Because almost all Schwalbe tires perform very well in the rolling resistance tests, the Schwalbe Jumbo Jim is the fat bike tire that can't be left out of the fat bike section. I'm testing the LiteSkin version of the Jumbo Jim because I want to know how low rolling resistance of a fat bike tire can go. A TL-Easy SnakeSkin version of the Jumbo Jim is available as well which should be a bit slower because of the stronger sidewalls.
The Jumbo Jim is built from the same materials that are also used to create the fast-rolling Schwalbe mountain bike tires. This means the Jumbo Jim uses a 127 TPI folding casing with tubeless-ready beads and the well known Schwalbe PaceStar compound. The tread pattern looks like it can handle a wide range of conditions with the relatively low, wide spaced center knobs and huge shoulder knobs that should provide plenty of cornering grip.
The fat bike section is made possible by Wolf Tooth Components
|Model||Jumbo Jim LiteSkin|
Bought in store
Wolf Tooth Components
|New or Used||New|
|Specified Weight||990 grams|
Size and Weight Measurements
|Size and Weight Measurements (Bike Wheel: 559-65C, Pressure: 16 psi / 1.1 bar)|
|Measured Weight||1079 grams|
|Measured Width Carcass||95 mm|
|Measured Width Tread||98 mm|
|Measured Height||84 mm|
|Measured Knob Height Center||3.7 mm|
|Measured Knob Height Edge||6.8 mm|
|Measured Total Thickness Sidewall||0.55 mm|
|Measured Total Thickness Center (excluding knobs)||1.65 mm|
Specified weight of the Jumbo Jim LiteSkin is 990 grams, my sample comes in at a much higher 1079 grams. The sub-1000 grams specified weight is probably a marketing gimmick, If you can get your hands on a 990 grams Jumbo Jim, don't let it go again. The maximum width of the casing is 95 mm, the shoulder knobs stick out a bit further and measure 98 mm wide. The height of the tire is 84 mm. The volume of the Jumbo Jim is good and in line with other 26 x 4.00 rated tires.
The Jumbo Jim has some surprisingly big knobs. The center knobs have a height of 3.7 mm which is not bad. The shoulder knobs are huge on this tire and have a maximum height of 6.8 mm. The shoulder knobs on the Jumbo Jim are the biggest I've seen yet. Because this is the LiteSkin version of the Jumbo Jim, the sidewalls have a thickness of just 0.55 mm. The 0.55 mm sidewall measurement is in line with the 'regular' Schwalbe MTB tires. The SnakeSkin version will come in close to 0.85 mm.
Rolling Resistance Test Results
|Rolling Resistance Test Results (Speed: 29 kmh / 18 mph, Load: 42.5 kg)|
|Rolling Resistance 20 psi / 1.4 Bar||23.3 Watts|
|Rolling Resistance 16 psi / 1.1 Bar||24.7 Watts|
|Rolling Resistance 12 psi / 0.8 Bar||28.7 Watts|
|Rolling Resistance 8 psi / 0.6 Bar||36.9 Watts|
|Rolling Resistance Coefficient (Crr) 20 psi / 1.4 Bar||0.00698|
|Rolling Resistance Coefficient (Crr) 16 psi / 1.1 Bar||0.00740|
|Rolling Resistance Coefficient (Crr) 12 psi / 0.8 Bar||0.00860|
|Rolling Resistance Coefficient (Crr) 8 psi / 0.6 Bar||0.01106|
In the rolling resistance test, the Jumbo Jim shows us what's possible and outperforms all other fat bike tires that have been tested up to now. At the very low air pressure of 8 psi / 0.6 bars, the Jumbo Jim stretches its legs and outperforms the next best tire by 6.5 watts. Even at the higher air pressures, the Jumbo Jim performs very strong although the gap to the competition is a bit smaller at 2.7 watts at 20 psi / 1.4 bars.
Although the Jumbo Jim performs very strong, it must be said that the LiteSkin sidewalls are much thinner and weaker than the competition, getting the Jumbo Jim to seal might be a bit harder when used in tubeless form. The SnakeSkin version of the Jumbo Jim might have matched the competition better in that regard. I do expect the SnakeSkin still has a lower rolling resistance than the competition. From experience with the normal sized Schwalbe MTB tires, I expect the Jumbo Jim SnakeSkin to come in at 39 - 40 watts at 8 psi / 0.6 bars.
Puncture Resistance Test Results
|Puncture Resistance Test Result (higher is better)|
|Puncture Resistance Tread||6|
|Puncture Resistance Sidewall||5|
As expected from a tire built to provide race performance, the Jumbo Jim comes in at the bottom of the list in the puncture resistance tests. Still, puncture performance isn't that bad as it comes just a few points short in both the tread and sidewall puncture tests.
As expected from Schwalbe, the Jumbo Jim LiteSkin performs very strong in the rolling resistance test. If you're looking for a fat bike tire with race performance, the Jumbo Jim is the only tire worth considering as it will save you close to 15 watts for a pair of tires. Although the sidewalls are thin and performance in the puncture test isn't that great, it does have bigger knobs than the competition and should provide plenty of grip.
Rated 5 out of 5 because it simply is the fastest fat bike tire and that's by far the most important criteria on this site. I'm looking into testing the SnakeSkin version as well, but I'm convinced it will perform very strong as well and provide some additional sidewalls strength/sealing.
VERDICT: Highly Recommended
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