Your inseam — the length from your crotch to the floor — decides how far down you reach on a bike far more than your height does. Here is how to measure it accurately in a minute.
Two riders the same height can differ by several centimetres of leg, and it is leg length, not height, that tells you whether you will flat-foot a bike. That is why the simulator asks for your inseam. You only need a wall and a hardcover book.
Back to the wall, book pulled up snug like a seat — measure from the top of the book to the floor.
Step by step
Take your trousers off and wear thin socks (no shoes) — jeans and shoe soles both add centimetres and throw the number off.
Stand with your back and heels against a wall, feet a few centimetres apart, standing up straight.
Put a hardcover book between your legs, spine facing up, and pull it up firmly until it presses where a bike seat would — snug, the way your weight sits on a saddle.
Keep the book level and mark or note where its top edge meets the wall.
Measure straight down from that mark to the floor. That distance is your inseam — enter it in the simulator.
Tips for a number you can trust
Press firmly. A soft, low book reads too long. Your body weight compresses a seat, so mimic that firm contact.
Measure in socks, ride in boots. Riding boots add roughly 2–3 cm of sole, so a borderline tip-toe result on paper often becomes balls-of-feet in real life.
Both feet share the load. The simulator assumes you can put both feet down; on a tall or wide bike many riders are comfortable on the balls of both feet rather than flat.
Seat height & wheelbase come straight from the manufacturer’s published specs, verified across the maker’s site, media reviews and spec databases.
Handlebar & footpeg positions aren’t published by any manufacturer. Where a true side-profile photo exists, we mark five reference points on it (front & rear axle, seat, grip, peg) and convert pixels to millimetres using the known wheelbase as the scale. Where it doesn’t, we research the grip and peg heights and estimate the horizontal reach from class-typical geometry.
Every result is cross-checked against how reviewers describe the bike’s posture (upright / sporty / committed), and each bike page carries a data-confidence badge so you can see how solid its numbers are.
The drawing is a clean schematic — one shared template per bike type (naked, sport, cruiser, adventure, touring, dirt), anchored to each bike’s real seat, grip and peg coordinates — so you compare riding positions, not paint jobs.
Your figure is a stick model built from your height and inseam using standard body-proportion ratios, then posed by inverse kinematics — hips on the seat, hands on the bars, feet on the pegs — with the same posture solver for every bike.
Bottom line: seat height & wheelbase are hard data; handlebar/footpeg geometry and ground reach are calibrated estimates (see each bike’s data-confidence badge). Always sit on the real bike before you buy.