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What Is The Right Pressure?

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Hello Steve.

Wow, how fortunate are we to have you here?

 

Can you tackle one of the 'urban myths' that we've probably all heard: that to heat the tyre up and raise the pressure you actually need to take air out, which allows the rubber to flex and heat, resulting in higher pressures.

If there's truth to this, can you clarify when it's applicable?

It's a frequent debate during very cold days; should riders change pressures, and if so is this done by adding a little air or removing some?

 

Thanks, Julian.

 

Good question.

 

Lets start with facts:

 

* YES lowering the PSI will result in higher temps, but not much more than 10 deg F

* The increase in temp is not enough to make a cold slick track magically give great grip.

* 1 second in faster lap time can equal 10 def F in temperature increase (depending on the track)

* Decrease in PSI will affect the handling and stability of the tire and thus the setup.

 

 

So you must ask yourself: If lowering the PSI gives more temperature and more grip, then why don't I run lower PSI all the time? (this question alone busts the myth right away)

 

I have observed riders lowering their PSI on cold days. I think it helps them mentally feel OK about their next session. I do not think its a major factor and is commonly very much over emphasized. If I saw someone doing it, I would not scold them. But I would not go out of my way to recommend it, and I certainly would not emphasis it as a solution to a cold track.

 

Thanks, makes sense.

Can I ask you one more question re wet riding? Another mith says that it's a good idea to put more air in the tyres, in an effort to keep the grooves open. The opposite being that with low air pressures (and considering that temps and pressures won't rise from riding) the 'flat spot' in contact with the track closes the grooves in the tyres. What are your thoughts on this? I can understand the logic - is there any evidence to suggest that it could be happening?

Thanks again,

Julian.

 

Regarding rain conditions on a racetrack: Yes, you would consider going up a couple of PSI if it raining. This helps keep the tread grooves from closing in and not channeling water. When its wet, the bigger concern is getting the water out of the way, next is grip. The stresses on the tire in the wet are much less than the dry so going higher on the PSI may reduce the dry grip, but does not come close to affecting the grip in the wet since the forces are much less. the big concern is getting the water out of the way.

 

Hydroplaning is the first thing you must handle.

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Hi Steve,

 

I have a set of NTec Sportsmarts fitted to my ZX6r. (In UK)

 

Looking at your reply re-track pressures (Page1), I am thinking they would be OK to run Cold at 31F & 21/22R in the Dry and upping pressures slightly maybe, +2F & +3/5R if on a wet track.

 

As there is no mention of Sportsmarts in your list of Tyres I am basing these pressures on the NTec construction.

 

Cheers,

 

Andy

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Hi Steve,

 

I have a set of NTec Sportsmarts fitted to my ZX6r. (In UK)

 

Looking at your reply re-track pressures (Page1), I am thinking they would be OK to run Cold at 31F & 21/22R in the Dry and upping pressures slightly maybe, +2F & +3/5R if on a wet track.

 

As there is no mention of Sportsmarts in your list of Tyres I am basing these pressures on the NTec construction.

 

Cheers,

 

Andy

 

Hmmmm, Never used the Sportsmarts. But if they are N-Tec construction your post would right in the ball park.

 

What does the local supplier recommend for this particular tire on the street? and on the track?

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Hmmmm, Never used the Sportsmarts. But if they are N-Tec construction your post would right in the ball park.

 

What does the local supplier recommend for this particular tire on the street? and on the track?

 

Steve,

 

Sorry no sure as I had them fitted at the school last month, used first time on a very/very wet stowe circuit. tyre pressures were set by fitter. Not sure what the front pressure was but rear was set at 27psi cold.

On the road I run them at the recomended pressures of 36F & 42R, but on the ZX6r it feels as if the suspension is working harder than with my previous Mich 2CT's. So may adjust pressures sightly for road use.

 

But saying that I feel a lot more confident with the Dunlops fitted over The Bridgestones or Michelins.

 

Andy

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What is the correct tire pressure for the Dunlop D211 GPRacer slicks (Made in France) off the warmers?I tried them in the 23psi rear and 33psi front off the warmers.Is this correct?

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