Tyre pressure

[Kklee]

Lower

 

Ok.  Thanks.

[Roberttan]

For changing tyres,  if not possible to get the same load index, it should be higher, not lower.   Lower would mean the max load is reduced.

sorry no offence

as written low load index the Max load is lower ( that's correct)

let me quote you an example

your Original Load index 88 = 560kg(per tire) x 4 = 2240kg= can carry max car total weight.

Ideally any tire or size change you best follow this 88 as reference

Should you put a tire with Load index 86=530kg(per tire) x 4 =2120kg , if you are very very sure your Max load does not exceed 2120kg you are Fine (but do remember to achieve the Max load you are require to fill your tire at Max Pressure (tire) which will be quite harsh ride.

I am open and do share your view

BUt that is issue insurance and warranty , any expert here can share  

thanks

[Enye]

load index simply indicates the max load per tire 

 

why would it affect the tyre pressure recommended by the manufacturer?

 

carry heavier load or travel long distance just put in higher tyre pressure as recommended by manufacturer

 

if you change to a lower load index tire, just make sure the total weight of car would not exceed the load rating

 

 

 

[inlinesix]

load index simply indicates the max load per tire 

 

why would it affect the tyre pressure recommended by the manufacturer?

 

carry heavier load or travel long distance just put in higher tyre pressure as recommended by manufacturer

 

if you change to a lower load index tire, just make sure the total weight of car would not exceed the load rating

 

 

http://www.mycarforum.com/topic/1301436-an-interesting-article-on-air-pressure-load-index/

[inlinesix]

sorry no offence

as written low load index the Max load is lower ( that's correct)

let me quote you an example

your Original Load index 88 = 560kg(per tire) x 4 = 2240kg= can carry max car total weight.

Ideally any tire or size change you best follow this 88 as reference

Should you put a tire with Load index 86=530kg(per tire) x 4 =2120kg , if you are very very sure your Max load does not exceed 2120kg you are Fine (but do remember to achieve the Max load you are require to fill your tire at Max Pressure (tire) which will be quite harsh ride.

I am open and do share your view

BUt that is issue insurance and warranty , any expert here can share  

thanks

 

This is what i get from owner manual:

195/55 R 16 87 V RSC

195/55 R 16 87 H,V M+S RSC

195/55 R 16 87 V M+S A/S RSC

Pump 33 psi

 

 

205/45 R 17 84 V M+S A/S RSC

205/45 R 17 84 V M+S RSC

205/45 R 17 84 V RSC

205/40 R 18 82 W RSC

175/60 R 16 82 H M+S RSC

Pump 38 psi

[Enye]

http://www.mycarforum.com/topic/1301436-an-interesting-article-on-air-pressure-load-index/

 

my point is ....with a higher load rating tyre at the same oe recommended tyre pressure, the load capacity would be higher than the lower load rating at the same oe recommended tyre pressure

 

why do you want to adjust the tyre pressure downwards on a higher loading rating tyre just to match the lower load capacity of the lower load rating tyre at the oe recommended tyre pressure?

 

unless you find the oe recommended tyre pressure on the higher load rating tyre too hard and uncomfortable for travelling

[inlinesix]

my point is ....with a higher load rating tyre at the same oe recommended tyre pressure, the load capacity would be higher than the lower load rating at the same oe recommended tyre pressure

 

why do you want to adjust the tyre pressure downwards on a higher loading rating tyre just to match the lower load capacity of the lower load rating tyre at the oe recommended tyre pressure?

 

unless you find the oe recommended tyre pressure on the higher load rating tyre too hard and uncomfortable for travelling

 

For my car, minimum pressure is 38psi at load index 84.  That's equivalent to 460kg load capacity.

 

Now, new tyre has load index 88.  If i continue at 38psi, it would be 515kg load capacity.  Why do i need such a high load capacity?

 

I will juz lower it to 33psi to give me the equivalent load capacity.

[Enye]

For my car, minimum pressure is 38psi at load index 84.  That's equivalent to 460kg load capacity.

 

Now, new tyre has load index 88.  If i continue at 38psi, it would be 515kg load capacity.  Why do i need such a high load capacity?

 

I will juz lower it to 33psi to give me the equivalent load capacity.

