Continental Grand Prix 5000 S TR - Hooked Vs Hookless Rims
Contents
Hookless rims have popped up over the years as an alternative to the classic hooked rims that have been around for ages. Although we're not (yet) fans of hookless rims, it appears they're becoming more popular even though they come with some obvious drawbacks.
We see the main drawbacks are the requirement for hookless compatible tires and a maximum allowed inflation pressure of 73 psi - 5.0 bars. With the release of the Grand Prix 5000 S TR, which is now hookless compatible, the first point might now be a problem of the past as the Grand Prix 5000 S TR is probably one of the most popular and best performing tubeless tires out there.
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The maximum allowed air pressure of 73 psi - 5.0 bars is also quickly becoming less of a problem as many road bike riders are moving to 28 or 30 mm tires and run them at lower air pressures for increased comfort, lower vibration losses, and better tubeless re-sealing.
We've tested the 28, 30, and 32 mm versions of the Grand Prix 5000 S TR with a classic hooked aluminium rim, a hooked carbon rim, and a hookless carbon rim (all close to 22 mm internal width). We left out the 25 mm version of the Grand Prix 5000 S TR as, although it's hookless compatible, we do not feel it's a good fit for hookless rims that are often much wider than standard, and the 73 psi - 5.0 bar maximum pressure in combination with a 25 mm tire will be too low for most riders.
We decided to also throw a hooked carbon rim into the mix so we can see if there's any difference between carbon and aluminium rims.
As usual, the averaged data of those tests will be available free for everyone. Pro Members can open the individual tire data and dig into the results further.
Test Set up and Conditions
When testing the same tires with different wheels, there will always be some differences as some wheels have more spokes or some hubs have more resistance. We always subtract the wheels' unloaded resistance when calculating the tires' final rolling resistance.
What this comes down to is that we're purely measuring the difference between the rims itself. There are still some small differences that we can't measure (bearing losses, spoke losses, rim losses) when the wheel is unloaded but the largest contributor will be taken out of the equation with the unloaded wheel measurement.
We used the following 3 wheels:
- Shimano LX 670 hub + aluminium rim (hooked)
- DT Swiss hub + carbon rim (hooked)
- Zipp 303S carbon wheel (hookless)
The wheels all have different weights, and we added some extra weight to the machine to compensate for the differences.
Test Conditions
- Speed of 29 km/h / 18 mph
- Total wheel load of 42.5 kg / 94 lbs
- Temperature between 21.5-22.5 °C / 71-72 °F
- Diamond plate drum surface
- 77 cm drum diameter
Test Results - Average Results of 28, 30, and 32 mm Grand Prix 5000 S TR
| GP 5000 S TR Rolling Resistance 28, 30, 32 mm Average | ||||
|---|---|---|---|---|
| Rim | Hooked Aluminium | Hooked Carbon | Hookless Carbon | |
| Rim Internal Width | 22.0 mm | 22.4 mm | 22.7 mm | |
| Average Tire Width (73 psi - 5.0 bar) |
31.17 mm | 31.23 mm | 31.23 mm | |
| Rolling Resistance 73 psi / 5.0 bar |
9.59 Watts | 9.43 Watts | 9.34 Watts | |
| Rolling Resistance 65 psi / 4.5 bar |
10.00 Watts | 9.78 Watts | 9.83 Watts | |
| Rolling Resistance 58 psi / 4.0 bar |
10.48 Watts | 10.28 Watts | 10.43 Watts | |
| Rolling Resistance 51 psi / 3.5 bar |
11.25 Watts | 10.96 Watts | 11.17 Watts | |
From the results above, it's quite obvious the rim type isn't going to make a huge difference. The differences between the 3 different rims all fall within the test's margin of error.
To make things even more inconclusive, a 0.1 watt measurement error of the wheels' unloaded "static" resistance can make a drastic change to the final results.
When not considering the margin of error of the tests, we see a trend where the aluminium rim performs just slightly worse (~ 0.2 watts), and the hookless rim drops off a bit sharper at the lower air pressures.
Test Results - Individual Tire Rolling Resistance Data (Pro Members)
The next section is only accessible by our highly valued Pro Members. This section includes all test data of the individual tires.
Conclusion
We conclude hookless rims do not perform measurably better or worse than hooked rims. In the averaged results, we see a maximum difference of 0.29 watts which can easily be the result of the margin of error of the tests.
When not considering the margin of error, we see a trend where the aluminium rim performs a bit worse, and the hookless rim drops off slightly more at lower air pressures. The individual test results confirm this trend.
This trend might then not result from the hooked or hookless system itself but in a difference in the shape of the rim itself or how tight the tire fits around the rim.
We also noticed the hookless Zipp 303 rims do not have much of a bead lock which might be more important than the whole hooked vs hookless debate.