Shimano FAQ for dummies

[flipwils11]

OK, bumping this thread to clarify what I have currently. This isn't the original derailer for my bike (a 1994 Stumpjumper FS) as I replaced with this XT version around 1996. Seems to fit as this is a FD-M739 (read the model # off the unit) which seems to fit when I recall upgrading to this XT one.

So it's a bottom pull, but what about the clamp? My Stumpjumper is a steel frame but I see 31.8 clamps out there, 28.6, etc. Which one is the clamp that will fit my bike (I'm still looking at XTR parts on ebay).

 

[Charlieboy28]

28.6

 

[FluffyChicken]

That's a bottom pull/top-swing mech.

The marks above it I assume from the original mech would have been a traditional/bottom-swing mech.

The numbers you are talking about are the diameter of the tubing, measure it with something like vernier callipers or remember the gap where the clamp bolts, take it of, make the gap again and use a ruler.

or quite often it's stamped on the band somewhere.

 

[FluffyChicken]

Now according to this
http://www.bikepedia.com/QuickBike/Bike ... &Type=bike

it originally had Shimano Deore LX and would have looked like this (using info http://www.fa-technik.adfc.de/Herstelle ... en.html#94 ) and image search for FD-M560 (M561 is top pull) the other 'modern' style currently on your bike hadn't been introduced by then.

 

[FluffyChicken]

Oh and a nice place to see what shimano (and other parts) look like is this Euro-Asia Imports site. (linking to front mechs for you)
http://www.euroasiaimports.com/productc ... -c1611.htm

 

[Anthony]

OK, bumping this thread to clarify what I have currently. This isn't the original derailer for my bike (a 1994 Stumpjumper FS) as I replaced with this XT version around 1996. Seems to fit as this is a FD-M739 (read the model # off the unit) which seems to fit when I recall upgrading to this XT one.

So it's a bottom pull, but what about the clamp? My Stumpjumper is a steel frame but I see 31.8 clamps out there, 28.6, etc. Which one is the clamp that will fit my bike (I'm still looking at XTR parts on ebay).

As Ben says, your bike must originally have had a conventional-swing (high band) fm, as top-swing (low band) didn't come out until 1996. If you find the current fm works and the clamping position is sound, then there is no reason to change.

On many Tange Prestige frames however, you can't fit a top-swing mech as the seat tube was externally butted at the base, so a low clamp won't fit. I don't know what seat tube they used for the 94 Stumpjumper, but yours seems if anything to taper inwards at the base. If it does, the fit of the clamp may be quite marginal. Not necessarily a problem, as the tube must be internally butted at that point, but nevertheless it could argue for fitting a conventional-swing mech.

 

[flipwils11]

Bumping what has become my Shimano questions thread with another one, this time on my 1995 Stumpjumper everyday rider project. (thread is here: http://www.retrobike.co.uk/forum/viewto ... 82c92ae45a)

It has the original 1995 XT rear derailer and the grip shift 800 shifters, which are 8speed. The rear hub is the original as well, LX. My question is I was planning to convert it to LX 7speed brake/shifter pods (LX ST-M560) but I'm unsure of what I can do with the 8speed rear setup. Any idea if I can use a 7 speed rear cassette with the XT (1995 era) derailler and LX rear hub?

BTW the answers have helped me a ton so I really appreciate the time and responses from everyone!

 

[Neil]

Bumping what has become my Shimano questions thread with another one, this time on my 1995 Stumpjumper everyday rider project. (thread is here: http://www.retrobike.co.uk/forum/viewto ... 82c92ae45a)

It has the original 1995 XT rear derailer and the grip shift 800 shifters, which are 8speed. The rear hub is the original as well, LX. My question is I was planning to convert it to LX 7speed brake/shifter pods (LX ST-M560) but I'm unsure of what I can do with the 8speed rear setup. Any idea if I can use a 7 speed rear cassette with the XT (1995 era) derailler and LX rear hub?

BTW the answers have helped me a ton so I really appreciate the time and responses from everyone!

The mech should be fine.

Although make sure you've got the mech stop points done accurately.

In terms of cassette, a spacer should be all that's required - as you're effectively going backwards in compatibility, and using a spacer, my addled brain suggests no need to change the dishing of the rear wheel.

 

[hydorah]

This is my favourite resource for dating bicycle bits:

http://www.vintage-trek.com/component_dates.htm

Just thought I'd chuck that into the pile of excellent resources already sign posted

 

[flipwils11]

Re:

Hey guys, me again. Thanks to this helpful thread and all the responses, I know the top swing, bottom pull XTR M900 derailler that I need to buy. I just need to hit the buy it now button on fleabay.

For my 1994 Stumpjumper FS, the green bike pictured in this thread, I'm assembling a parts list to convert it to M900 XTR, leaving the cranks, headset, and brakes alone since I have upgraded parts there already that I'm keeping. Here's what I have so far, looking for input on the bottom bracket (I've read the Sheldonbrown website but it's difficult to get to the answer I'm looking for).

I'm looking for a long cage rear derailer, M900, that seems simple enough, but not sure which cassette to get. Are all 8 speed XTR cassettes created equal to fit my Ringle rear hub? I purchased a new old stock set of M910 shifter/brake levers (I like the gear windows) so I have those read. And as I said I know the front derailler I need. My last question is on the bottom bracket.

I purchased a brand new XTR UN91 "107mm-68mm" on ebay and probably should have researched first before I bought it. I am hoping that a) it's compatible with my 1994 steel framed stumpjumper for width and b) that the spindle size is what I need, given that my bike has Raceface cranks circa 1996 or so when I added them. The chainstay length seems to match the original Shimano LX (107-113) that my bike came with. What's the best way to decipher this compatibility equation on this XTR bottom bracket? Are there numbers on the cranks I should be looking for that will give me specs to solve for the compatibility?