42T Crankset with 170 mm Square Taper Arms and Motsuv Narrow-Wide Chainring 104 BCD Black

Step up from 38T for long stretches of steady pedalling

This 42T crankset pairs 170 mm square-taper crank arms with a Motsuv narrow-wide chainring. It suits riders who spend most of their time on sealed cycleways or firm gravel. If you often reach your highest gear on 38T, the 42T ring gives you more distance per pedal turn.

The 42T sits between 38T and 44T in the range. Keep the same cassette and it raises your gearing by about 10.5% over 38T. It also keeps your lowest gear about 4.5% lower than 44T for starts and short rises.

Key Features

• The 42-tooth ring gives you taller gearing for open sections while keeping a lower gear than 44T on the same cassette.
• Alternating narrow and wide teeth help keep a compatible chain engaged on a single-ring drivetrain.
• The 170 mm crank arms keep the same pedal circle when replacing another pair of the same length.
• The four-bolt 104 mm BCD mount lets you replace the chainring separately when it wears.

Specifications

• Crank arm length — 170 mm
• Bottom bracket interface — square taper
• Crank arm material — aluminium alloy
• Chainring — Motsuv 42-tooth narrow-wide
• Chainring mount — four-bolt 104 mm bolt circle diameter (BCD)
• Chainring outside diameter — 176 mm
• Colour — black

Benefits

1. Settle into a lower cadence on open paths. At the same speed and in the same rear gear, 42T takes fewer pedal turns than 38T.
2. Keep a slightly easier gear for short rises. Compared with 44T on the same cassette, 42T lowers every gear by about 4.5%.
3. Keep the crank length that suits you. If your current 170 mm arms feel comfortable, you can change the gearing and keep the same pedal circle.

Common Questions

• Q: When should I choose 42T over 38T?
  A: Choose 42T if you frequently reach your highest gear on open routes. If your route has frequent steep climbs or stop-start sections, 38T gives you lower gearing with the same cassette.
• Q: Why choose 170 mm arms with a 42T chainring?
  A: Choose 170 mm if that crank length suits your fit. The crank length sets the size of the pedal circle. The 42T ring and rear sprocket together set the gear ratio.
• Q: How do I check whether the 176 mm ring will clear my frame?
  A: Check the space around the drive-side chainstay with the ring in its intended position. Allow room for the chain on the ring. Also check the installed chainline and clearance for both crank arms.
• Q: What does 104 BCD mean?
  A: It is the diameter of the circle through the centres of the four mounting bolts. Use the 176 mm outside diameter to check space around the chainring.

Summary

Choose this 42T crankset if 170 mm arms suit your fit and 38T feels too low on open routes. Before fitting, check your square-taper bottom bracket, chainline and clearance for the ring and chain.