Does Alpinestars Run Small? Sizing Guide for Riders

Short answer: for a lot of riders, yes. Alpinestars is an Italian brand cut on a European pattern, and the size on the tag doesn't mean what an American shopper expects. Here's what the chart actually says, what riders report, and how to pick your size without a return trip to the post office.

The number on the tag is a Euro size

RevZilla's Alpinestars chart states it plainly: the numeric sizes shown are Euro sizing [1]. A "52" is not a 52-inch chest. It maps to a chest of 102–106 cm (about 40–42 in), which the same chart lines up with US 42 and an alpha size of Large [1]. If you wear a 44 suit jacket and grab a 44, you'll end up in a jacket built for an 86–90 cm chest, the XS row [1].

A few rows from the men's leather jacket chart

Euro	USA	Alpha	Chest (cm)	Waist (cm)
48	38	SM-MD	94–98	80–84
50	40	MD-LG	98–102	84–88
52	42	LG	102–106	88–92
54	44	LG-XL	106–110	92–96
56	46	XL-2XL	110–114	96–100

Source: RevZilla's Alpinestars men's leather jacket sizing [1]. Notice that the alpha sizes overlap ("SM-MD", "LG-XL"). That's a hint that the letter size alone won't land you in the right jacket.

What riders report

On r/motorcyclegear, riders discussing Alpinestars jacket sizing commonly report going up one or two sizes from what they'd expect [2]. RevZilla's own review summary for the T-GP Plus R v4 jacket notes that some customers find it runs small in the chest and shoulders [3]. Neither is a universal rule. Plenty of slim riders are fine in their chart size, but if you're broad through the chest or shoulders, plan on the larger option when you're near the top of a range.

How to pick your size

Measure your chest around the fullest part, under the armpits, with the tape level [1]. Breathe normally.
Read the cm column, not the letter. Find the row your chest falls in.
Check the arm column. Alpinestars measures arm from the top of the shoulder (acromion) down to the wrist bone [1]. Long-armed riders sometimes need the next size for sleeve length alone.
Between sizes or broad-shouldered? Go up. The rider reports above point that direction, and a too-tight jacket pulls armor out of place.
Leather or race-style? RevZilla suggests taking a deep breath when you measure for leather or race gear, adding roughly a quarter to three-quarters of an inch, to leave room for a back protector [4].

Gloves and boots run on their own charts

Don't carry your jacket logic over. Alpinestars men's gloves are sized by hand circumference behind the knuckles: Medium is 8–8.5 in, Large 8.5–9 in, XL 9–9.5 in [1]. Boots are listed in EU sizes, where a 44 equals US 10–10.5 and a 45 equals US 11 [1].

Pants and race suits

Race suits use the same Euro numbering, with inseam and hip ranges added. A Euro 52 suit is listed for an 83–84 cm inseam and 103–107 cm hips [1]. If you plan to wear an airbag under a suit, RevZilla notes you'll need to account for the extra room it needs to deploy safely [1].

The bottom line

Alpinestars doesn't really "run small" so much as it speaks Euro and cuts close. Measure, read the centimeters, and size up if you're between rows or carry your width up top.

Measure once. We'll do the chart math.

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Sources

Size charts change. Always check the chart on the exact product page before you buy. Last checked October 15, 2026.