Slippery sons of...

Oh, hello. We're talking about the tire mousse. Makes you long for chocolate a bit, but ultimately a mousse insert, or tire mousse or Bib Mousse, as coined by Michelin, replaces the standard inner tube in a dirt bike tire and totally and completely eliminates flats.

The tire mousse has all sorts of benefits but also some drawbacks. No, nothing is ever perfect but the mousse comes close at least when it comes to riding your dirt bike without threat of encountering a flat tire. Yes, it's true you will not experience a flat tire if you replace the tubes in the tires with a mousse insert.

But more on that later.

Michelin developed the Bib Mousse in the 1980s which was readily received by those who ride off-road, where flats primarily occur. The Bib Mousse stands up very well against thorns, sharp-edged rocks and the pounding tires get from aggressive off-road riding. Over the years, the integrity of the tire mousse gained traction as more and more riders began to use them even for racing Motocross. In recent years, other manufacturers have developed their own mousse tire inserts and though the tire mousse generally gets marketed as proprietary for the specific tire maker, size usually only matters, therefore if you match the appropriate mousse size with your tire size regardless of brand you should have little problem running the mousse.

Benefits of the Tire Mousse System

Bottom line, the tire mousse eliminates flats. Instead of air inflating the tire, a foam tube or insert replaces the air and expands the tire. No tire pump necessary. Punctures have no effect on tire pressure and you can readily ride across razor sharp glass without losing tire pressure.

A foam insert inflates the tire in a mousse system

That's why the mousse was created and it performs as advertised. Some riders can't seem to ride one day without encountering a flat. If that describes you, the mousse system makes your life much easier and ride day becomes a more enjoyable outing rather than a frustrating exercise in tube repair or replacement.

If you race hare scrambles or other off-road events the competition probably uses the tire mousse therefore if you want to legitimately compete then install the mousse.

Problems with the Tire Mousse

Whether you want the Michelin Bib-Mousse or the Goldentyre G-Mousse or Nuetech's Nitro Mousse these things prove quite difficult to install. You need a lot of patience and probably some help. Installing the tire mousse requires grease or similar lubrication which turns the foam tube into a slithery, slippery snake.


Expect to get one section in only to have another section pop out and you might wonder how on earth the mousse will ever fit inside the tire. Don't worry, it does - granted you have the right size. Work at it, use your feet, grab a second pair of hands and/or lots of tire spoons - eventually you will get it to stick. And, the more you do it the easier it gets - just like all those inner tube replacements you once did.

Static Air Pressure

You cannot change the air pressure in the tire with a mousse insert installed - a pro or con depending on riding conditions. The Bib Mousse gives an equivalent air pressure of about 13 psi, the G-mousse ranges between 12 and 16 depending on model and the Nuetech mousse offers 11 to 12 psi. Riding conditions can dictate higher or lower air pressure something easily done with inner tubes but not when using a mousse insert.

Tire Mousse Weighs More

Though the mousse insert has made in-roads with some Motocross riders, most stick with inner tubes (though a growing number use a mousse in the rear wheel only) because the mousse adds roughly double the weight of an inner tube:

  • Standard heavy duty tube weight: 2 - 3 lbs.
  • Average mousse weight: 4.5 - 5 lbs.

When constantly looking for ways to reduce weight, adding a heavier component to your dirt bike comes across as counterproductive. Until you blow a tire on the track, which does happen.

Significant Cost Difference

The high-end Bridgestone Ultra Heavy Duty inner tube costs about $40 ranking on the more expensive side for inner tubes. Compare that to the Michelin Bib Mousse which costs $130. You will pay more up front but if you ride regularly and tend to encounter flats, the moderately priced $20 Artrax Ultra Heavy Duty Tube breaks even at seven flat tires. That's probably a lot for most riders but think of the time involved in repairing or replacing the tube.

Tire Mousse Wears Out

Tire mousse inserts do not last forever but neither do tubes. The manufacturers suggest replacing every six months or so but we hear riders getting a year or more out of the mousse insert. Heat, excessive high-speeds, not enough lubrication and incorrect sizing (this is where Michelin says to only use the Bib Mousse in their tires) can affect how long a mousse lasts. You know the time has come for a new mousse when the tire feels flat.

Not Infallible

We offer you proof the pros use tire mousse inserts in Motocross but also proof these things don't come foolproof. (See photo) Ben Lamay had an issue with his tire mousse when it squirmed its way out, or if you prefer, exploded out of the tire, and bound up in the swingarm. Looks like a Black Snake firework.

Ben Lamay had a tire mousse blowout at the 2019 Fox Raceway Motocross

Feels Kind of Funny

The tire mousse might feel funny at first but as you probably won't ever be the wiser after a few rides. The funny feeling comes from a "dead" feel as you don't get the rebound an inner tube provides. We have it on good word that unless you regularly ride on inner tubes then make a quick switch to a mousse you probably won't notice much of a difference.

This ends a (hopefully) all-encompassing tire mousse guide to help you make an informed decision on what to run inside of your tires.