Change Shimano Compact rings to Standard

[ianMac]

I want to change my compact to 53/39 rings.

The only markings on the existing rings are 'Shimano 50-F' and 'Shimano SG-X 9S/10S 34-F'.

Anything I can find on the net talks about 'BCD' or 'PCD'...but this doesn't help me!

What chain rings are compatible? If there aren't any I am happy to replace the whole chainset if necessary, but again, which one?

Thanks for your help,

Ian

 

[smokeysmoo]

IIRC Compacts have a BCD of 110mm, and Doubles have a BCD of 130mm, therefore the rings don't interchange. I'm sure though you can get 52T 110mm BCD rings so you won't be far off.
Any rings with 110 BCD will be compatible

 

[HLaB]

Yip, the biggest you can go is 38/52 without changing your cranks. I'm currently running a 38/52 FSA compact.

 

[amaferanga]

I don't think there is a 38/52 limit with 110bcd. Why would that be?

If you don't believe me then have a look here: http://www.spacycles.co.uk/products.php?plid=m2b0s149p0

110 bcd outers up to 53 available and 110 bcd inners up to 44.

 

[accountantpete]

Go to eBay - there are more people doing the reverse (going to compact) so you will get a good price for the compact and a relatively cheap price for the standard.

 

[simon.r]

Anything I can find on the net talks about 'BCD' or 'PCD'...but this doesn't help me!

It's easy enough to work out the BCD of your existing chainrings:

http://sheldonbrown.com/gloss_bo-z.html

 

[ianMac]

Thanks everybody. Understand this now and got what I wanted from spa cycles!

 

[HLaB]

I don't think there is a 38/52 limit with 110bcd. Why would that be?

If you don't believe me then have a look here: http://www.spacycles.co.uk/products.php?plid=m2b0s149p0

110 bcd outers up to 53 available and 110 bcd inners up to 44.

Cheers, you learn something everyday I hadn't seen larger before but its good to know you get them.

 

[Deleted member 1258]

I'm on a compact chainset and run 42/50, I got my chainrings from here
http://www.dotbike.com/p/3593