What size bike do I need?
Direct answer · Cyclesite
Bike size is based on your height and inside leg measurement. For road bikes: 5'3"-5'6" = 50-52cm, 5'7"-5'9" = 54-56cm, 5'10"-6'0" = 56-58cm, 6'1"+ = 60-62cm. Mountain bikes use S/M/L sizing: 5'4"-5'7" = Small, 5'8"-5'11" = Medium, 6'0"-6'3" = Large. Always check the specific brand's size chart as geometry varies between manufacturers.
Last reviewed: 2026-09-21
Road bike sizing
Road bikes are measured by seat tube length in centimetres. General guide: under 5'3" = 47-49cm (XXS), 5'3"-5'6" = 50-52cm (XS/S), 5'7"-5'9" = 54-56cm (M), 5'10"-6'0" = 56-58cm (M/L), 6'1"-6'3" = 58-60cm (L/XL), over 6'3" = 61-63cm (XXL). Women-specific bikes often run smaller, check each brand's chart.
Mountain bike sizing
Mountain bikes use letter sizing. Under 5'4" = XS, 5'4"-5'7" = Small, 5'8"-5'11" = Medium, 6'0"-6'3" = Large, 6'3"+ = XL. Reach and stack measurements matter more than seat tube length for modern MTBs. If between sizes, go smaller for more agile handling or larger for more stability.
How to measure yourself
You need two measurements: overall height (stand against a wall, mark the top of your head) and inside leg/inseam (stand with feet 15cm apart, measure from floor to crotch). The inside leg determines standover height, you should be able to straddle the top tube with both feet flat on the ground and at least 2-5cm of clearance.
Average used bike prices by category (UK)
| Category | Average price | Sample size |
|---|---|---|
| Road Bikes | £1,268 | 43 |
| Mountain Bikes | £1,256 | 27 |
| Electric Bikes | £2,043 | 13 |
Last updated: 2026-10-20
Related Questions
What happens if I buy the wrong size bike?
A bike that's too large is uncomfortable and hard to control. A bike that's too small causes back pain and knee problems. Minor mismatches can be adjusted with stem length, seatpost height, and handlebar width, but a full size off is not fixable with adjustments.
Can I use Cyclesite to filter by frame size?
Yes. Cyclesite has frame size filters, so you can search your size range directly instead of reading every description to find out whether a bike would fit.
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