We've already presented our first riding impressions of 2007 XTR cranks and brakes. Here's the bit that's really interesting, though - the wonderful world of changing gear...

Dual Control lever from the front

...and from behind. The thumb hook does the same as flicking the lever up - we found that we never used it

Graduated adjustable shifter mount

Rider's-eye RF+ view

Shifters can be mounted either inboard of the levers...

...or outboard. We like this setup a lot

The bit at the other end of the cable

Shifters

This is the big one. When it comes to groupset performance, shifting is the first thing everyone thinks of. And it's especially pertinent here - XTR is going up against SRAM's superb X.0 transmission, and Shimano has a history of, shall we say, controversial shifter designs.

The good news is that Shimano has moved away from its previous somewhat dogmatic stance over shifting ergonomics. So XTR will be available with either a completely redesigned Dual Control brake lever/shifter or with all-new RapidFire Plus separate shifter pods. And the new rear mech will come in conventional or Low Normal versions, both available in two cage lengths (long and slightly less long).

We rode both variants, and had a good old fiddle with the myriad positioning possibilities of the separate brake lever/RF+ pod combination. The Dual Control levers are a lot neater-looking than the old ones, although they still seem quite bulky. From the saddle they look kind of odd - the levers are actually mounted below the bar, with the blades being cranked to bring the business end up to where your hands are. Operation is as always - pull the levers to brake, push them up or down to change gear. Shimano's recommended combination is Low Normal mechs with DC levers, and that's what we had - push down on the lever for harder gears both ends.

Shifting is, as you'd expect, super-clean. Almost too clean - downshifts at the rear (that's an upward flick of the lever for a lower gear) don't really have much of a click. It changes gear every time, but you pretty much just have to assume that it's worked - there's not much in the way of tactile feedback. Combine that with the considerably reduced throw, the fast-reacting Instant Release mechanism and the fact that you can now shift multiple gears in both directions and it takes a little getting used to. We fully expect that a few more hours would have it feeling like the most natural thing in the world, though.

One thing we did have a spot of bother with was the front shifting. Again, it's super-smooth, but if you find yourself dropping into a nadgery descent in an excessively small chainring you might experience a spot of bother. The small throw makes it easy to shift at the rear while braking, but the throw on the front shifter is considerably larger - a few times we found ourselves on the brakes but wanting to get into the big ring, and the movement required is a little awkward. Again, more familiarity will help, as of course would better anticipation of the terrain. On the other hand, one of the joys of having all the controls at your fingertips is that it reduces the need to anticipate what's coming quite so keenly...

We're definitely getting to like Dual Control, though. Not for everything, but for racing or anywhere were you need to make super-frequent shifts, it feels very suitable.

The new RapidFire Plus shifters also have Instant Release for fast shifting and Multi Release to change multiple gears in both directions - push the release lever a little way and you go one sprocket, push it further and you get two. The new shifters also have Two-Way release, which is possibly our favourite new feature of the whole groupset. As well as the traditional RF+ style of downshifting with the thumb and upshifting with your index finger (assuming a conventional rear mech), the new shifters let you use just your thumbs - yes, just like SRAM's trigger shifters (although those don't really lend themselves to index finger shifts unless you have quite peculiarly articulated fingers). The really clever bit is that you're not just trying to push the lever the same way from two different directions - it actually moves both ways.

This is great in all sorts of ways. If you like to brake with your index fingers, being able to shift both ways with your thumb is a boon - that's one of the reasons that SRAM triggers are so popular. But even the most obsessive finger-braker occasionally finds that being able to shift with a finger is handy - if you're climbing with your weight forward, and especially if you're standing, the finger shift is much more accessible. But if you're descending, weight back and on the brakes, the thumb option falls readily to hand, or at least thumb.

The action is a delight, too. Without actually having both systems available to ride back-to-back we're not sure if it's quite as fast on downshifts as X.0, but it's certainly pretty brisk. And being able to do double upshifts is handy.

None of this is the best bit, though. No, the best bit is the sheer range of adjustability on offer. This is a huge deal from Shimano, which has been pushing one-piece, fixed-relationship, this-is-ergonomic-and-if-you-don't-like-it-your-fingers-must-be-wrong controls for what seems like ever. Obviously if you're running separate shifters and brake levers there's a bit of scope for running them at different angles and spacing, but XTR takes this another step by having a slotted shifter mount - loosen a bolt and you can slide the shifter pod in and out to get just the right relationship between brake lever and shifter.

It gets better, though. We like to run brake levers well inboard and use one finger right on the end. Ordinarily that puts the shifters a bit of a stretch away, and even with the XTR pods adjusted right the way out they're still a bit of a long way away. But that's not a problem, because you can just mount them outboard of the brake lever and slide them a little bit the other way instead. Splendid.

So, the first impressions are very good - it's hard to see anyone not being able to find a setup that suits them amongst all the options and everything works great. The only negatives seem to be things that can be firmly categorised as "special circumstance niggles". And of course there's the looks, which are of course entirely subjective. We're not completely sold yet, but we're pretty sure that the final silver/grey product will tempt us more than the nearly-black prototype bits. We'll have to wait until October to find out, though...