kimconyc

I have a wheel with a Dura Ace 7800 rear hub (older model with taller splines) and I know that I can only put a Shimano 10 speed cassette on there.

My question is whether or not I can put the newer DA 7900 series cassette or Ulegra 6700 series on there.

Does anyone know if the new Shimano cassettes are compatible with the old(er) 7800 rear hub?

Jed19

So what are people like us who have these hubs suppose to do? Is Shimano gonna keep making the 5600, 6600 and 7800 cassettes, or are we
screw*d?

HillRider

The hub is certainly an orphan but has Shimano gone back to the shorter splines on all of it's 10-speed cassettes too? I don't think they have and any model Shimano 10-speed cassette should fit later hubs. I know 105 5600-series and Ultegra 6600-series cassettes fit the 7800 Dura Ace hubs and Dura Ace and Ultegra wheel sets that were "10-speed-only".

operator

Not sure anymore, you confused me. Post deleted. Going to confirm at the shop.

rydaddy

Here's a shot of the 7900 cassette. Hard to tell if these work for tall splines or not (they appear tall). I hope the newer 10-speed cassettes work since I just built a 7800 set of hubs and they should last a looooong time...

Davet

The "new" 6700/7900 series cassettes will fit on the "old" style 8/9 speed hubs but not the 7800 10-speed only hubs. The 10-speed only hubs have taller splines which aren't compatible with 8/9 speed cassettes. Shimano has abandoned the '10 only' hub configuration and has gone back to the 8/9 configuration for all their new hubs/cassettes.

HillRider

So the only cassettes that will fit a 7800-series hub and the former Dura Ace and Ultegra wheel sets are 7800, 5600 and 6600-series? Better stock up now if you have one of the 10-speed only hubs or wheels!

I'd be more annoyed with Shimano for this if Campy hadn't done so much of the same thing. A pox on both their houses!

Jed19

I have two sets of the 7800-series hub laced to Mavic Open Pro rims, which I like very much . Should I try selling them for top dollar now, before I get really screw*d looking for replacement cassettes?

paisan

I'd look into swapping out cassette bodies before I sold the wheels or stocked up on cassette's. I'm not sure if it's possible but it would be alot cheaper than either of your other options.

Jed19

I just talked to Technical Support at Shimano America. I was informed that there should be no issue(s) with the new 10-Speed cassettes running on 7800-Series hub.

On the other hand, the freehub body is not interchangeable, in the sense that a 7900 freehub body won't be able to fit on a 7800 hub.

So, according to Shimano, no need to get rid of my 7800-hub wheelsets, or stock up on 5600/6600/7800 cassettes.

rydaddy

I was searching and came across this from easton. It seems the newer cassettes will work on Shimano 10 hubs.

https://www.eastonbike.com/downloadab...ty%20Chart.pdf

kimconyc

I was in the same boat as you. I really didn't want to re-lace the wheels to different hubs.

Thanks for all the great information. Much appreciated!

HillRider

Hmmm, the 7900 freehub body won't work on a 7800-series hub but I wonder if the Dura Ace 7700 Ti freehub body or earlier Ultegra 6500 body would.

kimconyc

Wait, are you saying that the 7900 cassette won't fit on a 7800 hub? I thought we cleared this up already. Hmm...

The DA 7800 hub as opposed to the newer DA 7850 hub has taller splines and is only 10-speed Shimano compatible (unless you physically modify another cassette to make it fit).

My OP was to verify that the newer Shimano cassettes (DA 7900 and Ultegra 6700, specifically) will fit on a DA 7800 hub. I'm totally confused now again...

rydaddy

HillRider's talking about switching the freehub body on a 7800 hub so that it will take all types of cassettes. My understanding is that it's not possible. Doesn't change the answer you were looking for. The newer cassettes should fit.

davidad

The 7800 DA freehub was a mistake and shi_mano knew it rather quickly. They went to an inboard bearing and oversize aluminum axle to make a lighter hub.
The whole idea of the freehub was to move the rt side bearings outboard to prevent bent and broken axles.
The freehub bodies of the older and newer hubs are not interchangeable.

HillRider

Yeah, I forgot the major configuration change they used to fit the Al freehub body. So much for grafting on a different freehub body.