Chainring Compatibility Question.

[smokeysmoo]

Will Ultegra 6700 34/50 chainrings fit a Dura-Ace 7950 compact chainset?

 

[boydj]

As long as they have the same BCD - bolt circle diameter - you should be ok. 53/39 will be 130 bcd, and 50/34 will be 110 bcd.

 

[RecordAceFromNew]

You might want to give sjs a call, they seem to know a bit about cross compatibility per this.

While often true one should not rely on same bcd rings being always compatible. I can tell you that some of the xtr and xt rings e.g. are not interchangeable despite having the same bcd's because of the raised or recessed profile at the holes, or that Campag's 110mm bcd compact rings actually has one hole offset...

 

[Rob3rt]

You might want to give sjs a call, they seem to know a bit about cross compatibility per this.

While often true one should not rely on same bcd rings being always compatible. I can tell you that some of the xtr and xt rings e.g. are not interchangeable despite having the same bcd's because of the raised or recessed profile at the holes, or that Campag's 110mm bcd compact rings actually has one hole offset...

Correct. Similar with the new SRAM Red kit, the chainset has a hidden bolt behind the crank arm, should you use a different chainring, you would have to mount it off rotation to that it was designed for, meaning the chain catching pin between the crank arm and chainring would be placed elsewhere and thus not work if you drop the chain down there.

 

[fossyant]

Down side though is I recon it will look terrible - you've got very different surface treatments.

Praxis Works are making replacements

http://shop.praxis-works.com/DA7950-SETS_c11.htm