TRP has managed to position itself as a serious contender in the brake market over the last few years, thanks in no small part to their downhill-focused G-Spec Quadiem stopper that shot to the top of the class when talking about modulation. That brake was made for the likes of Aaron Gwin, but the high-performance arm of Tektro has a new G-Spec model out, this one being a lighter weight brake intended for use on a trail bike.
The G-Spec Trail SL employs the same four-piston caliper as the DH brake - but with different sized pistons - combined with a lighter weight perch. It retails for $149.99 USD per end without rotors, making it $30 USD pricier than the budget-oriented Slate 4 and putting them up against SRAM's $154 USD (w/ rotor) four-piston Guide RS brake. So, let's find out how the two compare.
TRP G-Spec Trail SL
• Intended use: trail
• Mineral oil system
• Four-piston caliper
• CNC two-piece caliper
• 14/16mm pistons
• Tool-free indexed reach adjust
• Weight: 312 grams (front, w/o rotor)
• MSRP: $149.99 USD
• More info: www.trpcycling.com
Rotors range from $29.99 USD to $59.99 USD, and that does bump the price of the Trail SL up past where the Guide RS sits. They're available in all the sizes, as well as both six-bolt and Centerlock mounting, and you can find a ton of small parts on their website; if you prefer to fix things yourself, you can probably order what you need instead of having to go to a shop.
The trail bike-oriented G-Spec Trail SL lets you tinker with reach via an indexed dial. There's a four-piston caliper at the other end that works with Shimano pads, too.
TRP makes a point of saying that the Trail SL's finned caliper is the same as what's used for the downhill-oriented G-Spec Quadiem, but that's only partly true. While the Quadiem caliper is home to four 16mm diameter pistons, you'll find 14mm and 16mm pucks inside of the Trail SL's. Both use the same pads, though. The idea with the differently sized pistons is to have the smaller ones lead by just a hair so as to have a controllable initial bite, with the 16mm pistons delivering more power later in the lever's throw.
Externally, the two-piece caliper looks massive compared to the pared-down blocks of aluminum from everyone else, but TRP has machined a load of cooling find onto its roof. It also has the new sleeker bleed fitting and, just like with the Quadiem, you can fit a set Shimano brake pads if that's what you're into.
Up at the other end, the Trail SL's master cylinder and lever blade look like a Weightwatcher's version of the Quadiem's setup. You'll spot the same indexed reach adjustment dial, as well as the same lack of adjustable bite point; TRP makes no apologies for that, instead choosing to go with a simpler, possibly more reliable design.
The clamp is hinged to make life easy, and it plays nice with both I-spec II and Matchmaker mounts as well. It's worth noting that the similarly priced Guide RS sports the same tuning options.
Dry and loose? That's when some extra control comes in handy, and the Trail SLs have it.
The brake's name makes it impossible to mistake their intended use, but I went ahead and bolted them onto Mondraker's 150mm-travel Foxy Carbon XR 29 that is most definitely not a trail rig in most parts of the world. Squamish's often steep singletrack is also most definitely not your average trail riding, either, so I ran them with 180mm rotors front and rear that work well for my 160-ish pound weight. Not your average trail riding then, but if TRP's weight-conscious four-piston stoppers work well here, they'll probably well everywhere.
When I reviewed the DH-friendly G-Spec Quadiem, I said, ''First, they've been impressively consistent,
'' and ''They offer a remarkable amount of feel and modulation, especially for a four-piston brake intended for downhill use.
'' Yeah, I liked 'em a lot, and it's no surprise to me that I could start the G-Spec Trail SL review by using similar words.
If you read that original G-Spec Quadiem review, you'd also know that they offer that relatively gentle initial grab that I prefer over that stick-in-the-spokes power that, while certainly not useless, is also a lot easier to come by than telepathic-like modulation. The Quadiem doesn't really have that brick wall type of power, but what they do have is class-leading modulation, and TRP has done well to carry that same thing over to their four-piston trail brake.
The indexed reach adjustment refused to migrate during my time on them, and the dial is easy to turn.
I used my set of Trail SLs with metallic pads (they come stock with semi-metallic pads installed) and found the power to be enough for my needs and 160lb-ish mass, but also down just a touch compared to the Guides with the same sized rotors. That said, TRP's power comes on in a very linear, direct, and easy to understand way, possibly because there's no tricky linkage driving the plunger as there is on some of the competition. Or maybe that's not the reason why, but my braking fingers tell me that there's certainly something different going on regardless.
As you might expect, that kind of control is nothing but a boon when it's wet or you're near your personal limits. Sure, I think the Guide RS has more outright power, but TRP has 'em beat when talking about modulation. Same goes for Shimano, too, but the big Blue S has a ton more initial bite than anyone else bar the Germans at Trickstuff.
Fade? Pump up? No and no.
Squamish is full of the kind of descents that make your brakes fade and the bottom of your feet burn, but TRP's trail-oriented stoppers proved themselves to be consistent performers. Okay, at 160lb, I'm not the heaviest guy out there, but I can certainly get two-piston brakes to wither under me. That's no surprise, of course, and it's also no surprise that these four-piston brakes don't. I also had exactly zero reliability concerns; the reach setting didn't migrate, there were no weird moose-moaning noises, and I experienced no pump-up, either.
Okay, no fence sitting here: SRAM's Guide RS or TRP's G-Spec Trail SL? The price difference is kind of a wash, although you'll end up spending more on the latter because you'll also need to spring for a new rotor. Outright power? The Guides take it, no question. Modulation? SRAM has always been among the best, and they still are, but TRP has got them with on that front. Reliability? It seems like every brake has its share of people who've had major issues, but Guides have never given me trouble. Neither has anything from TRP, so it's I'll call it even there as well.
So, if I had a set of the Guide RS brakes on my bike and they were performing, I wouldn't run out and buy a set of Trail SLs. On the other hand, if my bike needs a new set of brakes, I'd pick up a set of TRP's new stoppers. Now, if they had an adjustable bite point - if any of TRP's brakes had it - there'd be nothing left for me to moan about. Pinkbike's Take: