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MTB CRANK & CHAINRING FAQ | CANFIELD BIKES

*PLEASE NOTE:
• Canfield cranks are designed for use with 0mm offset rings on boost 148 frames
• Canfield cranks are SRAM GXP Compatible (will NOT work with DUB or Shimano bottom brackets)

HOW TO INSTALL CRANKS, BOTTOM BRACKET AND CHAINRING ON YOUR MOUNTAIN BIKE | Canfield AM/DH Cranks and Chainring Installation Guide and FAQ

  1. To mount either our standard tooth or narrow-wide chainring, please be sure to mount the chainring with the logo side facing the bottom bracket.
  2. When looking at the back (logo) side of the chainring, there is a countersunk cut in the ring that matches the retaining bolt locations. This will allow the chainring retention bolts to sit countersunk and flush on both mounting surfaces and allow proper retention between the chainring and crank.
  3. Mounting the chainring backward with the logo side out will not allow the bolt to sit at its proper, countersunk height and may cause damage to the chainring and bottom bracket when installed.
  4. Cranks are designed for use with a threaded SRAM GXP style bottom bracket and GXP style chainrings
  5. The NON-drive crank arm bolt must be tightened until the bolt fully bottoms, failure to do so will result in the crank arm coming loose shortly after riding.

Should I use a smaller chainring with shorter cranks? (Crank length and gear ratios)
A shorter crank arm is a shorter lever, so you have less mechanical advantage. When it comes to gear ratios, dropping 10mm in crank length (e.g. 170 to 160), is the approximate equivalent of going up two teeth in chainring size. However, you are also spinning smaller circles, which feel easier and negate some of the perceived increase in effort. So, you may want to try shorter cranks with your current chainring size, but if you want to keep the same gear ratio, you can go to a smaller ring.

Example: Final Gear Ratios Based on 29-inch Wheels and 51t gear on rear cassette.
• 170mm Cranks
      -30t front ring = 1.3/1 final gear
      -32t front ring = 1.4/1 final gear
• 160mm Cranks
      -30t front ring = 1.4/1 final gear
      -32t front ring = 1.5/1 final gear
• 150mm Crank
      -30t front ring = 1.5/1 final gear
      -32t front ring = 1.6/1 final gear

What width crank fits my mountain bike?
The two different sizes of Canfield AM/DH cranks refer to the width of the crank spindle which will correspond to the size of your frame’s bottom bracket width. The 73mm cranks will typically fit most all-mountain/enduro/trail bikes. Our 83mm cranksets typically fit downhill bikes. If unsure, please check your bike manufacturer’s specs.  

Do I need to use the included spacers when installing my cranks?
Canfield 68/73mm cranks will fit a 73mm bottom bracket without spacers. 68mm bottom brackets will require one 2.5mm spacer (included) on each side of the spindle upon installation.

Will Canfield cranks work with a press-fit bottom bracket?
All Canfield MTB cranks are designed for a SRAM GXP style threaded bottom bracket. There are some aftermarket cup conversion kits that adapt press-fit frames to work with GXP style threaded bottom brackets. 

We also have press-fit bottom brackets designed to work with Canfield Cranks available here.

What chainrings fit Canfield AM/DH cranks?
Canfield AM/DH cranks are designed to accept a SRAM GXP-style direct-mount chainring. We offer Canfield chainrings in regular and narrow-wide that are compatible with our crank sets, but there are many brands of chainring to choose from that are GXP direct-mount compatible.

Canfield Cranks have a slightly different offset than most cranks, so required chainring offset will differ as well. We recommend the following chainring offsets with Canfield Cranks:

• Non-Boost 142 frames: -3mm offset (normally sold for Boost frames)
• Boost 148 frames: 0mm offset (normally sold for Super Boost frames)
• Super Boost 157 frames: not compatible

My cranks are tight to install, how do I know when to stop turning the crank bolt? 
The NON-drive crank arm bolt must be tightened until the bolt fully bottoms. Failure to do can result in the crank arm coming loose during riding. The bolt will physically stop turning once completely tightened.

What is the torque spec for Canfield cranks?
65 to 70Nm. When new, may require up to 75Nm.

What crank length should I choose for MTB?
Crank length is important for proper fit and optimal performance on your mountain bike. Canfield Bikes offers many different crank arm lengths (including some of the shortest on the market) ranging from 150mm all the way to 170mm in 5mm increments. This allows riders of all sizes and ages the ability to customize their fit.

As a starting point, we recommend the following lengths based on inseam:

Geared trail/AM/enduro bike: 20% to 20.5% of inseam length
Example: With a 32" inseam, Lance runs 165mm on all trail bikes. 
20% = 162.5mm, 20.5% = 166.6mm
Downhill Bike: 19% to 19.5% of inseam length
Example: With a 32" inseam, Lance runs 155mm on his DH bikes.
19% = 154.4mm, 19.5% = 158.5mm
Singlespeed: 21% to 21.5% of inseam length
Example: With a 32" inseam, Lance would run 170-175mm if he hated himself enough to ride singlespeed.
21% = 170.7mm, 21.5% = 174.7mm 

 

Are shorter cranks better?
With the current crop of ultra-low bottom brackets on mountain bikes, shorter cranks allow for a little extra pedal clearance in rough terrain. But there are other benefits to shorter cranks. They can actually improve power and efficiency and help eliminate “dead spots” in your pedal stroke. Smaller riders and teens will also appreciate the ability to run shorter cranks on their bikes as they grow into new sizes. We have heard from many smaller riders praising us for the ability to actually get a bike to properly fit them thanks to the shorter cranks we offer. All Canfield MTB cranks are AM and DH rated for maximum strength and durability while being lightweight.