Whats your % of MAX tire pressure?

Equipment
1

Hi,

just wondering what tire pressure you folks are using on your road bikes (% of max).
I used to ride on 100% but having moved to a different country the quality of the roads makes it hard to stick with 100%. Really hurts me and my bike.

I am also wondering what impact does lower tire pressure have. Is the slight loss of speed worth the additional comfort?

thx

2

Lower pressure does not necessarily equate to slower. A softer tire can conform to small road imperfections and roll over them with ease while an over-inflated tire will “bounce” and lose speed since it can’t dissipate the energy anywhere except through the frame. A harder tire also may not corner as well, to a point, because the contact patch is smaller.

I run 95f/105r on my 25c GP5000 with latex tubes and weigh 175lbs

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3

Lower pressures does not mean slower. Running your tires at max pressure is generally a bad idea, because it compromises bike handling, efficiency and comfort.

The optimal tire pressure depends on many variables like weight of rider, tire, tire width, rim width, tubeless or not, road condition, weather, etc. In fact if your pressures are too high, you will be slower and your cornering will suffer, because you have less traction. That is because you will bounce around more whereas with lower pressures, your tire will continue to stick to the road and accommodate small imperfections in the road surface.

Here are pressures I rode (I weigh 71.5–75 kg):

  • 25 mm Michelin, inner tubes, narrow rim: 90ish psi on a narrow rim (typically I added 3–5 psi in the rear)
  • 28 mm Vittoria Corsa, inner tubes, narrow rim: 70–80 psi (max. pressure is, I think 105 psi)
  • 28 mm Vittoria Corsa Control, inner tubes, narrow rim: 60–75 psi (max. pressure is 85 psi).
  • 26 mm Pirelli P Zero, tubeless, wide rim: 60 psi (probably these tires measure about 28 mm on my rim)

You might look at the last figure and think I am crazy: 60 psi?!? But in fact, if you look at the Enve’s and Zipp’s air pressure tables, you’ll see that this is roughly the recommended pressure at my weight for their rims. Note that the max pressure for the rim is 72 psi. I have 3T rims and they don’t have an official table, but I can tell you the pressure is fine. I might experiment a little with the pressure, going a little higher and a little lower, but this feels about right.

There is a general trend towards lower pressures, wider tires and tubeless. And premium wheelset manufacturers like Enve and Zipp wouldn’t release wheelsets optimized for lower pressures if they believed it made their customers much slower :wink:

Here is some general advice:

  • Don’t go for max pressure. That’s almost never the right answer.
  • Higher pressure does not mean more efficient. The actual curve will be a U, i. e. to the left and the right of the optimum (lower and higher pressures), rolling resistance and other things will become worse.
  • Get the widest tires you can comfortably fit and go lower. Wider tires are not slower.
  • Different tires may have different pressures they feel comfortable at. Look at the 20 psi difference in max pressure for the two Vittoria tires, which are otherwise identical (same rims, same width, same rider). Also look at the max pressure of the rim.
  • I would lower the pressure in bad weather or when the road surface was very bad. Even when I lose on rolling resistance, I’d win on comfort and have more traction. Safety beats anything, then comes enjoyment. If your bike beats you up each time you ride it, that’s no bueno.

For more concrete advice you have to tell has what setup you are running.

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4

Higher pressure is probably slower than lower pressure. To see what you should be running, check out the Silca tire pressure calculator.

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5

thanks a lot! i went down from 8,5 bar to 5,5 front and 5,8 back.

curious to try it out.

Probably for riding my rollers I will need to go back to max i guess? any experiences with this?

6

Why do you want to go back to max pressure? The only people who ride their bikes at 8,5 bar/120 psi are people who ride on tracks. I. e. effectively nobody. You should not ride pressures that high, neither indoors nor outdoors. Unless you have a track bike and you, well, ride on the track.

Leave the pressure alone once it is set correctly for outdoor rides. Of course, you’d need to check every now and then how much air has escaped, but just stick to the proper pressure. 80 psi sounds reasonable.

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7

I’ve actually been doing some testing on this. Started at 90/92 Front/rear PSI for a 60 mile ride on Cervelo P2 with Flo Carbon wheels 60/90. Running 700x25. Running Conti 5000 Clinchers.

Following week (same 60 route) I ran 85/86, felt a little better

Following week (same route again) I ran 80/81 and it felt REALLY good over some of the rougher roads, and I still averaged 20mph+ over a 60 mile solo ride (I have a 264 FTP, so nothing crazy).

Riding again tomorrow, and will stick to the 80/81 for now, and I may try a 77/78 the following week. I’m not riding solo tomorrow.

Take all that for what it’s worth.

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8

Max pressure is a safety rating, not a recommendation for PSI to use.

It is 50% of the pressure needed to blow a tire off the rim. You should essentially ignore it (unless you plan in putting in even more pressure).

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9

thx, still I think that the resistance on rollers is unreasonable high with lower pressure tires. Is that not so?

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10

Why are you worried about rolling resistance on a roller? The entire purpose of rollers is to give you resistance by introducing friction. As long as the pressure is high enough to ensure your tires don’t heat up, i. e. normal pressures, you are good. Tire tread is probably more important. The rolling resistance curve should be similar as for asphalt, so higher ≠ better necessarily. Of course, you could optimize for more less comfort since rollers don’t have potholes and corners. But if you worry that much, you should get an extra wheel set with indoor tires.

If you are not willing to do that, just run the same pressure as you would for an outdoor ride. So not max pressure, far from it.

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11

I’m running Conti GP5000 28mm clinchers at 70/75 PSI. Max pressure is labeled at 8.0 bar/116 PSI. So it comes out to 60-65% of max PSI.

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