Tyre Pressures

[Jebhead]

Anyone have a link for recommended tyre pressures? i don't trust these guys in the shop here, i think they just put in whatever they feel like....

JH

[MoonRiverOasis]

What car? - they're all a little different..

There should be either a sticker in the driver's door jamb with the manufacturers recommended pressures, or it should be stated in the owner's manual,,

[Jebhead]

What car? - they're all a little different..

There should be either a sticker in the driver's door jamb with the manufacturers recommended pressures, or it should be stated in the owner's manual,,

They are 265/40/22.

JH

Edited November 14, 2011 by metisdead
Use default forum font when posting.

[MoonRiverOasis]

OK, cool

So in order to know what the proper pressures should be, we need to know:

1. The car manufacturers' recommended pressures for the OEM tires.

2. The Load rating of the OEM tires (e.g. 112V, 111H, 109S etc)

3. The Load rating of the new tires..

Edited November 14, 2011 by MoonRiverOasis

[Jebhead]

OK, cool

So in order to know what the proper pressures should be, we need to know:

1. The car manufacturers' recommended pressures for the OEM tires.

2. The Load rating of the OEM tires (i.e. 112V)

3. The Load rating of the new tires..

WOW.....where might one get all that info then?

I read on a website that rule of thumb for pressure is to add 1psi per inch, eg i have gone from 17" ( recommended 29psi ) to 22", does 34psi sound "about right" for the above mentioned tyre size?

JH

[MoonRiverOasis]

OK, cool

So in order to know what the proper pressures should be, we need to know:

1. The car manufacturers' recommended pressures for the OEM tires.

2. The Load rating of the OEM tires (i.e. 112V)

3. The Load rating of the new tires..

WOW.....where might one get all that info then?

I read on a website that rule of thumb for pressure is to add 1psi per inch, eg i have gone from 17" ( recommended 29psi ) to 22", does 34psi sound "about right" for the above mentioned tyre size?

JH

That's wrong - it's got absolutely nothing to do with the rim diameter -it's all about the load rating (which corresponds to sidewall stiffness).

The correct rule is: Adjust the OEM recommended PSI pressures by subtracting the load rating of the new tire from the load rating of OEM new tire.

Examples:

if the OEM tire is 109S and the new tire is 112V, and the OEM pressure is 29PSI:

109 - 112 = -3

29PSI - 3 = 26 PSI

If the OEM tire is 112H and the new tire is 111R, and the OEM pressure is 32PSI:

112 - 111 = 1

32PSI + 1 = 33 PSI.

If you didn't swap your spare tire, you should be able to look at it to determine the OEM load rating that corresponds to the vehicle manufacturers recommended pressures.

Edited November 14, 2011 by MoonRiverOasis

[transam]

Open the drivers door and you will see a sticker somewhere on the body panel telling you all.

[Payboy]

Or try here.

[MoonRiverOasis]

Or try here.

Cool link, but beware that many cars in TH come with different OEM tire fitments to other markets. Always best to read your tires as fitted, and RTFM for the correct recommended pressures

[Jebhead]

OK, cool

So in order to know what the proper pressures should be, we need to know:

1. The car manufacturers' recommended pressures for the OEM tires.

2. The Load rating of the OEM tires (i.e. 112V)

3. The Load rating of the new tires..

WOW.....where might one get all that info then?

I read on a website that rule of thumb for pressure is to add 1psi per inch, eg i have gone from 17" ( recommended 29psi ) to 22", does 34psi sound "about right" for the above mentioned tyre size?

JH

That's wrong - it's got absolutely nothing to do with the rim diameter -it's all about the load rating (which corresponds to sidewall stiffness).

The correct rule is: Adjust the OEM recommended PSI pressures by subtracting the load rating of the new tire from the load rating of OEM new tire.

Examples:

if the OEM tire is 109S and the new tire is 112V, and the OEM pressure is 29PSI:

109 - 112 = -3

29PSI - 3 = 26 PSI

If the OEM tire is 112H and the new tire is 111R, and the OEM pressure is 32PSI:

112 - 111 = 1

32PSI + 1 = 33 PSI.

If you didn't swap your spare tire, you should be able to look at it to determine the OEM load rating that corresponds to the vehicle manufacturers recommended pressures.

Very interesting.

Works out 35psi.

Many thanks.

JH

[beano2274]

Different pressure if you fill with Air or Nitro.

[Jebhead]

Different pressure if you fill with Air or Nitro.

Enlighten me.....

JH[/i]

[transam]

Different pressure if you fill with Air or Nitro.

Enlighten me.....

JH

He means Nitrogen, not the BOOOOOOOOOOM Nitro.

