Tyre Pressures

GrubbyMX · Post by **GrubbyMX** » Mon Jan 30, 2006 9:36 pm

For those of you with 14" GIII Potenza's what pressure are you running
them at?
Have just had a set fitted and they came back @ 34lbs. Grip is
fantanstic but the ride is a tad harsh.

Learned comments anyone?

regards
Ralph

Grant · Post by **Grant** » Mon Jan 30, 2006 10:48 pm

I run mine at 30psi. Grip is much better than my capabilities and nerve so
that's not a problem. I'm on my third set now and find at that pressure they
ride well, grip well, are reasonably quiet and wear very evenly. The even
wear makes me think the pressure is about right for my driving. All four
tyres wear at the same rate as well.
Just been called out to an urgent fault. Should be a very pleasant drive
with the roof down, stars out and still 24 degrees out there!
Grant.

Grant · Post by **Grant** » Mon Jan 30, 2006 10:48 pm

I run mine at 30psi. Grip is much better than my capabilities and nerve so
that's not a problem. I'm on my third set now and find at that pressure they
ride well, grip well, are reasonably quiet and wear very evenly. The even
wear makes me think the pressure is about right for my driving. All four
tyres wear at the same rate as well.
Just been called out to an urgent fault. Should be a very pleasant drive
with the roof down, stars out and still 24 degrees out there!
Grant.

Ian · Post by **Ian** » Mon Jan 30, 2006 10:54 pm

The specialist books I have, suggest using the factory (Mazda) recommended
tyre pressures for road use.

Ian · Post by **Ian** » Mon Jan 30, 2006 10:54 pm

The specialist books I have, suggest using the factory (Mazda) recommended
tyre pressures for road use.

MadMaz · Post by **MadMaz** » Mon Jan 30, 2006 11:37 pm

Hi Ralph

It really depends on fast you drive and how many fast corners you take on a
regular basis.

- For average driving for tyres of those specs run 32 psi in the front and
28psi in the rear for a rear drive car the weight of an MX5.
- If you generally drive quickly, run 36 psi in the front and 32 psi in the
rear.
- On the track, pump them all up to close to 40 psi all round.

The harsher ride is the trade off for better handling qualities at speed,
especially in what is a reasonably lightweight car. (approx 1040Kg).

I've seen cars running at Pukekohe Track Test Days that ran tyre pressures
that were too low and tore the tread off the outer left hand side tyres (the
track is right handed) right down to the steel belts after only 5 or 6 laps.
The tyres were almost rolling off the rims.

The quicker you want to go, the higher is the tyre pressure recommended as a
general rule.

Most road tyres are rated at about 42 psi max as a guide, so you'll
certainly be fine with 36 psi.

It all comes down to how fast do you want to go and how much do want to
trade ride in exchange - and general tyre wear.

Cheers
Mark

MadMaz · Post by **MadMaz** » Mon Jan 30, 2006 11:37 pm

Hi Ralph

It really depends on fast you drive and how many fast corners you take on a
regular basis.

- For average driving for tyres of those specs run 32 psi in the front and
28psi in the rear for a rear drive car the weight of an MX5.
- If you generally drive quickly, run 36 psi in the front and 32 psi in the
rear.
- On the track, pump them all up to close to 40 psi all round.

The harsher ride is the trade off for better handling qualities at speed,
especially in what is a reasonably lightweight car. (approx 1040Kg).

I've seen cars running at Pukekohe Track Test Days that ran tyre pressures
that were too low and tore the tread off the outer left hand side tyres (the
track is right handed) right down to the steel belts after only 5 or 6 laps.
The tyres were almost rolling off the rims.

The quicker you want to go, the higher is the tyre pressure recommended as a
general rule.

Most road tyres are rated at about 42 psi max as a guide, so you'll
certainly be fine with 36 psi.

It all comes down to how fast do you want to go and how much do want to
trade ride in exchange - and general tyre wear.

Cheers
Mark

Graeme H · Post by **Graeme H** » Tue Jan 31, 2006 9:26 am

I had a wheel alignment done last year and my 15" GIIIs were reinflated to about 35 on the advice of the tyre guy. I found them frightening, especially in the wet.It was like driving on a road full of marbles. I lowered the pressure to about 30 psi, and the change was an amazing improvement. 26 is the recommended pressure, so I generally keep mine between 28-30.

Graeme H

From: Ralph Dog <ralph.dog@clear.net.nz>
Date: 2006/01/30 Mon PM 09:36:59 GMT+13:00
To: MX5List <mx5list@mx5club.org.nz>
Subject: Tyre Pressures

For those of you with 14" GIII Potenza's what pressure are you running
them at?
Have just had a set fitted and they came back @ 34lbs. Grip is
fantanstic but the ride is a tad harsh.

