Bike gear ratio calculator
Pick your chainrings, cassette, and tire. See every gear’s ratio, rollout, and speed at your cadence — then compare a second setup before you buy.
Example: 50/34 compact with an 11–32 cassette on 700×28c at 90 rpm. Total range 428%. 50/11 is about 52 km/h. 34/32 is the climbing gear.
Road compact vs SRAM AXS
A Shimano-style 50/34 with 11–34 covers similar ground to SRAM 48/35 with a 10–36. SRAM’s 10-tooth cog buys back top-end that smaller rings would lose. Use Compare to overlay both at the same cadence.
Gravel 1× and climbing gears
A 40T with 10–44 XPLR is a typical gravel 1×. Lowest ratio sits near 0.91 — easier than a road compact’s 34/32. If you tour loaded, check that the low gear is at or below 1.0 before you leave the small ring behind.
MTB Eagle range
32T × 10–52 is a 520% cassette. The steps get wider on the climbing cogs. That is normal: you trade even spacing for not walking the steep pitches.
FAQ
How do you calculate bike gear ratios?
Gear ratio is chainring teeth divided by cassette cog teeth. A 50/11 is 4.55; a 34/32 is 1.06. Higher ratio = harder / faster at the same cadence.
What are gear inches and metres of development?
Development is how far the bike rolls in one pedal revolution (ratio × tire circumference). Gear inches is the equivalent penny-farthing wheel diameter. Speed at cadence is development × rpm × 0.06, in km/h.
What does 428% or 520% gear range mean?
Range is hardest gear divided by easiest, as a percent. 50/34 × 11–32 is about 428%. SRAM’s “520%” Eagle figure is cassette-only (52 ÷ 10). This calculator shows both drivetrain range and cassette range.
Is 1× or 2× better?
2× usually has tighter steps and more overlap between rings. 1× is simpler and common on gravel and MTB. Compare a 50/34 + 11–34 against a 40T + 10–44 on this page — the chart shows gaps and overlap immediately.
What is cross-chaining?
Big ring + biggest cogs, or small ring + smallest cogs. The chain runs at a steep angle and wears faster. We grey those combos when Avoid cross-chaining is on — the same idea as Crossing / Ritzelrechner.
Does tire size change my gears?
Yes. A fatter tire rolls farther per revolution, so the same 50/11 is slightly faster on 700×32c than on 700×25c. Circumferences here follow common ETRTO rollouts (700×28c = 2136 mm). Enter a measured rollout if you have one.
Gearing is chosen. Wear still adds up. Tiiks tracks kilometres on your chain, cassette, and chainrings after every ride, so you replace them on time — not after they skip.
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