MICHELIN Bib Mousse M15 – Front mousse insert 80/100-21 & 90/90-21
The MICHELIN Bib Mousse M15 is a closed-cell foam insert designed to replace conventional inner tubes in off-road front tyres sized 80/100-21 and 90/ delivers a stable, low-pressure feel while eliminating punctures and pinch flats in demanding terrain.
Main features
- Front mousse insert for off-road motorcycle tyres in sizes 80/100-21 and 90/90-21.
- Approximate equivalent of 0.9 bar (13 psi) inflation pressure for consistent grip and comfort.
- Lighter than an ultra heavy duty inner tube while removing the risk of punctures and pinch flats.
- Developed by MICHELIN for Cross Country, Rally, Enduro and Motocross competition use.
- Engineered to be used exclusively with selected MICHELIN off-road competition tyres.
Technical details
| Manufacturer | MICHELIN |
| Product name | MICHELIN Bib Mousse M15 |
| SKU | 057333 |
| Mounting position | Front wheel |
| Compatible tyre sizes | 80/100-21, 90/90-21 |
| Approximate pressure equivalent | 0.9 bar (13 psi) |
| Construction | Closed-cell foam mousse insert |
| Intended use | Off-road competition: Cross Country, Rally, Enduro, Motocross |
Designed tyre combinations
The Bib Mousse M15 is dimensioned to match MICHELIN off-road competition tyres in the listed front sizes, providing optimal fit and performance in their specific casing is typically paired with selected MICHELIN motocross lines such as StarCross 5 in 80/100-21 and enduro lines such as Enduro Medium in 90/90-21, as well as other compatible MICHELIN off-road fronts in these sizes.
- Motocross use with selected MICHELIN 80/100-21 front tyres.
- Enduro and special test stages with selected MICHELIN 90/90-21 front tyres.
- Rally and cross-country competitions where consistent low-pressure performance and puncture resistance are critical.
Performance advantages
- Eliminates punctures and pinch flats: Solid foam construction removes the air chamber, so sharp rocks, roots and rim impacts do not cause flats.
- Consistent low-pressure feel: Delivers approximately 0.9 bar (13 psi) equivalent support throughout its service life, contributing to predictable grip and steering precision in loose or technical terrain.
- Optimised for competition pace: Developed for intensive off-road racing where stability, control and reduced downtime are essential.
- Weight advantage over UHD tubes: Offers reduced rotating mass compared with many ultra heavy duty inner tubes, contributing to more responsive suspension behaviour.
Service life and installation notes
MICHELIN Bib Mousse M15 is designed with a typical service life of up to around six months from the first time it is mounted on a motorcycle, with intensive competition use significantly accelerating optimal durability and heat management, it is intended to be installed using dedicated MICHELIN Bib Mousse fitting gel during tyre mounting.
Correct matching of the mousse to the tyre size, the exclusive use with MICHELIN off-road competition tyres and the use of fitting gel all contribute to consistent performance, controlled operating temperature and an extended usable lifespan under off-road racing conditions.
