GearGrindr sprocket logoGearGrindrV1.2

Choose two components

And we'll find the third

Component database

Every shifter, derailleur, and cassette currently known to GearGrindr. These are the numbers feeding the compatibility math.

Note: published cable-pull, leverage, and cog-pitch values are rounded to one or two decimals, so the math for a manufacturer's own matched set (same brand + same speed count for shifter, derailleur, and cassette) rarely lands exactly on the listed cog pitch. GearGrindr treats those designed-together stacks as 0% deviation by using the calculated pitch (shifter pull × derailleur leverage) instead of the rounded cassette value — the cog pitch column below is still the published figure.

How the math works

Officially, you stay inside one groupset. In reality, drivetrains are just cable pull times derailleur leverage compared against cog pitch. GearGrindr does the math so you can build the bike you actually want.

01
Cable per click

Every shifter pulls a specific amount of cable each time you click. Shimano 11s road = 2.7mm. SRAM 11s MTB = 3.8mm. Etc.

2.7 mm
02
Times leverage

The derailleur multiplies cable pull into lateral cage movement. A 1.4 leverage means 1mm of cable becomes 1.4mm of sideways cage movement.

× 1.4
03
Equals cog spacing

That movement should equal the cassette's cog-to-cog distance. If it does, the chain lands on the next cog cleanly.

= 3.78 mm

GearGrindr compares this calculated movement against the cassette's actual cog pitch. A deviation under ±1.5% indexes perfectly. Up to ±4% usually tunes in. Beyond ±8%, don't bother.

Update log

What's changed in GearGrindr over time. Newest first.

  • V1.2

    Added Shimano GRX (10/11/12-speed) shifters and derailleurs. Added this update log.

  • V1.1

    Cog ladder rotated to a horizontal strip; clearer separation between Shifters, Derailleurs, and Cassettes in the database.

  • V1.0

    Component database page added; system discriminator introduced to prevent false LinkGlide / Dyna-Sys matches.

  • V0.9

    SRAM DH 7-speed (X-Actuation) groupset added; assorted database fixes.

  • V0.8

    Cog Ladder and Deviation Chart visualizations added.

  • V0.7

    Database expanded to ~70 entries (Shimano, SRAM, Campagnolo, microSHIFT, Box, Rotor); fixed leverage-as-divisor calculation bug.