Tire Pressure Starting Point

[Renault78law]

https://info.silca.cc/silca-professiona ... calculator

[Pierre86]

@Cubist If you're running 7 bar/101 psi that's WAY too high.

I'd definitely go with the TyreWiz numbers.

As @nyebo mentioned, why not start a little above that recommendation and work your way down?

Just Google pro peloton tyre pressure. You will find out it is not high at all. 60psi will def give me pinch flats all the time. Some guys are running 140 psi. That is extreme I admit. But 7 bar is a totally normal number for 23-25 mm tyres.

Don't do what the pro's do, a lot of the time they'll do something a certain way just because thats the way they've always done it. Most pro's are running their tires too high

[Cubist]

https://info.silca.cc/silca-professiona ... calculator

This one seems a lot better IMO. Suggests 97/6.7 front nd 99.5/6.9 back for mild roads. Going to try it today.

[nycebo]

Thanks.
OK, so with GP4000 28mm on a 20mm internal rim, you may have an actual diameter of close to 32mm. That tire is a huge baloon relative to other nominal 28mm tires. Super comfy ride I bet. 60 - 65 psi is also what I would use in that situation. At 28mm actual measure, I won't go less then 70 psi. 60 psi is too squirmy and significantly increases the chance of pinch flats.

Not quite. With my calipers and that setup, I read 30mm on the front tire, 29.5 on the rear.

Again, I think the tendency to overinflate tires is too high. It stems from our days riding 19s and 21s. Back then, being too low on pressure could really create a problem and vastly increase the risk of pinch flats. I've not found that at all with 25s and 28s.

[Hexsense]

@Cubist If you're running 7 bar/101 psi that's WAY too high.

I'd definitely go with the TyreWiz numbers.

As @nyebo mentioned, why not start a little above that recommendation and work your way down?

Just Google pro peloton tyre pressure. You will find out it is not high at all. 60psi will def give me pinch flats all the time. Some guys are running 140 psi. That is extreme I admit. But 7 bar is a totally normal number for 23-25 mm tyres.

Pro use tubular on good road, right? Tubular 25c is similar in width to most 23c clincher. We'd have to check what pressure pro use for 28c tubular as the indicator for 25mm clincher. Then tubeless can run a bit lower for comfort and speed on bad road (but not neccessery to do so, if the road isn't bad).

Anyway, I'm using 25c front/ 28c rear (GP5000, which is narrower than GP4000sII) at 70psi if i know the road is smooth. And 65psi if I know i'll be on bad route.
But for OP's weight, I'd start the experiment at 80psi and slowly reduce it.

[boleiro]

Man, I posted to this the other day but I don't see my post now?

I did forget to mention that my tires are 28c tubeless. Actual width on 21mm internal rims is 29.5. I tried that silca calculator and it seemed reasonable... 78 Rear / 76 Front. After listening to the velones podcast with Zinn talking about tire pressure, I kind of settled on 80 Rear / 75 Front. So pretty close.

I'll get out on a ride this Saturday to try it out... should be interesting. Thanks all for the info... always a big help.

[jlok]

Have you seen Vittoria Tire Pressure recommendation? It says 105/110 psi for wet/rough road conditions on Corespun 320tpi clincher 65-75kg total weight. It doesn't mention the width, but I think it's too high?

https://www.vittoria.com/eu/tirepressure

[Miller]

Tubeless is more or less immune to pinch flats. You can run tubeless way lower than clincher if you have to. Anyway a lot of the discussion here about tyre pressure is macho BS just like the gearing discussions.

[Miller]

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[alcatraz]

What's the narrowest tire that allows you to keep the power down without bottoming out and bouncing around/depleting you? That's likely the fastest tire.

It could be a 23@~100psi, could be a 25@~90psi or a 28@~75psi, and so on.

To the people out there running a 28 or 32mm tire at pressures as low as 60psi. Don't you feel like sizing down and upping the pressure a smidge? Could be a little bit faster...

[jlok]

What's the narrowest tire that allows you to keep the power down without bottoming out and bouncing around/depleting you? That's likely the fastest tire.

It could be a 23@~100psi, could be a 25@~90psi or a 28@~75psi, and so on.

To the people out there running a 28 or 32mm tire at pressures as low as 60psi. Don't you feel like sizing down and upping the pressure a smidge? Could be a little bit faster...

On rough roads where my latest gen CamelBak Podium would shoot out, 28mm Pro One TLE works great. As you said, 28mm at 60psi up front bounces much less than 25mm at 70psi at those roads.

When I go back to smoother roads, I couldn't feel the 28mm holding me back and I just love the comfort. Maybe I have already accustomed to it. However, I'm still itching for the aero benefits of true 25mm front tire on my Bora WTO 45 DB. I have tried putting 23mm GP5k clincher (24ish when mounted) and 25mm Pro One TLE at the back (26 when mounted), but the height differences lessen the trail and I'm a little bit uncomfortable with that during high speed descending. Maybe I will try again.

[IrrelevantD]

What's the narrowest tire that allows you to keep the power down without bottoming out and bouncing around/depleting you? That's likely the fastest tire.

It could be a 23@~100psi, could be a 25@~90psi or a 28@~75psi, and so on.

To the people out there running a 28 or 32mm tire at pressures as low as 60psi. Don't you feel like sizing down and upping the pressure a smidge? Could be a little bit faster...

Ideal is somewhere between 25 and 28 where I live. We have our fair share of smooth blacktop, but also enough chip'n'seal and broken/crap concrete to justify a little wider tire. I've been running road tubeless for over 10 years, I started out on 23's at about 105PSI. 28's at ~70 are just as fast (maybe faster) , and a lot more comfortable. Also, there is a very noticable difference in the number of punctures, or at least the ammount of lost sealant, when you get down below 80PSI. Since I started running mainly 28's, (maybe 6~8 months) I can only remember one, and that was a roofing nail that got stuck very close to my sidew2all.

[Cubist]

Silca Tyre Pressure calculator is the lick.

[Marin]

Forget calculators.

Drop the pressure in small steps until the front tire feels squirmy under hard cornering, then raise by 0.2 bars or so.
Rear a bit harder than the front, or same procedure as the front, but for hard climbing out of the saddle.

This method takes into account your riding style and the level of feedback you expect from your tires.