Learned comments anyone?

regards
Ralph

http://miata.cardomain.com/id/britracinggreen

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Sometimes (quite often actually) the bonnet catch has some play in it, instead of using grease you could try wrapping some insulation tape around the loop, I have seen lots of 5's with this modification :O)

...the tape comes in lots of pretty colours, maybe even a nice shade of pink...

Graeme H · Post by **Graeme H** » Tue Jan 31, 2006 9:26 am

I had a wheel alignment done last year and my 15" GIIIs were reinflated to about 35 on the advice of the tyre guy. I found them frightening, especially in the wet.It was like driving on a road full of marbles. I lowered the pressure to about 30 psi, and the change was an amazing improvement. 26 is the recommended pressure, so I generally keep mine between 28-30.

Graeme H

From: Ralph Dog <ralph.dog@clear.net.nz>
Date: 2006/01/30 Mon PM 09:36:59 GMT+13:00
To: MX5List <mx5list@mx5club.org.nz>
Subject: Tyre Pressures

For those of you with 14" GIII Potenza's what pressure are you running
them at?
Have just had a set fitted and they came back @ 34lbs. Grip is
fantanstic but the ride is a tad harsh.

Learned comments anyone?

regards
Ralph

http://miata.cardomain.com/id/britracinggreen

From keyaccounts@waipunahotel.co.nz Fri Apr 27 17:43:21 2007
Content-class: urn:content-classes:message
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Subject: RE: A Couple of Rattles
Date: Tue, 31 Jan 2006 09:45:08 +1300
Thread-Topic: roof
Thread-Index: AcYlypfc4dl9vyqOQga91yldgxZnowAEwwHw
From: "Nicky Patchett" <keyaccounts@waipunahotel.co.nz>
To: "MX5List" <mx5list@mx5club.org.nz>
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Sometimes (quite often actually) the bonnet catch has some play in it, instead of using grease you could try wrapping some insulation tape around the loop, I have seen lots of 5's with this modification :O)

...the tape comes in lots of pretty colours, maybe even a nice shade of pink...

Badcat · Post by **Badcat** » Tue Jan 31, 2006 9:51 am

i run toyo FM9Rs at the std size - 185-60-14.
personally i run mine at 30 PSI front and rear on the street.
at the track, i DROP the pressure 2 pounds, as the extra heat generated
pumps them back up 3-4 pounds.
but everyone has a different theory, so i could be full of shit.

ken

From: Graeme H <graeme.hakin@xtra.co.nz>
Date: 2006/01/31 Tue AM 09:26:53 GMT+13:00
To: MX5List<mx5list@mx5club.org.nz>
Subject: Re: Tyre Pressures

I had a wheel alignment done last year and my 15" GIIIs were reinflated to

about 35 on the advice of the tyre guy. I found them frightening, especially
in the wet.It was like driving on a road full of marbles. I lowered the pressure
to about 30 psi, and the change was an amazing improvement. 26 is the
recommended pressure, so I generally keep mine between 28-30.

Graeme H

From: Ralph Dog <ralph.dog@clear.net.nz>
Date: 2006/01/30 Mon PM 09:36:59 GMT+13:00
To: MX5List <mx5list@mx5club.org.nz>
Subject: Tyre Pressures

For those of you with 14" GIII Potenza's what pressure are you running
them at?
Have just had a set fitted and they came back @ 34lbs. Grip is
fantanstic but the ride is a tad harsh.

Learned comments anyone?

regards
Ralph

http://miata.cardomain.com/id/britracinggreen

ken newell

Badcat · Post by **Badcat** » Tue Jan 31, 2006 9:51 am

i run toyo FM9Rs at the std size - 185-60-14.
personally i run mine at 30 PSI front and rear on the street.
at the track, i DROP the pressure 2 pounds, as the extra heat generated
pumps them back up 3-4 pounds.
but everyone has a different theory, so i could be full of shit.

ken

From: Graeme H <graeme.hakin@xtra.co.nz>
Date: 2006/01/31 Tue AM 09:26:53 GMT+13:00
To: MX5List<mx5list@mx5club.org.nz>
Subject: Re: Tyre Pressures

I had a wheel alignment done last year and my 15" GIIIs were reinflated to

about 35 on the advice of the tyre guy. I found them frightening, especially
in the wet.It was like driving on a road full of marbles. I lowered the pressure
to about 30 psi, and the change was an amazing improvement. 26 is the
recommended pressure, so I generally keep mine between 28-30.

