What tyre pressure???

ClimbBoy

Really elementary I'm sure but I have a Cube Aerial fitted with Schwalbe Blizzards 25x622 and was wondering what PSI people tend to inflate their tyres to?

Mine tend to go down a fair bit after a handful of rides and don't want to over-inflate!

STEFANOS4784

It will say on the tyre.....l.That said i inflate mine to 120psi but lose a little bit when removing the pump

topcattim

Try looking at Sheldon Brown's website. I wouldn't advise just looking at what it says on the tyre, that will just show a range, and it would be a mistake to simply inflate it to the maximum shown on the tyre.

Simple rule he gives is to sit on your bike and ensure the tyres deflect (bulge) a bit under load. If they don't, you've overinflated. Actual psi will depend on tyre and your weight, but for example I weigh 70kg, ride Pro Race 3s in the summer and tend to have the rear at about 105 to 110 and the front at 100. I've always vaguely suspected that these pressures are too high, but never get round to any experimentation.

An overinflated tyre will give you a harsh ride and will offer less grip, particularly when cornering.

Joe86

STEFANOS4784 wrote:

It will say on the tyre.....l.That said i inflate mine to 120psi but lose a little bit when removing the pump

Something I have been curious about is the loss when you are removing the pump and you have the 1-2 second gap before it comes off. How much is likely to be lost? I thought it might be worth anticipating the potential loss, and maybe doing 5-10 PSI higher than you want, which when some escapes might result in the ammount you want. Or is it likely to be higher than 5-10 PSI?

Cheers

teagar

120psi is pretty high, especially considering the poor road surfaces in the UK.


Anything more than 100psi is unlikely to give you any real performance gain but just make your ride harder.

Mark Alexander

It depends on the usage. Don't ignore the quoted pressures on the wall of the tyre but try different pressures and se how you feel. if it says 100-120 then try those and 110. Testers put up to 160 and sometimes more if tubs.

In my Pro Race 3's i have about 110-120 in the summer and lower it a bit in the winter. Too low can cause you to be more susceptible to punctures.

STEFANOS4784

I reckoon it's about 10 psi loss, from what i've heard anyway, i wouldn't obsess about pressures though really...........

Joe86

STEFANOS4784 wrote:

I reckoon it's about 10 psi loss, from what i've heard anyway, i wouldn't obsess about pressures though really...........

Ok, well I usually only go to about 100 PSI on mt 700 25mm tyres, so what I have been doing seems about right. Thanks!

Mark Alexander

He's right, as long as you're comfortable, and it's safe, it's not a big thing.

huuregeil

Joe86 wrote:

Something I have been curious about is the loss when you are removing the pump and you have the 1-2 second gap before it comes off. How much is likely to be lost? I thought it might be worth anticipating the potential loss, and maybe doing 5-10 PSI higher than you want, which when some escapes might result in the ammount you want. Or is it likely to be higher than 5-10 PSI?

Cheers

Very, very little indeed. With the pump on, the valve is pushed open by the pressure of the pump. The instant the pressure on the pump side starts to drop, the valve closes. This will happen very fast. The whoosh of air you hear when you remove the pump is simply the pressured air in the pump hose, not any leakage from the tyre.

In other words, just pump and don't worry about it - there's no way you could correct for any leakage, it's just way too small in the grand scheme of things.

ride_whenever

you lose virtually nothing if you're using your pump properly, you shouldn't need to force it onto the valve, it should just fit fairly losely then you lose the lever to lock into place, so when you undo the lever the valve closes immediately. The long hiss is usually air escaping from the pump rather than the tube.

Or at least that's what i've found with a track pump and a digital pressure guage (it has a tiny dead volume so only loses about 0.1 psi from a tyre!

ex-pat scot

Pump it hard enough to avoid pinch flats.

Allow a little deflection from road bumps.

DOn't trust the accuracy of pressure gauges. They are uniformly crap.

Flasheart

Yay someone else with an Aerial
I changed my Schwalbe Blizzards to Michelin Pro 3's not long after I got the bike. These I run at 115PSI, I ran the Schwalbe Blizzards at the rating on the sidewall and got a puncture within the first week :evil:

softlad

STEFANOS4784 wrote:

It will say on the tyre.....

it won't. it will only tell you the maximum rated pressure, which is of no practical use in establishing what a given rider's optimum pressure should be...

STEFANOS4784

Well whatever, the questions been answerd.
Answer; Same as the outcome of most threads people are 'right' dependent on what they happen to use :P

STEFANOS4784

And just to clarify the correct answer;

SheldonBrown wrote:

Savvy cyclists experiment with different pressures, and often even vary the pressure for different surface conditions.