Bike Size Guide
Bike Size Guide
Getting the right bike size is essential for comfort, performance, and safety. An incorrectly sized bike can cause back pain, knee strain, and reduce your control on the road or trail. Use this guide to find your perfect fit.
How to Measure Yourself
1. Measure Your Height
Stand straight against a wall without shoes. Place a book flat on top of your head so it touches the wall. Mark where the bottom of the book meets the wall, then measure from the floor to the mark with a tape measure.
2. Measure Your Inside Leg (Inseam)
Stand with your back against a wall. Place a hardback book or ruler between your legs, spine up, as if sitting on a saddle. Pull it firmly upward. Measure from the top of the book straight down to the floor.
Quick Bike Size Chart
This general chart works for most adult bikes. For brand-specific sizing, see the detailed guides below.
| Rider Height | Rider Height (cm) | Road Bike Frame (cm) | Mountain Bike Frame (inches) |
|---|---|---|---|
| 4'10" - 5'1" | 148 - 155 | 47 - 49 | 13" - 14" (XS) |
| 5'1" - 5'5" | 155 - 165 | 49 - 52 | 15" - 16" (S) |
| 5'5" - 5'9" | 165 - 175 | 52 - 54 | 17" - 18" (M) |
| 5'9" - 6'0" | 175 - 183 | 54 - 56 | 19" - 20" (L) |
| 6'0" - 6'3" | 183 - 191 | 56 - 58 | 21" - 22" (XL) |
| 6'3" - 6'6" | 191 - 198 | 58 - 61 | 23"+ (XXL) |
Understanding Bike Sizing Systems
- Road bikes typically use frame size in centimetres (e.g. 52cm, 54cm, 56cm)
- Mountain bikes usually use inches (e.g. 17", 19") or letter sizes (S, M, L)
- Some brands like Giant use their own sizing (XS, S, M, M/L, L, XL)
- Specialized uses S-Sizing (S1-S6) on many newer models
If you fall between two sizes, consider your riding style: size down for a more agile, responsive feel, or size up for more stability at speed.
Brand-Specific Size Guides
Each manufacturer has slightly different geometry. Use these detailed guides for the most accurate fit:
- Giant Bike Size Guide - Road, mountain, gravel, and e-bike sizing
- Specialized Bike Size Guide - Road, MTB, e-bike, and S-Sizing explained
- Kona Bike Size Guide - Gravel, MTB, and all-mountain sizing
- GT Bike Size Guide - Mountain, road, BMX, and kids' sizing
Clothing & Equipment Size Guides
- Giant Clothing Size Guide - Jerseys, shorts, and the Giant Fit System
- Specialized Shoe Size Guide - EU, UK, and US conversions
- Specialized Glove & Clothing Size Guide - Apparel, gloves, socks, and shoe covers
Still Not Sure?
Our team are happy to help you find the right size. Get in touch with your height, inside leg measurement, and the bike you're interested in, and we'll recommend the best fit for you.