Tyre Pressures
04-02-2007, 09:29 PM
#26
Surf Hard, Drive Hard
Join Date: Feb 2007
Location: Indialantic, Florida
Posts: 7,840
Likes: 0
Received 11 Likes
on
9 Posts
Originally Posted by MissyK
depends, lower the profile, the higher the pressure.
if ur running stock which is 45 profile then 36/38 max
but im running profile 35 so i run 40-42psi for daily. if i put 32psi bye bye to my tyres in long run. but when we go tracking i lower it to 36psi as due to heat etc it will rise well about 40.
60psi in a stock rx8 tyre? hes crazy........
if ur running stock which is 45 profile then 36/38 max
but im running profile 35 so i run 40-42psi for daily. if i put 32psi bye bye to my tyres in long run. but when we go tracking i lower it to 36psi as due to heat etc it will rise well about 40.
60psi in a stock rx8 tyre? hes crazy........
Agreed............Yeah, I'm not running stock either, but my first comment was based basically on stock as I assumed the thread first started with. Actually, now that I re-read it, it was this one and another thread about tire pressure but.....if people are very close to 40(assuming when cold....and maybe I shouldn't have), then 38 to 40psi could be a little much on stock size. I guess that's all I was trying to say. No Worries!
Last edited by Mazurfer; 04-02-2007 at 09:37 PM.
04-02-2007, 09:34 PM
#27
Surf Hard, Drive Hard
Join Date: Feb 2007
Location: Indialantic, Florida
Posts: 7,840
Likes: 0
Received 11 Likes
on
9 Posts
Ha Ha.......I edited and moved it because I realized the guy with 60psi wasn't in this thread at all........I could go find it, but too lazy! 
Do you talk to yourself often?
Do you talk to yourself often?
04-02-2007, 09:52 PM
#28
Registered User
Join Date: Aug 2003
Location: Brisbane Australia
Posts: 778
Likes: 0
Received 0 Likes
on
0 Posts
When I fitted my tyres (245's), I emailed the tyre company's technical department in Europe, who recommended 260kPa (~38psi). As I keep on saying, the most important criterion is even tread wear. Too low pressure = edge wear. Too high pressure = wear in the middle. Not a bad idea to measure tread depth across the profile from time to time.
04-02-2007, 09:56 PM
#29
Surf Hard, Drive Hard
Join Date: Feb 2007
Location: Indialantic, Florida
Posts: 7,840
Likes: 0
Received 11 Likes
on
9 Posts
Originally Posted by labrat
When I fitted my tyres (245's), I emailed the tyre company's technical department in Europe, who recommended 260kPa (~38psi). As I keep on saying, the most important criterion is even tread wear. Too low pressure = edge wear. Too high pressure = wear in the middle. Not a bad idea to measure tread depth across the profile from time to time.
04-02-2007, 10:05 PM
#30
Shootin' from the hip
Thread Starter
Join Date: Apr 2005
Location: Sydney, Australia
Posts: 7,584
Likes: 0
Received 0 Likes
on
0 Posts
This is what I was getting at Mazsurfer - it's horses for courses.
I wouldn't run 40psi in 45 profile rubber but I would with 35 profile tyres.
For the record, I'm not stock either - 235/40's on 8.5 rims.
I reckon 34psi is the absolute minimum for the stock rubber for road use, even on poorer roads.
But the general message remains the same, hence the point of the thread. Check your pressures regularly and ensure you have optimum psi for your chosen rubber/rim/suspension combo. It really does make a lot of difference in this car.
I wouldn't run 40psi in 45 profile rubber but I would with 35 profile tyres.
For the record, I'm not stock either - 235/40's on 8.5 rims.
I reckon 34psi is the absolute minimum for the stock rubber for road use, even on poorer roads.
But the general message remains the same, hence the point of the thread. Check your pressures regularly and ensure you have optimum psi for your chosen rubber/rim/suspension combo. It really does make a lot of difference in this car.
04-02-2007, 10:10 PM
#31
Surf Hard, Drive Hard
Join Date: Feb 2007
Location: Indialantic, Florida
Posts: 7,840
Likes: 0
Received 11 Likes
on
9 Posts
Originally Posted by Revolver
This is what I was getting at Mazsurfer - it's horses for courses.
I wouldn't run 40psi in 45 profile rubber but I would with 35 profile tyres.
For the record, I'm not stock either - 235/40's on 8.5 rims.
I reckon 34psi is the absolute minimum for the stock rubber for road use, even on poorer roads.
But the general message remains the same, hence the point of the thread. Check your pressures regularly and ensure you have optimum psi for your chosen rubber/rim/suspension combo. It really does make a lot of difference in this car.