[Jebhead]

Different pressure if you fill with Air or Nitro.

Enlighten me.....

JH

He means Nitrogen, not the BOOOOOOOOOOM Nitro.

I understand what he means, but a tonne of feathers is the same weight as a tonne of lead, so how does 35psi of nitro differ from 35psi of compressed air? Enlighten me......

Thanks

JH[/i]

[beano2274]

there is a small difference in the pressure in your tyres when filling with Nitro, mine used to have 30psi, now with nitro 32psi.

Am not a techie person, but when I bought them the guy told me to fill them to that pressure and keep it at that, maybe google might help you.

[funcat]

...so what is the "real" difference between the "air" and "nitro"...???

[rizla]

...so what is the "real" difference between the "air" and "nitro"...???

Nitrogen ( N2) is an inhert gas and doesn`t expand as much as air under temp rise...it is far more stable and normally doesn`t contain as much moisture as air....it is more heavy than air too, so dont breathe it in as you WILL die, floods your lungs and oxygen cant get in.....

Oops, or do you mean Nitro ?????

[MoonRiverOasis]

i have gone from 17" ( recommended 29psi ) to 22"

Works out 35psi.

If your new load index is a full 6 points lower than than OEM tires, I would be very concerned that you've got an unsafe fitment (it sounds like you have a passenger car tire on an SUV or pickup).

Have a look at the table here to see how the load index corresponds to the weight rating of the tire: http://en.wikipedia....code#Load_index

6 points lower load index means between 150-210KG less weight capability per tire, so 600-840KG less vehicle weight safely supported.

Normally you wouldn't go down on load index, you'd either keep it the same or perhaps go up. I'm never going to hit the maximum GVM of the car, so I normally try to keep it in the -1 to +3 range, if you're perhaps going to have a full load on board, use a 0 to +3 range when buying tires.

If above +3, the tire is so far out of original spec that pressures would have to be dangerously low to maintain any ride quality.

Edited November 14, 2011 by MoonRiverOasis

[ignis]

recommended tyre pressures on my pickup says 32, [245x16] this is what I put in, very good ride and handling, yet often see Vigo's at the air pumps putting in 45 all round notice most are 225x15.

Is this the recommended tyre pressures for a Vigo ? or recommended tyre pressures to tip over

[transam]

recommended tyre pressures on my pickup says 32, [245x16] this is what I put in, very good ride and handling, yet often see Vigo's at the air pumps putting in 45 all round notice most are 225x15.

Is this the recommended tyre pressures for a Vigo ? or recommended tyre pressures to tip over

Vigo 265/70x16 have 29psi all round. If you run 45psi you will wear the centre of the tyre out in short order and have a bumpy ride.

[MoonRiverOasis]

recommended tyre pressures on my pickup says 32, [245x16] this is what I put in, very good ride and handling, yet often see Vigo's at the air pumps putting in 45 all round notice most are 225x15.

Is this the recommended tyre pressures for a Vigo ? or recommended tyre pressures to tip over

I bet if you read the sidewall of their tires it'd say words to the effect of "maximum inflation pressure: 45 PSI" - which is what you'd put in if you were going to leave the car in storage (so the tires stay round), but not what you put in if you're going to be driving it...

[ignis]

recommended tyre pressures on my pickup says 32, [245x16] this is what I put in, very good ride and handling, yet often see Vigo's at the air pumps putting in 45 all round notice most are 225x15.

Is this the recommended tyre pressures for a Vigo ? or recommended tyre pressures to tip over

I bet if you read the sidewall of their tires it'd say words to the effect of "maximum inflation pressure: 45 PSI" - which is what you'd put in if you were going to leave the car in storage (so the tires stay round), but not what you put in if you're going to be driving it...

No it is when I am waiting to use the air pump, there always appears to a 'Normal' single cab or Ext cab Vigo and they set the monitor to 45

[transam]

recommended tyre pressures on my pickup says 32, [245x16] this is what I put in, very good ride and handling, yet often see Vigo's at the air pumps putting in 45 all round notice most are 225x15.

Is this the recommended tyre pressures for a Vigo ? or recommended tyre pressures to tip over

I bet if you read the sidewall of their tires it'd say words to the effect of "maximum inflation pressure: 45 PSI" - which is what you'd put in if you were going to leave the car in storage (so the tires stay round), but not what you put in if you're going to be driving it...

No it is when I am waiting to use the air pump, there always appears to a 'Normal' single cab or Ext cab Vigo and they set the monitor to 45

Had a pucture fixed on the PCX, 60psi

Edited November 15, 2011 by transam