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Tyre pressure logic ...


Arkaneslayer
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"No offense but jap car can use 17"s also right ?

 

To me there should be a minimum psi for tyres especially when their shape is 'fixed', can u imagine if its a balloon?

 

Just my view "

 

of cos jap cars can use 17" but there will be recommendations for different load ratings of the 17" tyres.

 

re your minimum psi - how do you determine that?

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"It should go by volume, bigger tyres need higher volume to fill up. "

 

not true. chk this site :

 

http://classic2.alfisti.net/english/service/reifendaten.htm

 

 

 

205/50-16 = 10.69 litres of air

 

205/45-17 = 9.91 litres of air

 

 

 

the logical thing to do would be to increase air pressure to maintain volume of air isn't?

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the formula assumes an even load distribution but in reality, braking or cornering will naturally exert more force on the respective tyres. but heck the formula, i reckon my butt dyno more accurate as each of us hv individual preferences for that 'perfect' ride/handling balance. wink.gif

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Neutral Newbie

Hmmm, that merits careful consideration...maybe we have to simulate the actual conditions with a volunteer couple from MCF!!! [sly][sly]

Edited by GDIzen
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"how do you determine the exact psi"

 

Hi! there, ArkaneSlayer,

 

I don't use butt-dyno, because there's a good chance for "Oh! sheeit!!"

 

I started by asking around for the pressure use on the particular tyre, 1st from the tyre shop where I mount the tyre & from friends & relations.

 

Correct pressure is determined by the timing of a run at the end of which, analysis of tyre performance & handling problems is reviewed.

 

Car makers won't review tyres from different manufacturers, only their tyre supplier. They'd only do it for the super car class, when a set of parameter as determined by the design of the car & suspension system is given, the tyre manufacturers are given the specs and are invited to send it for testing.

 

As mentioned by my previous post, the Enzo Ferrari is shod with Bridgestones, that's because they're partners in the F1 team. Similarly, if an oil change on the Enzo that cost US$732 is not observed, will cost an engine replacement of US$200,000 because warranty is void for not using the specified Shell engine oil.

 

On my car, there's no factory recommendations on brands of tyres so any tyres will do, as long as the specified parameters are followed, as I've gone to +1, it's over-exceeded already. But the current set of tyres don't have a settled tyre pressure yet, as I haven't done a test run. But it should be able to keep an old Alfa 155 2.5L V6 from leeching at my butt.

 

Rgds

 

Paul Yong

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"Correct pressure is determined by the timing of a run at the end of which, analysis of tyre performance & handling problems is reviewed."

 

yes ... we seem to be getting somewhere but still, your regular folk would not have the luxury, interest or equipment to do as you do ....

 

what kinds of analysis of tyre performance? what kinds of handling problems? i'm sure normal city driving dun require such indepth analyses rite? and your regular folk ain't gonna be literate in this area anywayz ... moreover we not are deciding optimum tyre pressures for tracking purposes...

 

still having read all that you wrote, i am unable to determine what is the optimal tyre pressure as a regular city driver base on your methods.

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Neutral Newbie
hmmmm...... just sidetrack abit:- for a parked car which is subjected to vibrations in the dark corner of a isolated carpark, which tyre pressure is good?? tongue.giftongue.gifwink.gifwink.gif

and I wondered???...sly.gifsly.gifsly.gif whose car might that be...laugh.giflaugh.giflaugh.gif

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another check - the all popular toyota corolla G9.

 

Kerb weight for auto car - 2590 lbs

add passengers & stuff - 310 lbs

total = 2900lbs

tyre size - 185/65-15

 

tyre pressure based on weight to be carried :

 

(2900/4408)*44 = 28.95 psi

 

recommended tyre pressure in the toyota corolla manual = 30 psi.

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"optimal tyre pressure as a regular city driver"

 

Hi! there, ArkaneSlayer,

 

If it's only for city driving, just follow what's printed on the sticker by the side of your car door.

 

Rgds

 

Paul Yong

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