Do Thais Have An Obsession About Overinflated Car Tyres?

[Jezz]

Is it just me? My wife’s family have one of the ‘All New’ Isuzu V-cross 4x4 4-door pickups. As I’m the main driver, I try to adhere to manufacture’s recommendations for tyre pressures. It clearly states on the driver’s door frame 29 psi all round. This is repeated in the manual. I double checked with the Isuzu dealer on discovering all four wheels had pressure of 38 psi. They checked the notice on the door frame and reduced all four tyres to 29 psi. Today it when in for the first 10000 kilos service and I asked again about tyre pressures. This time they said 29 psi was too little, and manufacture’s recommendations should be ignored – stating it should be 35-40 psi. Any thoughts?

[funcat]

They always do...as to "manufacture’s recommendations should be ignored" -it's up to you whom you believe

[TommoPhysicist]

I put 52psi in my pickup tyres, yours is low, the v-cross is quite a weighty beast.

PS

As far as I know Isuzu don't make tyres, so you should be using the pressures printed on the rubber of the tyre, and then pressuring according to the weight of the vehicle on those tyres. Heaver the vehicle, the neared the max PSI, lighter the vehicle, the neared to the minimum PSI.

Edited April 2, 2012 by TommoPhysicist

[transam]

29 is spot on. If you over inflate you will wear them out prematurely. The middle of the tread will disappear.

[Jezz]

Well, it's a mixed bag of ideas so far!

[transam]

Well, it's a mixed bag of ideas so far!

But mine is correct . Also over inflating will put more stress/wear and tear on the suspension.

My 4x4 l put 30 rear, 32 front.

[mackes]

Take a look at the rubber area which contact the road, it should not be to narrow, you should use the full width of the paving. If only some inch in the middle the pressure is too high. If going outside the tyre profile its too low. So it is a little bit dependant on the weigh of the car (front and rear can be different).

[Jezz]

I'm aware that there'll always be a bit of leeway - fully laden, cold or hot tyres etc. But there's a huge difference between the published recommendations and the twice changed advice of the same main Isuzu dealer. (29psi to 40psi)

[transam]

I'm aware that there'll always be a bit of leeway - fully laden, cold or hot tyres etc. But there's a huge difference between the published recommendations and the twice changed advice of the same main Isuzu dealer. (29psi to 40psi)

It's wrong advice. The sticker will show tyre pressures for loaded and unloaded. On a Vigo the pressures are the same.

[funcat]

Well, it's a mixed bag of ideas so far!

But mine is correct . Also over inflating will put more stress/wear and tear on the suspension.

My 4x4 l put 30 rear, 32 front.

It is correct,if it says 29 on the door sticker it should be 29psi...the number on the tire says the max pressure safe for the tire.

Overinflated tires wear faster and the ride is more "bumpy" as well...

[MAJIC]

Yes they do. My wife is like a Hawk,watching out for the tyre pressures,I tried to explain to her once that we have low profile tyres and that's why they look flat.

As Sods Law would have it,when we go to garage for air she is invariably right

Edited April 2, 2012 by MAJIC

[funcat]

There is something called a "pressure gage" very handy and not expensive....

[Jezz]

Yes they do. My wife is like a Hawk,watching out for the tyre pressures,I tried to explain to her once that we have low profile tyres and that's why they look flat.

As Sods Law would have it,when we go to garage for air she is invariably right

That's another angle. I've used two air machines at two different filling stations within minutes and got completely different readings!

[richard_smith237]

I put 52psi in my pickup tyres, yours is low, the v-cross is quite a weighty beast.

PS

As far as I know Isuzu don't make tyres, so you should be using the pressures printed on the rubber of the tyre, and then pressuring according to the weight of the vehicle on those tyres. Heaver the vehicle, the neared the max PSI, lighter the vehicle, the neared to the minimum PSI.

Woah... back off there !! ... My Range Rover is a weighty beast, your V-cross is a light weight in comparison...

Normal load is 35 on the front and 40 on the rear under normal load conditions. You might be over cooking things just a dash !!!

Note: I suspect over pressure is much safer than under-pressure - I had blowout due to under-pressure a few years back after driving 5 hrs non stop. I suspect the under-pressured michelins overheated (how did I know it was under-pressured, cos after changing the wheel?, I stopped off at the next station and all were approximately 10psi under-pressure, I check more regularly now).

This might be why Thai's like over-pressured tyres.

Edited April 2, 2012 by richard_smith237

[transam]

I put 52psi in my pickup tyres, yours is low, the v-cross is quite a weighty beast.

