Race Face SIXC Crankset Review

by Brian Mullin on July 17, 2010

I have been testing a set of the Race Face SIXC (silent C) cranks for almost 2 months now, and they have proven to be stiff, durable, have been good shifting, and are made of uber bling carbon fiber. The SIXC cranks are made with their Optimized Carbon Technology program, and have been created for All Mountain biking, so they are slightly overbuilt in comparison to the usual carbon cranks. They are strong enough for mellow freeride, but light enough to appease a weight weenie (like me) or a cross country rider.

In a nutshell: carbon fiber is a high strength, high stiffness material that when combined with a resin matrix creates a composite with exceptional mechanical properties!

Race Face SIXC Cranks
The crankset has an external bottom bracket, aluminum chainrings, carbon arms, and a CNC CrMo spindle, which is molded onto the drive side arm, and includes their spline “EXI” interface for the non drive arm. The SIXC all carbon composite arms are engineered and manufactured in their British Columbia factory, and are hollowed out, with the unneeded material removed from the core, and offer exceptional strength to weight ratio. I tested a 175 mm set in the 22/32/bashguard version (they come in double and triple configurations), and it weighed in at 752.1 grams, including the arm end covers (pedal boots).

Measured Specs (175mm):
Bottom bracket – 94.9 grams
Spacers – 1.3 grams (each)
Drive arm, spindle, chainrings – 457.7 grams
Non drive arm – 179.6 grams
Pedal washers – 2.5 grams
Pedal boot covers – 16.1 grams
Total – 752.1 grams

The EXI interface external bottom bracket system is easy to install or remove with standard tools, and has a fully adjustable chainline. There are multiple spacers to adjust for different bottom bracket widths and front derailer types, with micro spacers for exact fine tuning of the chainline if required. The bearing cups are triple wiper sealed, and the bearings are filled with Phil Wood grease. Installation was very straight forward, put on the bottom bracket, slide the drive side arm with its spindle into the BB, mesh the other arm on and tighten down with the 8mm bolt.

Installation steps:
1) Lube the threads of each bottom bracket cup, insert the drive side BB cup and tighten it to 47 N-m, insert the non drive BB cup and tighten it to 47 N-m.
2) Lube the race on the crank arm spindle, insert the spindle with its nifty guide cap into the BB, give it a few taps so that it lays flush against the bottom bracket, remove the spindles guide cap.
3) Lube the spindles spline and the non drive side crank arm threads, put on the non drive side crank arm 180 degrees to the drive side crank arm, tighten it down with a torque wrench with a 8mm socket to a monstrous and manly 61 N-m (it takes a lot of turning to get it there).
4) Done!

Impressions
The shifting was fine, perhaps not quite XTR, but pretty darn close. The gear changing between 22 to 32 to 22 was fairly short, and it made the jumps quickly, even under extreme loads. I felt no flex in the system, so it was as stiff as I could discern. The simple subdued graphics were a welcome change from the usual advertisement patterns of some bike products, and the cranks had an understated and functional look to themselves. They came with their innovative ‘Pedal End Boots’ (two colors), which go over the end of the carbon crank arms to protect them, like bashing hard into rocks, which is common, especially in All Mountain terrain. They are such useful units, that I have used them on other cranks, even non carbon ones, and at only 16 grams a pair, they are light, and offer extra cushioning when banging into things. I have slammed the cranks down hard on the bashguard, and it shows minimal damage, and certainly helped protect the more fragile teeth of the chainring.

The SIXC cranks are stiff, offered instant power access, were highly efficient, with no noticeable slop. I do a lot of slow speed hard torque moves on technical terrain, which puts incredible amounts of stress into the drivetrain system, and these cranks were superb in that realm. They offered fast acceleration, and provided a snappier feel while cranking and mashing on the pedals. These cranks are currently in a category by themselves, since no one offers an All Mountain carbon crankset.

Bottom Line
The Race Face SIXC carbon cranks are pretty darn sweet, they are light, stiff and offer good shifting. I liked the integrated bashguard, the choice of double or triple chainrings, and the Pedal End Boots. The SIXC cranks are nicely engineered and manufactured, and the overbuild and chainring combination’s really fit in with the All Mountain paradigm. This is an amazing lightweight crankset, that is all carbon (outside of the CrMo spindle and pedal inserts), has incredible power transition to the wheels, looks great and has very cool bash guards for the crank arm ends. They are one of the stiffest, and snappiest cranks I have ever used. Crackalicious!

Happiness is a nice Stiff one.

Strengths
– Stiff
– Lightweight
– Arm end caps
– Carbon

Weaknesses
– Pricey
– Not quite XTR shifting

Overall Rating: 4 Flamin’ Chili Peppers

MSRP $669

SIX Cranks Features

  • 3mm of chainline adjustability and fine tuning.
  • Pedal and spindle inserts are co-molded in place for a secure bond.
  • CNC 7075 aluminum chainrings.
  • “EXI” spline interface for the non drive arm to BB spindle.
  • Light CNC machined CrMo BB spindle is molded onto drive side crank arm.
  • Offered in either a triple ring set-up or Double ring with lightweight 7075 alloy bashguard.
  • All alloy Torx 30 hardware.
  • Crank bolt puller cap makes crank removal a snap with just an 8mm hex wrench.
  • Bearings feature our new custom triple wiper seal to better retain grease (Phil Wood waterproof grease) and keep contaminants out.
  • 2 sets of Pedal End Boots (gray and black).

SIX Cranks Specs

  • Intended use: All Mountain
  • Size: 170, 175mm and 68/73mm BB shell
  • Weight: 760g (175mm 22,32,44)
  • Color: Matte Carbon with orange decals or white decals
  • Chainline: 49 to 52mm
  • Chainring Configuration:
  • 22,32,44 22,32,44 & Bash 22,32 & Bash 24,36 & Bash

SIXC Cranks url: http://www.raceface.com/components/cranks/sixc/sixc/

{ 2 comments… read them below or add one }

Anonymous October 23, 2010 at 5:28 am

I just signed up to your blogs rss feed. Will you post more on this subject?

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Brian Mullin - Gram and Pastajet October 31, 2010 at 8:58 pm

I will keep covering as many Race Face products as I can! Thks.

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