krems81 

Hi,

I have a 135bcd shimano dura ace crankset, and since campy's chainrings are all 135bcd, I'm wondering if its normal and kosher to put campy chainrings on this crank? Would there be any compatibility issues?

Thanks,
Brian

HillRider

Are you very sure about the BCD on those Dura Ace chainrings? Every Shimano outer and middle road chainring and crank I've ever seen has a bcd of 130mm except the compact rings which are 110 mm. I've never seen any Shimano cranks with a 135 mm bcd.

LWaB

Shimano has never produced a 135 BCD crank.

krems81 

Interesting. I will have to remeasure. Thanks.

urbanknight

Or if you have chainrings on the crankset right now, see if the BCD is stamped like it usually is.

Peter Jon White

Since their introduction in the early 1970s Dura Ace cranks have had 130mm bolt circle chainrings. There is not now nor has there ever been any 135mm Shimano chainring.

HillRider

I'm not sure about every maker but I know neither Campy nor Shimano stamp the bcd on their chainrings. The rings are engraved with the maker's name, the tooth count and, more recently, whether for 9 or 10-speed but no bcd value.

If you are not sure, you have to measure the distance between bolt holes carefully and look up or calculate the bcd from that.

forensicchemist

and if I recall, Campy 130 BCD is not the same as Shimano 130 BCD: 1 bolt is slightly offset on the Campy making you use only campy chainrings.....

HillRider

Right idea but the wrong details. Campy does not, and AFAIK has never has made 130 mm bcd chainrings.

What you are thinking of is Campy's compact cranks with a nominal 110 mm bcd. Campy made the bolt circle 110 mm like everyone else BUT offset one bolt a bit so their rings wouldn't fit on any other 110 mm crank and no other 110 mm chainrings would fit on a Campy compact crank. Cute huh?

Again, IIRC, they only did this for the Record and Chorus compact cranks. Centaur, etc. did use a standard 110 mm bcd and would accept other makers rings.

K6-III

The only other manufacturer that commonly uses 135mm BCD is Miche.

forensicchemist

Yea, thats what it is.....thanks HillRider....I knew there was something there, just not positive what it was. Thanks for clearing it up...

spin-n-grin

Heard the same, but don't remember from where. One of the holes is millimeters shy of a perfect bolt circle.

forensicchemist

Re-read Hillriders post...he's got it right.