Jump to content

Dura Ace - 7900 casette on 7800 groupset


Tjokkits

Recommended Posts

Hi guys I now need to replace my DA casette so I have the 7800 and those casettes were discontinued one now has to use the 7900, only thing they say 11-27 and 11-28 wont work on 7800, but i saw on some overseas forums some people did it and it worked. So before I fork out cash is there any hubbers who tried this, and what was the outcome?

 

Thanks

Link to comment
Share on other sites

The Shimano Dura Ace CS-7900 Cassette is compatible with the Dura Ace RD-7900 rear derailleur and the RD-7800 rear derailleur except for 11-27 and 11-28 . The RD-7800 rear derailleur does not have ample chain wrap capacity to handle the CS-7900 in 11-27 and 11-28. These cassettes must be used with the RD-7900. The CS-7900 is optimized for the Dura Ace CN-7900 chain, but it is compatible with the Dura Ace CN-7801 chain.

Link to comment
Share on other sites

The Shimano Dura Ace CS-7900 Cassette is compatible with the Dura Ace RD-7900 rear derailleur and the RD-7800 rear derailleur except for 11-27 and 11-28 . The RD-7800 rear derailleur does not have ample chain wrap capacity to handle the CS-7900 in 11-27 and 11-28. These cassettes must be used with the RD-7900. The CS-7900 is optimized for the Dura Ace CN-7900 chain, but it is compatible with the Dura Ace CN-7801 chain.

 

Sounds like a whole lot of marketing to get you to buy a new RD. Unless the 7900 is actually shorter than the 7800? Which I doubt

 

Some time ago I was told that I could not use a 9speed Dura Ace RD with a 10 speed grouppo ... after installing it I went back to show them it works perfectly. The speed of an RD is determined by the shifters, nothing else! The shift increments differ from 9 to 10 speed.

And the total width of the cassette between 9 & 10 or 11 speed cassettes has not changed.

 

That 9 speed RD of mine will be able to handle 11 speed cassette, no problem.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Settings My Forum Content My Followed Content Forum Settings Ad Messages My Ads My Favourites My Saved Alerts My Pay Deals Help Logout