What is the “best” tire pressure is a question that I get from about half my clients and the other half should be asking about tire pressure as they are likely just pumping up their tires to triple digits without thinking about other options. One answer to all of these questions is “it depends.” This article aims to get you a few pounds per square inch closer to your ideal tire pressure for your event. (Above: Photo Cred Erika Fulk Detroit Spoke)
In choosing a tire pressure we hope to change the way your bike behaves: improve rolling resistance, handling, speed and safety. All tires are different but each tire has an ideal level of deflection, or size of contact patch between the tire and pavement. If you pump up your tire too much, the contact patch can be too small or change shape in a way that is not ideal for rolling resistance or cornering confidence. Run too little tire pressure and you risk having a contact patch that is too large, the tire may roll slow or even fold or roll off the rim in corners. Too high or too low a pressure depends on a few variables, the type of event you are participating in, rider weight, road condition, and tire size. Let’s evaluate a few different examples.
Tire pressure example one: the dry criterium.
In a criterium, you have many unique stresses on your bike and tires each lap. You face cornering challenges along with bad road conditions as crits are usually found in downtown areas that have many turns. If you are running 23mm width tires you will usually run a few PSI higher pressure than if you are running 25mm tires. The larger volume of 25mm tires lets you keep the same shape contact patch as a 23mm tire just at less pressure supposedly creating less rolling resistance. Rolling resistance will change with different tires and different pressure but for this article we will focus on choosing a general pressure for the event.
In a criterium, we see confidence in cornering as a necessity. Mix that with bad roads and you will find that less tire pressure will make you more confident in the turns and you will get less rattled over pot holes or bad pavement. For a 150 pound rider, on a 25mm tire, 80-85PSI is recommended. The side of your tire may say differently but the side of your tire does not know what weight you are, nor does it know the application or stresses you are about to put it though. At 80 psi you don’t run the risk of the tire rolling or folding in a turn but you have a nice round contact patch for confidence in turns and smooth riding over bumps. If you weigh more or less than 150 lbs usually 1 psi up or down for every 3-5 lbs is a good place to start. Its always good pre-ride a crit course. Also to note, the common floor pump bought at a bike shop will read differently from another brand of pump. 87psi on your pump may be 95psi on your buddy’s pump. That is a huge difference. Make sure you know what your ideal pressure feels like and be able to make some decisions on the fly.
Tire pressure example two: the wet criterium.
Rain in a criterium is an extra variable that deserves special attention. If we compare bicycle racing and criteriums specifically to MotoGP we can get some insight into fundamentals that are applied in a large scale. MotoGP has a much larger tire, larger contact patch, but also faster speeds. MotoGP changes to entirely different tires for different conditions and even different tracks. While a norm in MotoGP, cycling is slower to catch up in technology. There have been a few tires of late that have marketed themselves as compounds that perform better in wet conditions. Michelin along with a couple other brands have different compounds that are said to be better in rain. Sometimes these tires have slightly higher rolling resistances and less flat protection but that is expected on a softer compound designed to keep you glued to the ground in wet conditions. Much of this new idea to ride the tire suited to your conditions comes from changing compounds based on track type or weather like in MotoGP.
Whether or not you decide to invest in a specific set of tires for those rainy days you should always lower your tire pressure. In rain you want the largest contact patch possible. You may think “I can handle the corners with normal pressure and I’ll save energy on the straights over those running rain pressure” This way of thought usually proves dangerous. Even if you don’t crash from lack of traction in corners, you will lose more energy closing the gaps created by your rival cornering faster than you than you will make up on the straights. As a 150 pound rider I would chop 5-10 psi off of dry crit conditions to run 70-80psi in a wet criterium. As we dip below 70 PSI be confident in the accuracy of your pump. If your pump has been dropped multiple times on the ground and the gauge is 10 PSI off and 70 psi becomes 60 psi you start to get in to the danger zone for clincher tires to roll off the rim. Well-glued tubulars can go lower in PSI and can be a perk in technical wet criteriums, but you start to get side effects below 70 PSI with tires bouncing and poor rolling resistance. Lower pressures brings a large contact patch, it also makes it easier to pinch flat. Look out for holes a little more closely, you will float over them with ease with lower pressure but hit one too hard and you may flat your tube as it gets pinched between your tire and rim.
Tire pressure example three: the road race.
Road races have a huge variety in conditions. Generally, run a few psi higher in a road race to try and really get your tire at peak performance in regards to rolling resistance. In a dry road race on smooth roads our 150 pound rider could run 90-100 psi and have a fast rolling tire with no issues in the corners if there are any. This 150 pound rider should lose a few psi if the roads are rough or if there is a technical section of road where corning would be a factor in maintaining peak speeds.
We hope this helps you at least to think more of the rider type you are and how your tire pressure can be changed to maximize performance and speed. Above is a basic tire pressure gauge put together by Michelin tires. Note these pressures have no description of conditions to run these pressures at, so consider them dry conditions on smooth roads to minimize rolling resistance. Read back for how to adjust these pressures for ever changing road conditions or rain.
Zack Allison’s affinity for cycling started when he was 14 racing on the East Coast and his enjoyment of the sport lead him to pursue his BSEd in Exercise Science from Colorado State University, in Fort Collins, Colorado. He currently races for Elevate Pro Cycling, a UCI continental men’s road team. Growing up in the sport with many great mentors, he loves to pay it forward, using a combination of education and race experience. You can often find him zooming around on Fort Collin’s many gravel roads or on its countless mountain bike trails. Learn more about Zack.