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Chain ring size(5 posts)

Chain ring sizelikesbikes
May 30, 2001 9:58 PM
What is the standard size of a modern road bikes big and little chain rings? How much difference can a derailure handle?

I am wanting to get lower gearing for hills by way of either a smaller chainring, or a different cassete. I'm trying to stay away from a tripple, though it might be cheaper than buying a new cassete and a different chain ring.

Anybody got thoughts on this?
re: Chain ring sizePingPong
May 31, 2001 2:37 AM
Standard used to be 52-42, but now th wider 53 -39 is more common.

If you have shimano cranks you can put a 38 on the small ring, -campag 39. I have gone for this 38 option on my road bike and I guess it keeps me spinning up the hills a fraction longer.

As you can see, there is not much scope with the chainrings, the change to a 38 is only worth it if your 39 is getting worn.

I had a similar problem to you and put a cassette with a 11-28 on the back which helped a bit, but became frustrating on flatter terrain due to the increased gaps between cogs. It was a seven speed bike, which meant dropping cadence by about 15 to 20 rpm for an upshift.
If you have 9speed the often discussed 12-27 cassette might do the job without leaving too many gaps.

There is a lot of talk on this board about toughing it out in pro style gears in order to get stronger, but it is better to try and match their riding style - ie keep the pedals turning over quickly than matching their gear selections. A triple may be the best way to do this.

When I last visitied the alps a large portion of riders had triples, the majority of those seen stopped at the roadside grimacing had doubles.
check this out !?Matrix
May 31, 2001 7:08 AM
I'm running a singlespped Zurich 40-15 ..but must use gears..SO i'm going to XT cassette 12-32 & XT r derailer & just a 40 tooth front....a 32 ring rear can climb with 46 tooth front :the same as a 40front-26 rear...
I just don't like but one chainring up front....
re: Chain ring sizemr tornado head
Jun 3, 2001 11:34 AM
I went to an older Sugino crank with a smalller BCD, and managed (somehow) in various trades and deals to end up with a 36 tooth inner ring to fit.

This, with the wider (13-28 6 speed rear) gets me up most hills. However, I *am* eyeing a triple up front and a closer (11-25 or so) gearing in back due to the limitations in gearing jumps this proposes.
One Possible Snag.....grz mnky
Jun 5, 2001 4:43 PM
The crank with the smaller BCD is not likely to have the 9 speed spacing, so a 9 sp. chain is not going to shift cleanly. May be a problem, or not.