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Hello All,
I know this is going to be a rather philosophical topic but I was curious over a couple of things that were proposed by a fellow trackie regarding components choices.

1. What is the advantage of using 3/32" over 1/8 chainrings, cogs, chains? I've heard weight and obviously width but any others?

2. Would using a smaller chainring/cog combo be better for acceleration over a standard combo for a given gear ratio? For example would a 42x12 be better than a 49x14 combo for acceleration/efficiency/etc?

I am curious to what anybody has to say on this since on the road going from a 39x12 to a 53x16 seems to "feel" bigger in the larger chainring/cog combo (disregarding the fact that it IS only a little over 1" larger).

Is there any physics behind the two scenarios?

Any and all opinions would be very much appreciated.

Dan
 

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No Crybabies
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Smaller chain works with smaller (narrower) gears. May be a wider selection of what you want in one width or the other. I've found 3/32" to be quieter. I'm using a 1/8" Izumi chain now, and it's like a motorcycle chain - no way it could EVER fail, but it's beefy and kind of loud. After <a href="http://www.midcalracing.com/fixed/blownupcog.htm">totally exploding</a> a 3/32" cog on my fixed bike a couple of years ago, I went to 1/8" to be safer.

No difference in different sized sprockets for a given ratio. The only thing someone might suggest is that larger sprockets require the chain to bend slightly less, which might result in slightly lower friction. However, they also weigh more. In a blind test, no one could ever tell the difference. What's likely much more important is what gears are available for the ratio you want, given your crank BCD, and then what chain length do you want or need. Different sized sprockets for a given ratio will result in different chain lengths, if that matters.
 

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Old, slow, and fat.
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i must be the princess with the pea then, 'cause I swear that big chainrings and bigger cogs feel different than the similar gear inch sizes with smaller rings and cogs.

Smoother somehow.

As for the rest of it, wel... As a trackie, I've run both 3/32 and 1/8 chains with little noticable difference between em. 3/32 is gonna weigh a titch less. If you're running road cranks (130/135 BCD vs. 144 BCD), rings for 1/8 rings may be harder to find.

YMMV

M
 

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Life is better on the big ring!

This isn't about friction or ratios or angles, it's a state of mind. Compacts have something to do with make-up or Corvairs, not cranksets or framesets.
 

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Given the same gear ratio, sensitive trackies often claim that running more teeth (49x14) run smoother and with less friction than (42x12). I might be able to tell the difference in teeth wear after several years (load is distributed over 63 teeth compared to 54), but I'm not sure I could tell the difference. 1/8 is more popular with sprinters while many pursuiters/ endurance riders go with 3/32, sometimes claiming there is less friction on a 3/32 drive train. I kind of doubt the difference is significant but I guess if you win by .01 seconds it might make a difference.
 
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