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TRP Launches G-Spec TR12 Mountain Bike Derailleur and Shifter 2

A new 12-speed mountain bike rear derailleur and shifter for trail bikes follow in the footsteps of the G-Spec DH drivetrain released previously.

TRP Launches G-Spec TR12 Mountain Bike Derailleur and Shifter

A new 12-speed drivetrain option is now available for trail and enduro mountain bikers. TRP released the G-Spec TR12 rear derailleur and shifter today, in addition to the G-Spec GH7 downhill-specific drivetrain launched previously. Both derailleur and shifter have unique features not seen on 12-speed offerings from SRAM or Shimano, but those features come at a premium price.

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TRP TR12 Rear Derailleur Features

  • Hall Lock – adjustable
  • Ratchet Clutch – Adjustable
  • On-off clutch switch
  • Chain length indicator
  • B-Tension indicator

TRP TR12 Shifter Features

  • Linear actuation on the release lever
  • Tactile grip built into the lever
  • Carbon upper cover and advanced carbon lever
  • Tool free cable replacement
  • Adjustable advance lever with 40 – degree adjustment

TRP TR12 Drivetrain Prices

First Impressions and Installation of the TR12 Drivetrain

TRP sent us the components to check out, so we swapped out a SRAM X01 derailleur and GX shifter while keeping the SRAM Eagle cassette to pair the TR12 with. We did not have a chance to try the system with a Shimano 12-speed cassette.

TRP TR12 weights were within a few grams of the SRAM parts they replaced.
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The first thing you notice when you when you swing out the derailleur cage is the Ratchet Clutch sound when it returns from extension. This clutch is used on their DH7 derailleur as well, and as we found with the DH7, there is no noticeable ratchet sound on the trail from the TR12. The clutch has an on/off lever (off for maintenance and adjustment, on for riding), and the tension of the clutch is adjustable via two 2mm hex set screws on the back of the derailleur. Out of the box, factory-set clutch tension should be dialed. TRP says they've included this adjustability to improve the longevity of the system. Over time, the tension of a clutch can diminish, and these adjusters allow tension to be restored. The adjustment is very sensitive. Just 1/8 of a turn of these hex nuts can impact clutch friction, resulting in a stiffer feel in shifting and potentially influencing suspension performance.

 

Clutch adjustment screws. Generally there is no need to adjust these out of the box.
Adjust if clutch tension diminishes over time.

The Hall Lock featured on the DH7 shows up on the TR12, too. Developed by John Hall, Aaron Gwin's mechanic, the Hall Lock is a lever that quickly flips up, allowing a clockwise rotation of the derailleur, easing wheel removal and installation. Tension can be adjusted on the Hall Lock using a 2mm hex set screw.

 

Hall Lock down for riding.
Hall Lock up for wheel removal, maintenance and tuning.

Chain length indicator. Line up the two chain links and you're set.

Handily, there is a chain length indicator at the top of the derailleur cage. When chain length is correct, the two chain link symbols should line up when the derailleur and chain are in the smallest cog. TRP installation instructions say to sort out chain length before any tuning (which makes sense). On our initial install, the chain felt a bit slack, even though the indicators were lined up. After tuning the B-gap screw, our the chain length indicators were no longer lined up, but a bit of chain slack had been removed. Even though the chain still felt slack in the small cog, the derailleur position looked appropriate in the largest cog, so we stuck with it. TRP says the guide is there to get you in the ballpark for chain length, and John Hall says, "use the closest link that adds a little bit of pressure onto the clutch." Suspension designs and chain growth in a system may require you to adjust your length accordingly.

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The tool-free cable port on the shifter is a nice touch.
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Installing the cable was easy thanks to tool-free access in the shifter, and setting high- and low-limit screws was just like with any other derailleur. B-gap setup is aided with a little white line on the back of the derailleur. TRP recommends 6.5 to 7.5mm between the upper pulley and the largest cassette cog. Getting a measuring tape back there for any accuracy is near impossible, but the line is a good starting point. Our inclination was to have the tips of the cassette cog teeth touch the line, but that caused a fair amount of jumping around in the system. TRP let us know that they tend to run the gap on the snug side, and that's where we found optimized shifting performance.

