pesce.del.giorno said:

Oops, premature discharge.
The question is, how can you tell from tyre markings whether they are run-flat or not?

pesce.del.giorno said:

pesce.del.giorno said:

Oops, premature discharge.
The question is, how can you tell from tyre markings whether they are run-flat or not?

The sidewalls will have a definite sign. Impossible to miss.

https://www.blackcircles.com/helpcentre/tyres/how-do-i-know-if-my-tyres-are-run-flat-tyres

How do I know if my tyres are Run Flat tyres?

You will be able to check whether your current tyres are Run Flat tyres by checking the sidewall.

Unfortunately there is no industry standard code to represent this and different manufacturers use different symbols or letters. These are as follows:

• Continental – SSR
• Dunlop – DSST or ROF
• Goodyear – ROF or EMT
• Bridgestone – ROF or RFT or RSC
• Michelin – ZP
• Hankook – tyres will be marked with HRS or have B at the end of the product number (e.g. K115B)
• Pirelli – RSC
• Yokohama – ZPS

Why is tire pressure so important?

I HATE pieces that say to check the tyre placard on the door- WRONG!!!!!

That only applies if you have the original tyres (manufacturer and brand) fitted
ALWAYS go by the pressure on the tyre itself-ALWAYS

hint (looks at me mum here) do NOT inflate my muddies to 60psi as the tyre placard says- or else they all blow out within a hundred kilometers on the freeway (dont they mum???) when the tyre says clearly max pressure is 32psi

Talking from experience

:-(

DUH!
never heard of Run Flat Tires

They werent in any state to be driven on at all after being driven at high speed 30psi over their maximum (basically double their max pressure) rating for over a hundred km…..

Besides which I havent found a run flat muddie yet (gee I wish) I use plugs and the onboard air compressor for flats

> I HATE pieces that say to check the tyre placard on the door- WRONG!!!!!

I hate it even more when there is no placard by the door because the label on the new car was printed on cling film that peeled itself off within one month of purchase.

Ogmog said:

DUH!
never heard of Run Flat Tires

Me neither. Thanks for the link.

The second hand Triton I recently purchased had the tyres pumped up to 48 psi I checked them because I thought the ride was too juddery. Though the tyres have a max of 86 psi according to a quick glance at the sidewall. I reduced it to 32 and was happy with the result.

mollwollfumble said:

> I HATE pieces that say to check the tyre placard on the door- WRONG!!!!!

I hate it even more when there is no placard by the door because the label on the new car was printed on cling film that peeled itself off within one month of purchase.

Thats a feature, not a bug lol

Personally I wonder how many people have had accidents because they religiously follow those placards- which are totally useless unless you keep to the exact brand and model tyres that were fitted from the factory (and how many people do that???)

My ute is a an extreme example, but even car tyres can vary enormously in pressure ratings depending on brand
The ute had 16” split rim hilux rims with those lt things on it from the factory- useless on road as well as off road, now has 15” sunrasia mags fitted with fairly chunky m/t’s (mud errains)- same rolling dia, same load rating so fully legal, but due to totally different design and purpose, they can be deflated down to 12psi min in mud work (lower with bead clamps) and max of 32psi- where the factory lt’s(light truck) are rated at 65psi max and door placard says to run them at 60psi..
Put that much pressure in the mudders and well they go boom very quickly (around 90 km according to google maps)- I wish I had pictures of them, the tread had separated almost completely from the carcase and the left front actually did separate and start slapping the rockslider, (which is why she stopped lol)
Towtruck had to be called and all 4 tyres replaced (at $280 each- cries)

She was mumbling about cheap tyres- they werent cheap (nothing on a 4wd is cheap lol), they were simply not designed to run at high speed at twice their maximum pressure!!!

Tyre placard has now been removed (although I doubt she will ever put air in my tyres again if she borrows it lol

boppa said:

mollwollfumble said:

> I HATE pieces that say to check the tyre placard on the door- WRONG!!!!!

I hate it even more when there is no placard by the door because the label on the new car was printed on cling film that peeled itself off within one month of purchase.

Thats a feature, not a bug lol

Personally I wonder how many people have had accidents because they religiously follow those placards- which are totally useless unless you keep to the exact brand and model tyres that were fitted from the factory (and how many people do that???)

My ute is a an extreme example, but even car tyres can vary enormously in pressure ratings depending on brand
The ute had 16” split rim hilux rims with those lt things on it from the factory- useless on road as well as off road, now has 15” sunrasia mags fitted with fairly chunky m/t’s (mud errains)- same rolling dia, same load rating so fully legal, but due to totally different design and purpose, they can be deflated down to 12psi min in mud work (lower with bead clamps) and max of 32psi- where the factory lt’s(light truck) are rated at 65psi max and door placard says to run them at 60psi..
Put that much pressure in the mudders and well they go boom very quickly (around 90 km according to google maps)- I wish I had pictures of them, the tread had separated almost completely from the carcase and the left front actually did separate and start slapping the rockslider, (which is why she stopped lol)
Towtruck had to be called and all 4 tyres replaced (at $280 each- cries)

She was mumbling about cheap tyres- they werent cheap (nothing on a 4wd is cheap lol), they were simply not designed to run at high speed at twice their maximum pressure!!!

