How Does the Tire Pressure Affect the Speed of Your Bike?

Posted by tan xiao yan on

As Speed and Furious hailed as a blockbuster, it is apparent that speed can render speed pursuers both excitement and vehemence. Then another question that most cyclists are concerned about will be how to speed up on the basis of safety guaranteed. Tire, as an integral accessory of bikes, can be adjusted to produce various traction and resistance. Having the ideal tire pressure will make a huge difference on how your bike behaves, sometimes in very counter-intuitive ways.

Tire pressure will affect your rolling resistance and traction, as two most important figures that decide the speed, as well as the comfort of your ride. When the friction is larger than traction, the bike slows down gradually; while if the previous energy and traction are more powerful, the bike is inclined to speed up. From personal experience, you must find out that if your pressure is too high, the tire will bounce up and down, as it will not be able to conform to the terrain. But a newly inflated tire usually can make you cycle faster on an asphalt street. With too low pressure, you will increase the rolling resistance. Have you the same experience that a tire with less gas in it slows down the bike and enforce you to pedal harder?

Tire Pressure, cycling speedTypically on pavement, higher pressures will allow your bike to roll faster and climb easier because the higher your tire pressures are, the more bulged your tire will be, then the fewer frictions are created on smooth pavements, but up to a certain point where you want the highest pressure allowed for your particular tire. There is a sweet spot where your tires will roll the fastest.

On the other hand, with a lower tire pressure you'll enlarge the contact patch and get a lot more frictions with the ground which countervails the forward energy on your tire; thus you'll be slower. It has been found that a bike uses less energy to conform to a surface irregularity than to roll or bounce over it. Off-road, in squishy conditions, lowering pressure may give you better traction. This is why you should use slightly lower pressure for your front tire for safety. If your surface was as smooth as glass for example, then the ideal pressure that would minimize rolling resistance will be very high, 150 psi+ (if your tires could take it). Real roads are not as smooth as glass, the small pebbles and irregularities will “steal” energy from you. For example, say you're riding in a rock garden and the rocks are damp and slippery after the rain. The more hold the tire has, the more stable you'll be.

When mountain biking this is even more pronounced. The surface irregularities are much bigger off road. Using too much pressure will make you bounce excessively on every rock and root you roll over, losing precious energy and traction. If your pressure is too low you risk pinch flatting. For XC riding, an ideal pressure to be 24 psi in the back and 20 in the front with 2.35 tires.

Research has shown that the optimal tire pressure for a given surface will depend on many factors. The terrain you are riding on is a big factor: is it a twisty single track, wide open hard pack or a road? It also depends on the surface you’re riding on and type of tire/tube. Type of bike and suspension (or lack thereof), body weight, median surface irregularities, tire volume, tire width and tire tread all factor into the optimal pressure. Tire volume, rider weight and median surface irregularities are probably the most important of the lot.

Therefore, it is necessary to adjust Tire Pressure, cycling speedyour tire pressure in a customized manner so as to ensure speed. The trick of finding out which pressure is best for your weight and the kind of riding you do is keep testing.

How should the tire pressure to be changed appropriately?

Firstly, test your tire pressure with a tire pressure gauge. Most good track pumps will have one integrated into the pump so you can see how high the pressure is. You should consult the user manual or bike shop if you are not familiar with testing by hand. The maximum is a good place to start which will prevent pinch flats. But usually it can be less, and the ride will be better. Secondly, get yourself in the saddle, and check the tires. You can try out different pressures until you find what’s right for you. The rule is that the back tire should slightly bulge when you ride. And then that pressure, duplicated in the front, may be the same with 10% less psi.