Do Thais Have An Obsession About Overinflated Car Tyres?

[transam]

<deleted> close this topic someone ....!!!!.

Noooooooooo, some here care about YOUR safety.

[TommoPhysicist]

<deleted> close this topic someone ....!!!!.

Noooooooooo, some here care about YOUR safety.

Some put OVERINFLATED values on their opinions!

[Crossy]

Really like to hear from a particular poster to show me a car or light truck that uses 50 to 60 psi.

Me too, but check out JAS21's post http://www.thaivisa....ost__p__5189083 have a look at the 2WD Hi-ride on 205R16C's rear pressure 58psi.

Would have thought 205's would have been rather skinny, but they are the exception that proves the rule.

[Kwasaki]

Really like to hear from a particular poster to show me a car or light truck that uses 50 to 60 psi.

Me too, but check out JAS21's post http://www.thaivisa....ost__p__5189083 have a look at the 2WD Hi-ride on 205R16C's rear pressure 58psi.

Would have thought 205's would have been rather skinny, but they are the exception that proves the rule.

Yep ! even smaller commercial tyres 195R15C front 2.75 bar ( 40 psi ) rear 4.50 bar ( 65 psi )

Oh !! "David006" hold up there, how about we get on to overinflated with nitrogen in tyres, I have an obsession .

Edited April 4, 2012 by Kwasaki

[JAS21]

<deleted> close this topic someone ....!!!!.

NO ... I think that we should keep this going ... go for 100 posting and then 200 postings ... even if the odd person repeats themselves. Of course I'm wondering why Isuzu don't advise adjustment of pressures for loaded pickups ... someone must have an opinion

[TommoPhysicist]

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.

[Kwasaki]

<deleted> close this topic someone ....!!!!.

NO ... I think that we should keep this going ... go for 100 posting and then 200 postings ... even if the odd person repeats themselves. Of course I'm wondering why Isuzu don't advise adjustment of pressures for loaded pickups ... someone must have an opinion

I guess 65 psi rear for this or 3psi below max pressure written on the side of the tyre wall.

Edited April 4, 2012 by Kwasaki

[TommoPhysicist]

I have also been reading forums sharing information about overinflated tyres, mainly based in the USA and Canada.

Consensus appears to be.

You can over-inflate the tyres 50% above max sidewall pressure without risk of blow-outs.

Over-inflating by 33% on the recommended pressure MAY in a worst case scenario increase your stopping distance by 6%, although a report from one tyre manufacturer suggests this not to be the case. Also if you are running on pumped tyres, you will likely be driving at a much slower speed to compensate for the bumpiness.

Many of the people are running their tyres at 50% to 100% over pressure with little or no bad consequences.

My personal use for a pickup may be vastly different that yours, it rarely reaches speeds of 50kmph, usually 20-30kmph along dirt roads filled with farm style loads. I use a pickup properly.

To those who claim the door sticker is always correct,

well maybe if you are running stock tyres at stock load on a stock car

but what about those of us with raised suspension, wheel spacers, oversize rims, different manufacturers tyres, unusual loads, and different temperatures.

It can't be the correct advice for every condition!

Edited April 4, 2012 by TommoPhysicist

[fredtitmus]

ooooooooh,im tyred !!!!!

[JAS21]

Well we have made 100

[funcat]

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...

[funcat]

I have also been reading forums sharing information about overinflated tyres, mainly based in the USA and Canada.

Consensus appears to be.

You can over-inflate the tyres 50% above max sidewall pressure without risk of blow-outs.

Over-inflating by 33% on the recommended pressure MAY in a worst case scenario increase your stopping distance by 6%, although a report from one tyre manufacturer suggests this not to be the case. Also if you are running on pumped tyres, you will likely be driving at a much slower speed to compensate for the bumpiness.

Many of the people are running their tyres at 50% to 100% over pressure with little or no bad consequences.

My personal use for a pickup may be vastly different that yours, it rarely reaches speeds of 50kmph, usually 20-30kmph along dirt roads filled with farm style loads. I use a pickup properly.

To those who claim the door sticker is always correct,

well maybe if you are running stock tyres at stock load on a stock car

but what about those of us with raised suspension, wheel spacers, oversize rims, different manufacturers tyres, unusual loads, and different temperatures.

It can't be the correct advice for every condition!

...of course,the door sticker applies only to the "stock" set up...if you change size of wheels,tires,or suspension the "manufactures recommendations" will no longer apply...

[arthurwait]

over inflated tires = bone jarring ride, more chance of skidding, reduced stopping distance, more chance of wheel spinning ..........WHY because there's less rubber in contact with the road!

Most people with Pick-up's on this board DON'T load em like a Thai running a business would - ie overloaded so why over inflate the tires?!?!?!

