Seems like not common knowledge: Tyre pressure vs speed

[Caravan]

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=72

 

The European Tyre and Rim Technical Organization (ETRTO) establishes the standards for tires sold in Europe, and recognizes that the tire's deflection must be minimized and controlled in order to surpass high speed driving stresses. In order to accomplish this, the tire inflation pressure recommendations and the tire's rated load capacities are customized when speeds exceed 160 km/h (99 mph) for all tires up to and including a V-speed rating, and when speeds exceed 190 km/h (118 mph) for all tires that are Z-speed rated and above

 

The Autobahn's unlimited speed opportunities explain why many German vehicles identify alternate tire inflation pressures to accommodate higher than North American highway speeds and heavier than typical two-passenger loads. In order to accommodate higher speeds, the tire size and inflation pressure recommendations are tuned beyond what is branded on the tire's sidewalls. These increases in recommended tire pressure are usually determined by agreement between the vehicle and tire manufacturers. In the absence of such an agreement, apply the following:

 

Beginning with the vehicle manufacturer's recommended tire pressure for normal highway conditions, tire inflation pressures are initially increased and then the tire's rated load capacities (branded on the sidewalls) are reduced as speeds climb.

 

How many people increase tyre pressure for the trip up north (easily hit >160km/h)?

[Good-Carbuyer]

You may be aware that increasing the tire inflation pressure is the norm for hypermiling, not just for driving speed[:p]

[Dumb]

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=72

 

The European Tyre and Rim Technical Organization (ETRTO) establishes the standards for tires sold in Europe, and recognizes that the tire's deflection must be minimized and controlled in order to surpass high speed driving stresses. In order to accomplish this, the tire inflation pressure recommendations and the tire's rated load capacities are customized when speeds exceed 160 km/h (99 mph) for all tires up to and including a V-speed rating, and when speeds exceed 190 km/h (118 mph) for all tires that are Z-speed rated and above

 

The Autobahn's unlimited speed opportunities explain why many German vehicles identify alternate tire inflation pressures to accommodate higher than North American highway speeds and heavier than typical two-passenger loads. In order to accommodate higher speeds, the tire size and inflation pressure recommendations are tuned beyond what is branded on the tire's sidewalls. These increases in recommended tire pressure are usually determined by agreement between the vehicle and tire manufacturers. In the absence of such an agreement, apply the following:

 

Beginning with the vehicle manufacturer's recommended tire pressure for normal highway conditions, tire inflation pressures are initially increased and then the tire's rated load capacities (branded on the sidewalls) are reduced as speeds climb.

 

How many people increase tyre pressure for the trip up north (easily hit >160km/h)?

 

 

Sorry cant understand why must increase tyre pressure for higher speed. Why want to reduce tyre's load capacity? I only know or I think speeding will reduce the car's weight.

[Hamburger]

Sorry cant understand why must increase tyre pressure for higher speed. Why want to reduce tyre's load capacity? I only know or I think speeding will reduce the car's weight.

higher speed which built up higher temperature and pressure in the tyres, need more air or higher pressure to sustain it.

 

the latter i also dont know.....

[Gasguzzler]

It's basically aerodynamics.

 

On a properly designed car, there is more downforce on the car due to higher speed of air flowing over the car. Hence, you will need higher air pressures to prevent the tyres from exploding from the load.

 

It's just like you will increase tyre pressure if you are going to transport a full load of passengers or goods.

 

High performance tyres with higher speed rating has stiffer sidewalls to support the downforce too; you will realise that higher speed rated tyres have higher load capacity as well.

 

Increasing air pressure of your tyres are especially important if your car is fitted with properly designed and calibrated aerodynamic kits like spoilers which generates more downforce at high speeds (>160km/h); yes, spoilers don't help with anything lesser than 160km/h.

Edited December 17, 2011 by Gasguzzler

[Carbine-]

to reduce tire flex maybe...

[Boyboy]

i follow a simple rule. not saying that it's necessarily the right way.

 

I adjust pressure to achieve even wear area to the edge. if the contact area extends to sidewall, it's underinflated. if contact area does not cover the thread pattern, then it's overinflated.

