Chainring BCD Chart
 

I know most of you know how to measure for proper chainring size, but here is for those who do not. I hope this is useful to someone.:)
http://i131.photobucket.com/albums/p...ainringBCD.gif

Thanks,

I was just going to look that up on Sheldon Brown's site, but this one is a nice printable version. Good to make this one a sticky.

Tom

that does seem handy. there was a similar post a few weeks ago aswell.

personally I would love to find one of these tools. I inquired to Park about them but it is no longer made. Park did tell me that since all new cranks are 4 bolt (yes 4 bolts on the chainwheels) you didn't need one. a quick look arouind a bike shop the other day I saw only 5 bolt cranks. they must be C&V bikes then LOL

http://www.bikeforums.net/attachment...6&d=1293202219

Your welcome..... If this helps just one person it was worth it, and now it was.

1.7x(c-c distance) for 5 bolt cranks

If the person trying to figure out what size chainring they have does not know how to, this may confuse them even further, as this method is never an exact figure. Example------ 1.7 X 76.4 = 129.88 The correct answer is 130 BCD....... Some people rather just see it in black and white rather then have to figure it out on paper.

I always hate it when I get my 129.88 BCD rings mixed up with my 130 BCD rings.

Believe it or not, some people would be confused........ A lot of bicycle measurements are confusing enough to some people without giving them something else to figure out. If anyone can use this chart great........ if not that's fine too.