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Tire Tech: What’s the best tire pressure for road & gravel bikes?

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Welcome to Tire Tech, Bikerumor’s new mostly-weekly series on bicycle tires. Like our Suspension Tech and AASQ series, we want to hear from you so we can get answers to the questions you have about tires, whether it’s road, cyclocross, fat, plus, gravel, or mountain bike.

In our first installment of Tire Tech we discussed proper air pressure for mountain bike tires. If control is the end game on singletrack, riders on the road crave speed and efficiency. No rider wants to waste a watt, but how much pressure is ideal for pavement and gravel riding?

The Trickery of Perceived Speed

The right air pressure for gravel riding requires an understanding of the conditions.

For years the formula was easy — inflate your tires to the max limit and ride away. It wasn’t very scientific, but our collective impressions led us to believe rock-hard tires equalled a fast roll. To put it plainly, we were all wrong! The sensation we felt wasn’t sweet velocity, it was little more than amplified vibrations transmitted through the bike. As those vibration frequencies increased, our perception of speed did as well. We may have duped ourselves, but we had help from throughout the industry.

At the same time we were bouncing down the road on our overfilled tires, many of the leading manufacturers were creating simulated tests to measure rolling resistance. Even today most of those tests use a steel drum to replicate the road surface. As air pressure is increased rolling resistance values typically go down. But even thorough testers like Jarno Bierman of Bicycle Rolling Resistance agree, there is a tipping point whereby a rougher surface will not benefit from higher tire pressures.

In recent years a number of studies have been performed in real-world settings comparing a wide range of variables. Those tests have pitted riders against cobbles, chip-sealed roads, dirt corrugations, and other surfaces far more textured than any steel drum. The results have created a sea change in how road-biased riders approach the pump. Riders are now pushing the lower limits of PSI in an effort to bolster comfort and performance. Gravel riders, the close cousin to the mountain biker, made the change quickly. Road purists have been a little slower to make the leap.

Tire Pressure and the 15% Drop

Too much air pressure feels fast but it is considerably slower than the optimal pressure.

One of the first bike scientists to delve into tire pressure was Frank Berto. In the 1980s he deduced that all tires — regardless of volume, material, or size — were at their optimum with 15% loaded compression in the sidewall. This footprint not only allowed for the ideal amount of shock attenuation, but it it afforded good braking and cornering traction. He claimed that this small 15% of sidewall flex garnered all of the positive benefits of a pneumatic tire without incurring the excessive hysteretic flexing losses of under-inflation.

The most important aspect of a tire’s compression is the ability to absorb irregularities in the road surface. By enveloping minor imperfections the wheel rolls forward with no loss of forward energy and doesn’t deflect, bounce, or chatter. If you have ever plowed over corrugations in a dirt road with over-inflated tires you know how hard it is to maintain speed. As general rules go, Berto’s drop seems to have survived the test of time, but it’s virtually impossible to accurately gauge 15% of squish in a tire sidewall.

How Much Tire Pressure is Enough?

Proper tire pressure is essential for efficiency on gravel.

Ask a tire pressure guru how much air is best and they’ll say “Not too much, but not too little, either.” Only time and experience can serve as your guide. You will have to carefully evaluate your tire width and consider the load on the tires to gain the ideal amount of tire deformation. Wet or slick surfaces will especially benefit from lower pressures and more meat on the ground. A freshly paved road with a glass-smooth, marble-like surface will benefit from higher PSI. Like everything in life — it is a balance. If you go too low you run the risk of a rim impact and the damage that goes with it. A soft tire also squirms in turns, and that excessive flex can prematurely wear the treads and sidewall.

The negatives at the upper reaches of PSI are less obvious, but usually manifest themselves in the form of rider fatigue, compromised braking, and less cornering control. Although it might feel faster, don’t be fooled — higher pressure usually isn’t.

What About Tubeless Tires?

Tubeless tires let you go lower without the risk of pinch flats. But unless you’re hopping curbs or there are serious potholes in your route, going low enough to increase the risk of pinch flats might be a little too low for confident handling anyway on pavement. For gravel, where tubeless is taking hold more quickly, it’s a balance between soaking up the bumps and preventing tire squirm in the corners.

But make small adjustments to find the right spot for you and your riding conditions. Tire pressure changes in a higher volume 700×40 tire will be more noticeable than in a 700×25 because of percentages. On a bigger volume tire, you might be maxing out at 55psi, so reducing it to 50psi is a ~9% change. On a road bike, you might be maxing at 100psi, so dropping it 5psi is a 5% change. If you’re a mountain biker, too, and have been riding plus or fat bikes, you know this all too well…1-2psi changes can make or break a tire’s performance there!

The takeaway is this: There are simply too many variables (rim width, tire width, rider weight, surface conditions, etc.) to make any hard and fast rules. But, try running a little bit lower pressure and see how you feel. Do you feel fewer vibrations? Do you feel fresher after a long ride? Do you have more traction and control? Or are you squirming around or bottoming on the rim? Make notes on your phone until you get it dialed, because going from memory — ride to ride just doesn’t work out IRL. Pro Tip: Once you find the right tire pressure for your set up, use a silver Sharpie and write it on the tire’s sidewall near the valve stem. (Oh, and most likely, you never need to get anywhere close to the max pressure rating stamped on the sidewall.)


This Episode presented by Terrene Tires. At Terrene, we put riding at the center of the experience. We understand what matters most—be it an afternoon on your favorite stretch of singletrack, a long day on an unending dirt road, or a worldwide tour. We took what we have learned through decades in the bicycle industry to bring you tires that are designed to ride how you do. From the very beginning of the process until the tread hits the dirt, we bring together our experience in product development and a passion for riding to create tires that are ready to ride for people that live to.

