creature3

Until recently, I have always run my tyres at 34 p.s.i. However, I read an article by a motoring person, and I do forget his name at the moment, that said that manufacturers pressures should be followed as the manufacturer has put a lot of time and effort into getting the car to handle properly, thus their (manufacturer)tyre pressures should be correct for optimim handling. It was also said the inflating the tyre to over the recommended pressure will actualy reduce the contact patch, resulting in less grip. The writter said also that while higher pressures were nessecary for race-track work, or high speed driving, for everyday driving there was no need to increase the pressures.

What do other members think?

davway

what happens if you have a car that has a different brand of tyre than it did when it come from the factory? also what do you do if said tyre has NO inflation recommendaions on it anywhere?

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creature3

I would assume that the recommended pressures from the factory cover all makes of tyres suitable for the car. Of course different diameter tyres would require different pressures due to the sidewall thickness (height) lessening with larger dia. tyres such as 18" and 19" etc.

Most tyre manufactures only put a maximum pressure and load onto their tyre sidewalls.

venomXR6

car manufactures only put the minimium recomemded tyre manufactures presure on the tyre placcard for comfort. not .for handling or tyre wear stay with what your running or you will have only the centres of the tyres left cheers

xbgs351

Obviously the author isn't well informed.

bushute

Agreed! The author is certainly not talking from experience when he says to increase pressures for track days. Hacking the car thru corners and hard braking on track days puts a LOT more heat into the tyres - consequently the internal gas (air or nitrogen) will expand at a greater rate. Running higher pressures means the tyre pressure will EXCEED even the manufacturer's recommended max. Your road going tyre pressure aint gonna cut it on the track - THEY NEED TO BE REDUCED FOR TRACK DAYS!!!! The ambient air temp makes a diff too.

Things that have an impact on tyre pressures:
- weather conditions - air temp, rain, snow!!
- driving conditions - hard corners or straights
- driving style - turn in hard or take the long apex through a corner
- gas used - air or nit
- tyre compound - thermodynamics of the compound
- suspension setup - camber, toe, spring and damper rates etc
- weight
- road surface - guage of top coat (country road or hot mix), dirt etc

Bottom line - every car and driver is different and there is NO one pressure that is perfect. You have to play with your pressures in order to find what is right for you and your setup. It takes time but is worth it.

Pressures are certainly a science with lots of variables. They aren't like a "bolt on" where it either works or it doesn't. Its more like the weather, you can try and try to get real close but never exact, sometimes you're not even close. Ultimately, the only way to get accurate results is to use a pyro. Have a look the thread (18" tyre pressures) for some info on pyros and tyre temp.

Good luck.