Racing underwear size guide

Fireproof underwear is sized on your body, the same measurements as a suit, because it has to sit close to the skin to do anything at all. It is also the layer that decides whether the suit over the top of it still fits.

The quickest way to get it right

Watch out for paired sizes

Most mid range tops and long johns are not sold in single sizes. They come as XS-S, M-L and XL-XXL, which means there are only three garments in the whole range and each one has to stretch across two suit sizes. The OMP Tecnica Evo, the Sparco RW-7 and the Alpinestars ZX Evo V3 all work this way.

That is fine if you sit in the middle of a band. If you are on a boundary, a range sold in single sizes will fit you better than the paired one. The Sparco RW-11 Evo runs XS through to XXXL as seven separate sizes, and the Alpinestars Race V3 runs S to XXL. Worth the difference if you are hard to fit.

Tops and bottoms by brand

SparcoLetters follow their suit ladder. XS to XXXL depending on the range.▼

Letter	Suit size	Chest (cm)	Waist (cm)
XS	44 / 46	86 – 93	74 – 81
S	48 / 50	94 – 101	82 – 87
M	52 / 54	102 – 109	88 – 97
L	56 / 58	110 – 117	98 – 105
XL	60 / 62	118 – 125	106 – 113
XXL	64 / 66	126 – 133	114 – 121

Sparco publish no separate underwear chart. These are the bands from their own man body size chart, which is what their underwear letters follow.

AlpinestarsXS to XL published. XXL and 3XL are sold without published measurements.▼

Letter	Chest (cm)	Waist (cm)
XS	86 – 90	72 – 76
S	90 – 94	76 – 80
M	94 – 98	80 – 84
L	102 – 106	88 – 92
XL	106 – 110	92 – 96

From the size guide on the Race V3 Top Tech Layer. Two things to know. Their own chart jumps from 98 cm to 102 cm between M and L, so a 98 to 102 cm chest falls in a gap; ring us if that is you. And they sell XXL and 3XL without listing the measurements, so ring us for those as well rather than working them out from the XL row.

WaleroXS to XXXL. The only brand here that publishes garment lengths as well as body measurements.▼

Tops

Size	Height (cm)	Chest (cm)	Length (cm)	Sleeve (cm)
XS	153 – 164	86 – 92	68	70
S	164 – 172	92 – 97	70	72
M	170 – 180	97 – 102	72	74
L	174 – 186	102 – 112	74	76
XL	182 – 190	107 – 117	76	78
XXL	182 – 190	112 – 122	78	80
XXXL	188 – 196	122+	81	83

Leggings and long johns

Size	Height (cm)	Waist (cm)	Side (cm)
XS	153 – 164	56 – 59	100 – 102
S	164 – 172	59 – 76	101 – 104
M	170 – 180	76 – 84	104 – 106
L	174 – 186	84 – 92	106 – 108
XL	182 – 190	92 – 97	108 – 110
XXL	182 – 190	92 – 97	110 – 112
XXXL	188 – 196	102	112 – 115

Walero size on height as much as chest, so read both columns. The XL and XXL height bands really are the same on their chart; the difference between those two is chest and waist, not length.

OMP and SabeltSold in letters with no published measurements.▼

OMP put a size chart on every suit, shoe and glove product page but not on their underwear, and Sabelt publish nothing for the UI-100. Rather than convert from another brand’s chart and get it wrong, size these from your OMP or Sabelt suit size, or send us your chest and waist and we will confirm before it ships.

Socks

Socks go by shoe size, not by clothing size, and the two brands that publish a ladder do not use the same one.

Alpinestars do not make an XS sock. OMP sell theirs in XS, S, M and L but only publish the shoe range for XS, which is UK 5 to 5.5. Walero sell XS, S/M and M/L. Nomex socks are noticeably thicker than everyday ones, so if you are buying boots at the same time, try them on together or allow for it.

Balaclavas

Most of the balaclavas we stock are one size and stretch to fit, including the whole Sparco RW-4, RW-7 and RW-10 range, the Alpinestars ZX Evo, the MOMO Pro and the Sparco Pista. Where a balaclava is sized, it is sold as two: Adult S/M and Adult L/XL. That covers the OMP One Evo and Tecnica Evo, the Alpinestars Race V3 and the Walero open face.

Open face and full face is a fit decision as much as a preference. An open face balaclava leaves the eye opening wide and suits a full face helmet with a wide aperture. A full face balaclava has a smaller eye slot and sits tighter across the nose. If you wear glasses, the open face is the easier one to get on without dragging the arms out of place.

Sparco bands from sparco-official.com. Alpinestars from the size guide on their Race V3 Top Tech Layer. Walero from walero.uk. Sock ladders from the size options on the products themselves. All checked 2 August 2026. OMP and Sabelt publish no underwear measurements at all, which is why they are not tabulated above.