PS

As far as I know Isuzu don't make tyres, so you should be using the pressures printed on the rubber of the tyre, and then pressuring according to the weight of the vehicle on those tyres. Heaver the vehicle, the neared the max PSI, lighter the vehicle, the neared to the minimum PSI.

, You obviously know nothing about automobiles eh. .

You should remove your post before someone gets killed.

Edited April 2, 2012 by transam

[TommoPhysicist]

@transam

You should read some of the American forums, where the good old boys discuss such matters endlessly.

My tyres are wearing evenly at 52psi.

@Mr. Smith

I will happily trade a little less grip for a lower chance of a flat in the hills.

(My tyre max pressure is 60psi)

Edited April 2, 2012 by TommoPhysicist

[transam]

@transam

You should read some of the American forums, where the good old boys discuss such matters endlessly.

My tyres are wearing evenly at 52psi.

Don't believe you.

52 psi is above the SAFE pressure on the side of the tyre wall. Your tyre size is fitted to many different vehicles and the motor manufacturer together with the tyre manufacturer work stuff out. A tyre AND it's advised pressure is an integral part of the suspension dynamics. Your advice borders on lunacy, old boy.

[TommoPhysicist]

@transam

You should read some of the American forums, where the good old boys discuss such matters endlessly.

My tyres are wearing evenly at 52psi.

Don't believe you.

52 psi is above the SAFE pressure on the side of the tyre wall. Your tyre size is fitted to many different vehicles and the motor manufacturer together with the tyre manufacturer work stuff out. A tyre AND it's advised pressure is an integral part of the suspension dynamics. Your advice borders on lunacy, old boy.

I don't believe I have stated by pickup tyre size, or tyre manufacturer.

[transam]

@transam

You should read some of the American forums, where the good old boys discuss such matters endlessly.

My tyres are wearing evenly at 52psi.

Don't believe you.

52 psi is above the SAFE pressure on the side of the tyre wall. Your tyre size is fitted to many different vehicles and the motor manufacturer together with the tyre manufacturer work stuff out. A tyre AND it's advised pressure is an integral part of the suspension dynamics. Your advice borders on lunacy, old boy.

I don't believe I have stated by pickup tyre size, or tyre manufacturer.

Think you are digging yourself into a very deep hole. Please delete your 52 psi post. There's a good ""old Boy''

[hakku]

I'm with TA here, the pressure on the sidewall is maximum pressure and not related to driving pressure. Follow the door sill instructions. A bit higher doesnt hurt (i wrote "a bit' as in few psi), under pressure is more dangerous since it builds up heat rapidly.

Hak

[Carib]

52 psi is ridiculous by any standard on a lightish SUV, unless it is loaded with tree logs. The data given on the tire sidewall is an indication of what the tire can safely handle, put there by the tire manufacturer, what it says on the door jam sticker tells one what the right pressure is for that type of car with a given size of tire. High press will give a rough ride and less road contact, think braking distance, it will also put more strain on wheel bearings / shock absorbers / total suspension.

[barefoot1988]

they always add more than the recommended level. including engine oil and every single cakes availailble

[WarpSpeed]

I put 52psi in my pickup tyres, yours is low, the v-cross is quite a weighty beast.

PS

As far as I know Isuzu don't make tyres, so you should be using the pressures printed on the rubber of the tyre, and then pressuring according to the weight of the vehicle on those tyres. Heaver the vehicle, the neared the max PSI, lighter the vehicle, the neared to the minimum PSI.

Well stated Tommo, yours might be a tad high maybe best around 45 to 48 depending on what your maximum stated on the sidewall is but I'd take the tire manufacturer recommendations over the vehicle manufacturer any day which have NO idea which tire you have after your first set and most are recommended too low anyways in favor of ride performance over tire performance and safety..

The shop is correct, this has been beaten to death but it's not a standard applied to ALL tires..It takes some consumer and technician common sense and knowledge, if a tire is max rated @ 50 PSI it should be at least upper 30's to low 40's to be close to proper sidewall support, wear, performance and safety characteristics..

[funcat]

It looks like it's gonna be another long one....

[WarpSpeed]

I'm with TA here, the pressure on the sidewall is maximum pressure and not related to driving pressure. Follow the door sill instructions. A bit higher doesnt hurt (i wrote "a bit' as in few psi), under pressure is more dangerous since it builds up heat rapidly.

Hak

Hak I think 52PSI in his case may be extreme but didn't read all the way through to see what his maximum is likely that exceeds his max though.

