MTB Tire Test: Continental Race King RaceSport Tubeless 29x2.2

This review is a comparison between a traditional butyl inner tube and a tubeless mountain bike set up, which is something I always wanted to know. I have chosen the Continental Race King RaceSport 29 x 2.2 for this test because it proved to be the fastest of the three mountain bike tires I had the chance to test up to now. I'm going to assume the difference shown in this review will be the same for every other tire out there (a 29 x 2.2/2.25 at least). So you can use this as a reference to calculate the rolling resistance of a tire when mounted tubeless.

As a reference, this review has now been superseded by a much more detailed special article which also includes a latex tube and measurements at 15 psi / 1.0 bar. I highly recommend you to read the special article instead of this short review.

During normal testing, I use a standard Continental 29er butyl inner tube with a weight of 225 grams. For this test, I mounted the tire with tubeless rim tape and 60 ml Stan's NoTubes tubeless sealant to seal it. Even though this tire is not rated Tubeless-Ready, it was no problem to get it inflated (with a compressor), although it did take 3 days to completely seal. I've been using a Race King RaceSport with 60 ml sealant on my own bike for some time already. With this set up there is a 150 grams weight advantage for the tubeless tire.

Manufacturer Specifications

Manufacturer Specs
Brand	Continental
Model	Race King RaceSport Tubeless
Year	2014
Supplied By	Bought in store
New or Used	New
Mileage	0 km
Price Range	High
Buy At
Manufacturer part number	0100545
TPI	3/180
Compound	Black Chili
Bead	Folding
ETRTO	57-622
Size Inch	29"
Width Inch	2.20
Specified Weight	540 grams
Max Air Pressure (psi)	65
Made In	Pro Data
Available Sizes	29x2.20 29x2.00 27.5x2.20 26x2.20 26x2.00

Continental Race King RaceSport Tubeless Test Results

Size, Weight, and Thickness Measurements

Size, Weight, and Thickness Measurements
Specified Weight	540 grams
Measured Weight	497 grams
Measured Width Carcass	55 mm (un-round)
Measured Width Tread	51 mm
Measured Height	55 mm (un-round)
Measured Knob Height Center	2.5 mm
Measured Knob Height Edge	2.5 mm
Measured Total Thickness Center (excluding knobs)	1.7 mm
Measured Total Thickness Sidewall	Pro Data
All size measurements are taken at an air pressure of 35 psi / 2.4 bars on a 17.8 mm inner width rim.

No difference, same as with inner tube.

Rolling Resistance Test Results

Rolling Resistance Test Results
Inner Tube	None (60 ml sealant)
Measured Width	55 mm
Rolling Resistance Real tire width in mm: 47-50 = 42 psi/2.9 bar 51-55 = 38 psi/2.6 bar 56-60 = 34 psi/2.3 barHigh Air Pressure (38 psi / 2.6 bar)	Pro Data
Rolling Resistance Real tire width in mm: 47-50 = 35 psi/2.4 bar 51-55 = 32 psi/2.2 bar 56-60 = 29 psi/2.0 barMedium Air Pressure (32 psi / 2.2 bar)	Pro Data
Rolling Resistance Real tire width in mm: 47-50 = 28 psi/1.9 bar 51-55 = 25 psi/1.7 bar 56-60 = 23 psi/1.6 barLow Air Pressure (25 psi / 1.7 bar)	17.4 Watts CRR: 0.00522
Rolling Resistance Real tire width in mm: 47-50 = 21 psi/1.4 bar 51-55 = 19 psi/1.3 bar 56-60 = 17 psi/1.2 barExtra Low Air Pressure (19 psi / 1.3 bar)	Pro Data
Rolling Resistance 55 psi / 3.8 bar	Pro Data
Rolling Resistance 45 psi / 3.1 bar	Pro Data
Rolling Resistance 35 psi / 2.4 bar	Pro Data
Rolling Resistance 25 psi / 1.7 bar	Pro Data
The MTB section is a multi tire size section, air pressures have been adjusted to the measured casing width. 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.

When comparing the exact same tires, with the only difference being a tubeless set up or a butyl inner tube.

• At 55 psi/3.8 bar, the tubeless set up has 2.5 watts less rolling resistance
• At 45 psi/3.1 bar, the tubeless set up has 2.9 watts less rolling resistance
• At 35 psi/2.4 bar, the tubeless set up has 3.8 watts less rolling resistance
• At 25 psi/1.7 bar, the tubeless set up has 5.0 watts less rolling resistance

Puncture Resistance Test Results

Puncture Resistance Test Results (higher is better)
Total Puncture Score Tread	29 Points
Total Puncture Score Sidewall	Pro Data
Tread Puncture Force Sharp Needle	7 Points
Tread Puncture Force Blunt Needle	No Data
Tread Total Tire Thickness	1.7 mm
Sidewall Puncture Force Sharp Needle	Pro Data
Sidewall Puncture Force Blunt Needle	No Data
Sidewall Total Tire Thickness	Pro Data

No difference, same as with inner tube.

Hard Surface Static Grip Test Results

Static Grip Test Results
Wet Grip Average	No Data
Wet Grip Center	No Data
Wet Grip Edge	No Data
Measured Knob Height Center	2.5 mm
Measured Knob Height Edge	2.5 mm
Grip in points = coefficient of friction * 100 MTB grip test rim width = 30.0 mm
Wet Grip Test and Off-Road Tires (info)

Conclusion

The lower the pressure, the bigger the advantage for the tubeless mountain bike tire. At a pressure of 55 psi, there is a 2.5 watts advantage for the tubeless tire. Dropping pressure to 25 psi results in a 5 watts per tire advantage for the tubeless tire. When going off road you want low air pressure tires for increased grip, comfort, power efficiency and lower surface rolling resistance. With a drop off in tire rolling resistance of just 1.9 watts between a high pressure of 55 psi and a low pressure of 25 psi, this is certainly true for this tubeless mounted Race King.

RATING: 5.0 / 5
TEST VERDICT: Highly Recommended

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