Between 29-35 PSI would be what i'd think of using................ oh hang on there's a handy sticker thingy inside the drivers door............

Another with some sense THAT CAN READ.

Pickups are for work, only someone completely daft would buy it to drive around town, then complain about a bumpy ride.

It could be something to do with the price.

[arthurwait]

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 you shouldn't believe it as it's not true end of silly you..!! Actually I'm countering the nonsense of amateurs..BTW can you answer my previous post about where you get your recommended tire pressures from the tire manufacturer from?? I also have one very important and undeniable fact behind my posts that segregates them from the other less informed here and that's literally both thousands of miles and hot laps on DOT tires over the last 25 years without a single failure due to wrong pressures only mechanical failures due to contact or other and even those have been few and far between..

To aid your comprehension I highlighted the pertinent part..

So as not to confuse I've competed on Goodyears, BFG, Kumho, Yokohama, Firestone, Bridgestone and Hoosier STREET LEGAL DOT approved tires all with better then average results and not a single failure anything related to tire pressures (except one time when a "crack" crew I hired for a race improperly installed the new valve stems on the new rims we had and the air leaked out on the pace lap and incredibly they weren't even Thai ).. Never hired another "crack" crew again after that, trained them all myself, problem solved.. That also doesn't consider the thousands of miles traveled in work trucks of my own, my support vehicles to get to the track and so on..

You are a professional chassis engineer ?

[Kwasaki]

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 you shouldn't believe it as it's not true end of silly you..!! Actually I'm countering the nonsense of amateurs..BTW can you answer my previous post about where you get your recommended tire pressures from the tire manufacturer from?? I also have one very important and undeniable fact behind my posts that segregates them from the other less informed here and that's literally both thousands of miles and hot laps on DOT tires over the last 25 years without a single failure due to wrong pressures only mechanical failures due to contact or other and even those have been few and far between..

To aid your comprehension I highlighted the pertinent part..

So as not to confuse I've competed on Goodyears, BFG, Kumho, Yokohama, Firestone, Bridgestone and Hoosier STREET LEGAL DOT approved tires all with better then average results and not a single failure anything related to tire pressures (except one time when a "crack" crew I hired for a race improperly installed the new valve stems on the new rims we had and the air leaked out on the pace lap and incredibly they weren't even Thai ).. Never hired another "crack" crew again after that, trained them all myself, problem solved.. That also doesn't consider the thousands of miles traveled in work trucks of my own, my support vehicles to get to the track and so on..

You are a professional chassis engineer ?

Chassis engineer what has that to do with tyre pressures, and your question is. ?

[arthurwait]

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 you shouldn't believe it as it's not true end of silly you..!! Actually I'm countering the nonsense of amateurs..BTW can you answer my previous post about where you get your recommended tire pressures from the tire manufacturer from?? I also have one very important and undeniable fact behind my posts that segregates them from the other less informed here and that's literally both thousands of miles and hot laps on DOT tires over the last 25 years without a single failure due to wrong pressures only mechanical failures due to contact or other and even those have been few and far between..

To aid your comprehension I highlighted the pertinent part..

So as not to confuse I've competed on Goodyears, BFG, Kumho, Yokohama, Firestone, Bridgestone and Hoosier STREET LEGAL DOT approved tires all with better then average results and not a single failure anything related to tire pressures (except one time when a "crack" crew I hired for a race improperly installed the new valve stems on the new rims we had and the air leaked out on the pace lap and incredibly they weren't even Thai ).. Never hired another "crack" crew again after that, trained them all myself, problem solved.. That also doesn't consider the thousands of miles traveled in work trucks of my own, my support vehicles to get to the track and so on..

You are a professional chassis engineer ?

Chassis engineer what has that to do with tyre pressures, and your question is. ?

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

[Kwasaki]

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.

[pipo1000]

Just read the Vigo/Michelin tyre wall. DANGER underpressure/overpressure can result in tyre failure, follow ''vehicle'' manufacturers advice.

MAX pressure 44 psi That means THAT tyre can be fitted to a vehicle REQUIRING that sort of pressure for it's designed use, NOT for a Vigo where 29 psi is the safe pressure.

Some still don't understand that the ''give'' in a tyre is all part of the grip and suspension set up. There is absolutely NO advantage to over inflating except the steering will be lighter, you know why, cos you will reduce the under pressure (vehicle weight) tread contact area, so reducing grip, that's why over inflated tyres wear out the middle tread,

My English is not so well,but I thought you were British so yours should be allright.

What I read from your post is that this Michelin tyre was fitted on a Vigo.

Next I understand that you say that this tyre can NOT be fitted on a Vigo where 29 psi is the safe pressure and the tyre requires 44 Psi.So why were they fitted on a Vigo then?

