Cyclocross - Has anyone installed a larger (44 T or greater) chainring on a 90's Trek Multitrack?
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03-27-12, 11:00 AM
From reading and internet research, it seems that the old 1990's cro-moly Trek multitracks are somewhat popular as a base for DIY cyclocross bikes so I'm going to ask this here.
Has anyone installed a crankset with a chainring larger than the 42t that seems to have been the norm on these bikes? It seems that some bikes have limitations on the largest chainrings they will accept and I'm thinking about getting a Shimano CX50 46/36 crankset installed as part of a complete upgrade on my Trek 730. I'm curious if anyone has installed a larger crankset and if it caused any problems.
03-27-12, 11:20 AM
I'm not sure if the new CX50 will fit, but you could always fit a Shimano Deore M591 Crankset (48/36/26) and remove the small chainring.
03-27-12, 03:19 PM
Does it look like it'll clear the chainstay?
I can't imagine, other than the chainring physically hitting the chianstay, that you'd have trouble going up two teeth. If you were headed to like a 53t chainring, and it STILL CLEARED the chainstay you might run into trouble with the shape of the FD, but for a 44? You're good to go.
I'm running a FSA Vero Compact 50/34T and even before I shimmed it over to a MTB chainline it cleared the chainsty just fine. Remember that the MultiTrack runs a 135mm mountain hub OLD so if you put a double on it you'll want to shim it over to 47.5mm (centered) or more or you might get the big chainring seriously rubbing on the chain when you have the chain on the small ring and anywhere near cross-chained in the 3 smallest cogs in back. Mine sure did!
03-27-12, 06:23 PM
What I'm looking for is a double crankset with a 9 or 10 cog cassette that will give me small cog jumps with as little chainline issues as possible. I don't know a lot about bicycle mechanics but it's my understanding that a double has fewer issues than a triple. I'm pretty committed to my old Trek right now so I'm doing research online to get a good idea what I want before I haul it down to the LBS.
I'm running a Sora 8-speed with the FSA crankset on my 720 and it seems to work pretty well.
It's a heavy pig (over 25lbs even with carbon bars and stem) but it rides pretty well. It's one heavy CroMo frame.
03-27-12, 06:43 PM
Fyi a 44t chainring is 7_1/4" across.. Diameter.. 48t is 1/2inch more
measure the clearance, where the chain line is ..
03-29-12, 09:58 AM
Mountain bikes have longer chainstays than CX bikes. Longer chainstays mitigate chainline issues.
I have a neo-retro road bike with long chainstays, 52/42/30 chainrings, and 12-26 8 speed cassette.
It can be ridden in the 52/26 combination with no issues, smooth and quiet.
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