Arai Helmet Liner Sizes Explained

So you're trying to replace your Arai Helmet liner & are getting a bit confused by the different options available. No worries, we're here to help. You may be getting a new liner to freshen up the old one, or to fine tune your helmets fit.  So how do you read Arai helmet liner sizes?

Arai COrsair-X Helmet Liner

For this example, we’re going to use the Liner for an Arai Corsair-X. We are NOT going to be discussing cheek pads, that's for a different guide. These liners are listed with both a Roman numeral & a size in millimeters. The Roman numerals correspond to helmet shell sizes. For the Corsair-X numbers are as follows:

  • I =XS
  • II = S
  • III = M&L
  • IV=XL
  • V = 2XL 

Just to recap, that means the M and L Corsair-X helmet share the same shell size.

The size in millimeters represents the thickness of the interior lining. For the Arai Corsair X, these are the sizes available:

  • 12mm
  • 10mm
  • 7mm
  • 5mm

In order to check what liner comes with your size helmet AND which size liner it can accept, please see the chart below:

Let's say you have a Small size Corsair-X, that means your shell code is II and it includes a 7mm liner (Blue dot that is filled in the chart). It can also accept a 10mm liner or a 5mm liner (Empty blue dot). When buying the Arai liner you may see it displayed as II - 5mm, II - 7mm, and II - 10mm.

If your Small sized helmet is a bit too big & your head sits too far inside, you'd want to get the thicker liner (the II-10mm). If the helmet is too snug and sits too low in the helmet, you'd want the thinner liner (the II-5mm).  And if you want to replace your original you'd get the II-7.

IMPORTANT: This info above can VARY based on the Arai helmet model you choose. Above we discussed the padding for a Corsair-X. Below you can see the same info for the Arai Regent-X, XD4 and Signet-X

Arai Signet-X Size Chart

We hope this blog post helped to explain Arai's unique sizing system for their helmet lining!


1 comment

Ron colpo

Ron colpo

Thank you for this excellent reference information, it explained to exactly what I need to order my new Arai helmet liner

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