As you can see, the B-Gap indicator line is a bit higher up than one may think it should be. This is where our system shifted best and TRP says they tend to run a smaller B-Gap as well.

Since this is a new-to-us system, it took a little longer than normal to get the bike shifting well in the stand. Added component features mean more things to consider and tweak when setting up the drivetrain. This particular shifter and derailleur went on to two different test bikes, one of belongs to a tester who works at a local shop. A few of the shop's mechanics had a chance to work on the drivetrain while on his bike (a Specialized Stumpjumper EVO). There was a consensus among the mechanics that the added features and adjustments were less intuitive than what they typically work on. No task was insurmountable, but there will be a learning curve with the TRP components and the added adjustment features. 

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We should note, as per TRP instructions, all adjustments were done with the clutch in the off position and the Hall Lock open to release any tension in the hanger pivot and bolt. If you're used to SRAM Eagle derailleurs with nothing but limit screws to worry about, the Hall Lock and clutch on/off switch may take some getting used to during maintenance.

SRAM GX Shifter and TRP TR12 Shifter
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The TR12 shifter will mount up easily to a SRAM MatchMaker. TRP also includes a single bar mount for use with other brakes. We removed our SRAM GX shifter from the MatchMaker on our CODE brakes and mounted up the TR12 shifter. We tend to keep our shifters as far from our knuckles as possible and have found the dual-position option on SRAM shifters keeps our knuckles scab-free. The TRP shifter paddles are large and grippy, but ended up being too close for comfort for this particular cockpit. If we had a left-facing MatchMaker mount, that would probably solve the problem, but we didn't at the time of testing, and that may put the shifter levers too far out of reach. Using the TRP bar mount on the inside of our brake levers put the shifter a bit too far away, so we stuck with the MatchMaker we had.

SRAM GX shifter with MatchMaker
Knuckle clearance is plentiful.
TRP TR12 shifter with MatchMaker.
Shifter paddles pushing hand further out on bar and still getting knuckle contact.

TRP TR12 On the Trail

Shifting in the work stand was sorted out and we were stoked to get out on the trail. General shifting performance during climbing or seated pedaling is crisp and the linear throw of the upshift lever is a nice touch. Unfortunately, throughout our test, the TR12 was fairly noisy on rocky or rough descents, and we managed to lose the chain on multiple occasions. Our contributing tester runs an upper guide and our in-house tester does not use a chainguide - both had chains come off during rides. We managed to capture a couple derailments on camera,  on portions of trail that seemed relatively tame. These were obstacles or sections of trail we've ridden countless times without considering chainloss.

 

To remedy the situation, we triple-checked chains, derailleur hanger alignment, cassettes and chainrings, and we adjusted clutch tension to the point of impacting shifting performance. Obviously that's not the intent of clutch or design of the system, but it didn't really help with chain retention anyway. We even tried going with less clutch tension because, why not? We adjusted chain length, both longer and shorter, tuned and re-tuned shifting, and we still had noise and wild rides for our chain on both test bikes even though shifting was working well. Despite every attempt to make it work, we just couldn't be confident in the system when the trail got rough.

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Chain derailment on a rather innocuous section of trail.
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Watching slow-motion footage, it appears as if the cage doesn't retract fast enough after being thrust forward by a bump. The lower pulley is thrown forward and seems stays in the forward position compared to the SRAM derailleurs we filmed. Tension on the TRP is similar to, or greater, than the SRAM derailleur we swapped out. This lack of retraction keeps the chain slack and bouncing around. It would also appear the derailleur is tucking inward toward the wheel. This combo is throwing the chain off of the chainring from below and to the inside.

Needless to say, we were disappointed with our TR12 experience. Considering the cost of the system, we expect performance and reliability to be nearly flawless  We want to give TRP the benefit of the doubt and are returning the derailleur so they can verify that there is no defect with the one we tested. We will update you with news as it comes, and we hope that the TR12 system can be a successful player in the drivetrain game. TRP's brakes are on point, their DH7 components work well and we expect the TR12 will find form, too.

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