Sometimes bike sizing charts or our bike size calculator will recommend two different bike frame sizing options.
This means that both the larger and smaller road bike frame size or mountain bike frame size recommended will be suitable for you. To help you make the right choice we asked a bike specialist Dr. Barney Wainwright for some advice.
The key measurement is reach which is how long the bike feels in the riding position. Reach is affected by your trunk length as well as the length of your arms. Trunk length, also known as upper body length or sitting height, is the measurement from your hips to your shoulders.
If your trunk length or sitting height is longer than average, then the larger of the two sizes recommended in the size chart will be ideal.
If on the other hand you have a shorter than average trunk height, then the smaller of the two recommended sizes will probably be best for you.
What Size MTB Should I Choose If I Am Between Sizes?
Sometimes bike size charts will recommend two different sizing options. This means that both the larger and smaller sizes recommended will both be suitable. It is a personal choice which size to go for, but most mountain bikers tend to opt for the larger size. So you don’t feel too stretched, you can (depending on the model) fit a shorter stem to improve the fit of a larger bike without adversely affecting the handling. This is the opposite to a road bike where it is better to lengthen the stem rather than shorten it.
Does Wheel Size Make A Difference
Predominantly there are three wheel sizes used on mountain bikes; 26", 27.5" and 29" but some others do exist like 27.5+ and becoming more prevalent 'Mullet MTBs' (27.5″ rear & 29″ front).
The size of wheel you pick will alter your riding position & riding style
What Size Bike Do I Need?
Below you'll find our general bike frame size guide, however it's always best to check the bike sizing chart on the specific model which will be more accurate once you've narrowed down your options. Click on the frame size you want to see the bike models that are right for you.
Bike Size
Road Bike Size
Mountain Bike Size *
XXS
44cm
13”(33 cm)
XS
48cm
15”(38 cm)
S
51cm
16”(41 cm)
M
54cm
18”(46cm)
L
56cm
19”(48cm)
XL
58cm
20”(51 cm)
XXL
60cm
21”(53 cm)
XXXL
62
22”(56 cm)