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Review: SRAM's New G2 Ultimate Brakes - Pinkbike

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The G2 caliper looks like a futuristic version of the original Guide, and it's said to be stiffer due to SRAM leaving more material around the two joining bolts.

What's New on the G2?

The G2 is the lightest four-piston stopper in SRAM's catalog, although it's within a handful of grams of the Guide Ultimate that we reviewed back in 2015. They are light, though, at just 242-grams (without a rotor), and that's with SRAM actually leaving more material on the caliper.

Wait, what? We're used to hearing about companies paring just a few grams off their latest creation, but SRAM has actually left extra material around the two bolts connecting each side of the caliper. They've also removed less material from the pad pockets in each of the caliper's face. The idea with all that is to up the caliper's rigidity, which in turn should make for a firmer feel at the lever when you're pulling it like your life is at risk. We all end up there sometimes. If you're looking for numbers, SRAM is citing a 7-percent increase in power from those changes.
In comparison, the original Guide caliper (left) looks pretty simple. SRAM had a steel heatsink hidden inside of it (right) that isn't needed on the G2 caliper.
There are updates inside the caliper as well. Gone are the aluminum pistons with an insulator in their center, with four phenolic pistons used instead. They're still a 14/15mm combo, though, whereas a Code sports 16/17mm pistons. Phenolic is a funny looking word that refers to the pistons being made of a special resin rather than steel or aluminum, and they're said to do a better job of shrugging off the heat build-up that can happen down at the caliper during a long, hard descent. SRAM says they're so effective at that job that they've been able to ditch the steel heatsink that was hidden inside the previous Guide caliper. There are now three pad compounds to choose from as well; organic, metallic, and the new 'power organic' that's said to offer a more aggressive initial bite and better heat management than a traditional organic pad. Power organic is now the stock pad option.
The new caliper fits SRAM's Bleeding Edge fittings.
There's a load of changes at the caliper, but things are basically the same up top. The Ultimate's carbon blade rotates on a sealed bearing, and you have dials to tinker with both reach and pad contact point. The carbon blade is a matte UD job that looks like it's aluminum at first glance, so your friends might not notice that you've sprung for the high-end model. I wish you could see the carbon weave because, well, it plain looks cool, but that's small beans.
I bolted the new G2s onto our Giant Trance Advanced 29 for testing.

How'd They Perform?

As fun as locking a wheel up can be, power is nothing but trouble if you can't use it properly, and I've long rated SRAM's Guide stoppers, along with Magura's, at the top of the list when it comes to modulation. My concern was that a bump in power, along with a firmer feel at the lever, might mean that the G2 loses some of the control that its predecessor was known for. That's a non-issue, though, as they feel every bit the SRAM brake that they are. That means an initial bite that's relatively gentle, at least compared to four-piston brakes from Shimano and others. That's with the new power organic pads, too, and it's always helpful when traction is low and the chances of going down are high. Picture wet, steep rock faces, of which there are always plenty to choose from here in Squamish, BC, and you'll get the idea. Locking up can mean a quick trip to the ground.
The G2's pad contact adjustment offers the same wide effective range as the Guide, and the tool-free reach adjustment refused to creep in or out during use.
Speaking of power, there's plenty of that as well. But with four pistons and claims of a stiffer caliper, that does make sense. Where do they slot in on the all-out power rankings? According to my bro-science-calibrated pointer fingers, I'd say that they're a tick or two below a Code or Saint brake on that front, but still with enough power for everyone short of plus-sized riders who are really pushing things. And maybe serious downhill racers. But the big differentiator between those two heavier options is that early braking control I was talking about above; the G2 is firm but just less abrupt.

The other question that needs answering: Are they consistent and reliable? I've had them on my strange Giant Trance Advanced 29 for a few months now, which probably isn't enough time for me to comment on the latter. That said, I've had zero issues with the G2's predecessor, so I have high expectations for these. They have been completely consistent (and quiet), with zero change in lever feel from day one. The end of the G2's lever throw is quite firm, too. A perfect bleed? Definitely, but there's a good combination of firmness without a hint of that nasty wooden feeling regardless.

Pinkbike's Take:


bigquotes The new G2 is essentially an updated Guide brake that's going to be a good choice for anyone who doesn't need Code-like power. That's a lot of us, I suspect, and they make a lot of sense for trail riders and enduro types who fall into that category. Mike Levy

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