Replacing Ultegra 11-28 with 12-30 - cassette won't tighten

chrisaonabike

My OH now has her new Canyon, and we replaced the cassette (11-28) with a 12-30 this evening.

We were very careful to put all the cogs and spacers on in the right order, yet once the lock ring was as tight as it would comfortably go, the cassette was still not tight - there seemed to be quite a bit of slack still to take up.

Put the 11-28 back on, tightened up fine. But with the 12-30, it was as if the lockring wouldn't screw in enough to immobilise all the cogs.

Any idea what dumb thing we might have missed?

Both cassettes Ultegra, bike not been ridden at all yet.

nicklouse

did you fit the required spacer on first? it is most likely stuck to the big cog on the old cassette.

have a read.

viewtopic.php?f=40101&t=12905742

MouseJunior

Thanks for the reply - it made us go back and have another look at the spacer.

Turns out there's a special (wider) spacer on the Mavic hub when using a Shimano or SRAM cassette. We'd been so careful in removing all the cogs and spacers of the "old" cassette and replacing them with the new cassette that we hadn't clocked the difference in that first spacer. The solution was to omit the first Shimano 1mm spacer and use the Mavic one in its place. It's now nice and tight and no wobble at all.

carrock

that spacer is probably because the hub is wider to allow an 11 speed cassette.

You should use that spacer PLUS the 1mm spacer that came with the cassette.

mamba80

i wouldnt do that, some of the newer shimano 10sp stuff ie the 12-30 - comes with the 1mm spacer built in.

bus_ter

Does it work ok? I thought 28 was the largest cassette you could fit with a normal Ultegra rear derailleur.

MouseJunior

You're quite right - the technical documents do say the largest sprocket with RD-6700 is 28t. We changed it on the basis that Canyon sell the Roadlite with an option of a 12-30 cassette so we figured it would work.

To be fair, I've only ridden it for ~30 miles but so far, so good.

Forgive my innocence, but if it all goes horribly wrong, what warning signs should I look out for? :shock:

nferrar

Probably your rear mech ripping off the frame As long as you don't use the big:big combo though you should be fine, clearly the top jockey wheel is not fouling the biggest sprocket if you've already ridden 30 miles (assuming you've been into 1st at least once in that time).

carrock

MouseJunior wrote:

You're quite right - the technical documents do say the largest sprocket with RD-6700 is 28t. quote]

The new for 2013 Ultegra derailleur ( designated RD-6700A ) has a 30 tooth capacity )

lm_trek

Did you have much trouble getting the original off?? tried last night on mine couldn't budge the damn thing!!