shape, too, so it's not the end of the world if I have to replace it. These shifters were in a bunch of parts I had been given to from a bike that was salvaged from Hurricane Harvey. Ordinarily I'm not a huge fan of STI shifters - mainly because I think they look ugly as sin - but since they were a gift I thought I'd try to make them work.

This is incorrect. Check that the inner cable isn't frayed or otherwise impeded in it's movement through the housing or in the shifter itself. The symptoms actually sound more like an incompatible rear derailleur but I assume you've ruled that out. Good luck!

The cables and housing are new so it can't be that. The derailleur and shifters both came from the same bike (to my knowledge) which must have been working at one time. The derailleur is Shimano Tiagra. I thought basically all Shimano indexed derailleurs and shifters, except Dura Ace, were compatible as long as you used the right cassette (according to Sheldon Brown). Seems to me not shifting evenly up and down with new cables and housing indicated the ratcheting mechanism inside the shifter is malfunctioning, because it's not pulling and releasing the cable evenly..

One more thing to add - the new shifting cable housing I used is indexed shifting housing, not just plain spiral wound housing like brake cable housing.

Nope. Times have changed. Tiagra 4700 is not compatible and it’s been over 25 years since Dura Ace had the odd shifter pull/RD actuation ratio.

And… nearly all new double road FD’s won’t work with older index shifters; even the lowly Claris

John

I was mainly thinking of parts in that general era of cycling. Since I could care less about new bikes like they sell at bike stores or online nowadays I have no idea of what goes with what of them.

Weird. I love 6500 and 5500 stuff, it's all worked great for me. Shifters work with road and MTB rear derailleurs from back then.

I was mainly thinking that 9 speed Sora isn’t close to the Dura Ace 74XX series era which is why I asked about your Tiagra RD.

John

From what I've read Sora and Tiagra were closely related to each other, with Sora usually being finished in black and Tiagra being somewhat more polished. That could be why there were both types of parts on the salvage bike, which I believe was some type of lower to mid-range Specialized bike.

At this point, if you are confident in cables, compatibility and setup, you are pretty much left with a dead shifter. I suppose not too surprising since it went through a hurricane. You might check out Microshift for an inexpensive replacement.

Remove the cable from the RD. Holding light tension on the cable with one hand, operate the shifter up and down several times, and count the clicks in each direction. If you get eight distinct click both ways and feel the cable moving with each click, the shifter is okay. There's only one ratchet mechanism for up and down, and it can't pull a different length of cable in different directions.

The pawl that arrests the downshift may be sticking, skipping a click, and you'll feel that with this test. If lubrication doesn't fix it, you can try removing the cover to access the pawl, and work it with a dental pick, and lubricate the shaft with penetrating oil. Worst case you'll break it and then you can buy a replacement.

I haven't had to take apart a Sora 9 yet (mine have been very reliable so far), but other shifters need some substantial disassembly to expose the ratchet mechanism, like removing the lever from the body, and the main torsion spring from the shaft. Reassembly is sometimes tricky, more like clock work. I imagine there's a MeTube video somewhere, or something on SnapFace.

agreed… I have 6500 shifters shifting an m737 xt rear over 9 speeds and a m901 xtr front over a triple on my 91 volpe. Shifts flawlessly.

That is a great setup. Did you do anything special to get the m901 FD to shift with a road triple shifter?

John

Okay I'll give that a try. Thanks.

The low gear is the only one that works because you are pushing that final gear into the stop. Go to your high gear, click the shift once and then adjust it until it is in the second gear with no chain noise.

I got it working finally. Seems to bee indexing just fine now. Thanks for all the help.

I had to get a barrel adjuster… but I think with a shimano crankset it would work flawlessly. I have a sugino with different spacing between the rings, and it works well, with 2 positions in the middle
ring for trimming

That is good to know. I’m running an M910 RD and an M900 FD with a 6500 triple crank, but the front is still friction.

I have a set of STi shifters waiting to be installed but have been concerned that the left would not index with the M900 FD.

I did a temporary fix with a pair of Kelly Take-Offs to get the shifters up to the handlebars.

John

https://cimg2.ibsrv.net/gimg/bikefor...5d30eb042.jpeg
Here’s that bike.

both my main rides have non standard indexing setups… my de Rosa has 8!speed Sachs shifting over a 7 speed shimano freewheel.

Re. "dead' shifter

The only failure that commonly occurs on STI levers is the failure of the ratchet mechanism - either won't engage to move the cable, won't hold the cable in place with a click. If the shifter is making the correct number of clicks, and pulling and releasing cable as you shift, then the problem is elsewhere, as OP discovered. The spacing between the clicks does not change or wear over time such that shifting is affected, in my experience.