Big Bike Book Size Guide

Helmets Size Guide

How to measure your head

Using a soft tape measure or a piece of string and a ruler, wrap it around your head approximately 2.5cm (1 inch) above your eyebrows and above your ears. Keep the tape level all the way around. Take the measurement in centimetres. If you only have inches, multiply by 2.54.

Helmet sizing varies more between brands than clothing does. Shoei runs slightly smaller than Caberg at equivalent sizes. If you're on the boundary between two sizes, try both before buying.

General helmet sizing, head circumference in cm

Size cm inches Shoei Caberg Airoh
XS 53–54 20¾–21¼ XS XS XS
S 55–56 21¾–22 S S S
M 57–58 22½–22¾ M M M
L 59–60 23¼–23½ L L L
XL 61–62 24–24½ XL XL XL
XXL 63–64 24¾–25¼ XXL XXL XXL
XXXL 65–66 25½–26 XXXL XXXL XXXL

 

Helmet shape guide

Head shape Description Recommended brands
Round oval Width and length roughly equal Shoei, Caberg
Intermediate oval Slightly longer front to back Most brands, the most common fit
Long oval Noticeably longer front to back Airoh, Caberg Duke range


Clothing Size Guide

How to measure for clothing

  • Chest: measure around the fullest part of your chest, keeping the tape level under your arms. 
  • Waist: measure around your natural waistline. 
  • Hips: measure around the fullest part of your hips. 
  • Inside leg: measure from your crotch to your ankle. All measurements in centimetres.
Motorcycle jackets are cut to be worn over base layers. If you plan to wear a thick mid-layer in winter, go up one size.

Jackets, chest (cm)

Size Chest cm Chest in
S 86–91 34–36
M 91–97 36–38
L 97–102 38–40
XL 102–107 40–42
2XL 107–112 42–44
3XL 112–117 44–46
4XL 117–122 46–48

 

Trousers, waist (cm)

Size Waist cm Waist in
S / 28 71–76 28–30
M / 30 76–81 30–32
L / 32 81–86 32–34
XL / 34 86–91 34–36
2XL / 36 91–97 36–38
3XL / 38 97–107 38–42

 

Short leg lengths (Spada items)

Label Inside leg cm Inside leg in
Short / S 73–76 29–30
Regular / R 79–81 31–32
Long / L 84–86 33–34

 

Gloves Size Guide

How to measure for gloves

Using a tape measure, wrap it around the widest part of your palm, excluding the thumb. Keep your hand flat and fingers together. Measure in centimetres. Alternatively, measure in inches: your glove size roughly equals your palm circumference in inches.

Size Palm cm Palm inches (approx)
XS 16–17 6¼–6¾
S 17–19 6¾–7½
M 19–21 7½–8¼
L 21–23 8¼–9
XL 23–24 9–9½
XXL 24–26 9½–10¼
XXXL 26–28 10¼–11

Motorcycle gloves should fit snugly with no excess material at the fingertips. A glove that is too long at the fingers will bunch under your grips. If between sizes, size down for short-fingered gloves, size up for gauntlet styles.

Footwear Size Guide

How to measure for boots and footwear

Stand on a sheet of paper and draw around your foot. Measure the distance from the back of your heel to the tip of your longest toe in centimetres. Use this measurement to find your size below. Sidi uses EU sizing, match your foot length to the EU column, not the UK column.

Sidi boots run true to EU size but can feel narrow on wide feet. If you have a wide foot, consider going half a size up. Spada footwear runs slightly large, if between sizes, size down.

UK EU US Foot length cm
5 38 6 24.0
5.5 38.5 6.5 24.3
6 39 7 24.7
6.5 40 7.5 25.3
7 41 8 25.7
7.5 41.5 8.5 26.0
8 42 9 26.7
8.5 43 9.5 27.0
9 43.5 10 27.3
9.5 44 10.5 27.7
10 44.5 11 28.0
10.5 45 11.5 28.7
11 46 12 29.3
12 47 13 30.0

Still unsure? Email us at bigbikebook@feridax.com or call +44 (0)1384 413841, we're happy to advise on specific products before you order.