Graeme H

From: Ralph Dog <ralph.dog@clear.net.nz>
Date: 2006/01/30 Mon PM 09:36:59 GMT+13:00
To: MX5List <mx5list@mx5club.org.nz>
Subject: Tyre Pressures

For those of you with 14" GIII Potenza's what pressure are you running
them at?
Have just had a set fitted and they came back @ 34lbs. Grip is
fantanstic but the ride is a tad harsh.

Learned comments anyone?

regards
Ralph

http://miata.cardomain.com/id/britracinggreen

ken newell

EricW · Post by **EricW** » Tue Jan 31, 2006 11:51 am

I run the Kumhos on my 94 at 28 PSI all round, seems to give very good
results in both the grip and ride departments, although you might want them
a little harder if going a little quicker.

The tyres have over 40K on them now and look good for at least another 10,
so I guess that pressure does them no harm

Eric

EricW · Post by **EricW** » Tue Jan 31, 2006 11:51 am

I run the Kumhos on my 94 at 28 PSI all round, seems to give very good
results in both the grip and ride departments, although you might want them
a little harder if going a little quicker.

The tyres have over 40K on them now and look good for at least another 10,
so I guess that pressure does them no harm

Eric

Okibi · Post by **Okibi** » Tue Jan 31, 2006 3:43 pm

Tyre pressures are relative to the type of tyre, size of tyre, weight of the
car, personal preference, so I'm not going to confuse matters more by
stating my tyre pressures.

BUT ..

I was surprised at what Graeme had said because a couple of extra PSI
usually help in the wet as it keeps the tread open and reduces the chance of
aquaplaning.

- Dave.

Okibi · Post by **Okibi** » Tue Jan 31, 2006 3:43 pm

Tyre pressures are relative to the type of tyre, size of tyre, weight of the
car, personal preference, so I'm not going to confuse matters more by
stating my tyre pressures.

BUT ..

I was surprised at what Graeme had said because a couple of extra PSI
usually help in the wet as it keeps the tread open and reduces the chance of
aquaplaning.

- Dave.

EricW · Post by **EricW** » Tue Jan 31, 2006 4:45 pm

Ok, to clarify, the tyres on mine are the standard 185/14 and 28 is the
recommendation, as I said, it seems to work well

Eric

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When yiu use high PSI, the actual area that touching the road surface will
be reduced.
Thus, it cause poor performance on wet condition?

195/50/15 - 25 PSI I will try little higher but IU do not like too hush ride.
IMHO

Ben

On 1/31/06, David <miata@arach.net.au> wrote:

Tyre pressures are relative to the type of tyre, size of tyre, weight of
the
car, personal preference, so I'm not going to confuse matters more by
stating my tyre pressures.

BUT ..

I was surprised at what Graeme had said because a couple of extra PSI
usually help in the wet as it keeps the tread open and reduces the chance
of
aquaplaning.

- Dave.

--
Ben Nakagawa
Ben.Nakagawa@gmail.com

EricW · Post by **EricW** » Tue Jan 31, 2006 4:45 pm

Ok, to clarify, the tyres on mine are the standard 185/14 and 28 is the
recommendation, as I said, it seems to work well

Eric

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Precedence: list
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When yiu use high PSI, the actual area that touching the road surface will
be reduced.
Thus, it cause poor performance on wet condition?

195/50/15 - 25 PSI I will try little higher but IU do not like too hush ride.
IMHO

Ben

On 1/31/06, David <miata@arach.net.au> wrote:

Tyre pressures are relative to the type of tyre, size of tyre, weight of
the
car, personal preference, so I'm not going to confuse matters more by
stating my tyre pressures.

BUT ..

I was surprised at what Graeme had said because a couple of extra PSI
usually help in the wet as it keeps the tread open and reduces the chance
of
aquaplaning.

- Dave.

--
Ben Nakagawa
Ben.Nakagawa@gmail.com

Okibi · Post by **Okibi** » Tue Jan 31, 2006 5:25 pm

More rubber contacting the road surface doesn't always mean more grip.

The weight of the car is down force, pushing down on the tyres making them
grip.

The less contact area (on the road) the more down force each square
centimeter of remaining rubber has on the road.

Obviously you need to find a comfortable medium between grip and down force
depending on the road and conditions etc.

- Dave.

Okibi · Post by **Okibi** » Tue Jan 31, 2006 5:25 pm

More rubber contacting the road surface doesn't always mean more grip.

The weight of the car is down force, pushing down on the tyres making them
grip.

The less contact area (on the road) the more down force each square
centimeter of remaining rubber has on the road.

Obviously you need to find a comfortable medium between grip and down force
depending on the road and conditions etc.

