Whats the suitable tyre pressure for 15x8?

[im.Kusuma]

Halo.. :D

Just wondering, what is the suitable tyre pressure for 15x8 rims with 195/50 R15 tyres?

thankkss

[Lukey]

i run 38

[bennjamin]

why dont you read what the sidewall says on the tyres ?

[im.Kusuma]

why dont you read what the sidewall says on the tyres ?

Lol.. Because I thought it'd be different since the tyres are on 8" wide rims.. So I wanted to make sure

[bennjamin]

point taken....but its a guessing game since you are stretching 6.5 inch wide tyres onto a 8 inch wide rim. I would go what it says on the sidewall as since the PSI will increase when HOT , and the tyres are under even more pressure so excessive PSI could possibly result in a premature blowout or wear

[im.Kusuma]

point taken....but its a guessing game since you are stretching 6.5 inch wide tyres onto a 8 inch wide rim. I would go what it says on the sidewall as since the PSI will increase when HOT , and the tyres are under even more pressure so excessive PSI could possibly result in a premature blowout or wear

Thanks for the info ben, I will check the tyre pressure on the sidewall tomorrow :thumbsup:

[SHU-ES1]

i run 32psi on 15x8" 195/60/15 tyres.

[im.Kusuma]

i run 32psi on 15x8" 195/60/15 tyres.

Safe?

[SHU-ES1]

been running them on re001's for about 6 months now. no issues at all.

[im.Kusuma]

been running them on re001's for about 6 months now. no issues at all.

Thanks mate

[tinymoon]

I read from the carbibles saying that: So i just stick to this than other advice around which is driving me crazy (dealer said that 32PSI, BobJane comfirm 34, other mechanics say 36 some even say 38 (My tyre setup is oringinal 16" from Honda)


The Max. Pressure -10% theory.
Every tyre has a maximum inflation pressure stamped on the side somewhere. This is the maximum pressure the tyre can safely achieve under load. It is not the pressure you should inflate them to.
Having said this, I've given up using the door pillar sticker as my starting point and instead use the max.pressure-10% theory. According to the wags on many internet forums you can get the best performance by inflating them to 10% less than their recommended maximum pressure (the tyres, not the wags - they already haves inflated egos). It's a vague rule of thumb, and given that every car is different in weight and handling, it's a bit of a sledgehammer approach. But from my experience it does seem to provide a better starting point for adjusting tyre pressures. So to go back to my Subaru Impreza example, the maximum pressure on my Yokohama tyres was 44psi. 10% of that is 4.4, so 44-4.4=39.6psi which is about where I ended up. On my Element, the maximum pressure is 40psi so the 10% rule started me out at 36psi. I added one more to see what happened and it got better. Going up to 38psi and it definitely went off the boil, so for my vehicle and my driving style, 37psi on the Element was the sweet spot.

[Lukey]

from memory you gotta run higher psi when running stretched tyres

[im.Kusuma]

from memory you gotta run higher psi when running stretched tyres

.. o__o im lostt lol.. some went lower and u say higher? lol..

If you dont mind, please explain why? :(

[niiCk]

i would assume higher PSi for stretched too, to keep it stretched..but dont over do it. around 38 max would do i rekon..

[OMG.JAI xD]

You run higher pressures with lower profiles and/or higher speed ratings.
Ive done Pre delivery's on audis and their tyre placard goes by the different sizes available.
And i have seen pressures up to 45psi, and that was for a Q7 with 21" rims and air suspension.

Its really all trial and error. But pressures range from 30-40psi. On a stretched tyre setup I wouldnt recommend running very high pressures. Higher pressures than normal yes but not excessive.
Just take into consideration the facts that youre running a high profile tyre (for pressures, comfort) and stretching the tyres (decreasing sidewal rigidity) with a very low speed rating. (most 15-16" rims are within the 80-90 rating).

[Lukey]

its to do with the stretch of the sidewall and the bead of the tyre to the rim.

Oxer knows more about this than me, ill ask him next time i see him on msn

[im.Kusuma]

its to do with the stretch of the sidewall and the bead of the tyre to the rim.

Oxer knows more about this than me, ill ask him next time i see him on msn


thanks for that lukey :thumbsup:

@OMG.JAIxD : Yeah thanks, understood that man.. If i run 38psi, would that be safe for everyday driving?

[SHU-ES1]

high psi on low profile tyres and coilovers are not fun :( thats the reason i run 32psi. i've taken turns/bends harder than normal and haven't had any problems just yet. should i increase psi?

[niiCk]

yeah i wouldve thought 32psi was abit low..
trying up-ing the psi..

[OMG.JAI xD]

thanks for that lukey :thumbsup:

@OMG.JAIxD : Yeah thanks, understood that man.. If i run 38psi, would that be safe for everyday driving?

