Which Groupset?

You could

No you couldn't. Look at the way the sprockets are grouped on DuraAce cassettes.

I am impressed that you think a 12-27 comes with a 29T sprocket, by the way.

Also, I answered this some days ago

But you could use the Campagnolo cassettes on Shimano yes?

Only if you have matching wheels. The sprocket spacing is now the same, but the cassette rotor splines are still different

As Ludwig points out, I was using two Campag cassettes, as the free hubs (often) are a simple swap, and I'm using a Chorus cassette with my 9070.

Hence the 29.

But you don't get your 16.

Oh no! it's the end of the world!

As Ludwig points out, I was using two Campag cassettes

Do you even Hippy? There's no way he's going to buy Campag.

I have 2005 ultegra 10sp (6600/6650?) on my bike. can I upgrade the shifters to the modern hood design (105?) and would that improve shifting?

Do you even Hippy? There's no way he's going to buy Campag.

Pfft, all the GT winners these days are using it.

I'm sure we'll read about Amey buying a Super Record groupset in the near future

^^ as long you find the hood more comfortable than the old one, you'll be fine.

If it doesn't feel good, redo the cable/housing.

I have 2005 ultegra 10sp (6600/6650?) on my bike. can I upgrade the shifters to the modern hood design (105?) and would that improve shifting?

If its 6600, you'll struggle to improve the shifting as long as you've got it set up correctly. The best mechanical groupset I've had the pleasure of using.

Back on the Serotta recently, Ultegra 6800 is one hell of a groupset.

Yes. I'd already have put it on the Colnago if it wouldn't make my RS80s obsolete.

Do you even Hippy? There's no way he's going to buy Campag.

Thanks for saving me posting that.

These are the DA options..

11-23T: 11, 12, 13, 14, 15, 16, (17, 18, 19), (21, 23)
11-25T: 11, 12, 13, 14, 15, 16, (17, 19, 21), (23, 25)
11-28T: 11, 12, 13, 14, 15, 17, (19, 21, 23), (25, 28)

12-25T: 12, 13, 14, 15, 16, 17, (18, 19, 21), (23, 25)
12-28T: 12, 13, 14, 15, 16, 17, (19, 21, 23), (25, 28)

Oh no! it's the end of the world!

Do you even steady state?

You could always use multiple cassettes. It takes <5mins to change a cassette. Depending upto the terrain.

Or if you've got a spare wheel, I presume you would, you could use that and swap wheels.

Hippy you do know dura ace cassettes are generally considered a bit shit? there is threads with a more than an oh-it's-a-one-off number of people having broken theirs particularly at the big three cogs, which would seriously put me off tuning/customising them to make jumps bigger

Blasphemer!

I heard that they're actually made by Continental..

Hippy you do know dura ace cassettes are generally considered a bit shit? there is threads with a more than an oh-it's-a-one-off number of people having broken theirs particularly at the big three cogs, which would seriously put me off tuning/customising them to make jumps bigger

I've never had an issue with them so don't see any reason to look elsewhere.

have you considered Campag?

^^fair play, just a warning that's all

^I hear gp4000's are really good tires too? low rolling resistance?

I've never had an issue with them so don't see any reason to look elsewhere.

9000 cassettes received a Shimano stealth "upgrade" in early June that added a second rivet point between the largest cogs and the carbon carrier.

I posted this somewhere else but didn't have any joy so maybe here someone will know. I've been trying to buy the Ultegra 6800 groupset from pro bike kit with a discount code but none of the codes seem to be working - can anyone confirm if they've had more (or less) luck than i have?

Why not just call them?

It was a pain to find a phone number but i managed it, seems the PBK discount codes on Shimano groupsets have all been revoked.