Di2 10 speed rear mechs - obsolete?

964cup

Bar Shaker wrote:

You can Dremel out the splines on the freehub so an 11sp fits (just over 1mm removal required) or you can fit a 10sp cassette to an 11sp hub, with the spacer and limit the travel on the mech so it doesn't fall off the 10 gear (smallest cog). It will be 'close enough'.

If you do this to a Di2 mech, you will eventually break it. The motor will try to push it past the limit screw into the 11th position it "knows" it should have. Also the inter-cog spacing is different so change quality will be poor. And all of this is totally irrelevant anyway, since 7970 Di2 CAN'T TALK TO ANY OTHER Di2. If you buy a 6770/6870/9070 rear mech and try to connect it to a 7970 Di2 loom, you will fail.

JackPozzi

Just to be clear in the OP I was referring to 6770, don't think anyone has mentioned trying to get 7970 working with the newer stuff?

meanredspider

964Cup wrote:

Bar Shaker wrote:

You can Dremel out the splines on the freehub so an 11sp fits (just over 1mm removal required) or you can fit a 10sp cassette to an 11sp hub, with the spacer and limit the travel on the mech so it doesn't fall off the 10 gear (smallest cog). It will be 'close enough'.

If you do this to a Di2 mech, you will eventually break it. The motor will try to push it past the limit screw into the 11th position it "knows" it should have. Also the inter-cog spacing is different so change quality will be poor. And all of this is totally irrelevant anyway, since 7970 Di2 CAN'T TALK TO ANY OTHER Di2. If you buy a 6770/6870/9070 rear mech and try to connect it to a 7970 Di2 loom, you will fail.

Did I miss the bit where the OP said he had 7970? I think there's several of us with 6770 who are also interested in this problem. I'd like to think that there was a hack for an 11sp RD to get it to act in 10sp mode. It feels like it should be possible but then I haven't seen the innards of a Di2 RD - anybody know if there are details anywhere?

Besides that, has anybody yet needed a spare RD?

JackPozzi

meanredspider wrote:

964Cup wrote:

Bar Shaker wrote:

You can Dremel out the splines on the freehub so an 11sp fits (just over 1mm removal required) or you can fit a 10sp cassette to an 11sp hub, with the spacer and limit the travel on the mech so it doesn't fall off the 10 gear (smallest cog). It will be 'close enough'.

If you do this to a Di2 mech, you will eventually break it. The motor will try to push it past the limit screw into the 11th position it "knows" it should have. Also the inter-cog spacing is different so change quality will be poor. And all of this is totally irrelevant anyway, since 7970 Di2 CAN'T TALK TO ANY OTHER Di2. If you buy a 6770/6870/9070 rear mech and try to connect it to a 7970 Di2 loom, you will fail.

Did I miss the bit where the OP said he had 7970? I think there's several of us with 6770 who are also interested in this problem. I'd like to think that there was a hack for an 11sp RD to get it to act in 10sp mode. It feels like it should be possible but then I haven't seen the innards of a Di2 RD - anybody know if there are details anywhere?

Besides that, has anybody yet needed a spare RD?

Funnily enough, I first heard about the fact the mechs are obsolete in my LBS, with another guy in there with 2 broken mechs, both failed around the point where the mech attaches to the hanger! Trying to get them replaced as warranty items but unable to source

meanredspider

JackPozzi wrote:

Funnily enough, I first heard about the fact the mechs are obsolete in my LBS, with another guy in there with 2 broken mechs, both failed around the point where the mech attaches to the hanger! Trying to get them replaced as warranty items but unable to source

Wonder what was wrong there - 2 is a bit careless. Mine must be getting close to 4 years old

JackPozzi

They were used for cyclocross at a decent level so subject to more punishment than just road use, but still doesn't seem ideal...

meanredspider

JackPozzi wrote:

They were used for cyclocross at a decent level so subject to more punishment than just road use, but still doesn't seem ideal...

Nope. I'd be questioning the design of my mech hanger. It's job after all is to sacrifice itself rather than the mech or the frame

964cup

JackPozzi wrote:

Just to be clear in the OP I was referring to 6770, don't think anyone has mentioned trying to get 7970 working with the newer stuff?

Sorry, my misunderstanding. That's why using the model numbers helps.

In that case, 6870 RDs will plug in fine. There's a long thread already in here on issues with the latest firmware and mixing 6870 and 6770.

As far as I know, there is no way to hack an 11-speed RD to work with 10-speed cassettes; Leonard Zinn's article in Velonews is misleading - it is possible to hack *mechanical* 9000/6800 to work on 10-speed (if you're using an 11-speed chain) but not Di2.

Ugo has also posted in here (and others have suggested it on WeightWeenies) filing down 10-speed freehubs to accommodate 11-speed cassettes. The chap who did this on WeightWeenies had problems with freehub failure afterwards, so YMMV. In many cases a £50 freehub swap is all you need, though, so the total cost is 11-speed RD + chain + 11-speed cassette + freehub.

dodgy

964Cup wrote:

In many cases a £50 freehub swap is all you need, though, so the total cost is 11-speed RD + chain + 11-speed cassette + freehub.

This will be the next source of debate Not sure how simple that is for many wheels.

Bar Shaker

964Cup wrote:

In many cases a £50 freehub swap is all you need, though, so the total cost is 11-speed RD + chain + 11-speed cassette + freehub.

The rider may want a second cassette to save swapping them each wheel swap and he can fit an 11sp chain at the next change, so he could do the job quite cheaply.

There are several US companies hacking Di2, for everything from alternative levers to auto shifting based on cadence, speed and power, for time trialling. If none of these has hacked 10-11sp, or vice versa, my guess is it cannot be done.

964cup

dodgy wrote:

964Cup wrote:

In many cases a £50 freehub swap is all you need, though, so the total cost is 11-speed RD + chain + 11-speed cassette + freehub.

This will be the next source of debate Not sure how simple that is for many wheels.

It varies. So far I've done a set of Vision TC24s, and a set of DT Swiss RR252Rs, with nothing more than a 2-minute freehub swap. All recent-ish (back to at least 2008) Mavic wheels take 11-speed as standard. I know Zipps are a problem, requiring a bunch of expensive parts and a partial rebuild. I think Shimano factory wheels can't be upgraded (without rebuilding on a new hub) but haven't tried.

ugo.santalucia

JackPozzi wrote:

Funnily enough, I first heard about the fact the mechs are obsolete in my LBS, with another guy in there with 2 broken mechs, both failed around the point where the mech attaches to the hanger! Trying to get them replaced as warranty items but unable to source

That's where they jam and break... if you run Campagnolo mechanical you can simply replace the mounting plate, 16 pounds. Of course running Di2 in cyclocross is a bit foolhardy... to be honest running anything higher spec than Veloce/105 in cyclocross is plain daft...