Well put it this way.
Take the tyre youre putting on a rim as your base. So say 195/60/15 with 84w/x/y/z watever. The optimum pressure for that is around 32 psi with a light loaded car. If youre going to stretch that over a 8" rim Think of decreasing the tyre profile by a percentage. Theres a calculator somewhere around the net.
So in the end your tyre becomes a 195/40/15 or 195/50/15. If that makes any sense. So i would run a touch higher than 32psi. But 38 seems abit too much. Unless its only you or your missus in the car. Then should be ok-ish.

Personally i dont like pumping tyres up to 38 psi. If the tarmac is warm or hot, i know from going to street meets, that tyre pressures can rise up to 5psi if they heat up enough.
As I said. All about trial and error. Depends on your driving route. Driving style. The weight of the car. The load the car takes. ETC.
General rule of thumb is to look at the safety warnings on the tyre and look at the maximum pressures the tyre takes.
Usually something like 40psi@536kg (i just typed random numbers for kg so dont think theyre all that rating lol). give and take the heat theory and an optimum pressure would be 35psi after a drive on warm tarmac to the service station.
Sounds like alot of gibberish. But tyre pressures heavily relate to the way your car operates. From handling right down to fuel consumption.
Thats just my rule of thumb. Its different from car to car.

Street tyres should never be underinflated. Underinflating only works for 4wdriving/off road. Or sand/offroad buggys.

[im.Kusuma]

Well put it this way.
Take the tyre youre putting on a rim as your base. So say 195/60/15 with 84w/x/y/z watever. The optimum pressure for that is around 32 psi with a light loaded car. If youre going to stretch that over a 8" rim Think of decreasing the tyre profile by a percentage. Theres a calculator somewhere around the net.
So in the end your tyre becomes a 195/40/15 or 195/50/15. If that makes any sense. So i would run a touch higher than 32psi. But 38 seems abit too much. Unless its only you or your missus in the car. Then should be ok-ish.

Personally i dont like pumping tyres up to 38 psi. If the tarmac is warm or hot, i know from going to street meets, that tyre pressures can rise up to 5psi if they heat up enough.
As I said. All about trial and error. Depends on your driving route. Driving style. The weight of the car. The load the car takes. ETC.
General rule of thumb is to look at the safety warnings on the tyre and look at the maximum pressures the tyre takes.
Usually something like 40psi@536kg (i just typed random numbers for kg so dont think theyre all that rating lol). give and take the heat theory and an optimum pressure would be 35psi after a drive on warm tarmac to the service station.
Sounds like alot of gibberish. But tyre pressures heavily relate to the way your car operates. From handling right down to fuel consumption.
Thats just my rule of thumb. Its different from car to car.

Street tyres should never be underinflated. Underinflating only works for 4wdriving/off road. Or sand/offroad buggys.

wow.. mod should rep u for that lol..

Shitloads of useful info! thanks for that man :thumbsup:x99999 LOL

Well i also thought 38 would be abit too much too.. lol and yeah, everything that you just said made sense to me :thumbsup:
thank you :) hehe

I'll just stick to 34 - 36psi then.. Since i THINK its in between.. lol

[EG30]

38-40 psi wont be a bad idea in this case, may be even more depending on the design of your tyre's carcass.

with a rim that is way too wide for the tyre, the middle of the tread would be caved in away from the road contact patch, and overinflation would compensate for this somewhat.

best to determine by the temperatures of your inner, middle and outer tread areas with a pyrometer after driving for some distance.

[OMG.JAI xD]

38-40 psi wont be a bad idea in this case, may be even more depending on the design of your tyre's carcass.

with a rim that is way too wide for the tyre, the middle of the tread would be caved in away from the road contact patch, and overinflation would compensate for this somewhat.

best to determine by the temperatures of your inner, middle and outer tread areas with a pyrometer after driving for some distance.

In no way am I disagreeing with you. But overinflating the tyre can and will cause a blow out. (exceeding the maximum allowed pressure)
I think contact patch can be sacrificed for safety.
At the end of the day. Stretch is ok to a certain extent. But when it affects the profiles of the tyres its actually all for looks and there is no benefit from it.
15-16" tyres that are readily available on the market that most people use for stretch does not carry the high speed and load ratings most bigger diameter wheels do. And i dont think people will have the time to measure the temperatures of their tyres at different spots for everyday road driving.