I wouldn't run 40psi in 45 profile rubber but I would with 35 profile tyres.
For the record, I'm not stock either - 235/40's on 8.5 rims.
I reckon 34psi is the absolute minimum for the stock rubber for road use, even on poorer roads.
But the general message remains the same, hence the point of the thread. Check your pressures regularly and ensure you have optimum psi for your chosen rubber/rim/suspension combo. It really does make a lot of difference in this car.
04-02-2007, 10:16 PM
#32
Guest
Posts: n/a
Originally Posted by Mazurfer
Ha Ha.......I edited and moved it because I realized the guy with 60psi wasn't in this thread at all........I could go find it, but too lazy!
Do you talk to yourself often?
Do you talk to yourself often?
The voices talk back aswell 
04-02-2007, 10:39 PM
#33
New Member
Originally Posted by labrat
When I fitted my tyres (245's), I emailed the tyre company's technical department in Europe, who recommended 260kPa (~38psi). As I keep on saying, the most important criterion is even tread wear. Too low pressure = edge wear. Too high pressure = wear in the middle. Not a bad idea to measure tread depth across the profile from time to time.
Revolver, for out Michellin, 38 psi with 2 degree camber is slightly too much centre wear!
36psi is AOK
04-02-2007, 11:53 PM
#34
Shootin' from the hip
Thread Starter
Join Date: Apr 2005
Location: Sydney, Australia
Posts: 7,584
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by takahashi
Revolver, for our Michellin, 38 psi with 2 degree camber is slightly too much centre wear!
36psi is AOK
36psi is AOK
I'm happy with 36psi generally.
04-03-2007, 12:44 AM
#35
New Member
Oh yes, yours are 8.5. I do think that narrower rim gives more shoulder wear 
.
Revolver, dail the neg camber as much as you can on the front. I ain't seeing any abnormal tyre wear on the inner side of my Michellin. I am at -2.5 front, and -2 rear. That has been going on for more than 15000km.
Some Porsche owner told me -2 camber is not a big figure. He does not know what his is exactly, but Porsches 911 has a more agressive settings and they use OEM Michellin PS2.... with rountine check on tyre on the 20000km service. So they do not expect bad wear.... although our suspensions are diff from Porsche (Tein and MazdaSpeed >>>> than OEM Porsche haha) but it is worth a go.
So no fear I would say
, what is your setting atm?
. Revolver, dail the neg camber as much as you can on the front. I ain't seeing any abnormal tyre wear on the inner side of my Michellin. I am at -2.5 front, and -2 rear. That has been going on for more than 15000km.Some Porsche owner told me -2 camber is not a big figure. He does not know what his is exactly, but Porsches 911 has a more agressive settings and they use OEM Michellin PS2.... with rountine check on tyre on the 20000km service. So they do not expect bad wear.... although our suspensions are diff from Porsche (Tein and MazdaSpeed >>>> than OEM Porsche haha) but it is worth a go.
So no fear I would say
, what is your setting atm?
Last edited by takahashi; 04-03-2007 at 12:47 AM.
04-03-2007, 07:08 AM
#37
Respect my authoriti!
Join Date: Feb 2006
Location: Adelaide, Australia
Posts: 729
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DVS RX8
would it minimise understeer and maybe create abit of oversteer?
I used to run my old car like this and thought it had better turn in but also got abit loose sometimes.. ?
im running 34 all round on the 8 atm, 225's
I used to run my old car like this and thought it had better turn in but also got abit loose sometimes.. ?
im running 34 all round on the 8 atm, 225's
Yes I reckon it does but I really like that characteristic, used to it really.....harks back to my rally days!!!
PLus I am getting really good wear out of the tyres even though I hate them.....I know I am harping on about them but they suck!
04-03-2007, 07:11 AM
#38
Respect my authoriti!
Join Date: Feb 2006
Location: Adelaide, Australia
Posts: 729
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by FishoftheWeek
RC, have you driven down King William Rd , Hyde Park yet? I never really understood what people were complaining about, until yesterday. I swear I almost had to slow down just to get rid of the noise it was that bad.
Paved roads + Potenzas = a lot of noise at 50km/h
Paved roads + Potenzas = a lot of noise at 50km/h
BTW I met with another 8 fan....NT Rotorhead the other weekend for a coffee....I will send you a message next time and see if you can make it..... Lazy seems to be MIA at the moment and I'm not sure where the others AMG etc have gone too.....
04-03-2007, 05:00 PM
#39
Shootin' from the hip
Thread Starter
Join Date: Apr 2005
Location: Sydney, Australia
Posts: 7,584
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by takahashi
Oh yes, yours are 8.5. I do think that narrower rim gives more shoulder wear .
