Cyclists have long known about the importance of rolling resistance in selecting tyres for racing, group rides or even general training. A high rolling resistance will require more power to travel at the same speed, whilst low rolling resistance requires less power.
We performed a test on a variety of different inner tubes to see how they affected rolling resistance. We used a Continental GP 5000 clincher tyre in 25mm to perform the test, and you can see how the GP 5000 clincher performs here: GP 5000 DATA
The goal of this test was to evaluate the rolling resistance performance of different types of inner tubes.
Having previously tested a variety of tyres, it's also important to make sure your inner tube choice is also correct as this also affects your rolling resistance. In this test we kept with one model of clincher tyre - the Continental GP 5000 in 25mm.
Continental Race 28 light
Continental Race 28
The Tubolito inner tube was by far the lightest on test, weighing 64g less than a standard Continental Race 28 inner tube. This gives a wheelset saving of 128g, which irrespective of rolling resistance will be a little faster - for a flat course 128g will be a minimal to no real saving, but if travelling uphill at 16kph on a 10% gradient, a 128g weight saving would equate to 0.6w saved, or a speed increase of 0.02kph. However - rolling resistance has much more of an impact than weight, read on to see the difference in rolling resistance.
ROLLING RESISTANCE RESULTS
In order to test rolling resistance, we used the same tyres and swapped between them as a rider rode a bike on rollers, measuring power output and speed, as well as atmospheric conditions and bike/rider weight. This allows us to calculate what is known as the Coefficient of Rolling Resistance (or "Crr"), which can be used to model the power output required to travel on a normal road. A lower Crr is better - in that it requires less power to travel at the same speed.
The Vittoria latex tube was much faster than all other inner tubes, saving over 7w for a pair of wheels compared with a standard butyl Continental Race 28 inner tube.
The lighter inner tubes (Continental Race 28 light and the superlight Tubolito) were faster than a standard Continental Race 28 tube, saving 1.6-2.3w for a pair of wheels.
At 45kph, the difference between the fastest and slowest inner tubes would equate to around 11sec over 16km/10 miles.
In this test we found that there was a large difference in rolling resistance between different models of inner tubes, with standard butyl tubes being the heaviest and the slowest on test.
Latex inner tubes outweigh any small penalty from ultra light tubes like Tubolitos as the rolling resistance with a latex tube is so much lower (better). One small drawback with latex tubes is that they lose air overnight and require pumping up before a ride - so if you want to have an inner tube that's a little bit faster than a normal butyl tube and doesn't require daily inflation, a Tubolito would be a good alternative.