TRP TR12 rear derailleur and shifter review

TRP's trail and enduro TR12 12-speed mech and shifter are relative newcomers to the drivetrain market, but have been developed under the strict scrutiny of John Hall, Intense Factory Racing's lead mechanic, and downhill World Cup racer, Aaron Gwin.

Hall developed the mech with the idea of reducing chain slap and increasing performance, while Gwin helped develop the shifter, focusing on the cable release lever's ergonomics.

The result is the TR12 shifter and derailleur.

TRP TR12 rear derailleur and shifter specifications

Although I covered a lot of the technical details of the TR12 derailleur and shifter when it was announced last year, I'll run through its key features.

The TR12 derailleur is designed to work with other brands’ cassettes, chains and chainrings. It's said to be most compatible with SRAM’s 10-50t Eagle drivetrains, but TRP advises not to use the TR12 mech with sprockets over 50t setups – ruling out SRAM’s 10-52t and Shimano’s 10-51t cassettes.

A unique feature on the mech is the Hall Lock. Flicking this lever at the top of the mech prevents it from pivoting backwards on the hanger bolt too easily, in a bid to reduce chain slap. It can be set to on or off and has adjustable tension when it’s engaged.

There’s also a ratchet clutch to limit cage movement, which can be turned on or off and its tension increased using two 2mm Allen screw on the rear of the derailleur.

The mech features set up guides – small markers on the mech's body and cage – for chain length and b-tension position. It has a carbon fibre outer cage and upper link, while the inner cage, knuckle and parallelogram are made from forged aluminium.

The shifter’s upshift paddle has a 40-degree range of adjustment and both the shifter levers have a linear movement that's claimed to mimic the way a rider's thumb moves when shifting. The shifter's upper housing is made from carbon fibre.

The derailleur weighed 292g, while the shifter and cable weighed 126g.

TRP TR12 rear derailleur and shifter set up

Installation was straightforward, although it's crucial to follow TRP's instructions to avoid damaging the derailleur.

Set up was just as easy thanks to indicator guides for b-tension position and chain length, which proved invaluable, and the barrel adjuster on the shifter made indexing simple. Cable tension was easy to set, too.

To avoid encountering potential issues with a squeaking Hall Lock (read more on that below), TRP recommends applying anti-seize to the derailleur's b-tension screw and Hall Lock during assembly.

TRP TR12 rear derailleur and shifter performance

I did my main testing with a 10-45t Shimano XT setup, but also tried the 51t version and the mech shifted onto the big sprocket perfectly, hinting at a cautious approach from TRP.

Ignoring TRP's advice could invalidate the warranty, though.

With the adjustable tension set so that it locked the mech in place when I tried to move it by hand, it didn’t appear to reduce noise over rough terrain once riding.

The main pivot also began to creak, regardless of whether the Hall Lock was on or off. This didn’t affect performance, but made an otherwise silent bike quite noisy.

TRP advised applying anti-seize to the b-tension adjuster bolt where it contacts the hanger and where the Hall Lock clamps to the b-tension bolt. This cured the problem but I'm yet to encounter another derailleur on the market that needs anti-seize to stop it making noise.

The ratchet clutch's factory setting was quite loose, causing lots of chain slap, but it was easy to tension. This reduced chain slap a little, but I found the system noisier than SRAM or Shimano, and felt it interfered with the suspension action and shifting performance.

Finding the clutch tension's balance between reducing noise and chain movement, and not making downshifting too stiff, was tricky. Eventually I settled for a slightly hard-to-push cable pull shifter lever and a quieter bike.

My XT chain occasionally dropped down the cassette during long freewheel sections over rough ground (despite staying on the chainring), but in general stability was good.

The cage and upper link plus jockey wheels remained damage- and twist-free during the test period and the derailleur's parallelogram and main and cage pivots have also all remained virtually slop-free, despite a long and rigorous test period, with the mech racking up over 700km since fitting.

The shifter's cable pull paddle adjustment was useful and I had no problems getting it in the correct position for my tastes. The same couldn’t be said for the cable release lever that’s used to shift into a higher gear.

While its linear travel wasn’t a problem and felt good, the distance of the paddle from the handlebar, thanks to its position on the shifter’s body, meant that it wasn’t possible to shift gear without moving my hands along the bar. Rotating the shifter around the bar or moving it further along didn’t help solve the problem.

Although the paddle might be in the perfect position for Aaron Gwin's thumbs, the same couldn’t be said for mine.

Switching back to a Shimano or SRAM shifter felt like putting on an old pair of boots, highlighting the slightly unusual ergonomics of the TRP shift unit.

TRP TR12 rear derailleur and shifter bottom line

Overall, the TR12 mech and shifter has a quality and robust feel, which should be expected considering its price, and hasn’t succumbed to any of the abuse I threw at it.

However, the compromise required between light shifting and chain slap, and the cable release paddle location on the shifter, meant that, for me, Shimano and SRAM’s offerings still represent the best performance for the money out there.