Repair guides › Drivetrain

Convert 2x or 3x to 1x

Two front rings with a front derailleur: big ring for speed, small ring for climbing. Common on road, gravel and many hybrids (e.g. 50/34, 46/30, 36/22). The front derailleur pushes the chain between rings. The gap between the rings (e.g. 16 teeth on 46/30) plus your cassette range must fit the rear derailleur's total capacity. Avoid cross-chaining (big ring + biggest cog, small ring + smallest cog): it rubs and wears fast.

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Tools

• Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
• 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
• Chain tool: Oumers bike chain repair tool set ($)
• Quick-link pliers: Basic master link pliers ($)
• Quick links (match chain speed): Wippermann Connex Link 808 ($)
• Cable & housing cutter: Park Tool CN-10 ($$)
• Torx key set (T10–T50): TEKTON long arm Torx key set T10-T50 ($)
• 3/8" click torque wrench 10–60 Nm: Pro Bike Tool 3/8 inch Drive Click Torque Wrench Set 10-60 Nm ($$$)
• 3/8" ratchet + 14/15 mm sockets + 8 mm hex bit: TEKTON 3/8 inch drive socket set metric ($$)
• Square-taper crank puller: Park Tool CCP-22 ($)
• Chainring nut wrench: Park Tool CNW-2 ($)

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Steps

1. Pick a narrow-wide ring a little smaller than your current big ring (e.g. 40T replaces 46/30), in your crank's BCD. Riveted rings mean a new 1x crankset.
2. Remove the front derailleur, its cable and the left shifter (or leave the shifter and remove only the cable).
3. Fit the narrow-wide ring on the inner (or middle) position of the spider for a straight chainline, with the right spacers or short 1x chainring bolts.
4. Size the chain again for the new ring (biggest ring + biggest cog, skipping the derailleur, + 2 links; + 4 links if the biggest cog is 42T or larger).
5. A clutch rear derailleur or a chain guide stops chain drops on rough ground.

Torque

Diagram

Signs it needs doing

• Chain drops off inside or outside when shifting
• Rubbing in some gears (trim the front derailleur)
• Slow or hesitant up-shifts to the big ring
• Worn or bent teeth on the small ring

Related jobs

• 2x shifting and chainring care