Sizing Information – Tillett Racing Seats

P1 Rib Protector Size Calculator

Chest Measurement

Size Chart

Size	Inches	Centimeters
MINI	19" - 22"	48 - 56 cm
C	22" - 26"	56 - 66 cm
XS	26" - 32"	66 - 81 cm
S	32" - 36.5"	81 - 93 cm
M	36.5" - 40"	93 - 102 cm
L	40" - 44"	102 - 112 cm
XL	44" - 48"	112 - 122 cm

Sizing Tips

Take chest measurements with a tape pulled tight around the chest.
For men and young children: measure at nipple height.
For ladies: measure as high up under the bust as possible.
Breathe in and out, noting the average circumference.
If between sizes, choose the smaller size.
The fit should be snug with no gaps—like a crash helmet.
Use the additional rear adjustment before sizing up.

P1 DEFENDER Size Calculator

Driver Height

Chest Circumference

Size Chart

Size	Driver Height (mm)	Chest (cm)
C	< 1160	63 - 73
C+	1160 - 1340	69 - 78
XS-	1340 - 1520	59 - 68.5
XS	1340 - 1520	70 - 80.5
XS+	1340 - 1520	78 - 89
S-	1520 - 1700	68 - 80.5
S	1520 - 1700	78 - 90.5
S+	1520 - 1700	88 - 100.5
M-	1700 - 1880	78 - 92
M	1700 - 1880	88 - 101.5
M+	1700 - 1880	98 - 118.5

Note: Drivers over 1.88m should choose the M sizes.

Sizing Tips

Height must fit within the correct "Driver height" window, or one category shorter.
Take chest measurements with a tape pulled tight at nipple height.
Breathe in and out, noting the average circumference.
If between sizes, choose the smaller size.
Use the additional 30mm rear adjustment before sizing up.
It is more comfortable to use the height category below your actual height (allowed by regulations).
If your chest falls outside your height range, a special size may be required.