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If Only I Had Lexus Power
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827 Posts
Discussion Starter #1
Since the Tyre plate has no info for my oversized tyres, Could someone shed the light on tyre pressures for Bridgestone Potenza G3 225/60/R15 ( I have them At approx 32 psi front + rear and they grip like, well um --- something really grippy)

I have looked at their website but found nothing, failing this i will go visit my mate at bridgeys.

Cheers

Ash
 

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BOFH
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7,560 Posts
I would go at least 36psi front and 38psi rear. That''s basically what was recommended at the John Bowe course for 15" tyres if I remember correct.
 

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100MPH Hunter
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1,045 Posts
Should be at least 35-36 psi for even wear, but when you are on the drag strip, drop the rears a little to increase grip.
 

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If Only I Had Lexus Power
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827 Posts
Discussion Starter #7
there are no pressures on the sidewalls but thanks for the sugestion, I have fairly aggresive camber dialed in on the front, I will try inflating them (Tyres) a bit and see how it goes,see hopefuly they stay grippy.

Thanks Guys

Ash
 

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Birth, Drift, Death...
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3,039 Posts
i have those exact same tyres, have had for ages.

i have found in my car, (EB XR6 with superlows) and the way i drive - i call it from either 'spirited' to 'driving like a b!tch' that about 42 in the front and 36 or so in the rear is good.

the harder you corner and the more camber you have the more pressure you need - i have somewhere around 1-1.5 degrees neg camber and at 42 they still wear on the inner and outer edges faster than the middle, but thats because of the way i drive.

36 should be ok for rear, i set mine to about 38 and they wore slightly quicker in the middle - 36 should be perfect.
 

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Teh Pimp
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311 Posts
I would like to add something else to the equation... Pot holes!

A few days ago, mum ran over a massive pot hole (in XR8) that couldn't be avoided because of the road works (concrete barriers surrounding the road). She hit the massive bugger and when we looked at it, the tyre was bulging out and the rim was screwed. We had to use the spare but now it will cost $$$ to repair (suing of Council in place).

Point is: my mums psi rating was pretty low (about 30psi) so, the tyre shop said they should always be at least 36psi all around all the time and check about twice a week. If it was this high, the rim may have been saved...
 

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no tire smoke no fun!
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458 Posts
Rolllin ... 42 in front isn't it a bit high? i like 38 in front 36 rear. Do you have Z rated tires?
 

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Registered
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1,944 Posts
I must have shit tyres, as the sidewall max pressure says 36psi (15's)
 

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i pity tha fool
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1,040 Posts
max 36psi? probably coz lower profile tyres can take more pressure.. look at racer bikes versus mountain bikes(probably a poor example tho)
 

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If Only I Had Lexus Power
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827 Posts
Discussion Starter #16
One Ford Drone said:
I would like to add something else to the equation... Pot holes!QUOTE]


Yeah Damn pot holes .. i scraped my of 18's in a unavodiable pot hole. SA roads can be pretty shocking

So if i was to run approx 36 + 38 i should be in the ball park, and can fine tune as i go

Thanks for all you input guys
 

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Birth, Drift, Death...
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3,039 Posts
I must have shit tyres, as the sidewall max pressure says 36psi (15's)
i have never seen a tyre that has a max reccomended pressure on it - all the ones i have seen (being a mechanic thats a few) state "max pressure for seating bead on rim must not exceed XXpsi"

meaning that when trying to seat the tyre on the rim when fitting you should not use more than that amount of pressure, for whatever reason.

the way to figure out your best pressures takes a fair bit of trial and error.

basically, you just guess the starting pressure, say 36 rear and 42 front (as i said, if you hook round corners fairly quickly you want more)

take note of the tyre wear you are getting - (this is assuming your wheel alignment is good to start with)

if the tyre/s are wearing on the inner and outer edges then you should add a couple of psi, if they are wearing in the middle you should take a few psi out.

so, say you start with 36psi in the rears, and you notice they are wearing on the outside, a noticeable amount in a month or two, you add 6psi due to the fast wear, and after a month the tyre is now worn evenly.

take two or 4 psi out (remember its wearing the inside faster than the outside now) and the wear should be fairly even.

also rotating your tyres (only front to back, never diagonally) is a good way to make them last longer, but if you tend to do lots of burnouts it doesnt really pay - just means you will be up for 4 new tyres at once, instead of 2, then a little later another two (as you put the new tyres on the front and the semi worn on the rear)
 
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