SRAM's excellent Guide brake gets a revamp. Enter the new SRAM G2...
SRAM’s latest trail bike disc brake is the G2, and the top of the line is the Ultimate version – it has the name, but is it one of the ultimate mountain bike disc brakes on the market? Let’s find out. When we received SRAM’s top-end G2 Ultimate, included in the box were a set of the new stainless-steel HS2 disc rotors. At 2mm thick these have more meat on them than normal along with a redesigned brake track to increase friction, and a grey, heat-dissipating paint on the recessed spokes. According to SRAM, the HS2 rotor generates around 7% more power than the regular CentreLine rotors, so in theory you could run a smaller disc and save weight without compromising power. A HS2 rotor is a bit pricey however (£50-70 depending on size), making a full G2 Ultimate brakeset over £700!
Spending this much on a brake does mean you get some cool stuff, like fancy titanium bolts, a lightweight carbon blade with tool-free lever reach and bite point adjustment. The dial for the latter is a little easier than previous ones to turn, but the bezel for the Contact Point is still recessed in the body of the lever, so can be hard to access. Like all SRAM brakes, the lever attaches to the bar using a hinged clamp – which has a Matchmaker shifter mount pre-installed. It’s tricky to hold everything when you’re setting it up, but it’s worth persevering to clear some bar space.
While it looks pretty similar to the old Guide, and shares the same pad shape and hose connections, the SRAM G2 Ultimate unit is actually completely new. According to SRAM, the biggest advance is in terms of stiffness. The caliper is still a two-piece design that’s bolted together, but changes to the forging means they should resist flexing under extreme pressure better than the old caliper, with the aim of creating a firmer lever feel – and it works. The standard pads are the new Power Organic compound with the steel (grey) backing plate to improve the bite and reduce fade. They squealed a bit, but bedded in really quickly and pad wear has been pretty impressive, even in wet and muddy winter conditions.
The pad gap has also increased thanks to some changes to the machining around the pistons, which helps achieve a drag-free set-up, and the G2 is said to retain that gap as the pad wears, keeping lever feel more consistent. In this regard, credit must also go to the new phenolic pistons (a type of resin material) that glide in and out and resist heat so well that SRAM says it was able to ditch the previous steel heat sink.
Connecting the caliper to the lever is a new hose material with a smooth, matt finish that SRAM claims should resist kinking better than the old one. It’s also a bit easier to route through frames during installation.
And at the touchy, feely end is the familiar lever that’s largely unchanged from its predecessor. Having said that, there’s some additional machining around the master cylinder, while you still get the fancy carbon lever blade, sealed bearing pivot, reach and bite point adjustment. All up, with the included titanium hardware, the new front brake weighs 272g. That’s actually 25g heavier than the old Guide Ultimate we tested five years ago, although the new two-piece CLX rotors (£68) with alloy spider claw some of that difference back – they weigh 121g (180mm) and save a reasonable 30-40g over a full steel version.
Perhaps the biggest news is the new ‘Power’ pad compound — introduced to complement the sintered and organic offerings — and being the same shape as the Guide pad means you can run this in your generation one caliper. It’s an organic compound with a grey steel backing plate and is designed to offer improved bite and less tail-off during sustained braking.
While much has changed with the G2, it doesn’t feel dramatically different. Having said that, the Guide was already an excellent trail brake, and there are subtle improvements that can be felt in direct comparison with the old model.
The lever feels like it has a stronger return spring. Which it doesn’t. So we reckon this must be a result of the improvements to the piston area. There’s a really nice light action (once you’ve got past the initial breakaway of the Swinglink cam) from the broad, comfortable lever blades. Power comes in softly, particularly if you’re used to the immediate bite of a Shimano brake. Then resistance builds gradually at your fingertips as you pull harder, communicating perfectly the pressure being exerted at the caliper. This means modulation is superbly intuitive and natural with a sense of solidity as the pressure in the system builds.
Once you’re used to that feedback, the new Power pad lets you brake less and leave it later because you can trust the bike will slow down from the moment the pads hit the rotor. So far we’ve burned through a set of rear pads, but they have lasted well through several rides with filthy wet and gritty conditions.
And most importantly, we’ve not had any of the bite point inconsistency that continues to sporadically impede its Shimano XT and XTR rivals.
Finally, it’s a small detail, but the old Guide reach adjustment always felt graunchy and unpleasant to use. The new one is crisp and snappy.
This is a top stopper, and with the new oil-slick bolts has a cool aesthetic. What stops it getting a top mark is the hefty price and the fact that the CODE RSC is more powerful, cheaper and just as bling. Not the ultimate in outright stopping power then – for that there’s the 40g heavier Code – but the new G2 offers slick, dependable performance and is a delight to use.