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Has anyone tried the TP Checker kit? You get remote temp and pressure readings, from the 4 tyre valve sensors, displayed on your dash.
 

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I use 32psi all round on 255/40/17 Falkens on my GTR32. Seems to be wearing the center more than the outer edges of the tyre. If I drop the pressure, the car feels 'floppy'. Bit confused to be honest!
 

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Discussion Starter #25
Compensating for Driver Weight...

As mentioned at the start of this thread...

Is tosh.

It was my idea and fine theoretically, but I collected the car today running 36psi front and 34psi rear on 265/30/19x9.5 and it's bloody marvellous.
 

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My 33 Gtr is running 255/45/17 contisports not my choice but were on the car when i bought it.

It has standard dapmpers but aftermarket springs quite a stiff ride. What pressures would you reccomend?

Thanks
 

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I use 32psi all round on 255/40/17 Falkens on my GTR32. Seems to be wearing the center more than the outer edges of the tyre. If I drop the pressure, the car feels 'floppy'. Bit confused to be honest!
I use 30 to 32 psi R32 GT-R 255/40/R17 also and this seems the best pressure for road driving. 38 is WAY too high. Pressure is all about contact patch and is basically (although due to other factor not exactly) the weight of the car / 4 / psi of tyres give the contact patch area of each tyre in squared inches, so 3000lb / 4 / 30 = ~25 squared inches so about 5x5 inch contact patch on the road. You can work out the psi in reverse for tyre width and how much tyre you want on the road ratio to sidewall stiffness etc.

Basically wider tyres lower pressure.
 

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Cheers for the info skyline69 uk.:thumbsup: I shall try and get my pea sized brain around that! Ive just had new rear tyres fitted. Dropped the pressure to 30 psi and see how we go.;)
 

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hi there all anyone know the setting for trackng on r34gtr?
ive had it tracked up but the car seems to be running slightly to the left its a vspec if this help :)
 

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tbh I'm not surprised with all the different theories here, you walk around the paddock of any race meeting/trackday and ask 100 people what pressures you should run, and you'll get 100 different answers. My advice, go and find out what works for you.

Or start at road pressure, go out warm up the tyres, then let them back down to 2-4 psi lower than road pressure and go race. But take a pump with you, cos you cant drive home on that, you'll bugger your tyres/rims once they cool down. But hey thats just one of 100 theories to follow (or not)
 

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Don't agree with that. Seen too many pics of cars cornering hard practically on the rims because air has been let out.

Had a long discussion about with Colin CATDT at the Nurburgring.
let me set you boys (and girls) straight here.... :chuckle:

this is the practise I apply in rallying - but it should apply to circuit racing.

You start by picking the pressure you want to run (so for me, gravel tires etc = 27psi)
at the start of the day we bolt these tires on set to 25psi cold
tour to the first stage (so for circuit maybe a sighting or warmup lap)
check pressures, and reset warm to target pressure - as they will usually gain anywhere from 4 to 8 psi just road driving
after the 1st stage and while waiting to clock into the 2nd stage, re-check and balance the pressures (as different tires will gain more or less)

away you go - that set of tires is set - if conditions change we may change pressures, but usually not. and from experience, I can tell the crew what pressure to set the new set of tires at cold, so that when they bolt them on there is less adjustment needed - merely equalisation.

For circuit, it would be useful if you had a pyrometer to measure temp vs pressure - which would allow you to make a much more informed decision about pressures :)
 

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I use 30 to 32 psi R32 GT-R 255/40/R17 also and this seems the best pressure for road driving. 38 is WAY too high. Pressure is all about contact patch and is basically (although due to other factor not exactly) the weight of the car / 4 / psi of tyres give the contact patch area of each tyre in squared inches, so 3000lb / 4 / 30 = ~25 squared inches so about 5x5 inch contact patch on the road. You can work out the psi in reverse for tyre width and how much tyre you want on the road ratio to sidewall stiffness etc.

Basically wider tyres lower pressure.
Excuse the thread exhumation - I'm running ~38psi in my 18s. No wear on the centre lines (only the edges) and it feels like pooh if it drops much below this. I do wonder how hard the sidewalls are as the tyres are no brand shite.
 

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PRESSURES

tbh I'm not surprised with all the different theories here, you walk around the paddock of any race meeting/trackday and ask 100 people what pressures you should run, and you'll get 100 different answers. My advice, go and find out what works for you.

Or start at road pressure, go out warm up the tyres, then let them back down to 2-4 psi lower than road pressure and go race. But take a pump with you, cos you cant drive home on that, you'll bugger your tyres/rims once they cool down. But hey thats just one of 100 theories to follow (or not)
So what is the advised pressure for a standard 18 45 245 tyres on a gtr34 for road use.
 

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So what is the advised pressure for a standard 18 45 245 tyres on a gtr34 for road use.

34 psi front and rear with air

But saying that, I just had my P-zero rossos (on R34 Wheels) filled with Nitrogen, 33 psi front and rear so it is quite low considering it wont rise in pressure as bad as air so I could run them at 35-36 psi cold if I liked, but on the otherhand I do keep a larger contact patch area even when temps do go up however due to lower pressure.
 

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36 all round minimum would be a good starting place from my experience.

I tend to run my 275/35-18s on 10" rums at around 38 to reduce tramlining and front tyre edge wear.

Perhaps controversially I was advised to add 10psi all round to a road car for track day use, this was a consensus from a large group of instructors and touring car drivers at an industry event which included hot-laps. I took this advice with an Astra TDIturbo sport with 30 profile 18s at Donnington and it worked a treat for me, car felt great.
 

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I'll have a go with 34 cold this weekend as i'm travelling, i'll let u know how it goes, although the weather isn't exactly going to help me get any real driving out of them methinks. Thanks for the starter.
 

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i ask falken for best pressure, the introduction:

Skyline R33 GTR
Falken FK 452
265/35 ZR18 97Y front and rear
9,5x18 front and rear

street
cold: 2,3bar (33,35psi) front and rear

track
warm: 2,3bar (33,35psi) front and rear
 

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tbh I'm not surprised with all the different theories here, you walk around the paddock of any race meeting/trackday and ask 100 people what pressures you should run, and you'll get 100 different answers. My advice, go and find out what works for you.
And this is how this thread will continue. If everyone here had the exact same car/suspension/rims/tires/and weighed the same we would still have 100 different answers. Get it set for how YOU drive and WHERE you are driving. I autocrossed an S2000 on stock 16"s/Dunlop Star Specs at 40psi/front 31/rear. It worked great for that, but it was a nightmare on the street.
 

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What should the pressures be for an R33 GTR standard weight, normal road use fitted with 19x9.5 rims wrapped with 265x30x19 tyres, at the moment the pressures are 30lb at the front with 32lb at the rear.
 
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