My car came with 185-65-R14's with a max load pressure of 36PSI which would probably be a recommended pressure of 29 by the vehicle manufacture but only due to ride characteristics. Now my car has 205-45-ZR16's with a max load pressure of 50 PSI as you know there's a very good reason why there is such a substantial difference in those numbers and there is no way I'd run those tires @29 PSI maybe the 185's I'd run at 32 but still not 29 and the 205's no lower then 34 rears on FWD and 36 fronts. Now my current tires have gotten good wear and much of their performance has been fine under more then average extreme conditions which is my daily driving until my new tires installed just today which remain to be seen but are initially encouraging and I've also set them @34 rear and 36 front respectively with a max of 50PSI.

Tires with a recommended tire pressure that high do so to support the sidewall and the cord so as you know there's no standing rule and more credence has to be given to stated sidewall pressures over vehicle manufacturer pressures IMO..

As I have posted previously in other similar threads there are notable cases in the states where the vehicle manufacturer grossly underestimated the proper PSI settings and caused numerous tire failures especially on high set vehicles such as SUV's which have a high center of gravity and pose a real danger in roll over potential.. The cases, which included serious injuries and deaths, went back and forth between the tire manufacturer and the vehicle manufacturer over who was at fault and in the end it turned out in the tire manufacturers favor..

As I'm reading the OP which got off it's original track, the actual vehicle manufacturer Isuzu is now amending the original door sill recommendations through their service centers over the previous pressures and now recommending a higher one so the arguments here are in a contradiction with themselves and have gotten off track to attack one poster who's advice sounds a bit extreme..

Edited April 2, 2012 by WarpSpeed

[WarpSpeed]

Yes they do. My wife is like a Hawk,watching out for the tyre pressures,I tried to explain to her once that we have low profile tyres and that's why they look flat.

As Sods Law would have it,when we go to garage for air she is invariably right

That's another angle. I've used two air machines at two different filling stations within minutes and got completely different readings!

Must carry your own gauge, buy a good one and don't skimp and use it consistently it will show either a slight variance either way or be accurate but keep using it as it is consistent where the others are not..

[WarpSpeed]

I put 52psi in my pickup tyres, yours is low, the v-cross is quite a weighty beast.

PS

As far as I know Isuzu don't make tyres, so you should be using the pressures printed on the rubber of the tyre, and then pressuring according to the weight of the vehicle on those tyres. Heaver the vehicle, the neared the max PSI, lighter the vehicle, the neared to the minimum PSI.

Woah... back off there !! ... My Range Rover is a weighty beast, your V-cross is a light weight in comparison...

Normal load is 35 on the front and 40 on the rear under normal load conditions. You might be over cooking things just a dash !!!

Note: I suspect over pressure is much safer than under-pressure - I had blowout due to under-pressure a few years back after driving 5 hrs non stop. I suspect the under-pressured michelins overheated (how did I know it was under-pressured, cos after changing the wheel?, I stopped off at the next station and all were approximately 10psi under-pressure, I check more regularly now).

This might be why Thai's like over-pressured tyres.

Yes under pressure on an SUV specifically is far more dangerous then over pressure..Sod all that tire wear savings and suspension damage gobbledygook in that case which really doesn't apply anyways, safety is the primary issue the manufacturer only cares about their warrantee..

Edited April 2, 2012 by WarpSpeed

[WarpSpeed]

@transam

You should read some of the American forums, where the good old boys discuss such matters endlessly.

My tyres are wearing evenly at 52psi.

@Mr. Smith

I will happily trade a little less grip for a lower chance of a flat in the hills.

(My tyre max pressure is 60psi)

60 PSI? Still think 52 is a tad high.. I'd opt for about 46 in that case..

[Bung]

I ran 30-31 psi in my stock Vigo's tyres and got 95 000 klm's out of them. Any higher would make the ride noticably more uncomfortable.

I suggest the OP buy a tyre gauge, run them at 30 all round for a week then put 40 in for a week and see which he prefers......

[WarpSpeed]

I ran 30-31 psi in my stock Vigo's tyres and got 95 000 klm's out of them. Any higher would make the ride noticably more uncomfortable.

I suggest the OP buy a tyre gauge, run them at 30 all round for a week then put 40 in for a week and see which he prefers......

Uncomfortable is not the primary concern of P/U tire manufacturers, safety and load capacity are, in spite of so many buying and using them for sedans they aren't built primarily comfort, BMW's and the like are..

Edited April 2, 2012 by WarpSpeed