Fat Bike Tire Test: Maxxis Mammoth

The Maxxis Mammoth is Maxxis's first try at building a fat bike tire. The Mammoth has relatively low, closely spaced knobs center knobs that are made of a harder rubber compound (Dual Compound) to try to keep rolling resistance and wear to a minimum. The side knobs are much bigger and made of a softer compound to give as much cornering grip as possible. On paper, the Mammoth seems to be the perfect fat bike tire.

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I've tested the 120 TPI EXO version of the Mammoth to see how it stacks up to other top of the line tires. The 120 TPI EXO version comes with reinforced EXO sidewalls, but no tubeless beads. A 120 TPI EXO/TR version is available as well that features rubber coated beads to help seal the tire when used tubeless. Strange enough, the 60 TPI version actually has the same weight as the 120 TPI version, this is because it doesn't use reinforced sidewalls. I expect the 60 TPI version to be a much weaker tire.

Manufacturer Specifications

Manufacturer Specifications
Brand	Maxxis
Model	Mammoth
Year	2016
Supplied By	Bought in store
New or Used	New
Mileage	0 km
Price Range	High
Buy At	Ad Amazon.com
Manufacturer part number
TPI	120
Compound	DUAL
Bead	Folding
ETRTO	102-559
Size Inch	26"
Width Inch	4.00
Specified Weight	1270 grams
Max Air Pressure (psi)	30
Made In	Members Only
Available Sizes	26x4.00

Maxxis Mammoth Test Results

Size, Weight, and Thickness Measurements

Size, Weight, and Thickness Measurements
Specified Weight	1270 grams
Measured Weight	1271 grams
Measured Width Carcass	97 mm (un-round)
Measured Width Tread	98 mm
Measured Height	80 mm (un-round)
Measured Knob Height Center	3.0 mm
Measured Knob Height Edge	5.5 mm
Measured Total Thickness Center (excluding knobs)	2.40 mm
Measured Total Thickness Sidewall	Members Only
All size measurements are taken at an air pressure of 16 psi / 1.1 bars on a 65 mm inner width rim.

Specified weight of the 26x4.00 120 TPI EXO Mammoth is 1270 grams, my sample came in at 1271 grams which is pretty much spot on. The maximum width of the casing is 97 mm, the knobs stick out a bit further making the total width 98 mm on a 65C rim at an air pressure of 16 psi / 1.1 bars.

The knobs in the center of the tire have a height of just 3 mm, which is less than most other fat bike tires. The side knobs are much bigger and have a height of 5.5 mm. With a thickness of 0.95 mm, the sidewalls are of average thickness.

Rolling Resistance Test Results

Rolling Resistance Test Results
Inner Tube	None (60 ml sealant) (current protocol)	Schwalbe SV13J (390 gr) (test protocol)
Rolling Resistance 20 PSI / 1.4 Bar	Members Only	Members Only
Rolling Resistance 16 PSI / 1.1 Bar	Members Only	Members Only
Rolling Resistance 12 PSI / 0.8 Bar	35.2 Watts CRR: 0.01055	40.7 Watts CRR: 0.01220
Rolling Resistance 8 PSI / 0.6 Bar	47.2 Watts CRR: 0.01415	54.7 Watts CRR: 0.01640
All numbers are for a single tire at a speed of 29 km/h / 18 mph and a load of 42.5 kg / 94 lbs. Use the formula: RR (Watts) = CRR * speed (m/s) * load (N) to calculate rolling resistance at a given speed and load.

At very high air pressures, the rolling resistance of the Mammoth is OKish. When dropping air pressure, rolling resistance rises sharply and ends up at a very high 54.5 watts at an air pressure of 8 psi / 0.6 bars. My guess is this is because, at higher air pressures, the (almost) continuous center knobs help to keep rolling resistance relatively low. At lower air pressures, the sidewalls and edge knobs become the dominant factor and rolling resistance goes up big time.

I expected more from a first try from one of the biggest MTB tire manufacturers. I didn't expect a stellar performance from the Mammoth as their normal-sized MTB tires do not perform that great in the rolling resistance test either, but it's a disappointment to see this tire perform so bad at the low air pressures most fat bike riders like to use.

Puncture Resistance Test Results

Puncture Resistance Test Results (higher is better)
Total Puncture Score Tread	35 Points
Total Puncture Score Sidewall	Members Only
Tread Puncture Force Sharp Needle	8 Points
Tread Puncture Force Blunt Needle	Members Only
Tread Total Tire Thickness	2.40 mm
Sidewall Puncture Force Sharp Needle	Members Only
Sidewall Puncture Force Blunt Needle	Members Only
Sidewall Total Tire Thickness	Members Only

Although rolling resistance is quite high, the Mammoth with EXO sidewalls performs very strong in the puncture tests. The sidewalls on this tire are one of the strongest and also have a decent thickness. Running these in a tubeless configuration shouldn't be a problem at all. In the tread puncture test, it also performs on the upper end of the spectrum. If you're looking for a strong tire, the Mammoth is a good choice.

Conclusion

If you run your fat bike tires at air pressures over 16 psi / 1.1 bars, the Maxxis Mammoth might be a decent tire. If you like to go down to really low air pressures (< 12 psi / 0.8 bars), the Maxxis will really start to drag you down. In the puncture resistance tests, the Mammoth performs strongly. The bad part is you can find more puncture resistant tires that offer a lower rolling resistance, lower weight, and an even better puncture resistance.

I rate the Maxxis Mammoth 2 out of 5 because this is Bicycle Rolling Resistance and rolling resistance is the most important criteria. I know fat bikers like to drop air pressures to very low values to be able to ride over anything. Check the overview pages (overview) to see which tires perform better than the Mammoth.

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RATING: 2 / 5
TEST VERDICT: Not Recommended

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