The Schwalbe Jumbo Jim LiteSkin has been the fastest rolling fat bike tire since the launch of the fat bike section. The LiteSkin version of the Jumbo Jim (read review) comes with thin sidewalls that could be too sensitive for the more extreme fat biker. The SnakeSkin version of the Jumbo Jim solves this problem as it comes with reinforced sidewalls that can take much more abuse from rocks and other sharp objects. Another advantage of the SnakeSkin version is the much easier set up when using this tire in a tubeless set up.
From previous experience with the regular sized Schwalbe MTB tires, there isn't much difference between the LiteSkin and SnakeSkin versions of their tires. Only at the lowest possible air pressures does the rolling resistance of the SnakeSkin versions become slightly higher. The biggest drawback is the higher weight that comes with the reinforced sidewalls. In general, I only recommend the LiteSkin versions if you want to gain those last few seconds from your tires.
|Model||Jumbo Jim SnakeSkin|
|Supplied By||Bought in store|
|New or Used||New|
|Specified Weight||1090 grams|
26 x 4.80
26 x 4.40
26 x 4.00
Size and Weight Measurements
|Size and Weight Measurements (Bike Wheel: 559-65C, Pressure: 16 psi / 1.1 bar)|
|Specified Weight||1090 grams|
|Measured Weight||1164 grams|
|Measured Width Carcass||97 mm|
|Measured Width Tread||99 mm|
|Measured Height||84 mm|
|Measured Knob Height Center||3.4 mm|
|Measured Knob Height Edge||6.5 mm|
|Measured Total Thickness Sidewall||1.05 mm|
|Measured Total Thickness Center (excluding knobs)||1.65 mm|
Just like the LiteSkin version of the Jumbo Jim, my sample of the SnakeSkin version is quite a bit heavier at 1164 grams than the specified weight of 1090 grams. The maximum width of the casing of the 26 x 4.00 SnakeSkin is 97 mm. The edge knobs stick out a bit further resulting in a maximum tire width of 99 mm.
The knobs on the SnakeSkin version have a slightly smaller height than the LiteSkin version. The center knobs have a height of 3.4 mm and the edge knobs have a height of 6.5 mm while the LiteSkin came in at 3.7 mm and 6.8 mm respectively; this could be the result of normal production tolerances.
The most interesting measurement is the measurement of the thickness of the sidewalls: the sidewalls of the SnakeSkin version have a thickness of 1.05 mm while the sidewalls of the LiteSkin are much thinner at 0.55 mm.
Rolling Resistance Test Results
|Rolling Resistance Test Results (Speed: 29 kmh / 18 mph / 8 m/s, Load: 42.5 kg / 417 N)|
|Inner Tube||Schwalbe SV13J (390 gr)|
|Rolling Resistance 20 psi / 1.4 Bar||
|Rolling Resistance 16 psi / 1.1 Bar||
|Rolling Resistance 12 psi / 0.8 Bar||
|Rolling Resistance 8 psi / 0.6 Bar||
|Use the formula: RR (watts) = CRR * speed (m/s) * load (N) to calculate rolling resistance at a given speed and load|
Rolling resistance of the SnakeSkin version of the Jumbo Jim is pretty much the same as the LiteSkin version (read review) at air pressures of 12, 16, and 20 psi (0.8, 1.1, 1.4 bars). At the highest air pressure of 20 psi (1.4 bars), the rolling resistance of the SnakeSkin even comes in slightly lower than the LiteSkin version; I attribute this to the slightly lower knobs on the SnakeSkin version.
At the lowest tested air pressure of 8 psi (0.55 bars), the rolling resistance of the the SnakeSkin version comes in at 38.6 watts which is 1.7 watts more than the LiteSkin version. At the lower air pressures, the sidewalls become a bigger part of the total rolling resistance. At even lower air pressures of 6 and 4 psi, the disadvantage of the SnakeSkin version will likely become even bigger. I don't have the exact numbers as I didn't test both tires at these lower pressures, but my best estimate is a disadvantage of the SnakeSkin version of 2.5 - 3 watts at 6 psi (0.4 bars) and 4 - 5 watts at 4 psi (0.3 bars).
Puncture Resistance Test Results
|Puncture Resistance Test Result (higher is better)|
|Puncture Resistance Tread||7|
|Puncture Resistance Sidewall||6|
In the puncture resistance tests, the SnakeSkin version scores slightly better in both the tread and sidewall tests. Altough the sidewall score of the SnakeSkin version has increased by just 1 point when compared to the LiteSkin version (5 points Vs 6 points), I expect the real-life durability of the sidewalls to be much better as the total thickness of the sidewalls has increased from just 0.55 mm to 1.05. The thicker sidewalls should help significantly in the cut resistance of the sidewalls.
The LiteSkin version of the Jumbo Jim has been the fastest fat bike tire for quite some time. The SnakeSkin version is just as fast at the higher end of the air pressure range, at the low air pressure of 8 psi (0.55 bars), the rolling resistance of the SnakeSkin version is slightly higher (~ 5%). For this slightly higher rolling resistance (and 80 - 100 grams of extra weight) you do get sidewalls that are close to twice as thick (0.55 mm Vs 1.05 mm) which should result in a much more durable tire + easier tubeless set up.
At this moment, both the Jumbo Jim SnakeSkin and LiteSkin seem to be the tires to get if you're looking for some fast rolling fat bike tires. Check the fat bike overview page fat bike overview page to see if faster tires have been tested and how the Jumbo Jim compares to the competition.
VERDICT: Highly Recommended
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