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Shimano component compatability (kinda long)(3 posts)

Shimano component compatability (kinda long)Kurt H
Aug 2, 2002 6:32 AM
Hey folks,
I'm rounding up all of the spare parts in my bin in the hopes of building up a frame this weekend and am left with a few compatability questions. I realize I can probably find the answers to all of these through trial and error, but this just seems a heck of a lot easier :-)

Here's what I'm thinking of putting together, but am not sure it will all work:
Frame: Steel "all-rounder" - think Bridgestone XO-1, 26" wheels, canti studs, but pretty much road geometry.
Wheels: Off my old MTB (Shimano 8/9), add an Ultegra 12-27 cassette and semi-slick tires
Cranks: Hopefully a road triple I have sitting in the bin, but it may not clear the chainstays. I'm thinking of falling back to 26(28?)/38/48 rings to gain extra clearance and give myself a little lower range. Failing that, I'll pull out an old LX crankset.
Brakes: Either Avid Shorty's if I can use STI (my preference), or I can fall back to Canti's and a canti compatable brake levers.
Front and rear derailleurs: 9-speed XT

But now, my questions:
1) Will Shimano 8/9 speed MTB hubs fit a 9 speed Shimano road cassette? I'm not overly fond of the gearing options open for MTB cassettes (too wide) since this will see a good bit of time on either roads or fire roads and I have a triple to fall back on if it gets rough or I get tired.
2) Will XT front and rear derailleurs shift using STI, or do I have to use bar-ends or downtube shifters?
3) Does 9 speed XT use the same indexing as 9 speed road (i.e. if I can't use 9 speed STI, can I at least use 9 speed indexed bar-ends)?
4) If I need to use an LX crank, I don't have a spare MTB BB. Are square-spindled Shimano BB's the same for road and MTB, assuming the axle lengths are compatable to provide a workable chainline?

Thanks for the advice!
re: Shimano component compatability (kinda long)Spoke Wrench
Aug 2, 2002 7:47 AM
I love doing projects like this, but you have to be real careful or the bits and bobs that you have to buy to go with the parts you already have can approach the cost of a new bike.

1. A road cassette will fit the hub. A better question is, "will the hub fit the frame?" Modern mountain bike hubs are 135mm OLD, Most road bikes are 130mm, older road bikes were 126mm. I don't know what your frame is.

2. STI will shift the derailleurs, but I don't think an XT derailleur will work very well with road gearing unless it's a real old (pre compact drive) one. The issue is the derailleur cage matching the arc of the 48 tooth big ring. The newer ones are only rated for 44 teeth.

3. No problem, especially since they'll have easier to adjust friction shifting fronts. The front STI shifter, even when all of the parts match, is lots harder to get set up satisfactorily than the rear.

4. Actually they're the same part number - kinda. Your bottom bracket also has to match the shell width on the frame. Road and mountain frames tend to be different. Depending on how old your LX crank is, you probably need either a 68 shell width 110 spindle length, or a 73 X 113.

Good luck.
re: Shimano component compatabilityChen2
Aug 2, 2002 10:04 AM
I've had no success with replacing triple chain rings with aftermarket or generic rings. I think it's important that the middle ring be designed to run with a triple. That severally limits your options on road triple cranks. There use to be an RSX triple crank-set available with smaller rings (48-36-28 I think) but haven't seen any for sale lately.