No one makes 50/34 replacement chainrings?
07-22-05 | 12:34 PM
#1
Thread Starter
Race to train
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From: suffering on the back
No one makes 50/34 replacement chainrings?
I was looking at getting a compact crankset and was just wondering why nobody makes a replacement chainring for standard shimano cranks? any insight?
07-22-05 | 12:40 PM
#3
Cannondale Shill
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From: Kingston, ON, CAN.
Bikes: '06 CAAD8, SRAM Rival/Force and fixie of unknown origin
Because the bolt-circle diameter is different. The standard is 130mm and will only let you go down to a ring with a certain number of teeth (38 I think?) whereas compact uses a 110mm BCD and will let you go smaller.
07-22-05 | 03:22 PM
#5
Burnin' and Lootin'
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From: SoCA
07-22-05 | 03:34 PM
#6
Thread Starter
Race to train
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From: suffering on the back
Originally Posted by ggg300
07-22-05 | 03:45 PM
#7
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From: Burlingame, CA
The 50 tooth could be done, but the 34 tooth is physically impossible to do because of the 130mm BCD, thus the compact crank size of 110m BCD. SO the limiting factor actually is the 20mm difference between the BCD's.
07-22-05 | 03:58 PM
#8
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From: arlington, VA
Originally Posted by hmai18
Because the bolt-circle diameter is different. The standard is 130mm and will only let you go down to a ring with a certain number of teeth (38 I think?) whereas compact uses a 110mm BCD and will let you go smaller.
It used to be available by order from their site at www. chainrings.com, but it seems to have dropped off.
Since 35 is a multiple of 5, I would think that same approach would work for well for a 35 on a 5 bolt 130 bcd pattern, but nobody else makes anything smaller than 38T in 130 bcd. Maybe the folks at Warhawk already tried it. I work fairly close to them and sometime this year I'm going to custom order something from them, maybe I'll get some insight when I stop in.
If one has a 35T 110 or 94, maybe one could give it a try drilling 5 holes.
If not one could obtain or make a spider to mount a 110 BCD ring on 130 bcd cranks.
07-22-05 | 04:20 PM
#9
Burnin' and Lootin'
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From: SoCA
Originally Posted by jrennie
i have read the post on compact cranks, thats what peaked my interest, I was just wondering why you couldn't simply bolt a 50 tooth and a 34 to existing cranks for the same effect and why no companys made any.
3rd paragraph sets out size, not busting your balls or anything here
You could put a 50 on and a 38 w/o too much trouble but other than that...it just is not practical (i.e finding it/ordering it/and the price for it) with the standard cranks of today. A compact could go both ways, however. All of this is in that thread or in a link there. enjoy.
