No bike that fits yet?
Everything on this site starts from a bike that fits you, or from a fitter's numbers. If you have neither yet, this is how to get them, and what to bring back.
- Height or inseam
- not enough on their own, so I don't ask for them
- One reading
- good to about 5 mm with a plumb line; two averaged, ±3 mm
- Where they go
- I have my numbers · no account needed
Why I don't size you from your height
Two riders of the same height can need different sizes, because their legs, arms and backs differ. A size chart's height column guesses at all of that. I work out every size from where your saddle and bar actually sit, so I need those first.
Get a shop to set one up for you
Go to a shop and test ride the bikes you're thinking about. When one feels right, ask them to set it up for you: the saddle height, where the saddle sits and the bar. If it still feels right after that, measure it before you leave.
The measuring guide shows how. You need a tape, a plumb line, a level and the shop's blessing.
The five numbers to write down
- Bottom bracket, height from the floor
- up to the middle of the crank bolt
- Saddle, behind the BB
- along the floor, from the BB's mark back to the mark under the middle of the rails
- Saddle, height from the floor
- up to the middle of the rails
- Bar, forward of the BB
- along the floor, from the BB's mark to the mark under the middle of your bar clamp
- Bar, height from the floor
- up to the middle of your bar clamp
Measure the heights from the floor, and the distances along the floor from the mark under the bottom bracket, the middle of where the cranks turn. You don't need to do any sums. I take the bottom bracket's height off your saddle and bar heights for you.
Take each reading twice and use the average. One reading is good to about 5 mm, and two averaged to ±3 mm.
Type them into the first tab of 'I have my numbers', called 'The two points', just as you read them. 'From the floor' is already chosen.
Or have a bike fit
A fitter measures you on a bike and gives you a report. Every report I've seen prints these four:
- Saddle height
- bottom bracket to the top of the saddle, along the seat tube
- Saddle setback
- behind the cranks, to the middle of the rails
- Saddle to bar drop
- rail centre down to the middle of the bar clamp
- Saddle to bar
- horizontal, rail centre to the bar clamp
Type them in as they're written, on the second tab of 'I have my numbers', called 'The figures on my fit report'. It asks whether your fitter measured the setback to the saddle nose or to the middle of the rails.
What to bring back
The five numbers, and the bike they came off: its make, model, year and size, the stem's length and angle, and the spacers.
The numbers are all I need, and you don't need an account.
The bike is a back-up. If it's one of the 879 bikes in my catalogue, you can pick it as the bike you ride instead.
What I can't do for you
I can't put two bikes side by side for you until I have your numbers. Each bike's page still shows its geometry table.
Signed out, picking the bike you ride doesn't ask for your saddle height yet, so that way only places your bar. The numbers place both.
And I can't tell you whether you'll like how a bike rides. That's what the test ride is for.