The Gen2 Girder Carbon is Praxis's trail-focused carbon mountain bike crank, with a sculpted arm shape for better clearance on more frames. Choose the Girder for cross-country and trail riding, or the Girder HD, with a heavy-duty carbon layup, for enduro.

Highlights

• C.R.A.F.T. carbon arms made in-house by Praxis
• Girder 498 g, Girder HD 545 g (170 mm arm sets)
• Forged M30 alloy spindle (30 mm drive / 28 mm non-drive)
• 3-bolt direct-mount ring interface that takes any brand's 3-bolt DM ring
• 178 mm Q-factor

Girder or Girder HD?

Both share the same shape. The Girder is the lighter crank and suits most cross-country and trail riders. The HD uses a heavier-duty carbon layup for enduro, and Praxis suggests it for larger riders and anyone who is hard on their equipment or rides more aggressive trails. In this range the HD comes in 165 mm.

Chainline and rings

Praxis's Gen2 mountain bike cranks line the 3-bolt direct-mount interface up with the industry's standard ring offsets, so any brand's 3-bolt direct-mount ring gives the chainline you expect: a 0 mm offset ring gives a 55 mm chainline, a 3 mm offset ring gives 52 mm ("Boost") and a 6 mm offset ring gives 49 mm ("non-Boost"). A sticker on the back of the drive arm shows the options. Check which chainline your frame calls for before you choose.

The ring options come with a Praxis MTN DM1X ring: narrow-wide teeth, forged and machined 7000-series alloy, hard black anodised, and rated for 10/11/12-speed KMC, Shimano and SRAM chains. Praxis requires a clutch rear derailleur and recommends an upper chain guide for rough terrain.

Options

Compatibility & fit

Bottom bracket: needs a Praxis M30 bottom bracket (30 mm drive / 28 mm non-drive bearing), sold separately: BSA, BB90/92, T47 external bearing, or BB30/PF30.

Drivetrain: 1x Shimano or SRAM with a clutch rear derailleur; chain compatibility follows the ring you fit.

Power: Praxis lists Power2Max (NG and NG Eco) and SRM 3-bolt power meters, SRM power pedals and Garmin Rally power pedals for this crank.

The Tune Cycles workshop can fit the bottom bracket and crankset for you as a separate workshop service. Threaded shells need the right BB tool and press-fit shells need a proper bearing press, so it pays to have the shell checked and the bottom bracket fitted correctly first. The main crank bolt is torqued to 48–52 Nm with a torque wrench.