As for your question in another post why Toyota says 29 Psi and not 30,you could also ask why they don't say 28 or 31. But actually I find 29 Psi pretty low for a pick up,and hard to believe as my Nissan Navara says 34 Psi in the recommendations

Edited April 4, 2012 by pipo1000

[arthurwait]

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.

[Kwasaki]

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.

Well you should be more specific with questions, he is a professional racing driver with a lot of engineering knowledge, what more can I say when i keep seeing his posts getting removed.

Edited April 4, 2012 by Kwasaki

[arthurwait]

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.

Well you should be more specific with questions, he is a professional racing driver with a lot of engineering knowledge, what more can I say when i keep seeing his posts getting removed.

Teams employ chassis/tyre/race engineers to tell drivers how to set up a car .

A professional racing driver ? What series ?

[Kwasaki]

Just read the Vigo/Michelin tyre wall. DANGER underpressure/overpressure can result in tyre failure, follow ''vehicle'' manufacturers advice.

MAX pressure 44 psi That means THAT tyre can be fitted to a vehicle REQUIRING that sort of pressure for it's designed use, NOT for a Vigo where 29 psi is the safe pressure.

Some still don't understand that the ''give'' in a tyre is all part of the grip and suspension set up. There is absolutely NO advantage to over inflating except the steering will be lighter, you know why, cos you will reduce the under pressure (vehicle weight) tread contact area, so reducing grip, that's why over inflated tyres wear out the middle tread,

My English is not so well,but I thought you were British so yours should be allright.

What I read from your post is that this Michelin tyre was fitted on a Vigo.

Next I understand that you say that this tyre can NOT be fitted on a Vigo where 29 psi is the safe pressure and the tyre requires 44 Psi.So why were they fitted on a Vigo then?

As for your question in another post why Toyota says 29 Psi and not 30,you could also ask why they don't say 28 or 31. But actually I find 29 Psi pretty low for a pick up,and hard to believe as my Nissan Navara says 34 Psi in the recommendations

Not hard to believe at all, Toyota 4x4 big wheeled top of range trucks are 29 psi around as a recommended COLD pressure for OEM equipment for that vehicle, 3 - 4 psi can be gained on use.

The Nissan Navara is not the same, different tyres sizes, different loads, on the side of tyres there is a recommended max pressure for the tyre but as said before only used for a storage pressure.

And again what has been discussed if you change the tyre type then calculations can be made.

[Kwasaki]

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.

Well you should be more specific with questions, he is a professional racing driver with a lot of engineering knowledge, what more can I say when i keep seeing his posts getting removed.

Teams employ chassis/tyre/race engineers to tell drivers how to set up a car .

A professional racing driver ? What series ?

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.

[arthurwait]

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.

[fredtitmus]

This is like watching "match of the day". Im no expert on cars but when im carrying a heavy load in my van i would pump some more pressure into the back tyres,this has never had any adverse effects with my vans or my tyres.

To stick with the topic i would say that the thai's pump the pressure up because for eg if they are in a pickup carrying about 30 people for 6 hours or they were overloaded with crates of leo they would probably need it.Remember this isnt the west this is thailand and overloading is everwhere also the roads are not up to the same standard as the west.this maybe contributes to the obsession but this is just my observation im not an expert like all the racing drivers etc on here so forgive me if im wrong.

I think its a case of knowing your car,van with the tyres that are on it.

[mafumo]

Well getting up there in the numbers ,,,,,, perhaps they are getting overinflated ,,,, like it's not been used yet

[transam]

Just read the Vigo/Michelin tyre wall. DANGER underpressure/overpressure can result in tyre failure, follow ''vehicle'' manufacturers advice.

MAX pressure 44 psi That means THAT tyre can be fitted to a vehicle REQUIRING that sort of pressure for it's designed use, NOT for a Vigo where 29 psi is the safe pressure.

Some still don't understand that the ''give'' in a tyre is all part of the grip and suspension set up. There is absolutely NO advantage to over inflating except the steering will be lighter, you know why, cos you will reduce the under pressure (vehicle weight) tread contact area, so reducing grip, that's why over inflated tyres wear out the middle tread,

My English is not so well,but I thought you were British so yours should be allright.

What I read from your post is that this Michelin tyre was fitted on a Vigo.

Next I understand that you say that this tyre can NOT be fitted on a Vigo where 29 psi is the safe pressure and the tyre requires 44 Psi.So why were they fitted on a Vigo then?

As for your question in another post why Toyota says 29 Psi and not 30,you could also ask why they don't say 28 or 31. But actually I find 29 Psi pretty low for a pick up,and hard to believe as my Nissan Navara says 34 Psi in the recommendations

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.

[TommoPhysicist]

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.

Edited April 5, 2012 by TommoPhysicist

[mafumo]

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

[samsiam]

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