Do Thais Have An Obsession About Overinflated Car Tyres?

[Kwasaki]

Wheres the sticker inside the door....do you have to remove the paneling ??

For you to check it out is a good thing, as the OP is refering to tyres if pumped in some garages they are usually way over the top ( it's a bar pressure keeping it Thai related) for which I guess many of the posts here would say is not a good idea.

And no you shouldn't have to remove anything it's on display usually on the outer surrounds of the chassis where the drivers door closes, they give tyre psi / bar pressure recommendation of that vehicle fitted with oem tyres.

If you change from the oem e.g. larger tyre, smaller tyre, info is available for any adjustment in psi / bar.

Edited April 6, 2012 by Kwasaki

[Kwasaki]

You miss understand my posts. The Mich tyre on a Vigo has a MAX safe cold operating pressure of 44 psi, BUT THIS TYRE ON A VIGO NEEDS 29 psi. The tyre is made to fit MANY applications where different pressures might be needed. That's it. Vigo, stay safe, 29/30 psi.

According to data from the tyre manufacturers a 6% under-inflation can cause a 25% rise in tyre wear and a significantly increased chance of blow out due to tyre overheating. (I can give you a link if you insist but not hard to find yourself)

Tyre heating mainly caused by excessive flexing of the tyre walls. Under-inflate the tyre and the flexing increases so the heat increases.

Now according to Transam your correct tyre pressure is 29 (but he's now slipped in or 30) and I would like to ask how you can ensure that a tyre inflated to 29psi does not drop to 6% below that pressure. (6% would be 1.6psi)

A car tyre pressure is measured at cold (not driven)

But cold in the morning or cold in the afternoon?

A 5 degree temperature change can change the tyre pressure by 1psi, in Thailand it can easily be 15c in the morning but 35c in the afternoon, that would make a 4psi increase in tyre pressure between morning and afternoon.

Inflate to 29psi in the afternoon, and you could be running at 25psi next morning (12.5% under-pressure, more than twice the 6% danger level)

For a car using it's original tyres.

Mr. Transam, would you suggest changing tyre pressures twice a day to keep at 29psi?

Or are you now going to suggest we inflate to 29psi in the morning, and run at an over-pressure 33psi in the afternoon?

How often do we check our tyre pressure? 1.6psi is not much of a drop to hit danger.

You sound like a scientist who specializes in physics.

[Kwasaki]

So come on tyre guru's whats the definitive answer to the OP , or has that long been forgotten

Experienced to a point but no guru To answer the OP question my point of view would be " Not an Obsession, just a mis-understanding."

Edited April 6, 2012 by Kwasaki

[volk666]

Someone posted a page from Isuzu manual here, they indeed recommend apparently "overinflated" values for some of their models running on particular tires.

If that particular combination happens to be very popular in Thailand you can expect friends, neighbors and mechanics follow "I also drive a pickup truck so 50-60 psi is okay for me, too" logic, or "if I put 60 in the back, I can pump front tires to 60, too" reasoning.

Downsides to overinflating are negligible in the short term which also helps in establishing this new custom.

Next you have social pressure to overinflate just like everyone else, and testimonies from race track drivers don't help either - "I mean they are professional racers, right, overinflating is the cheapest way to add some real racing pedigree to my Isuzu."

Manufacturer recommendations? Who needs those? They are for pussies, we are past that stage, we racers now.

[Kwasaki]

That is not the case always in the levels of motor racing, why don't you ask him yourself when I raced motorcycles I was all of them.

I did ask.

Personally I think this thread is funny, people getting worked up over tyre pressures.

Yes that is not the case in all levels of motorsport, but usually is in professional motor racing.

But if someone wants to discredit other peoples points by calling them amateurs they really need to be a qualified professional on the matter themselves. It's a genuine question so people who are reading this thread looking for advice know whether to follow it or not.

As I'm sure you know what is good the track is not often that good for the road though.

" I did ask." OK good on ya.

If you think this thread is funny you want to go back and have a read of the ones on " Nitrogen in tyres " or tires.

To discredit other peoples points by calling them amateurs doesn't bother me if I am saying something that's incorrect about tyre knowledge or anything else then I would be seen as an amateur.

I don't think someone has to be professional either, just knowledgeable.

Following advice on TV could be questionable and another topic.

Lastly, with respect I wouldn't agree, what is learn on a track often gets transfer to the road as in R&D.

Edited April 6, 2012 by Kwasaki

[Hssl]

http://www.youtube.com/watch?v=4hEUeRFQL9A&feature=related

About 5mins in..........................

[samsiam]

I told my neighbour to carry inflated inner tubes for spare air in case he needed any.