[EG30]

In no way am I disagreeing with you. But overinflating the tyre can and will cause a blow out. (exceeding the maximum allowed pressure)
I think contact patch can be sacrificed for safety.
At the end of the day. Stretch is ok to a certain extent. But when it affects the profiles of the tyres its actually all for looks and there is no benefit from it.
15-16" tyres that are readily available on the market that most people use for stretch does not carry the high speed and load ratings most bigger diameter wheels do. And i dont think people will have the time to measure the temperatures of their tyres at different spots for everyday road driving.

How does 38-40psi or even 42 psi risk blowing out the tyre? Most tyres of that size has a max cold inflation of 42-44psi moulded onto the sidewall. And on the subject of manufacturer's recommendation the 195 section tyre on a 8" rim is way out of the recommendation; so if 100% safety is paramount it shouldnt be fitted at the 1st place but obviously the user likes the way it looks and is aware of it being a non recommended fitment.

You dont need to drive for a long time or agressively to establish a pattern of temperature rise on different parts of the tyre, I have used pryrometers ( both infrared and piercing type ) to work out a how much pressure I could run without ballooning out the middle of the tyre on my cars. I find 15-20 mins of normal road driving is plenty to give me an indication.

[OMG.JAI xD]

How does 38-40psi or even 42 psi risk blowing out the tyre? Most tyres of that size has a max cold inflation of 42-44psi moulded onto the sidewall. And on the subject of manufacturer's recommendation the 195 section tyre on a 8" rim is way out of the recommendation; so if 100% safety is paramount it shouldnt be fitted at the 1st place but obviously the user likes the way it looks and is aware of it being a non recommended fitment.

You dont need to drive for a long time or agressively to establish a pattern of temperature rise on different parts of the tyre, I have used pryrometers ( both infrared and piercing type ) to work out a how much pressure I could run without ballooning out the middle of the tyre on my cars. I find 15-20 mins of normal road driving is plenty to give me an indication.

Ever go over a pothole with 42psi at say, highway speeds? 90-100km/h.
Im not expressing my opinions to argue. But the questions being asked on this thread is simply a 195width tyre being stretched over a 8" rim. And everyone knows it is a safety issue. The question was, for everyday driving, what pressures are recommended.
High pressures are not for daily driving. Anyone that has the 195on8"rim setup is highly likely to have the car lowered.
Which brings my point to the potholes. Those kinds of pressures and add a sudden change in road surface can cause the tyre to fail.
Ask every member on this thread and see how many measure the temperature of their tyres with a pyrometer on a regular basis, if at all.
People dont take that much notice and detail to things like that. And thats the facts. If its not readily available at a service station, they most probably wont use it.
Ever see what happens to a tyre with a failing shock absorber? As you already know, the tyre is part of the suspension system. It absorbs the small changes in road surface to aid the springs and shocks. Increasing pressure will decrease the dampening effect the tyre gives and itll end up giving similar effects of a failing shock absorber as the tyre is constantly goes over uneven surfaces.

At the end of the day. No manufacturer will recommend 40+psi for daily driving on a 195/60/15 tyre.

[Lukey]

Halo.. :D

Just wondering, what is the suitable tyre pressure for 15x8 rims with 195/50 R15 tyres?

thankkss



At the end of the day. No manufacturer will recommend 40+psi for daily driving on a 195/60/15 tyre.

we talking about 195/50, not 195/60.

dont know if you didnt notice? :confused:

[OMG.JAI xD]

we talking about 195/50, not 195/60.

dont know if you didnt notice? :confused:

Dude... Same sh!t. They still wouldnt recommend 40+psi for daily driving. regardless of the profile in that rim diameter range.

[Lukey]

ysosrs?

im sure he knows and understands the risks of running an undersized tyres.

[im.Kusuma]

Calm down guys.. lol
I got my answer to the question already thanks to OMG.JAIxD ..
Im just gonna leave this thread open so members who are on the same boat as me can take a float lol

thanks again bro

[OMG.JAI xD]

Calm down guys.. lol
I got my answer to the question already thanks to OMG.JAIxD ..
Im just gonna leave this thread open so members who are on the same boat as me can take a float lol

thanks again bro

lol I dont know bro.. seriously I try to keep sh!t as simple as possible and yet people always try to prove a point and has something to add.. I dont know man I dont know ... must be a faulty IACV somewhere maybe I should clean it up... lol -.-"

[im.Kusuma]

lol I dont know bro.. seriously I try to keep sh!t as simple as possible and yet people always try to prove a point and has something to add.. I dont know man I dont know ... must be a faulty IACV somewhere maybe I should clean it up... lol -.-"

rofl.. its ozhomo man haha :p

dw.. chill.. have a wank and you'd be just fine :thumbsup:

[OMG.JAI xD]

rofl.. its ozhomo man haha :p

dw.. chill.. have a wank and you'd be just fine :thumbsup:

Im always chilled... I just like defending my honor. lol. Anyway enough spam..