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?

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

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