[metisdead]

An inflammatory post has been removed. Try again without the flames.

Edit: Drop the silly name calling as well, another post has been removed.

Edited April 6, 2012 by metisdead

[transam]

My main concern on this forum is folk remain safe with information given by a motor AND tyre manufacturer for a particular ride AND a particular tyre, and not listen to daft people who do THEIR own thing, and 90% of the time get away with it. Bit like drinking and driving. Couple of folk here should do a simple google search about tyre over inflation and what the MAX pressure stamp on a tyre means. Soooooooooooooooooooooo, simple.

[TommoPhysicist]

When the ambient temperature changes in Thailand can cause the tyre pressure of a parked car to alter by 4psi in a 24 hour cycle.

I would like to know how to keep my tyre pressure at a constant 29psi? and not 25psi or 33psi.

[metisdead]

Another post with silly name calling has been removed. Last chance, stop the name calling, or suspensions will occur.

[transam]

When the ambient temperature changes in Thailand can cause the tyre pressure of a parked car to alter by 4psi in a 24 hour cycle.

I would like to know how to keep my tyre pressure at a constant 29psi? and not 25psi or 33psi.

Sorry, can't reply. Seems my comments are name calling. No name calling, just my thoughts of folk who over inflate tyres. Soooooooooo, leave it there and google.

[Shurup]

You miss understand my posts. The Mich tyre on a Vigo has a MAX safe cold operating pressure of 44 psi, BUT THIS TYRE ON A VIGO NEEDS 29 psi. The tyre is made to fit MANY applications where different pressures might be needed. That's it. Vigo, stay safe, 29/30 psi.

According to data from the tyre manufacturers a 6% under-inflation can cause a 25% rise in tyre wear and a significantly increased chance of blow out due to tyre overheating. (I can give you a link if you insist but not hard to find yourself)

Tyre heating mainly caused by excessive flexing of the tyre walls. Under-inflate the tyre and the flexing increases so the heat increases.

Now according to Transam your correct tyre pressure is 29 (but he's now slipped in or 30) and I would like to ask how you can ensure that a tyre inflated to 29psi does not drop to 6% below that pressure. (6% would be 1.6psi)

A car tyre pressure is measured at cold (not driven)

But cold in the morning or cold in the afternoon?

A 5 degree temperature change can change the tyre pressure by 1psi, in Thailand it can easily be 15c in the morning but 35c in the afternoon, that would make a 4psi increase in tyre pressure between morning and afternoon.

Inflate to 29psi in the afternoon, and you could be running at 25psi next morning (12.5% under-pressure, more than twice the 6% danger level)

For a car using it's original tyres.

Mr. Transam, would you suggest changing tyre pressures twice a day to keep at 29psi?

Or are you now going to suggest we inflate to 29psi in the morning, and run at an over-pressure 33psi in the afternoon?

How often do we check our tyre pressure? 1.6psi is not much of a drop to hit danger.

Not sure where you got your numbers... Physics was my most favourite subject in school and university, it was a while back and I forgot a lot of it but here you go...

According to a Gay Lussac's law and my fiddeling with numbers, a 20 degree temp change (from 15 in the morning to 35 in the afternoon) will only cause 2 psi change in the pressure which is acceptable.

Here is the formula:

P1/T1 = P2/T2

Lets not be too picky about the numbers here. Underinflation is defitelly more dangerous than overinflation. A slight overinflation will not be noticed and will not affect the handling of a car. However overinflating to 50-100% from Recommended (from 29 to 45-60) will definitely affect your car's handling and tire (or was it TYRE? ) life.

P.S. Don't forget to change your units to SI if using the formula.

[Lickey]

Ford Ranger Hi Rider, NSF 28, NSR 20, OSF 34, OSR 24, Spare, 80, works for me,

[PattayaParent]

I always put in the car manufactruers recommended tyre pressure (30/32) but I've noticed when a Thai does it for me at a petrol station they always put in 50 rather than the 30 I tell them to.

So yes I'd say they have an obsession about overinflated tyres.

[Kwasaki]

I always put in the car manufactruers recommended tyre pressure (30/32) but I've noticed when a Thai does it for me at a petrol station they always put in 50 rather than the 30 I tell them to.

So yes I'd say they have an obsession about overinflated tyres.

Think about it, is not an obsession at all, it is a mis-understanding unless your your joking of coarse.

[how241]

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

True. I tend to keep them a few psi over, they seem to last a little longer.

[cowslip]

Yes they do, and it is even potentially dangerous.