- Dave.

poison · Post by **poison** » Tue Jan 31, 2006 6:17 pm

I went to a driver training day years ago and we all had to put our "standard"
tyres up to 34-6 PSI as we were doing some sliding and the reason given was
most roll overs occur when in a slide sideways the tyre rolls under and the
rim digs in causing the car to flip. The higher pressure certainly seemed to
make the car let go, although it did seem to let go more smoothly than with
the softer setting.

There must be a happy medium I guess.

Gazza
"PO1SON"

poison · Post by **poison** » Tue Jan 31, 2006 6:17 pm

I went to a driver training day years ago and we all had to put our "standard"
tyres up to 34-6 PSI as we were doing some sliding and the reason given was
most roll overs occur when in a slide sideways the tyre rolls under and the
rim digs in causing the car to flip. The higher pressure certainly seemed to
make the car let go, although it did seem to let go more smoothly than with
the softer setting.

There must be a happy medium I guess.

Gazza
"PO1SON"

MadMaz · Post by **MadMaz** » Tue Jan 31, 2006 8:26 pm

Hi Graeme

Crikey.

I run 38 psi all round in the BF Goodrich G Force Sports on my Astina.
They grip very well whether dry or wet - with an estimated 170 bhp at the
flywheel delivered through them via the transaxle - and the tyre wear
pattern is perfect. I choose them because they have a particularly thick
tyre bead and have very little sidewall flex - the diff between brands can
be considerable. The compound hardness is rated medium.

Roads in Franklin are well known as dangerous with tricky bends everywhere -
and the yet car sticks to the road like glue on any corner, wet or dry. And
it's a front drive.

Honestly, on Pukekohe Track if you're driving as fast as you can go and
don't run high tyre pressures, you'll eventually go straight off the end of
the back straight leading to the hairpin with overheated tyres - (or brakes
if they're not up to scratch) - seen it happen many times with tyre tread
showing damage on the left outers - and even worse with tyres sprung right
off the rims.

By the way, have finally found an MX5 I really like that's been offered for
sale to me later in the year when the owner is departing for overseas.
Really nice little NA that drives very well, is used only as a second car so
hasn't clocked up that many k's - paintwork in excellent nick, very tidy and
all systems A.O.K. (No, won't mention which colour...for now) It's
a
gleam machine that fits like a glove.

Cheers
Mark

MadMaz · Post by **MadMaz** » Tue Jan 31, 2006 8:26 pm

Hi Graeme

Crikey.

I run 38 psi all round in the BF Goodrich G Force Sports on my Astina.
They grip very well whether dry or wet - with an estimated 170 bhp at the
flywheel delivered through them via the transaxle - and the tyre wear
pattern is perfect. I choose them because they have a particularly thick
tyre bead and have very little sidewall flex - the diff between brands can
be considerable. The compound hardness is rated medium.

Roads in Franklin are well known as dangerous with tricky bends everywhere -
and the yet car sticks to the road like glue on any corner, wet or dry. And
it's a front drive.

Honestly, on Pukekohe Track if you're driving as fast as you can go and
don't run high tyre pressures, you'll eventually go straight off the end of
the back straight leading to the hairpin with overheated tyres - (or brakes
if they're not up to scratch) - seen it happen many times with tyre tread
showing damage on the left outers - and even worse with tyres sprung right
off the rims.

By the way, have finally found an MX5 I really like that's been offered for
sale to me later in the year when the owner is departing for overseas.
Really nice little NA that drives very well, is used only as a second car so
hasn't clocked up that many k's - paintwork in excellent nick, very tidy and
all systems A.O.K. (No, won't mention which colour...for now) It's
a
gleam machine that fits like a glove.

Cheers
Mark

black93 · Post by **black93** » Tue Jan 31, 2006 10:56 pm

Hi well here it my tupence worth. I attended an advanced driving school
about three years ago and the instuctors (all race car drivers and test
drivers) recomended that no car however light should run less than 35psi
and in medium to large cars up to 40psi. The local firestone dealer who
allso sels GIII's recomends the 40psi in the larger cars and close to
that in lighter cars. I run 38 psi in my mx5 and find the handeling is
great. It is certainly firm with the Bilsten shocks but I will live with
that for the handeling.

Terry

Mark O'Sullivan wrote:

[...]

black93 · Post by **black93** » Tue Jan 31, 2006 10:56 pm

Hi well here it my tupence worth. I attended an advanced driving school
about three years ago and the instuctors (all race car drivers and test
drivers) recomended that no car however light should run less than 35psi
and in medium to large cars up to 40psi. The local firestone dealer who
allso sels GIII's recomends the 40psi in the larger cars and close to
that in lighter cars. I run 38 psi in my mx5 and find the handeling is
great. It is certainly firm with the Bilsten shocks but I will live with
that for the handeling.

Terry

Mark O'Sullivan wrote:

[...]

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