The Motobike Mas 90/100-21 heavy duty motorcycle mousse is a nitrile rubber foam tire insert for rally & enduro racing front wheels. Tall-profile, Heavy-Duty option available. Eliminates front pinch flats. B2B wholesale from Tianjin, China.
| 1.1 Bar | Optimal speed performance |
|---|---|
| 0,8 bar | Best for deserts, grasslands, and gobi terrain |
| 0,5 bar | Optimal for forest trails |
| 0,3 bar | Extreme enduro mousse for technical off-road riding |
The Motobike Mas 90/100-21 heavy duty motorcycle mousse is a rugged closed-cell nitrile rubber foam tire insert engineered for the front wheels of rally racing, extreme enduro, and adventure motorcycles operating in the most demanding off-road conditions. With a 90 mm section width and 100% aspect ratio, the 90/100-21 provides a taller sidewall profile compared to standard 90/90-21 tires — delivering additional cushioning, rock deflection, and impact absorption for high-speed desert racing and multi-day rally events.
This heavy duty front mousse insert completely replaces the inner tube to eliminate dangerous front pinch flats, reduce unsprung rotating mass, and deliver consistent steering precision across thousands of kilometers of demanding terrain. Available in Medium, Standard, and Heavy-Duty density formulations, the 90/100-21 mousse is built specifically for rally and extreme enduro applications where reliability and durability are paramount.
As a Tianjin, China-based B2B manufacturer, Motobike Mas offers OEM private labeling, custom hardness formulations, and direct factory wholesale pricing for dealers, distributors, and race teams worldwide.
| Talla | 90/100-21 |
| Fitment | 90/100-21 front tires (rally, enduro, adventure front wheel) |
| Material | Closed-cell nitrile rubber foam |
| Density Options | Medium, Standard, Heavy-Duty |
| Peso | Approx. 1.1-1.3 kg |
| Rotating Mass Reduction | Up to 40% vs. tube + heavy-duty rim lock |
| Effective Pressure Equivalent | 8-12 psi |
| Service Life | 300-800 racing miles typical (rally endurance-rated) |
| Country of Origin | Tianjin, China |
In rally racing — where a single front flat can end a multi-day event — flat prevention is non-negotiable. The 90/100-21 heavy duty mousse eliminates front pinch flats, puncture flats, and valve stem failures entirely. For Dakar rally competitors, cross-country endurance racers, and extreme enduro riders, this means the confidence to push through rock fields, whoop sections, and high-speed gravel without fear of front-end failure.
The 90/100-21’s 100% aspect ratio provides a taller sidewall than standard 90/90-21 front tires. This additional sidewall height acts as a secondary cushioning layer, absorbing square-edge impacts and reducing deflection off rocks and ruts. Combined with the foam mousse’s inherent damping, the 90/100-21 setup delivers the most compliant front end available for extreme terrain.
By eliminating the inner tube and heavy-duty rim lock, the 90/100-21 mousse reduces unsprung rotating mass at the front wheel by up to 40%. At rally speeds exceeding 140 km/h, this reduction minimizes gyroscopic effect, allowing quicker steering inputs and reducing rider fatigue during marathon special stages.
Rally racing subjects equipment to extreme temperature variation — from cold morning starts to afternoon heat, from high mountain passes to desert floors. Unlike pneumatic tires where pressure fluctuates dramatically with temperature, a mousse insert delivers identical damping and steering characteristics regardless of ambient conditions.
Once installed, the 90/100-21 rally mousse requires zero maintenance for the life of the tire. No air pressure checks between special stages, no valve stem inspections at refueling stops, no gauges or pumps in the tool kit. For rally teams and endurance riders, this eliminates a significant logistical concern and reduces service time between stages.
