38T Crankset with 170 mm Square Taper Arms and 104 BCD Narrow-Wide Chainring Black

A step up from 36T for open cycleways and firm gravel

If your usual ride follows a long cycleway but still includes a few climbs, consider this 38T crankset. It pairs 170 mm square-taper arms with a 38-tooth narrow-wide chainring for a compatible single-ring drivetrain.

A 38T ring makes sense when you regularly reach your highest gear on a 36T setup. With the same rear sprocket, you travel about 5.6% farther per pedal turn. Compared with 44T, it keeps your lowest gear easier to turn on the way home.

Key Features

• The 38-tooth chainring gives taller gearing than 36T and lower gearing than 44T on the same cassette.
• Alternating narrow and wide teeth help keep a compatible chain seated over rough patches.
• The 170 mm arms retain the same pedal circle when replacing another pair of that 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
• Chainring mount — four-bolt 104 mm bolt circle diameter (BCD)
• Chainring — 38 teeth with a narrow-wide profile
• Chainring outside diameter — 160.3 mm
• Chainring material — 7075 aluminium alloy
• Chainring weight — approximately 72 g
• Crank arm material — aluminium alloy
• Colour — black

Benefits

1. Pedal at a slightly lower cadence on open sections. At the same speed and in the same rear gear, 38T needs fewer pedal turns than 36T.
2. Keep an easier climbing gear than 44T. If you ride rolling routes, 38T gives you some extra top-end gearing over 36T while keeping the gearing below 44T.
3. Keep a familiar crank length. If 170 mm arms already suit your position, you can change the gearing and keep the same pedal circle.

Common Questions

• Q: When should I choose 38T over 36T?
  
  A: Choose 38T if you often reach your highest gear on flat or gently rolling rides. Choose 36T if you value a lower gear for frequent climbs or stop-start riding.
• Q: How does 38T compare with 44T?
  
  A: With the same cassette, 38T gives lower gearing across the range. Choose 38T if your route includes climbs and 44T would make your lowest gear too tall.
• Q: How do I check whether this crankset fits my bike?
  
  A: Check for a compatible square-taper bottom bracket and a suitable chainline. The bare ring measures 160.3 mm across. Allow room for the chain where it passes the chainstay and check that both crank arms clear the frame.
• Q: What does 104 BCD tell me?
  
  A: It is the diameter of the circle through the centres of the four mounting bolts. Use the 160.3 mm outside diameter to check space around the chainring.

Summary

Choose this 38T crankset if 170 mm arms suit your fit and 36T feels a little low on open routes. Check that your lowest rear gear still suits your climbs and that the ring and chain clear the frame.