a combo effect
Have you ever wondered which tire is the fastest option for your setup? Knowing a tire's Coefficient of Rolling Resistance (Crr) can help make that determination. Rolling resistance is influenced by tire design, compounds, width, and contact patch. This article will help you consider all the right factors to lower Crr and increase your tire's speed and grip.
Resistance: the impeding, slowing, or stopping effect exerted by one material thing on another.
There are several types of resistance a rider must overcome on the bike. For example, when cycling uphill, gravity resists your rate of ascent. When pedaling into a headwind, the output required to maintain speed goes up due to wind resistance.
Your tires also resist forward motion due to two main factors: hysteresis and impedance.
what causes rolling resistance
Hysteresis is the main cause of rolling resistance in pneumatic tires. As a tire rotates under load, it goes through repeated cycles of deformation and recovery. Hysteresis results when the energy lost due to the deformation exceeds the energy gained in recovery.
Impedance can also increase a tire's rolling resistance when inflation pressure is too high for the surface being ridden on. Instead of traveling in a forward motion, the tire begins bouncing in a vertical plane, leading to a decrease in efficiency and grip.
Variables like tire construction (number and types of layers), rubber compounds, inflation pressure, and contact area to the ground all influence how well a tire manages energy loss due to hysteresis and impedance. The ideal combination of those variables depends on the types of surfaces you ride on and the internal measurements of your wheels.
how to optimize your setup
One way to lower rolling resistance is by manipulating a tire's contact patch (the amount of surface area in contact with the ground). Have you noticed the trend towards wider wheels and tires? Research has shown the shorter, wider tire contact patch with these setups not only lowers rolling resistance but also increases grip.
Paying close attention to inflation pressure is also critical to achieving a low Crr. Not too long ago, the standard wisdom was that pumping a skinny tire to 120+ psi was fast. Now we know through studies like Zipp's Rolling Road that higher volume, lower pressure setups are superior in real world conditions.
There are several tools available to help get your quest for low rolling resistance headed in the right direction.
Using an online Tire Pressure Calculator will give you a baseline to start from after taking into consideration variables like your weight, riding type, and tire size.
You can also view independent testing of different tire models at Bicycle Rolling Resistance, where factors like Crr, puncture resistance, and grip values are available.
The quickest way to increase your efficiency is by working with an ARC Performance Systems coach. We can analyze your setup and riding style to help you choose the optimal equipment for your next event or everyday training.
If you're interested in getting the most out of your training, optimizing your bike setup, and achieving your best possible results, click the button below to schedule a one-on-one consultation with a coach today!