Can I mix DuraAce 7800 and 7900 parts?

Paul Hough

I need some advice from any technical whizzes out there!  My race bike has all 7900 on it, but I need a 12-27 cassette for IMCDA.   The 7900 cassette is running $220 on sale right now, but I can get a 7800 12-27 for $100.   Is the machining that much different that it will cause shifting problems if I mismatch the parts?   Frankly, I would rather pay the difference if there is any degradation in performance, but the weight savings is insignificant.   Thoughts?

Nemo Brauch

 Usually you can mix & match the cassettes, but double check the Shimano Compatibility chart just to be sure.  The bigger issue is more likely going to be the series of your rear dérailleur.

bike.shimano.com/publish/content/gl...0Chart.pdf

 

 

Paul Hough

Nemo - many thanks! I didn't even know there was such a chart, and while it looks like you need a degree in Shimano to read it, I believe the answer is yes, the RD 7900 will sync up with a 7800 cassette. r/Paul

Chris G

It will work fine.