Learn · sizes
Whoop sizes: 65, 75, 85
Whoop sizes work like shoe sizes: the number is how far apart the motors are, in millimeters.
65 is the little one — it fits through chair legs and lives happily in your house. 75 is the middle kid — steadier, a bit more push. 85 is the big sibling — usually twice the battery, made for the backyard and the park.
Why you care: size decides where you can fly. Small house? 65. Gym or garage? 75. Outside with a breeze? 85.
The size is the wheelbase — motor-to-motor distance measured diagonally. Everything else follows from it:
- 65mm: 31mm props, ~19–26g, 1S. The living-room class: agile, harmless, and the cheapest crashes in the hobby.
- 75mm: 40mm props, ~24–40g, mostly 1S. More stable in the air and better in a gym or calm backyard; the spec-racing sweet spot.
- 85mm: 45mm props, usually 2S. Wind-capable, quicker, and where the DJI O4 camera builds start making weight sense.
- Bigger isn't better — it's different. Each step up buys stability and costs indoor-friendliness.
Use the size filter up top with the battery filter: 65mm+1S and 85mm+2S are the two classic setups.
- Inertia defines the feel: a 65 changes direction the instant you think it; an 85 carries momentum through corners. Gap margins that feel lazy on a 65 are tight on an 85.
- Class racing: 65mm is the classic tiny-whoop race class; 75mm spec classes (one-design builds) are where the competitive scene has consolidated — parity racing rewards lines, not wallets.
- Wind threshold: a 1S 65 gives up outdoors around a walking-pace breeze; a 2S 85 works in conditions that ground everything smaller.
- Prop discipline: prop size follows frame — and shaft/bore sizes differ per class, so your spares bin is per-size. Check each model's spec table.
- Wheelbase = diagonal motor-center distance; it caps prop diameter (props must clear each other and the frame), which sets disc area.
- Scaling laws bite fast at this end: mass grows roughly with the cube of linear size, disc area with the square — so each class up needs disproportionately more power, which is why 85mm pairs with 2S rather than a bigger 1S pack.
- Disc loading (weight per rotor area) predicts the feel: low-disc-loading 65s float and stop on a dime; higher-loaded 85s track like they're on rails and punish late braking.
- Response scaling: angular inertia grows ~r⁵ for similar structures — the deep reason a 65 flicks and an 85 carves, with identical rates configured.