Edited April 9, 2012 by cowslip

[PattayaParent]

I always put in the car manufactruers recommended tyre pressure (30/32) but I've noticed when a Thai does it for me at a petrol station they always put in 50 rather than the 30 I tell them to.

So yes I'd say they have an obsession about overinflated tyres.

Think about it, is not an obsession at all, it is a mis-understanding unless your your joking of coarse.

No misunderstanding, they even argue with me that 50 is the correct pressure, it probably says that's the max on the tyre walls, I should look sometime.

Edit: just checked and sure enough max pressure is 51 psi.

Edited April 9, 2012 by PattayaParent

[transam]

I always put in the car manufactruers recommended tyre pressure (30/32) but I've noticed when a Thai does it for me at a petrol station they always put in 50 rather than the 30 I tell them to.

So yes I'd say they have an obsession about overinflated tyres.

Think about it, is not an obsession at all, it is a mis-understanding unless your your joking of coarse.

No misunderstanding, they even argue with me that 50 is the correct pressure, it probably says that's the max on the tyre walls, I should look sometime.

Edit: just checked and sure enough max pressure is 51 psi.

It's crazy, and the dealers sent these guys to motoring school to learn stuff.

[Tanaka]

Can't believe that a so called ''race driver/mechanic'' is posting many posts that are a danger to you if you follow his advice.

Tyre pressure tech is very simple, a given tyre, a given vehicle. Motor and tyre manufacturer to many miles of testing so that YOU will be safe and the motor will keep traction.

That testing is placed on a sticker NEXT to the driver on the door jam to be sure it's of easy access.

There will be pressures stated for laden and unladen, some rides the pressures are the same whether laden or unladen.

If YOU fail to adhere to their figures, within a few pounds,, you will compromise the safety of you ride and passengers.

Lastly, when the rainy season comes, why are there so many trucks in the weeds ?.I'll tell you, over inflated tyres, the tyre cannot do it's thing.

I agree. And the given figure by the car manufacturer is a compromise between load and comfort. One should start with the recommendation and find what is best for your car and your way of driving. Remember a truck is light in the back and with high pressure unloaden, it will have virtually no grip on the rear wheels, not even in the dry. Especially with the original tyres

I have an Isuzu 4x4 with 3L engine and run 30psi rear and 35 front unloaden while the car is heavier up front when no load in the back. 29 or 30 front is just not enough but over 35 will give you a sluggish ride. The suggested pressure by Isuzu is 29psi front and rear.

Edited April 9, 2012 by Tanaka

[JAS21]

Can't believe that a so called ''race driver/mechanic'' is posting many posts that are a danger to you if you follow his advice.

Tyre pressure tech is very simple, a given tyre, a given vehicle. Motor and tyre manufacturer to many miles of testing so that YOU will be safe and the motor will keep traction.

That testing is placed on a sticker NEXT to the driver on the door jam to be sure it's of easy access.

There will be pressures stated for laden and unladen, some rides the pressures are the same whether laden or unladen.

If YOU fail to adhere to their figures, within a few pounds,, you will compromise the safety of you ride and passengers.

Lastly, when the rainy season comes, why are there so many trucks in the weeds ?.I'll tell you, over inflated tyres, the tyre cannot do it's thing.

I agree. And the given figure by the car manufacturer is a compromise between load and comfort. One should start with the recommendation and find what is best for your car and your way of driving. Remember a truck is light in the back and with high pressure unloaden, it will have virtually no grip on the rear wheels, not even in the dry. Especially with the original tyres

I have an Isuzu 4x4 with 3L engine and run 30psi rear and 35 front unloaden while the car is heavier up front when no load in the back. 29 or 30 front is just not enough but over 35 will give you a sluggish ride. The suggested pressure by Isuzu is 29psi front and rear.

Whether the truck is unladen or even unloaden does it make any difference to the tyre pressures, I don't understand why you should increase them, or decrease them if its fullly loaded, anyway the tyres are only flat at the bottom the rest of the tyre is round. Surely if the tyre is flatter at the bottom the pressure will increase anyway.

Edited April 9, 2012 by JAS21

[transam]

Can't believe that a so called ''race driver/mechanic'' is posting many posts that are a danger to you if you follow his advice.

Tyre pressure tech is very simple, a given tyre, a given vehicle. Motor and tyre manufacturer to many miles of testing so that YOU will be safe and the motor will keep traction.

That testing is placed on a sticker NEXT to the driver on the door jam to be sure it's of easy access.

There will be pressures stated for laden and unladen, some rides the pressures are the same whether laden or unladen.

If YOU fail to adhere to their figures, within a few pounds,, you will compromise the safety of you ride and passengers.