Revolver, dail the neg camber as much as you can on the front. I ain't seeing any abnormal tyre wear on the inner side of my Michellin. I am at -2.5 front, and -2 rear. That has been going on for more than 15000km.
Some Porsche owner told me -2 camber is not a big figure. He does not know what his is exactly, but Porsches 911 has a more agressive settings and they use OEM Michellin PS2.... with rountine check on tyre on the 20000km service. So they do not expect bad wear.... although our suspensions are diff from Porsche (Tein and MazdaSpeed >>>> than OEM Porsche haha) but it is worth a go.
So no fear I would say, what is your setting atm?
. Revolver, dail the neg camber as much as you can on the front. I ain't seeing any abnormal tyre wear on the inner side of my Michellin. I am at -2.5 front, and -2 rear. That has been going on for more than 15000km.Some Porsche owner told me -2 camber is not a big figure. He does not know what his is exactly, but Porsches 911 has a more agressive settings and they use OEM Michellin PS2.... with rountine check on tyre on the 20000km service. So they do not expect bad wear.... although our suspensions are diff from Porsche (Tein and MazdaSpeed >>>> than OEM Porsche haha) but it is worth a go.
So no fear I would say
, what is your setting atm?
Otherwise, I asked for -1 all round when I got the MS stuff installed. But who really knows wtf they ended up doing. I've been thinking of going back just to have the suspension checked now that it's been installed for a while (e.g. check everything is still securely fastened, etc - it gets a pounding on Sydney's goat tracks), so I might get them to check the camber again.
Personally, I think -2 or -2.5 is a bit too aggressive for street use but you seem to be going okay with it. I'll think about it. Thanks for the feedback.
04-03-2007, 05:04 PM
#40
Shootin' from the hip
Thread Starter
Join Date: Apr 2005
Location: Sydney, Australia
Posts: 7,584
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Rotor Convert
Yes I reckon it does but I really like that characteristic, used to it really.....harks back to my rally days!!!
It gets a bit repetitive but some of the stacks are truly spectacular. Those crazy Finns!
BTW, it's not some snuff movie. Apparently, none of the stacks shown resulted in serious injury.
Rally fans would love it. I'll try to remember to bring it to the Nats.
Meanwhile, I've got 5 discs to go
...
04-04-2007, 06:14 PM
#41
Registered
Join Date: Feb 2007
Location: Northern NSW, Australia
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
A good pressure gauge is less than $20.
I have a $100 compressor and fill them at home.
I used to put high pressures in my Holden with Turanza 225/55s but the insides of the tyres wore out way too fast. The only way I could get even wear was at 28 psi.
I have a $100 compressor and fill them at home.
I used to put high pressures in my Holden with Turanza 225/55s but the insides of the tyres wore out way too fast. The only way I could get even wear was at 28 psi.
04-04-2007, 06:41 PM
#43
Registered
Join Date: Feb 2007
Location: Northern NSW, Australia
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by takahashi
An excellent tyre gauge cost a lot more 
.
Low pressure for even wear? It is not the problem with your gauges, it is the problem with the tyres!
.Low pressure for even wear? It is not the problem with your gauges, it is the problem with the tyres!
04-04-2007, 06:45 PM
#44
Registered User
Join Date: Jan 2005
Location: Edinburgh, Scotland
Posts: 305
Likes: 0
Received 0 Likes
on
0 Posts
After reading my thread, I realised I should maybe up my tyre pressures. I have always been keeping mine at around about 32psi as per manufacturers recommendations and never thought to put them up to 36-38. Put them upto 36 the other day and damn, what a difference, car feels a lot sharper, and even rides a lot better... so thanks for this thread guys (and MissyK :p) :D
04-05-2007, 11:06 PM
#46
Registered User
Join Date: Feb 2007
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
hmm what tyre pressure would u guys suggest me trying/running?
235/45/17 front
255/40/17 rear
Tyres are bridgestone s03
im currently running 36psi all round, and the car doesnt feel right - it feels twitchy
i have tein flex on my car, spring rate front is 5 and rear is 4.
car is a s15 btw ~
235/45/17 front
255/40/17 rear
Tyres are bridgestone s03
im currently running 36psi all round, and the car doesnt feel right - it feels twitchy
i have tein flex on my car, spring rate front is 5 and rear is 4.
car is a s15 btw ~
04-06-2007, 02:19 AM
#49
Shootin' from the hip
Thread Starter
Join Date: Apr 2005
Location: Sydney, Australia
Posts: 7,584
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by s1five
thx for your informative input