Those with an affinity for obscure bike parts may remember SRAM's last foray into trigger shifters. The Gemini never made it onto the market for real - SRAM decided that it wasn't any good and pulled it. Their new "Impulse Technology" trigger shifters are all-new, completely redesigned and very timely...

Shimano appear to be heading back down an inflexible integration route. XTR's Dual Control shifter/brake levers are bound to trickle down to lower groupsets, but the hydraulic versions will only work with Shimano brakes. There's nothing much wrong with Shimano brakes, but plenty of people want to use Hope or Hayes or Formula. Not least the massed ranks of bike manufacturers, many of whom value the ability to spec one company's brakes, another's shifters and a third's cranks...

So for SRAM there couldn't be a better time to launch a stand-alone trigger shifter. And here it is. This is the X.7 shifter, designed to work with X-series rear mechs with a 1:1 cable actuation ratio. Fear not, though - there are also Shimano-compatible shifters.

We've only just got our hands on these (although we've ridden earlier versions briefly), but first impressions are very good. They've got an impressively solid feel, doubtless helped by the all-steel internals. They're splendidly clicky and we're most taken by the gear indicator built in to the bar clamp. The lack of a gear window sticking out anywhere else makes the shifters very flexible in terms of mounting. They'll sit happily with pretty much any brake lever and you can even mount them outboard of the brake lever if you like.

Unlike Shimano triggers, SRAM's have a little bit of an early-90s timewarp thing going on in that your thumb shifts in both directions. The main lever works in a familiar way - push it away and it pulls cable, giving you bigger sprockets. The release lever, though, works at ninety degrees to RapidFire+, lifting upwards towards the grip. It's positioned to be nudged upwards by your thumb when it's wrapped around the grip, although it's entirely possible to activate it with a finger or even a knuckle if you wish.

It feels a little odd at first, although if you like to brake with your first two fingers (as we do) you'll probably take to it quite quickly.

The accompanying X.7 rear mech shares the general look and feel of the existing X.0 item but with a bit more steel in it and an all-black finish. There's also an X.9 mech and trigger - the triggers have ball bearings and more alloy bits (lever, barrel adjuster etc), while the mech gets again, more alloy plus sealed cartridge bearing jockey wheels and added silveriness.

The Shimano-compatible shifters are called Attack and Rocket and are essentially the same as the X.7 and X.9 respectively, just with different cable pull. They're all 9-speed only. And of course there's still a full range of GripShift units.

More info at www.sram.com - we're off to chuck these on a bike and see how they go...