1994 Epic Chainring BCD?
 

How do I figure out the front chainring BCD on my 1994 Specialized Epic? I've been thinking about replacing the 42 tooth chainring with a 39.

I can get a new 39 tooth Sora chainring with a 110 BCD for under $17. The Sora is for a 9 speed chain, but my bike is an 8 speed. Should it still work?

Your crank probably has a 130 mm BCD. However, a bike that old may not still have the original crankset

Search: Sheldon BCD.

Thanks

Thanks, I don't think it's original. It is a Suntour Superb Pro. I'll check that Sheldon cite for info.
Jeff

If it's this one, 42 is about as small as you can go*: VeloBase.com - Component: SunTour CW-5000, Superbe Pro


* a 41T has existed, but wouldn't help much if you found one.

I think your right. 42 is probably the lowest you can go without a big cost. How about adding a larger cog on the rear? Freehubs are easy and freewheels can be changed with a little effort.

Or measure between the chainring holes and multiply by 1.701 for a 5 hole chainring. The Suntour cranks are listed in Brown's crib sheet

You can see how close the bolts are to the edge , teeth ? y/n? ...

144 bcd, you buy a new crankset , 42 is already minimum ..

135- 39, 130-38, 110-34 and etc..





....

https://cimg2.ibsrv.net/gimg/bikefor...c118caa7c5.jpg
https://cimg5.ibsrv.net/gimg/bikefor...d525063099.jpg

I measured approximately 75 mm between bolts. 75 x 1.701 = 127.6. Is the Sora chainring compatible with this style of chainring? Thanks everybody!

(Looking at the first picture, I notice the large chainring has PCD 130 printed on it! :o - Ugh!)

:lol: There ya go!

Going back to the original question: The make and model of the bike turns out to be irrelevant. The actual crank on the bike is useful information as is information found on the chainrings of that crank. Turns out that a Sora 110 BCD chainring will not work. $17 is an attractive price, but the make, model, and year of the bike was misleading information

Yea Bike brand is just paint on the frame, Everything else is bought by the factory from other companies..

if the component part order is big enough , the supplier may put the brand name of the customer on it...