Shimano 105 12-speed mechanical groupset breaks cover

Yes. I had no issues mounting the last 105 iteration onto a hangar. The "direct mount" is a bit of a misnomer but allows for a shallow profile design that keeps the mech directly under the chainstay even in the smallest sprocket, instead of the traditional outboard position.

There is a small piece (that looks lke a hangar extender) that you remove to mount directly onto a frame.

wtjs wrote:

Doesn't this look lik the dreaded bonded cranks?

I hope not. 105 is the currently the best crank that they produce.

The 105 cranks are full aluminium like previous models, they are not like the carbon/alloy bonded Ultegra cranks that failed spectacularly from the last series.

Matthew Acton-Varian wrote:

The 105 cranks are full aluminium like previous models, they are not like the carbon/alloy bonded Ultegra cranks that failed spectacularly from the last series.

Shimano don't make any carbon cranksets. 

Cynic...

Dura Ace 12 sp leak, previous 105 leak by KHS bikes, I'm sure there are others. Maybe it's easy accidentally to publish your updated website before embargo ends, but displaying an unreleased groupset at a major international bike fair...?

Of cause it's not a mistake if Shimano didn't want it shown/teased they wouldn't send them out.

Judging by Shimano's reported reaction when Shane asked them about it, it sounds more like a screw-up by Corratec.

Not sure that really tells you much. If it's a deliberate ploy to build hype through 'leaks', I wouldn't expect them to admit it.       

Interesting.  No GRX 12 speed DI2 version?

I would imagine that would not need testing, as GRX Di2 would be almost identical in mechanical operation to either Ultegra or 105 DI2. The 11 speed 2x GRX rear derailleur had the same large tooth capacity as its road counterparts, owing to the bigger gap in the front chainring. The main focus for 12sp GRX would be to get the cable pull right.

Common criticisms of Campagnolo's 13 speed Ekar, and some of the mechanical 12 speed groupsets out there from Chinese brands, who have the same issue of the indexing needing to be extremely precise in order to shift. You can get away with the barrel adjuster being one or two turns off perfect and still get reliable shifting on 11 speed, but you don't have as much leway with 12.

I may have misunderstood, but Shimano does not have a 12 speed XTR DI2 either. All current MTB groupsets are mechanical shifting only. People are asking for it now SRAM have gone all in with AXS (I think there are 3 Eagle AXS options avaiable at least) but Shimano's first XTR DI2 (11 speed) did not get taken up as much as it would have liked, so probably initially shelved. They may have done the same with GRX.

Shimano often wait and develop products until they are certain they perform as best as possible, so having to restart the fire on that could take time.

I wonder why there is a lack of take up? Personally, I'd be worried about twatting a very expensive rear mech on a rock and ruining it whilst off-road, which is much more likely that me doing the same on a road going Di2 setup.

Bowks wrote:

I wonder why there is a lack of take up? Personally, I'd be worried about twatting a very expensive rear mech on a rock and ruining it whilst off-road, which is much more likely that me doing the same on a road going Di2 setup.

Back in the day (30 years ago), mountain bikes quite often came with a metal bracket to protect the derailleur. Don't tend to see them any more, I guess because they're fugly.

Like spoke reflectors, dork discs and bar ends, these brackets are ugly and ruin your trail credibility. But the strength of modern derailleurs and the use of a seperate hangar meant they were no longer required. Back then, didn't most derailleurs mount onto the frame itself?

I also seem to like crashing drive side down, yet most damage I have caused is cosmetic. But modern off road derailleurs are pretty sturdy. SRAM's Eagle AXS is pretty popular, but it also came just a little later. It may be down to the fact that the DI2 system was wired, so you still had to thread electric cables through frames. Just as faffy to set up but if you damaged a cable (which was much easier to do than it is on mechanical, especially when routing around rear suspension onto the rear triangle). AXS negated that by being wireless, so setup was much easier. Considering a lot of road based teams are dipping into XC are Shimano sponsored, they are probably crying out for its return. But to reopen development means they have missed out on an iteration of R&D so will probably take longer to resurface.

But outside of XC and possibly Enduro racing, I don't see how electronic shifting is a game changer for MTB, as a reliable mechanical setup is much more convenient for regular maintenance or in the (slighlty more likely) event that something breaks, is more easily fixable.

I have never had the pleasure of riding an electronic groupset yet, but I would be more likely to try it out on road than off.

Having done extensive gravelling on my DI2 set up I'd say the likelyhood of a quick emergency shift means that Off road benefits more from Electronic shifting rather than less.

Although my experience of binning my gravel bike on the road and suspiciously losing the £300 Di2 rear mech 1 week later makes your second point valid.