RubeRad

Not much going on in BF/BM right now, so maybe a good time to ask a dumb question.

I have a specific question of the form "I currently have this part and that part, but I want to swap that part out for nother part -- will it be compatible"?

I tried searching, but didn't find a specific answer to my specific question (it's probably out there, but a lot of stuff comes up with the keywords "cassette road mountain"!!) And I looked in the stickies as well.

So I have a more general question. Is there a BF post or some other website out there with a grand-unified-theory bicycle compatibility drivetrain chart?

It would be really cool if somebody could make a website that held a database of all known (or at least common to get started) bicycle drivetrain parts and their specs (#cogs/rings, #teeth, cable pulls, long/short cage, wrap capacity, friction/indexing, etc.) so that anybody could come along and go through a bunch of menus to find a FD, RD, crankset, chain, shifters, and get a compatibility report.

If such a website doesn't exist, I should start it. I'd make tons from ad revenue (and probably shut down this forum!) Or maybe instead of a website, I could make an app and sell it for a few bucks.


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For those who are curious, here's my specific question:

I built up my crosscheck by stealing every component possible from my Trek 1000; so it currently has Sora 8sp brifters, 52/42/30 crankset, Shimano FD (2203?), 11-28 8sp cassette, Tiagra 9sp RD (long cage I think? how long is long? mine is about 76mm between pulley-centers)

I plan to upgrade to a 2x9 drivetrain in this progression (one step at a time, to limit cash outflow while maintaining a fully-working bike)

1. Replace brifters with Retroshift CX2 9-sp in friction mode.
2. Replace crankset with Shimano 600 double (52/39 I think) (I have this already, and I also have a nice sugino square taper BB ready to replace the current octalink)
3. Replace the cassette with 9sp 11-34 or 12-36 so I can switch the Retroshifts to their 9sp indexing (note left/FD is friction-only, so no issues there)

(I might have to reverse the order of 2&3, because I spend a fair amount of time in the granny gear already, and I'm not sure I could survive the temporary chainring jump from 30-39!)

So my question is, it seems most 11-34 or 12-36 are labeled "Mountain". When it comes to cassettes, are all 9sp shimano made equal, so swapping compatibility is merely a question of chain wrap and RD take-up capacity? Or will I have to get a mountain RD at the same time as the cassette (and how will that play with 9-sp indexing from the shifter?)

fietsbob

rear use shimano bar end for the lever, match the speed count on indexed,
Its the spacing between the cogs , the diameter is the tooth count, MTB RD should rise to clear the largest cog,
if not B screw increases that.
friction, speed count. it does not matter..

as far as Free websites that take hundreds of hours to develop, be my guest.

HillRider

You might have problems with #1 and #3. I have Retroshift CX2 10-speed shifters on one bike and the right shifter is index only, no friction position. The Microshift shifters they use are available in both index-only and index/friction switchable form and Retroshift seems to use the index only ones. Check with Retroshift but you may need to buy their plain brake lever/shift mounts and install your own Shimano downtube or barend shift levers to them get the friction option.

ThermionicScott 

I don't think the 11-34 or 12-36 cassettes with work with that rear derailleur. The Shimano techdoc specifies a maximum cog of 27T, and although there are reports of people having success with a 30 or 32, I think that's gotta be pushing the limit.

Best plan would be to get an MTB RD (or whatever SRAM RD handles big cogs) and stick with friction mode.

Bill Kapaun

9 speed Shimano/SRAM is compatible with 9 speed Shimano/SRAM.
The terms Mountain & Road are somewhat nebulous, referring to the the the tooth counts.
Road being close spaced and typically not exceeding a 25/27T largest cog, while Mountain going up to 30T+ largest cogs. Typically, you wouldn't see an 11T cog on a "road" cassette. Anything can happen though.
I use a 12-21 9 speed on my 86 Rockhopper. Although it "used to be" a Mountain bike, it now has a rack, rear baskets & fenders and is used as a grocery getter on flat pavement.

".....When it comes to cassettes, are all 9sp shimano made equal, so swapping compatibility is merely a question of chain wrap and RD take-up capacity?"

And max cog size.

RubeRad

You're right; I had somehow gotten it into my head that retroshifts were friction only left and friction/index right, but the picture clearly shows no dingle to switch friction/index.

Nuts. Looks like I would have to buy retroshifts, cassette, and RD all at once.

I guess, switching the plan to shimano barcons as fietsbob suggests, a new plan could be:

1. Shimano 9sp friction/index downtube/barcon shifters (crosscheck has downtube bosses!)
2. 9sp 11-34/12-36 cassette, mtn/touring RD (and chain) together
3. Retroshift CX2 with no levers.
*. Double crankset anytime after 1.

I kinda like that plan, as it puts the major purchase at the end rather than up front. I guess I'm on the hunt for some bar-end or downtube shift levers!