CX/Gravel Tire Test: Panaracer GravelKing R 40

Panaracer recently updated the GravelKing, which is now available in three different casing versions. The GravelKing R we have on test today has the fastest and lightest casing construction, made for gravel bikers looking for all-out performance. Also available is the "standard" casing, which is the most versatile, and a + (Plus) casing, which comes with additional protection.

All casing constructions are updated with a special TuffTex layer developed by Panaracer that adds protection and better sealing capabilities. The beads have been updated with a unique BeadLock bead that makes it much easier to inflate the tire even when compressed air is not available. This is pretty much a tubeless-ready 2.0 construction, as while the original GravelKings were available in a tubeless-ready casing, sealing and inflating weren't always that easy.

The compound also sees an update. The updated GravelKings now come with a new "ZSG Gravel" compound, a variation of Panaracer's ZSG compound, which we find on many of their high-end tires. The previous editions of the GravelKings could have been better performers in our wet grip test, and we always thought the compound could use improvement in that regard.

We already have tests of the new GravelKing X1 in both the R (read our review) and "standard" (read our review) casings available on our website. With today's test of the slick GravelKing R, we should get a very good look at Panaracer's new GravelKing lineup. We also tested the original GravelKing TLC (read our review) in the 40-622 size back in 2020, and when combining these four tests, we'll get an idea of how the new generation compares to the old TLC generation.

Manufacturer Specifications

Manufacturer Specs
Brand	Panaracer
Model	GravelKing R
Year	2024
Supplied By	Bought in store
New or Used	New
Mileage	0 km
Price Range	High
Buy At
Manufacturer part number	RF740-GK-R-SX2
TPI	-
Compound	ZSG Gravel
Bead	Folding
ETRTO	40-622
Specified Weight	0 grams
Max Air Pressure (psi)	60
Made In	Members Only
Available Sizes	28-622 (700x28c) 30-622 (700x30c) 35-622 (700x35c) 40-622 (700x40c)

Panaracer GravelKing R 40 Test Results

Size, Weight, and Thickness Measurements

Size, Weight, and Thickness Measurements
Specified Weight	0 grams
Measured Weight	369 grams
Measured Width Casing	39 mm (un-round)
Measured Width Tread	38 mm
Measured Height	36 mm (un-round)
Measured Knob Height Center	0.2 mm
Measured Knob Height Edge	0.2 mm
Measured Total Thickness Center (excluding knobs)	2.40 mm
Measured Total Thickness Sidewall	Members Only
All size measurements are taken at low air pressure on a 17.8 mm inner width rim.

Rolling Resistance Test Results

Rolling Resistance Test Results
Inner Tube	None (30 ml sealant)
Measured Width	39 mm
Rolling Resistance Real tire width in mm: 30-32 = 66 psi/4.6 bar 33-35 = 60 psi/4.1 bar 36-38 = 54 psi/3.7 bar 39-42 = 50 psi/3.4 bar 43-46 = 46 psi/3.2 bar 47-50 = 42 psi/2.9 barHigh Air Pressure (50 psi / 3.4 bar)	Members Only
Rolling Resistance Real tire width in mm: 30-32 = 55 psi/3.8 bar 33-35 = 50 psi/3.4 bar 36-38 = 45 psi/3.1 bar 39-42 = 42 psi/2.9 bar 43-46 = 38 psi/2.6 bar 47-50 = 35 psi/2.4 barMedium Air Pressure (42 psi / 2.9 bar)	Members Only
Rolling Resistance Real tire width in mm: 30-32 = 44 psi/3.0 bar 33-35 = 40 psi/2.8 bar 36-38 = 36 psi/2.6 bar 39-42 = 33 psi/2.3 bar 43-46 = 31 psi/2.1 bar 47-50 = 28 psi/1.9 barLow Air Pressure (33 psi / 2.3 bar)	18.9 Watts CRR: 0.00567
Rolling Resistance Real tire width in mm: 30-32 = 33 psi/2.3 bar 33-35 = 30 psi/2.1 bar 36-38 = 27 psi/1.9 bar 39-42 = 25 psi/1.7 bar 43-46 = 23 psi/1.6 bar 47-50 = 21 psi/1.4 barExtra Low Air Pressure (25 psi / 1.7 bar)	21.2 Watts CRR: 0.00635
The CX/Gravel 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.

Puncture Resistance Test Results

Puncture Resistance Test Results (higher is better)
Total Puncture Score Tread	40 Points
Total Puncture Score Sidewall	Members Only
Tread Puncture Force Sharp Needle	Members Only
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

Hard Surface Static Grip Test Results

Static Grip Test Results
Wet Grip Average	60 Points
Wet Grip Center	Members Only
Wet Grip Edge	Members Only
Measured Knob Height Center	0.2 mm
Measured Knob Height Edge	0.2 mm
Grip in points = coefficient of friction * 100 CX/Gravel grip test rim width = 23.0 mm
Wet Grip Test and Off-Road Tires (info)

Conclusion

With the GravelKing R test, we now have good data to compare the old GravelKing TLC generation to the new R and "standard" GravelKing casings. We're surprised the GravelKing R is heavier and rolls slower but offers better puncture protection than the original GravelKing TLC (read our review). Because of the separation into three casings options, we must admit that we expected an improvement in the rolling resistance tests for at least the lightest R casing.

In the grip tests, we also see nearly the same scores as we're used to seeing from the old generation. The main problem for the GravelKing in this test is that the file tread isn't the best option for hard surfaces, as it greatly reduces the contact patch, and grip will always be limited. The new GravelKing X1 did much better here, at least thanks to its more sturdy tread pattern.

Our conclusion is again that the new GravelKings are mainly an improvement in user-friendliness. Setting these up tubeless is much easier, and their sealing capabilities are much better, thanks to the new TuffTex layer and BeadLock beads.

RATING: 3.5 / 5
TEST VERDICT: Recommended

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