Lastly, when the rainy season comes, why are there so many trucks in the weeds ?.I'll tell you, over inflated tyres, the tyre cannot do it's thing.

I agree. And the given figure by the car manufacturer is a compromise between load and comfort. One should start with the recommendation and find what is best for your car and your way of driving. Remember a truck is light in the back and with high pressure unloaden, it will have virtually no grip on the rear wheels, not even in the dry. Especially with the original tyres

I have an Isuzu 4x4 with 3L engine and run 30psi rear and 35 front unloaden while the car is heavier up front when no load in the back. 29 or 30 front is just not enough but over 35 will give you a sluggish ride. The suggested pressure by Isuzu is 29psi front and rear.

Whether the truck is unladen or even unloaden does it make any difference to the tyre pressures, I don't understand why you should increase them, or decrease them if its fullly loaded, anyway the tyres are only flat at the bottom the rest of the tyure is round. Surley if the tyre is flatter at the bottom the pressure will increase anyway.

Think it will depend on the load capacity of a particular vehicle. A 4 door Vigo, the pressures are the same loaded or unloaded. My old Volvo Estate, if loaded to max carrying weight l think you had to bung in another 5 psi in the rear tyres.

[WarpSpeed]

Can't believe that a so called ''race driver/mechanic'' is posting many posts that are a danger to you if you follow his advice.

Tyre pressure tech is very simple, a given tyre, a given vehicle. Motor and tyre manufacturer to many miles of testing so that YOU will be safe and the motor will keep traction.

That testing is placed on a sticker NEXT to the driver on the door jam to be sure it's of easy access.

There will be pressures stated for laden and unladen, some rides the pressures are the same whether laden or unladen.

If YOU fail to adhere to their figures, within a few pounds,, you will compromise the safety of you ride and passengers.

Lastly, when the rainy season comes, why are there so many trucks in the weeds ?.I'll tell you, over inflated tyres, the tyre cannot do it's thing.

I agree. And the given figure by the car manufacturer is a compromise between load and comfort. One should start with the recommendation and find what is best for your car and your way of driving. Remember a truck is light in the back and with high pressure unloaden, it will have virtually no grip on the rear wheels, not even in the dry. Especially with the original tyres

I have an Isuzu 4x4 with 3L engine and run 30psi rear and 35 front unloaden while the car is heavier up front when no load in the back. 29 or 30 front is just not enough but over 35 will give you a sluggish ride. The suggested pressure by Isuzu is 29psi front and rear.

JFYI You don't agree, you're post is a complete contradiction to what he's been saying even if he has waffled and changed his own original stance as well and more agreeing with what I and others have said at this point..

I'd still like someone to answer the question posed pages ago.

How does one determine the tire pressure on a car that no longer has the manual or the specs listed and the tires are no longer the OEM size or spec model?

As well where does it state the tire pressures on the tire sidewall? It gives a max and minimum and then safe inflation is calculated in between, it's a sliding scale as has already been agreed to by nearly everyone posting here (eventually). And what does "over-inflate" constitute? What is your definition of over inflating? 2 lbs/6 lbs/10 lbs? If so how do you come by those figures?

BTW This is mostly rhetorical because I know no one here who thinks over-inflation is dangerous has the correct answer. I do though..

As for the premise of the OP, maybe they do over inflate but once again that is subjective..

Edited April 10, 2012 by WarpSpeed

[WarpSpeed]

From a trade paper about tyres

Disadvantages of Underinflation

An underinflated tire can't maintain its shape and becomes flatter than intended while in contact with the road. If a vehicle’s tires are underinflated by only 6 psi it could lead to tire failure. Additionally, the tire’s tread life could be reduced by as much as 25%. Lower inflation pressure will allow the tire to deflect (bend) more as it rolls. This will build up internal heat, increase rolling resistance and cause a reduction in fuel economy of up to 5%. You would experience a significant loss of steering precision and cornering stability. While 6 psi doesn’t seem excessively low, remember, it usually represents about 20% of the tire’s recommended pressure.

Disadvantages of Overinflation

An overinflated tire is stiff and unyielding and the size of its footprint in contact with the road is reduced. If a vehicle's tires are overinflated by 6 psi, they could be damaged more easily when running over potholes or debris in the road. Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in steering response and cornering stability up to a point. This is why participants who use street tires in autocrosses, track events and road races run higher than normal inflation pressures. The pressure must be checked with a quality air gauge as the inflation pressure cannot be accurately estimated through visual inspection.

This is a good info...

Yes, especially the highlighted portion is especially informative..

[sparebox2]

What petrol going through the roof, who wouldn't over-inflate their tyres.