Rally and extreme enduro applications demand careful density selection. The 90/100-21 is offered with a Heavy-Duty option optimized for the extreme loads of high-speed desert racing.
| Density | Effective Pressure | Best Terrain | Rider Weight |
|---|---|---|---|
| Medio | 8-10 psi | Technical enduro, muddy rally, mixed terrain | Under 75 kg |
| Standard | 9-11 psi | All-around rally, cross-country, desert | 75-95 kg |
| Heavy-Duty | 10-12 psi | High-speed desert, rocky terrain, extended durability | Over 90 kg |
This 90/100-21 heavy duty mousse insert fits all standard 90/100-21 front tires. The 90/100-21 size is less common than standard 90/90-21 or 80/100-21 sizes but is used on select rally, adventure, and enduro motorcycles where a taller front profile is specified.
| Especificación | 90/100-21 | 90/90-21 | 80/100-21 |
|---|---|---|---|
| Anchura de sección | 90 mm | 90 mm | 80 mm |
| Aspect Ratio | 100% | 90% | 100% |
| Sidewall Height | Tallest — max cushioning | Standard | Tall |
| Steering Feel | Plush, absorbs impacts | Balanced grip & feel | Quickest turn-in |
| Durability Rating | Heavy-duty / Rally rated | Standard | Standard |
| Lo mejor para | Rally, extreme enduro, desert | All-around enduro, off-road | Motocross, supercross |
| Mousse Weight | 1.1-1.3 kg | 1.0-1.2 kg | 0.9-1.1 kg |
The 90/100-21 heavy duty mousse is endurance-rated for 300-800 racing miles — significantly longer than standard mousse inserts due to its Heavy-Duty density option and optimized compound formulation for sustained high-speed operation.
Important: Never use petroleum-based lubricants on mousse inserts — they degrade nitrile rubber. Use only water-based mousse lubricant. For rally applications, ensure the mousse is fully seated before high-speed use — any imbalance will be felt through the handlebars at speed.
The 90/100-21 heavy duty mousse is specifically formulated for the demands of rally racing and extreme endurance events. Unlike standard mousse inserts designed for motocross motos lasting 20-30 minutes, this mousse is engineered to maintain consistent performance over multi-hour special stages and multi-day events. The Heavy-Duty density option uses a specialized compound formulation that resists heat buildup during prolonged high-speed operation — the primary cause of mousse failure in rally applications.
For Dakar Rally and similar events, Motobike Mas recommends the Heavy-Duty density option combined with fresh tire installation before the event start. Pre-running tires with mousse inserts for 50-100 km before the event allows the mousse to settle and conform to the tire casing for optimal performance.
Motobike Mas is a Tianjin, China-based manufacturer of mousse inserts for off-road motorcycle racing tires. We supply dealers, distributors, race teams, and aftermarket brands worldwide with factory-direct pricing and full customization.
| Factory Pricing | Direct wholesale — no middlemen |
| OEM / Private Label | Custom branding, packaging, and colors |
| Custom Formulations | Adjust density and material properties including rally-specific endurance formulations |
| MOQ | Contact for minimums |
| Shipping | Sea (FOB Tianjin), air freight, DDP available |
| Samples | Pre-production samples for evaluation |
The 90/100-21 is a less common front tire size used primarily on rally racing motorcycles and select extreme enduro applications. Its 100% aspect ratio provides a taller sidewall profile compared to standard 90/90-21 tires, offering additional impact absorption and cushioning for high-speed desert terrain and rocky rally stages.
Yes. The 90/100-21 fits the same 21-inch rim diameter as standard 80/100-21 and 90/90-21 front tires. The difference is in the tire’s section width and aspect ratio, not the rim diameter.
No. Mousse inserts are size-specific. A 90/100-21 mousse must be used with a 90/100-21 tire. Using the wrong size mousse will result in improper fitment, reduced performance, and potential safety issues.
The Heavy-Duty formulation uses a denser nitrile rubber foam compound with higher heat resistance, making it suitable for prolonged high-speed operation in desert and rally conditions. It offers extended service life at the cost of slightly firmer effective pressure (10-12 psi equivalent).
Yes. B2B clients can request samples for evaluation before committing to volume orders. Contact our sales team to arrange sample shipments.
Typical lead time is 15-30 days for standard OEM production, depending on quantity and customization requirements.
