Tire Test - Schwalbe Kojak

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Schwalbe Kojak Touring/E-Bike tire on a rolling resistance test machine

The Schwalbe Kojak is a "Performance Line" slick tire that's available for a decent price but doesn't use Schwalbe's most advanced technologies found in their "Evolution Line" tires. The Kojak is available as both a wire bead and a lighter folding version. Both the folding and wire bead versions use a 67 TPI casing, SpeedGrip compound, and RaceGuard puncture protection. I'm testing the 35-622 folding version of the Kojak.


Check Schwalbe Kojak Prices at Chain Reaction Cycles


The Kojak is a popular tire as it's a slick tire that's available for many different wheel sizes. The Kojak also comes in bigger sizes (32 - 50 mm) which isn't the case for most high-performance road bike tires that max out at 28 mm wide. I've often seen the Kojak recommend to people that are looking for a fast, slick tire to replace their MTB or touring bike tires. I totally understand why people recommend the Kojak as it looks blistering fast on an off the bike, but is it really faster than the tires you're replacing?


Manufacturer Specs
Brand Schwalbe
Model Kojak
Year 2017
Supplied By Bought in store
New or Used New
Mileage 0 km
Price Range Med
Price Chain Reaction Cycles
Part Number 11600020.01
TPI 67
Compound SpeedGrip
Bead Folding
ETRTO 35-622
Size Inch 28"
Width mm 35.00
Specified Weight 330 grams
Max Pressure 95
Made In Indonesia
Available Sizes 32-355 (18x1.25)
32-369 (27x1 1/4)
35-406 (20x1.35)
35-559 (26x1.35)
50-559 (26x2.00)
35-622 (28x.135)

Test Results


Schwalbe Kojak Touring/E-Bike on a rolling resistance test machine

Size and Weight Measurements


Size and Weight Measurements (Bike Wheel: 622-17C, Pressure: 60 psi / 4 bar)
Specified Weight 330 grams
Measured Weight 351 grams
Measured Width 33 mm
Measured Height 31 mm
Tread Depth 0.0 mm
Total Tire Thickness Center 3.9 mm
Total Tire Thickness Sidewall 0.55 mm

The specified weight of the (folding bead) 35-622 Schwalbe Kojak is 330 grams; my sample is a bit heavier at 351 grams. On my 17 mm wide rim (internal), at an air pressure of 60 psi / 4.1 bars, the Kojak has a maximum width of 33 mm and a maximum height of 31 mm.


The total thickness of the tire at the center of the tread is 3.9 mm. 3.9 mm is a bit less than most touring bike tires without thick anti-protection layers which generally have a thickness of 4 - 5 mm. It does is much thicker than most high-performance road bike tires that mostly have a tread thickness of less than 3 mm. The higher thickness means the Kojak should last much longer. The Kojak's sidewalls have a thickness of 0.55 mm which is extremely thin for a touring bike class tire. If you need strong sidewalls, this isn't your tire.




Rolling Resistance Test Results


Rolling Resistance Test Results (Speed: 29 kmh / 18 mph, Load: 42.5 kg)
Inner Tube Conti Tour 28 (170 gr butyl)
Rolling Resistance 90 psi / 6 Bar 20.5 Watts
Rolling Resistance 75 psi / 5 Bar 21.9 Watts
Rolling Resistance 60 psi / 4 Bar 24.8 Watts
Rolling Resistance 45 psi / 3 Bar 29.1 Watts
Rolling Resistance 30 psi / 2 Bar 37.5 Watts
Rolling Resistance Coefficient (Crr) 90 psi / 6 Bar 0.00615
Rolling Resistance Coefficient (Crr) 75 psi / 5 Bar 0.00656
Rolling Resistance Coefficient (Crr) 60 psi / 4 Bar 0.00743
Rolling Resistance Coefficient (Crr) 45 psi / 3 Bar 0.00872
Rolling Resistance Coefficient (Crr) 30 psi / 2 Bar 0.01124

Rolling resistance of the Kojak is a BIG disappointment. The Kojak looks fast, but it gets outperformed in the rolling resistance tests by "average" touring bike tires like the Schwalbe Marathon GreenGuard (read review) and Continental Contact (read review). When we look at the best performing tires in the touring bike category, rolling resistance of the Kojak is terrible. At an air pressure of 60 psi / 4.1 bars, rolling resistance of the Kojak comes in at 24.8 watts which is 7.5 watts more than the Schwalbe Marathon Almotion (read review) (17.1 watts -current fastest tire in touring bike category).


The Kojak is often recommended as a good upgrade to people that mainly use their mountain bike as a road bike. Please check the MTB overview page and be aware that a large part of the MTB tires actually have a lower rolling resistance than the Kojak!


What can we learn from this test? It's impossible to predict the rolling resistance of tires by just looking at them. Be careful your "upgrade" doesn't turn out to become a downgrade.



Puncture Resistance Test Results


Puncture Resistance Test Result (higher is better)
Puncture Resistance Tread 12
Puncture Resistance Sidewall 3
Puncture Factor Tread * 47
Puncture Factor Sidewall * 2
* Puncture Factor = Puncture Resistance * Total Tire Thickness
Puncture Factor provides a more realistic puncture resistance score for touring tires

In the puncture resistance tests, the Kojak scores very low when compared to touring bike tires. In the tread puncture test, it scores 12 points which is decent but on the low side. In the sidewall puncture test, performance is horrible with a Puncture Factor score of just 2 points. If you need any sidewall protection, this isn't your tire.




Conclusion


Schwalbe Kojak Touring/E-Bike on a rolling resistance test machine

If a tire looks fast, it doesn't mean it actually is a fast tire. The Schwalbe Kojak looks like a high-performance slick road bike tire, but our tests show rolling resistance is actually higher than an average touring bike tire like the Schwalbe Marathon GreenGuard (read review). On top of the high rolling resistance, puncture resistance is much lower than real touring bike tires. The low weight and decent price are the only positives I can think of.


If you're looking for really fast slick tires, I recommend taking a look at the 28 mm versions of popular road bike tires like the Continental Grand Prix 4000S II (read review) and Schwalbe One (read review). These tires are just a little bit smaller than the Kojak, but perform much better. For 26-inch bikes, the regular Continental Grand Prix (read review) might be worth a look as it's available in 28 mm for 26-inch rims.


Check Schwalbe Kojak Prices at Chain Reaction Cycles


RATING: 2 / 5
VERDICT:
Not Recommended


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Images


Schwalbe Kojak Touring/E-Bike tire on a rolling resistance test machine
Schwalbe Kojak Touring/E-Bike tire on a rolling resistance test machine
Schwalbe Kojak Touring/E-Bike tire on a rolling resistance test machine

(click to enlarge)

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