170mm Cranksets

Choosing a 170 mm crankset

If you’re replacing worn crank arms, check the length stamped on the inside of either arm. You can also measure from the centre of the bottom bracket spindle to the centre of the pedal axle.

Do you need crank arms or a set with a chainring?

Choose the arms-only option if your current four-bolt 104 mm BCD chainring still has life left. If you want to change your gearing or replace a worn ring, choose a set that includes the tooth count you need.

Which chainring size suits your ride?

Start with the tooth count on your current chainring. With the same rear gear and wheel size, fewer teeth make steep climbs easier. More teeth let you travel farther per pedal turn, but make starts and climbs harder.

• 32T and 34T offer the easiest gearing in this range for steep trails or frequent uphill starts.
• 36T and 38T suit rolling routes where you want a taller gear on the flats and still need to climb.
• 42T, 44T and 46T suit mostly sealed routes if your lowest rear gear still gets you up local hills.
• 48T and 52T offer the tallest gearing. Consider them if you often spin out in your highest gear on flat roads.

For example, moving from 42T to 38T lowers every gear by about 10% with the same rear gears. That makes climbs easier, but you’ll pedal faster to hold the same speed on the flat.

Check fit before ordering

• Bottom bracket: Check that the square-taper type and spindle length suit the crankset. Spindle length affects chainline and clearance between the cranks and frame.
• Chainring and chain: If you’re reusing a ring, confirm its four-bolt 104 mm BCD fit. For a narrow-wide option, check the product listing for chain compatibility.
• Frame clearance: If you’re fitting a larger ring, check that the ring and chain clear the drive-side chainstay. Check whether you’ll need a longer chain as well.