Pumped on this? Got a question you want answered? Email us. Want your brand or product featured? We can do that, too.

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FreeRider
FreeRider
5 years ago

I ride a road bike with $59 Clement Strada USH 700c x 32mm tubeless tires 120TPI at 60psi. I ride thru the city streets and bike trails in Seattle. Lots of variation in the road surfaces including rain, wet leaves, tree debris, tree roots pushing up asphalt and concrete, pot holes, steel trolley and light rail tracks, street marking paint, gravel, broken glass, steep hills, etc. I tire check pressure weekly although I don’t notice any loss of pressure. I ride 100+ miles per week. These tires roll fast, even with the slight tread pattern on them. I weigh 200lbs and get just the right amount of deflection at most speeds.

mudrock
mudrock
5 years ago

They could have stopped at “not too much, and not too little.” And no, I’m not pumped.

Tom
Tom
5 years ago

again all theory and no advice. First pitch – 200 lbs bike and me, 34mm tires. 60 psi on the road, aiming for 50 psi on gravel roads, though I haven’t experimented much with it. Could use more damping on the rough stuff, but concerned about bottoming the rim. On 25 mm tires, running about 105 on the road.

Benny
Benny
5 years ago

My usual answer is “as little as you can get away with and probably less than you are running now”.

My own answer at 170 lbs is 25r/20f on my MTB with 29×2.3″ tubeless tires, 35r/30f on my gravel bike with 650Bx47mm tubeless tires and 55r/45f on my road bike with 32mm tubeless tires.

Robin
Robin
5 years ago

CyclingTips had a good article in May that covered this. They discussed the variables that go into the tire pressure calculus and the research/data that support current thinking.

BTW, it’d be awesome if Anna Schwinn would interview Josh Poertner.

https://cyclingtips.com/2017/05/what-is-the-optimal-tyre-pressure-2/

id
id
5 years ago

Amazing that you wrote all these words without any real advice. No testing, no examples. Nada. Just a click bait title…. Weak writing.

Jeremy
Jeremy
5 years ago
Reply to  id

This. And using the “thesaurus “ function in word a little too much. What was the purpose and audience of this article? I learned absolutely nothing and the author made it difficult to read. I award you no points and may God have mercy on your soul.

ascarlarkinyar
ascarlarkinyar
5 years ago

Honestly we should throw out psi and go with durometer. It’s a better way to get everybody with different weights, tires, widths, rims, blah blah blah, on the same page. With that said, I like a 70 durometer for gravel.

will
will
5 years ago
Reply to  ascarlarkinyar

How would referencing durometer help? Durometer is the firmness of the rubber compound itself. Doesn’t matter how much air you put in your tire, the durometer won’t change.

Mr. P
5 years ago

The comments here are gold. Figure it out for yourself. The core message of this article is lower is better, how much you can get away with is up to you. Some of you are total hack riders; you need more pressure, some of you are smooth as butter; you can go less. Yes, it even goes down to riding skills. Can you experiment and figure it out? Or are you a bike media robot?

Robots, here are the magic numbers! 53.274psi front. 60.112psi rear.

Steev
Steev
5 years ago

*GRAVEL FARRRRRT

jxjjd
jxjjd
5 years ago

Meh its easy to find the right pressure for spees or comfort specially if not racing. No need to think about it too hard. Also for gravel do yourself a favor and ride tubeless

Tom
Tom
5 years ago

In mtb, you want enough pressure that you feel a muted “pong” when you hit a sharp rock or root, but not a harsh “ping”!

Sean
Sean
5 years ago

Complete useless article since psi is not the unit to measure pressure. If it would be written in bars it would be a different story…

Hexsense
Hexsense
5 years ago

agree with not releasing spreadsheet or guideline, variation is too large.
tire label sizing and weight is not nearly enough to say what pressure should i run.
For example, i have 3 rims with 15mm, 17mm and 21mm internal width, i weight 145lbs.
25c on 15mm internal width -> need 90-95psi to feel right, any lower it start to feel in hard corner.
25c on 17mm internal width -> need 80psi to feel right, any lower and i also feel squirm in the corner
25c on 21mm internal width -> anything above 55psi is no problem in corner, wide rim really stabilize the tire really well. Pressure above 80psi is way too hard (hard like 25c on 15mm internal width at 110psi+) so i set myself at 65-75psi. Happy medium

How would anyone recommend that 145lbs rider with 25c tire’s pressure would be? recommendation pressure = 65-95 psi? the range is too big that it’s useless! So just leave it blank and let user test with their own setting there.

joel w pontbriand
joel w pontbriand
5 years ago

the bike and I are roughly 290 lbs, with the bike being about 17. On my road bike with a high quality clincher i have found for me 112 psi in the back, 103 in the front is perfect on smooth flat roads which are quite abundant here in coastal nc. no pinch flats, wheel problems or anything detrimental. according to some of the crazy charts to “determine” your “correct” psi, i should be riding around 425 psi at all times!!!! heehee!

jvesik
5 years ago

Just do a search for Frank Berto’s tire pressure chart.

jvesik
5 years ago
Reply to  jvesik

I bought into the higher pressure is better Vredestein marketing of a while back. Always ran 130-140 psi on my Tri-Comp 23’s!

dontcoast
dontcoast
5 years ago

23psi front 28 rear gravelllll bruuuhhhh why you so stiff?
OR
50psi in my 40’s I huck my gravel meat!

pick a tire pressure and be a dick about it.

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