Bike Sizing Guide

Bike sizingChoosing the correct frame size

When you straddle the bicycle frame with your feet flat on the ground, as illustrated here, you should be able to clear the top tube (crossbar).

Although every manufacturer has their own sizing quirks, a bike’s frame size is based on the length of the seat tube (the tube that the seatpost goes into). Please see the tables below for sizing guides.

If you prefer more athletic riding, particularly mountain biking over rough terrain, you are safest with maximum clearance, so plump for the smallest possible frame – as long as you can still stretch your legs and the bike isn’t so short that it cramps your riding style.

If you like to sit upright, go for the biggest frame that still allows top tube clearance.
Calculating the correct frame size

You can get a rough idea of the size of frame you require if you measure your inside leg – crotch to floor – then subtract:

  • 9″ / 23cm or 10″ / 25cm for a road bike (or a mountain bike used as a road bike)
  • 12″ / 30cm for an athletically-ridden mountain bike.

Bike sizing tables

The following tables offer a rough guide to the correct frame size to choose however it is dependent on your riding style. If you have any queries please contact our sales team on 0845 257 0808 or 0131 331 5010 alternatively you can email us – enquiries@edinburghbicycle.com – If possible for sizing enquiries please include the rider height and inside leg measurement.


Road bikes

Bike Size Rider Height Rider Height (cm)
49cm 5′ 0″ – 5′ 3″ 152 – 160
52cm 5′ 3″ – 5′ 6″ 160 – 168
54cm 5′ 6″ – 5′ 9″ 168 – 175
56cm 5′ 9″ – 6′ 0″ 175 – 183
58cm 6′ 0″ – 6′ 3″ 183 – 191
61cm 6′ 3″ – 6′ 6″ 191 – 198

Giant road bikes sizing

Conventional Size (Equiv) Compact Sizing Rider Height Rider Height (cm)
49-51cm XS 5′ 2″ – 5′ 4″ 157 – 163
51-54cm S 5′ 4″ – 5′ 7″ 163 – 170
55-57cm M 5′ 7″ – 5’10” 170 – 178
57-59cm M/L 5′ 10″ – 6′ 0″ 178 – 183
58-60cm L 6′ 0″ – 6′ 3″ 183 – 191
61-63cm XL 6′ 3″ – 6′ 6″ 191 – 198

Merckx road bikes sizing

Like the majority of road bike manufacturers from Giant to Specialized, Merckx Cycles employ ‘compact geometry’. This means that Merckx frames have sloping top tubes rather than traditional horizontal top tubes.

Merckx Cycles’ sizing is quoted according to the actual seat tube length – 42, 45, 48, 51 or 54cm – measured centre to centre). This might cause confusion because most other companies quote a ‘virtual’ seat tube length based upon how long the seat tube would have been if the frame had been built with a horizontal top tube. Hence our Eddy Reckoner – if you normally ride a 51cm road bike you want a 42cm Merckx, and so on.

Traditional Road Bike Sizing Merckx Sizing Rider Height Rider Height (cm)
51cm 42cm 5′ 2″ – 5′ 4″ 155 – 163
53cm 45cm 5′ 4″ – 5′ 7″ 163 – 175
56cm 48cm 5′ 7″ – 6′ 0″ 175 – 183
58cm 51cm 6′ 0″ – 6′ 3″ 183 – 191
60cm 54cm 6′ 3″ – 6′ 6″ 191 – 198

Mountain bikes

Bike Size Rider Height Rider Height (cm)
13″ – 14″ 5′ 0″ – 5′ 2″ 152 – 158
15″ – 16″ 5′ 2″ – 5′ 6″ 158 – 168
17″ – 18″ 5′ 6″ – 5′ 10″ 168 – 178
19″ – 20″ 5′ 10″ – 6′ 1″ 178 – 185
21″ – 22″ 6′ 1″ -6′ 5″ 185 – 193
23″ – 24″ 6′ 4″ – 6′ 6″ 193 – 198

Commuter/Hybrid bikes

Bike Size Rider Height Rider Height (cm)
Extra Small 13″ – 14″ 5′ 0″ – 5′ 3″ 147 – 155
Small 15″ – 16″ 5′ 1″ – 5′ 5″ 155 – 165
Medium 17″ – 18″ 5′ 5″ – 5′ 9″ 165 – 175
Large 19″ – 20″ 5′ 9″ – 6′ 0″ 175 – 183
Extra Large 21″ – 22″ 6′ 0″ – 6′ 3″ 183 – 191

Touring bikes

Bike Size Compact Rider Height Rider Height (cm)
50cm 5′ 0″ – 5′ 3″ 152 – 160
52cm (46cm – 49cm compact frames) 5′ 3″ – 5′ 6″ 160 – 168
54cm 5′ 6″ – 5′ 9″ 168 – 175
56cm (50cm – 53cm compact frames) 5′ 9″ – 6′ 0″ 175 – 183
58cm 6′ 0″ – 6′ 3″ 183 – 191
61cm

BMX & Jump bikes

BMX & Jump bikes are usually only available in one size which will suit most riders however there are some exceptions. If you are unsure please contact us on 0845 257 0808 or 0131 331 4675 alternatively you can email us. If possible for sizing enquiries please include the rider height and inside leg measurement.

Kids’ bikes

Bike Size Wheel Size
2 – 4 years Balance Bike
3 – 5 years 12″
4 – 7 years 16″
5 – 10 years 20″
8 – 14 years 24″
11+ 13″ – 14″ adult

Frog Bikes

In contrast to many children’s bikes, Frog bikes are sized by the leg length rather than age. More info is available on the Frog Bikes website.

Frog Bike Minimum
inside leg (cm)
Approx min
height (cm)
Approx
min age
Tadpole 34 98 2-3
Frog 43 43 104 3-4
Frog 48 48 110 4-5
Frog 52 52 116 5-6
Frog 55 55 122 6-7
Frog 60 MTB 60 130 8-10
Frog 62 62 134 8-10
Frog 69 69 147 10-12
Frog 73 73 158 12-14

Find out more detailed information on kids’ bike sizing.

Women’s bikes

Women’s mountain bikes

Bike Size Frame Rider Height Rider Height (cm)
Extra Small 13″ – 16″ 4′ 9″ – 5′ 4″ 152 – 160
Small 5′ 4″ – 5′ 8″ 158 – 168
Medium 17″ – 20″ 5′ 8″ – 6′ 0″ 165 – 175
Large 6′ 0″ – 6′ 3″ 173 – 183

Women’s road bikes

Bike Size Rider Height Rider Height (cm)
44cm 4′ 10″ – 5′ 1″ 147 – 155
48cm 5′ 1″ – 5′ 3″ 155 – 160
51cm 5′ 3″ – 5′ 5″ 160 – 165
54cm 5′ 5″ – 5′ 7″ 165 – 170
57cm 5′ 7″ – 5′ 11″ 170 – 180

Women’s Giant road bikes

Conventional Size (Equiv) Compact Sizing Rider Height Rider Height (cm)
47cm 2XS 5′ 0″ – 5′ 2″ 152 – 157
49-51cm XS 5′ 2″ – 5′ 4″ 157 – 163
51-54cm S 5′ 4″ – 5’6″ 163 – 168
55-57cm M 5′ 6″ – 5′ 8″ 168 – 173
57-59cm L 5′ 7″ – 5′ 10″ 170 – 178

Looking for our Clothing Sizing Guide? Take a look >