Di2 10 speed rear mechs - obsolete?

mamba80 wrote:

... as I found out when I needed some spares for a set of carbon 10speed tubs, that were 18months old.

... or any other spare for anything they distribute...

Is it time to re-open the Campagnolo v Shimano debate ..................... :twisted:

Blimey, just been googling around, one or two places have them but mostly they're out of stock.

meanredspider wrote:

dodgy wrote:

Blimey, just been googling around, one or two places have them but mostly they're out of stock.

Well, first the thing has to either go wrong or get wrecked. Then you have to not be able to find a replacement (either new or used) then you still have the option to upgrade the hub to 11sp.

Going 11 speed is not necessarily an upgrade though. It isn't if it is flat enough that you don't need a wide range of gears and it isn't if you do enough miles that things wear out sooner and cost more to replace and that that bothers you more than having an extra gear you maybe don't need.

Going 11 speed should be because you want to and not because built in obsolescence forces you to. Why should this even be an issue with electronic shifting anyway unless it is a very deliberate nasty tactic on the part of Shimano to get you to waste money on them?

Rolf F wrote:

meanredspider wrote:

dodgy wrote:

Blimey, just been googling around, one or two places have them but mostly they're out of stock.

Well, first the thing has to either go wrong or get wrecked. Then you have to not be able to find a replacement (either new or used) then you still have the option to upgrade the hub to 11sp.

Going 11 speed is not necessarily an upgrade though. It isn't if it is flat enough that you don't need a wide range of gears and it isn't if you do enough miles that things wear out sooner and cost more to replace and that that bothers you more than having an extra gear you maybe don't need.

Going 11 speed should be because you want to and not because built in obsolescence forces you to. Why should this even be an issue with electronic shifting anyway unless it is a very deliberate nasty tactic on the part of Shimano to get you to waste money on them?

There is some good in 11 speed, while 10 was only bad...

http://whosatthewheel.com/2015/01/29/th ... witchover/

meanredspider wrote:

Agree. I have 2 10-speed Di2 bikes. Losing an RD on either would push me to upgrade the V to hydraulic braking and 11-speed shifting as it's my Up & Down bike. No point in 11 gears on the Foil - already run 12-23. But it's not great if Shimano aren't supporting their products for very long. Do we even know if this is definitely the case?

Historically, shimano do not support products when they introduce a new standard ie 9 to 10 or 10 to 11 speed wheels/gearing.
this isn't a big issue with mech 10sp as the stock is cheap to carry so there is plenty of NOS, not so with 10sp Di2.

there is no 10sp di2 stock, either Ultegra or DA listed on the Madison site, some 10sp mech but that's it.

But the wider point would be warranty, DA carries a 3 yr guarantee and if there is no possibility of a replacement 10sp mech, then the alternative is a refund but what good is that when you would need to buy a load of other stuff to get back on the road ?
when I had a warranty issue on some DA tubs, it was a refund and not a replacement 11sp wheel, that is Madisons policy and is alos an option in the Shimano 3 yr warranty doc.

I'd be pretty upset if I had 10-sp DA. At least most of the Ultegra is interchangeable with 11sp. I already have an 11sp freehub for the V. Bigger rear cassette options would be nice for the 20% inclines around here

My Disc for TT bike is ten speed, not possible to convert, I've just got a new 11speed DI2 TT bike. It's a doddle to make it work with the 10 speed cassette, do not worry!

JackPozzi wrote:

About hacking an 11 speed mech to run as a 10 speed though. Would it be possible? In theory it should be as far as I can tell, obviously shimano wouldn't recommend it but must be doable by some of the clever people out there?

The number of steps and spacing is a hardware feature of the rear mech. It mar be hackable but you would need to take the thing apart.

Much easier to fit an 11 speed, even if the free hub needs a couple of minutes with a dremel to take an 11 sp cassette.

Bar Shaker wrote:

JackPozzi wrote:

About hacking an 11 speed mech to run as a 10 speed though. Would it be possible? In theory it should be as far as I can tell, obviously shimano wouldn't recommend it but must be doable by some of the clever people out there?

The number of steps and spacing is a hardware feature of the rear mech. It mar be hackable but you would need to take the thing apart.

Much easier to fit an 11 speed, even if the free hub needs a couple of minutes with a dremel to take an 11 sp cassette.

The number of gears and spacing between each one is going to configured in the software/firmware.

Bar Shaker wrote:

The number of steps and spacing is a hardware feature of the rear mech.

Do you know that for certain? Or is it a stepper motor?

meanredspider wrote:

Bar Shaker wrote:

The number of steps and spacing is a hardware feature of the rear mech.

Do you know that for certain? Or is it a stepper motor?

Yes, because it is a stepper motor.

Stepper motors don't step, they spin a threaded rod. One revolution of a stepper motor will 'step' a block along this rod by a set distance. When one (or a set number of) revolution(s) has taken place, the motor waits for the next movement instruction. It will count each rod revolution and a revolution stops as the trigger for a completed revolution is reached. The scanner in a photo copied works the same way.

Now think of a wheel magnet and speed sensor. The sensor only triggers when the magnet passes. The sensor could not be used to tell you where the magnet was when it was anywhere other than exactly next to it. To ask an 11 speed mech to move in 10 speed increments, you would need to stop each rod spin a little bit more than one (or a set number of) revolution(s). As the difference between 10sp and 11sp is fractions of a millimetre, we are not talking about whole numbers of thread pitches, so the solution will be hardware, not software.

crikey wrote:

I believe the answer is to buy an 11 speed rear mech and re-programme it to work with 10 speed...

No. Can't be done. No other Di2 mechs are compatible with 10-speed (7970) Dura-Ace Di2. Completely different cabling system.

I do wish people would learn the model numbers, it would make these conversations much easier.

7970 = Dura Ace 10-speed Di2 - the original Di2. 4-wire analogue signalling.
6770 = Ultegra 10-speed Di2. 2-wire digital (eTube) signalling.
6870 = Ultegra 11-speed Di2. Also eTube. You can mix-and-match with 6770, but have to watch firmware versions.
9070 = Dura Ace 11-speed Di2. Again eTube. Completely interchangeable with 6870. Same caveats as 6870 for mixing with 6770.

7970 doesn't interchange with anything.

11-speed RDs don't work with 10-speed cassettes. It's the RD that "knows" how many speeds it has, so levers, FDs, batteries all interchange (within eTube Di2).

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'.