G-Spec TRP TR12 Derailleur and Shifter Kit

Review | G-Spec TRP TR12 Derailleur and Shifter Kit Tested

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James Vincent takes to the mountains of the Lake District with the G-Spec TRP TR12 derailleur and shifter kit for a full review.

It used to be that if you wanted a decent shifter and mech from someone other than either of the Big Esses, you were out of luck. Then all of a sudden it’s like we’re back in the 90’s and alternative drivetrains are popping up all over the place, only this time everyone’s got significantly better engineering at their disposal matched with a greater understanding of the materials and riders’ needs. Having built a solid reputation for themselves with their ever-increasing range of brakes (look out for a review of the Slate T4 Evo soon), TRP is the latest manufacturer to throw their proverbial 12-speed hat into the ring. The question is, does it offer anything better than what’s already available?

G-Spec TRP TR12 Derailleur

As with the downhill-specific DH7 shifter and short cage mech released a couple of years ago, the TR12 has been designed with input from Aaron Gwin and his mechanic John Hall.

G-Spec TRP TR12 Derailleur and Shifter Kit
The TR12 mech is showing plenty of battle scars but keeps on working

One of the stand out features of both the DH7 and this TR12 is the unique (to TRP), Hall Lock lever. Born out of a desire to make a really quiet drivetrain, it’s designed to stop the mech from rotating around the bolt that fastens it to the frame. There’s a handy lever to release tension and let you remove the wheel from the frame, and while engaged it does a great job of keeping things quiet. 

There’s a ubiquitous clutch mechanism too, although, unlike SRAM or Shimano, it’s ratcheted and gives a reassuring zzzip sound when pulling the lower cage back into place. It never gets too loud when riding though, and is easily adjustable. As an added bonus, the compact lever is tucked neatly out of harm’s way – having had several Shimano clutch levers snap off while riding, this is A Good Thing.

Set up is super easy, with a guide on the inner cage of the mech to help with adjusting the b-tension screw, and there’s another printed guide round the front to help with chain length – just line everything up and away you go. The mech is limited to cassettes with the largest cog of 50 teeth, so Shimano 10-51t or SRAM 10-52t cassettes are a no go. I ran the mech exclusively on an E*13 Helix R cassette (9-50t), with no issues.

Befitting of a high-end mech, there’s plenty of carbon fibre in the construction, which helps keep the weight to a respectable 285g, only slightly more than the equivalent XTR or XX1.

G-Spec TRP TR12 Shifter

Moving on to the shifter, and it’s clear that the same amount of thought has gone into this as the mech. Both shifter paddles have a linear action, designed to mimic our thumb’s own movement. The upshift lever is adjustable 20° in each direction so you can really dial it in to fit your own ergonomic needs. As it was, I tried it in a bunch of different positions but kept coming back to the default central position. Still, the option is there if you need it. 

G-Spec TRP TR12 Derailleur and Shifter Kit

The paddles themselves are heavily grooved for optimal grip, and if you push them hard enough will shift up 4 gears in one go. Downshifts are limited to one per push, and the lever only releases in one direction a la SRAM.

My only real gripe with the design of the shifter is that the rubber cover of the cable port is a little hard to reseat after changing the cable, but that’s a minor niggle and not something you’ll be doing all that often. 

IG-Spec TRP TR12 Derailleur and Shifter Kit on the trail

Installation of both the shifter and mech was very straightforward, and the printed guides on the mech took any guesswork out of getting both the chain length and b-tension right. 

Once out on the trail, shifting has been nice and accurate, with shifts towards the smaller cogs, in particular, being really precise and snappy. Out of the box, shifting back up to the larger cogs was equally good, if not quite as refined as offerings from SRAM or Shimano. Over time, however, I’ve found the design to be really susceptible to cable wear – after only four months’ use, shifting back up the cassette had deteriorated quite significantly. 

My Deviate Highlander test bike has a full-length cable outer, and the cable I replaced didn’t look especially corroded so I wouldn’t expect such a change in performance over such a relatively short period of time. I spoke with UK importers Upgrade about this, and they suggested lowering the clutch tension which I did. This is a really straightforward process, but even with the clutch fully disengaged, there was still more resistance than expected. It’s not a deal-breaker and over time you adapt, but it is especially noticeable when jumping back and forth between bikes with different drivetrains. 

Our tech editor Andi has been running a TR12 shifter and mech on his Cotic BFe for a month or so, and is yet to encounter any shifting issues but it’s something he’s going to be keeping an eye on, so stay tuned for any updates.

The TR12 rear mech itself is robust, and after four hard months in the Lakes, it’s wearing plenty of battle scars from some rather close encounters with some immovable rocks. In spite of this, the mech isn’t showing any sign of weakness or misalignment. There’s no wobble, and the shifting is still as precise and accurate as it was the day I fitted it. 

Three things that could be improved

  • Stiff shifting on the way up
  • Expensive
  • Mech doesn’t swing out of the way quite as easily to remove or install rear wheel

Three things we loved

  • Great feeling down shift
  • Robust and durable rear mech
  • Makes for a quiet drivetrain


As much as I love a robust and durable rear mech, the long term performance of the TR12 shifter leaves a lot to be desired, and after only a couple of months of use isn’t really comparable to offerings from either SRAM or Shimano. The two items aren’t cheap either – at £220 for the mech and £110 for the shifter, the TR12 drivetrain is at a similar price point to Sram Eagle X01 or Shimano XTR, and both these options perform significantly better than the TR12.

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Review Info

Brand: TRP
Product: TR12
From: Upgrade
Price: Rear mech £220, Shifter £110
Tested: by James Vincent for 6 months

Having ridden bikes for as long as he can remember, James takes a certain twisted pleasure in carrying his bike to the most inaccessible locations he can find, before attempting to ride back down again, preferably with both feet on the pedals. After seeing the light on a recent road trip to Austria, James walked away from the stresses of running a design agency, picked up a camera and is several years deep into a mid life crisis that shows no sign of abating. As a photographer, he enjoys nothing more than climbing trees and asking others to follow his sketchy lines while expecting them to make it look as natural and stylish as possible. He has come to realise this is infinitely more fun than being tied to a desk, and is in no hurry to go back.

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