helicoil bike pedal repair Unior Crank Saver Kit

helicoil bike pedal repair Unior Crank Saver KitA crank arm with stripped pedal threads is one of the more expensive failures a bike can hand a customer. Replacement crank arms ballpark from low three figures at the entry tier well into the four figures for premium carbon road and DH cranks; a stripped left arm on a high end Shimano or SRAM crankset can land in the same price band as a complete entry level groupset on its own. The Crank Saver Kit is the workshop intervention that turns that failure

A crank arm with stripped pedal threads is one of the more expensive failures a bike can hand a customer. Replacement crank arms ballpark from low three figures at the entry tier well into the four figures for premium carbon road and DH cranks; a stripped left arm on a high-end Shimano or SRAM crankset can land in the same price band as a complete entry-level groupset on its own.

The Crank Saver Kit is the workshop intervention that turns that failure from a parts purchase into a repair. The kit reams the existing pedal threads out to a larger oversize, cuts new threads in the reamed bore with a chase tap, and presses in a steel thread insert sized to the original 9/16″ × 20 TPI pedal-thread spec. The crank arm is back to standard pedal threads; the next pedal install is normal pedal-install work, not a salvage operation.

What's in the kit

• Reaming pedal taps for both the left (LH) and right (RH) crank arms; left pedals are left-hand thread to resist loosening under pedalling load, so the kit ships with one of each direction.
• Tap handle with the right interface for the reaming taps.
• Steel pedal-thread inserts (10-piece set) sized to 9/16″ × 20 TPI on the inside, with the larger thread on the outside that mates with the reamed bore.
• Steel storage case with our SOS foam cut-outs holding each component in its labelled position. The case earns its keep on the workshop bench: pulling out the kit shows you immediately whether anything is missing or out of place.

How the repair works

When a pedal threads come out of a crank arm with the pedal still attached, the threads in the arm are usually the failure point (aluminium thread under cyclic load, often after a previous over-tightening or cross-threading event). Replacing the arm is one option; the other, far cheaper option is the thread-insert repair the Crank Saver enables.

The reaming tap cuts the damaged threads out of the arm's bore and reams the bore to the insert's outer-thread size. The insert presses into the reamed bore (its outer threads grip the arm material; its inner threads are factory-cut to the standard 9/16″ × 20 TPI pedal spec). Once seated, the insert is mechanically fastened to the arm and won't back out under pedal-install or pedal-use torque.

A pedal threaded into the inserted bore takes the same torque spec as a pedal threaded into a fresh crank arm. The repair restores full strength.

Compatibility

• Aluminium crank arms with stripped 9/16″ × 20 TPI pedal threads (the standard pedal thread for adult bicycles)
• Both left (LH) and right (RH) sides; the kit includes taps for each direction.
• Not for carbon-fibre crank arms (the reaming step requires aluminium substrate; pedal-thread failures on carbon arms typically require manufacturer-warranty service or arm replacement).

Built in Zreče

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The Crank Saver Kit packages the workshop pedal-thread repair into one steel case with our SOS foam cut-outs; the case is the difference between a kit that lives on the bench and one that scatters through a parts bin within six months.

Pro tip from our mechanics

Most stripped pedal threads we see are the result of a pedal that backed out under riding load. Two prevention steps go a long way: tighten pedals to the manufacturer's spec (most current pedals call for around 35–40 Nm, with the pedal held still and the crank rotated, so torque is delivered cleanly), and always start the pedal threads by hand. A pedal that's hand-tight before the wrench engages is on-axis; one that takes a wrench to start is cross-threading.

For the broader crank-tools decision tree (puller selection, cap-tool gotchas, and when a crank is past saving): How to remove a crankset →.