Tyre placard has now been removed (although I doubt she will ever put air in my tyres again if she borrows it lol

what was she doing putting air in them in the first place?

She borrowed it to go pick up some stuff from up the coast, and so she checked the oil and water (and the tyres-grr) before she left
She looked at the non peeling off door placard and it said 60psi- so she put 60 psi in em….

(she thought they looked a bit flat- they actually werent but being mudders with very flexible sidewalls designed to be run at low pressure offroad, they had big sidewall bulges even when right at their maximum psi)

handy thing tyre gauges, particularly if they represent the real pressure in the tyre.

gauges that seriously underread, now there’s got to be some fun in that, it might say 35psi and you got 100psi.

there are other things one can do other than use of a reliable pressure gauge, or in addition, like looking at the bulge, on the bottom where the tyre meets the ground of course.

too much bulge makes the tyre walls flex, and at speed this generates heat. You may have seen someone driving down the road sometime, near flat tyre, smoke coming off it. You can feel the heat in the walls of tyres, after a run, immediately after, using a calibrated hand.

there is too the calibrated foot, with which you kick the tyre. This takes years of practice, and’s not entirely unreliable.

too flat a tyres increases tyre roll, like when cornering, like the tread moves across in relation to its centre position aligned with the rim, the tyre hangs onto the whatever surface best it can, there are forces, mass and velocity, and things tend to want to go in straight lines. Low-profile tyres have less of this, but a loss of compressability (distance between tread and rim), the tyre being a shock absorber of sorts. Great invention really, the pneumatic tyre. Genius idea.

anyway, while kicking the tyre, you can push the car side to side, inspect the tyre roll, and even if this is totally useless at telling if the tyre is too flat it demonstrates the properties of rubber, inflated with air, and tyre roll. This won’t work with larger vehicles, like trucks, for reasons that should be apparent.

generally by inspecting the bulge (on a flat surface, this is quite important), and kicking the tyre, with some practice you may be able to get the accuracy (within the parameters of ‘probably alright’, not too flat and not too tight), to +/- 10psi, but i’d expect a novice it’d be more like +/- 20psi. Comparison with the other tyres helps, again it has to be a flat surface, just an ant hill under one of them and you may put 80psi in the tyre just to get it looking the same.

Tyre kicking seems to be an average gauge for almost everything.

transition said:

handy thing tyre gauges, particularly if they represent the real pressure in the tyre.

gauges that seriously underread, now there’s got to be some fun in that, it might say 35psi and you got 100psi.

there are other things one can do other than use of a reliable pressure gauge, or in addition, like looking at the bulge, on the bottom where the tyre meets the ground of course.

too much bulge makes the tyre walls flex, and at speed this generates heat. You may have seen someone driving down the road sometime, near flat tyre, smoke coming off it. You can feel the heat in the walls of tyres, after a run, immediately after, using a calibrated hand.

there is too the calibrated foot, with which you kick the tyre. This takes years of practice, and’s not entirely unreliable.

too flat a tyres increases tyre roll, like when cornering, like the tread moves across in relation to its centre position aligned with the rim, the tyre hangs onto the whatever surface best it can, there are forces, mass and velocity, and things tend to want to go in straight lines. Low-profile tyres have less of this, but a loss of compressability (distance between tread and rim), the tyre being a shock absorber of sorts. Great invention really, the pneumatic tyre. Genius idea.

anyway, while kicking the tyre, you can push the car side to side, inspect the tyre roll, and even if this is totally useless at telling if the tyre is too flat it demonstrates the properties of rubber, inflated with air, and tyre roll. This won’t work with larger vehicles, like trucks, for reasons that should be apparent.

generally by inspecting the bulge (on a flat surface, this is quite important), and kicking the tyre, with some practice you may be able to get the accuracy (within the parameters of ‘probably alright’, not too flat and not too tight), to +/- 10psi, but i’d expect a novice it’d be more like +/- 20psi. Comparison with the other tyres helps, again it has to be a flat surface, just an ant hill under one of them and you may put 80psi in the tyre just to get it looking the same.

i can get the pressure of the race car tyres right with a knee to the top centre piece of tread

>i can get the pressure of the race car tyres right with a knee to the top centre piece of tread.

i’d think with low pressures (soft walls too) and familiarity that way, it’s probably easier.