 

I also go by 'feel'. Personally i like higher pressure, to reduce tire sidewall flex. better stability at high speed. on paper, my tires are probably 10-20% overinflated but the wear pattern is fine

 

of course, if u wanna use this method, ensure your alignment is done properly first. (which should be always the case anyway)

[Mllcg]

i thought lower pressure tyres gives more grip?

[Elfenstar]

i thought lower pressure tyres gives more grip?

 

It does. If you're doing a drag race, great. If not, then the higher speeds = higher heat = higher chance of failure.

 

Failing tyre at higher speeds but with excellent grip or working tyre at higher speeds but with lesser (but still good) grip? Its your call.

 

P.S. Lower pressure also = lowered aquaplaning capabilities.

Edited December 17, 2011 by Elfenstar

[Caravan]

to reduce tire flex maybe...

 

You got it. That's the main reason.

[Mllcg]

It does. If you're doing a drag race, great. If not, then the higher speeds = higher heat = higher chance of failure.

 

Failing tyre at higher speeds but with excellent grip or working tyre at higher speeds but with lesser (but still good) grip? Its your call.

 

P.S. Lower pressure also = lowered aquaplaning capabilities.

 

is 225psi considered ok?

[XenonWhite]

i'm running on 270kpa up to Genting and back... Even now as well..

[Sky61]

but when we go tracking, we let off air pressure in the tyres before our hot laps. doesnt that go against this theory of high speed more air pressure? In the track,full throttle is the norm,and u can hit excess of 250km/h on the long straights.

[Jchuacl]

U should use use tyres with stronger sidewall, and you won't need to pump higher pressures.

 

i follow a simple rule. not saying that it's necessarily the right way.

 

I adjust pressure to achieve even wear area to the edge. if the contact area extends to sidewall, it's underinflated. if contact area does not cover the thread pattern, then it's overinflated.

 

I also go by 'feel'. Personally i like higher pressure, to reduce tire sidewall flex. better stability at high speed. on paper, my tires are probably 10-20% overinflated but the wear pattern is fine

 

of course, if u wanna use this method, ensure your alignment is done properly first. (which should be always the case anyway)

 

[Beehive3783]

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=72

 

The European Tyre and Rim Technical Organization (ETRTO) establishes the standards for tires sold in Europe, and recognizes that the tire's deflection must be minimized and controlled in order to surpass high speed driving stresses. In order to accomplish this, the tire inflation pressure recommendations and the tire's rated load capacities are customized when speeds exceed 160 km/h (99 mph) for all tires up to and including a V-speed rating, and when speeds exceed 190 km/h (118 mph) for all tires that are Z-speed rated and above

 

The Autobahn's unlimited speed opportunities explain why many German vehicles identify alternate tire inflation pressures to accommodate higher than North American highway speeds and heavier than typical two-passenger loads. In order to accommodate higher speeds, the tire size and inflation pressure recommendations are tuned beyond what is branded on the tire's sidewalls. These increases in recommended tire pressure are usually determined by agreement between the vehicle and tire manufacturers. In the absence of such an agreement, apply the following:

 

Beginning with the vehicle manufacturer's recommended tire pressure for normal highway conditions, tire inflation pressures are initially increased and then the tire's rated load capacities (branded on the sidewalls) are reduced as speeds climb.

 

How many people increase tyre pressure for the trip up north (easily hit >160km/h)?

 

I increase tyre pressure by 20kpa when i go for long distance drives up north.

 

[Beehive3783]

to reduce tire flex maybe...

Yes, you're right.. the rationale is to reduce sidewall flexing at high speeds which reduce the chances of the sidewall structure breaking down and rupturing due to the forces acting on the tyre at high speeds. Any slight pressure on the tyre is significantly increased when travelling at high speeds.

[Beehive3783]

is 225psi considered ok?

It's KPA, not PSI.. PSI is in double digits.

[Jchuacl]

225 kpa I supposed that's what you mean. Some tyres heat up faster than others, you'll need to measure to confirm.

 

 

is 225psi considered ok?