[transam]

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

Thanks Hak, your post really simplifies what l have been trying to put over.

.

.

[WarpSpeed]

So who do manufacturers employ to decide on tyre pressures ? The question is already there.

No it isn't as simple as that, the question as you say is a recommendation, there is still a range, so from OEM equipment, when people fit, over size tyres and different rims calculations have to be made.

Yes I know all that. I'm not sure what it has to do with my point though.

My question was in reply to Warpspeed saying he is dealing with amateurs when discussing tyre pressures. So I was being inquestive to whether he is a professional in this matter. Either a professional chassis or tyre engineer.

This is a bit off topic but requires a response as my qualifications are called into question numerous times and several not so politely. Does the word "professional" somehow escape you? I used that term as did Kawasaki several times. Yes I'm a professional on all counts, tire, chassis and driving but just to correct your misinformation the "chassis engineer" does not determine a cars tire pressures which just illustrates how little you actually know about the inner workings of a professional racing program at any level beyond what you hear Steve Slater spouting on ESPN..

The "tire engineers" are the ones that make "recommendations" of tire pressures to the team and drivers and they are generally not employed by the teams they are employed by the series tire provider or teams tire providers they are in it for the R&D info so they handle that directly. The same with "chassis" engineers except they are employed by the teams but deal with suspension setups, spring rates, sway bar settings and the like in conjunction with the recommended tire PSI settings they are NOT the last word on the final setup the driver is, you just never see this part on ESPN it's behind the scenes..

The teams do dozens of laps to determine by the drivers input which is best and then logged by the engineer as the best in a given set of conditions to go with and in the end it's always the DRIVERS preference which pressures are applied not an engineer who's never had one lap in a car at speed and who's figures are often wrong when real world circumstances are applied.. What is determined as best on paper or on a computer isn't always the best in real world application and that's a proven fact and also why they build models and do tests in every instance to test an engineers concept in real practical applications whether it be the space shuttle or the Burj Dubai..

The only time an engineer is the final word is when the driver is a complete novice that requires coaching and that also means he has taken little knowledge with him up through the ranks and frankly I don't know any drivers in this day and age that are that much a novice..

As Kawasaki said not every level is the same, I came up giving hours of my time freely to learn from the top "pro" programs as an apprentice first doing and then applying it to my own program and tweaking along the way based on tire manufacturer. A good example is Hoosier tires. I had been running them for several years with great success in another series (wins, standing track records, fastest laps etc.) and then cross competed in another series that had just made the change to Hoosier as their spec tire and I was worlds apart on the tire pressures and the other teams who were applying what thought they knew in tire pressures to the previous tire were burning the tread off the Hoosiers in 20 minutes where as I was getting good wear. In a 4 hour race if they're changing tires every 20 minutes to my once in 4 hours it's pretty plain to see who will win..

The catch was that the supplier didn't have enough tires to sustain that level of use either and also didn't agree with what the teams were running and put out a memo to all programs to up their pressures substantially and guess what? I was already running the recommended pressures and there were much better funded teams out there than mine..

Based on the above example of an entire series of multiple vehicle manufacturers, all running stock based cars and on the same spec DOT approved tire how is it that whether or not it was FWD, RWD, AWD front engine, mid engine, Mercedes, Acura, BMW, Toyota, yada, yada regardless, the spec TIRE manufacturer recommended very near the same pressures on all vehicles and none were based on the vehicle manufacturers pressures? Where did they come by those figures??

Edited April 10, 2012 by WarpSpeed

[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

Thanks Hak, your post really simplifies what l have been trying to put over.

.

.

If you only knew??? He also mentions over-inflating, or is it?? No one has answered that question yet including you have they??

Edited April 10, 2012 by WarpSpeed

[TommoPhysicist]

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

Thanks Hak, your post really simplifies what l have been trying to put over.

.

.

If you only knew??? He also mentions over-inflating, or is it?? No one has answered that question yet including you have they??

Read Hakku's post veeeeeeeeeeeery slowly, then read it again veeeeeeeeeeeeeeeeery slowly, THEN, even you might understand what l have been trying to put over. You have condoned inflating a tyre OVER the SAFE MAX pressure printed on a tyre. That's it, no further waffle Wop Speed. You seem to look at THAI motoring as if we are on a race or rally track instead we are looking at regular rides, trucks in the main. As I said before, your talk is dangerous to those who ''might'' not understand stuff.

Safe Max pressure printed on my tyre is 65psi.

I run it at 52psi, so now you are agreeing with me that I am good to go.

Nice for you to agree that I win the discussion, thanks.