 

i like my car to be ready to carry full load at all times

 

rather than to make additional effort to visit the air pump whenever a full load or long distance trip is required

 

so i always pump my tires to carry full load at oe recommended tyre pressure

 

each to his own lah

 

  

[inlinesix]

i like my car to be ready to carry full load at all times

 

rather than to make additional effort to visit the air pump whenever a full load or long distance trip is required

 

so i always pump my tires to carry full load at oe recommended tyre pressure

 

each to his own lah

 

  

 

It is ok over maintain the same air pressure at the expense of harsher ride.

 

I check air pressure every month.  Somemore, no need visit air pump.

[Kklee]

sorry no offence

as written low load index the Max load is lower ( that's correct)

let me quote you an example

your Original Load index 88 = 560kg(per tire) x 4 = 2240kg= can carry max car total weight.

Ideally any tire or size change you best follow this 88 as reference

Should you put a tire with Load index 86=530kg(per tire) x 4 =2120kg , if you are very very sure your Max load does not exceed 2120kg you are Fine (but do remember to achieve the Max load you are require to fill your tire at Max Pressure (tire) which will be quite harsh ride.

I am open and do share your view

BUt that is issue insurance and warranty , any expert here can share  

thanks

 

So lower or higher would be more appropriate?

[Kklee]

load index simply indicates the max load per tire 

 

why would it affect the tyre pressure recommended by the manufacturer?

 

carry heavier load or travel long distance just put in higher tyre pressure as recommended by manufacturer

 

if you change to a lower load index tire, just make sure the total weight of car would not exceed the load rating

 

 

IIRC,  the load index indicates the load of the tyre at a corresponding pressure.

Higher pressure equates to less contact with the road.

[Muser]

For my car, minimum pressure is 38psi at load index 84. That's equivalent to 460kg load capacity.

 

Now, new tyre has load index 88. If i continue at 38psi, it would be 515kg load capacity. Why do i need such a high load capacity?

 

I will juz lower it to 33psi to give me the equivalent load capacity.

Afaik, for the same tyre type and size (diameter and width), tyres with lower and higher load ratings can only handle the same load. Only at higher tyre pressures will the additional load rating be utilised. If you upgrade to a totally different tyre type, different story lah.

 

This article explains why, and I've excerpted the relevant section: "The above chart correctly shows that an extra load tire is not rated to carry any more load than a standard load tire when both are inflated to the same pressure (up to the standard load tire's "maximum load" pressure of 35 psi). This is because a tire's load capacity is a function of its size (which determines the size of the "air chamber"), its construction (which determines how much pressure can be held) and the actual air pressure used (which determines how many air molecules are forced inside the chamber). Tires with equivalent physical dimensions typically carry equivalent loads (until they reach their maximum load pressure)." - https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=195

 

IIRC, the load index indicates the load of the tyre at a corresponding pressure.

Higher pressure equates to less contact with the road.

Load index indicates potential max load capacity when higher pressures are used. It doesn't magically increase load capacity if you maintain the same tyre pressure, assuming same tyre type and size with the only variable being load rating.

Edited June 24, 2017 by Muser

[Roberttan]

Afaik, for the same tyre type and size (diameter and width), tyres with lower and higher load ratings can only handle the same load. Only at higher tyre pressures will the additional load rating be utilised. If you upgrade to a totally different tyre type, different story lah.

 

This article explains why, and I've excerpted the relevant section: "The above chart correctly shows that an extra load tire is not rated to carry any more load than a standard load tire when both are inflated to the same pressure (up to the standard load tire's "maximum load" pressure of 35 psi). This is because a tire's load capacity is a function of its size (which determines the size of the "air chamber"), its construction (which determines how much pressure can be held) and the actual air pressure used (which determines how many air molecules are forced inside the chamber). Tires with equivalent physical dimensions typically carry equivalent loads (until they reach their maximum load pressure)." - https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=195

 

 

Load index indicates potential max load capacity when higher pressures are used. It doesn't magically increase load capacity if you maintain the same tyre pressure, assuming same tyre type and size with the only variable being load rating.

my Dear Muser

well said

[Earthboy]

For my car, minimum pressure is 38psi at load index 84. That's equivalent to 460kg load capacity.

 

Now, new tyre has load index 88. If i continue at 38psi, it would be 515kg load capacity. Why do i need such a high load capacity?

 

I will juz lower it to 33psi to give me the equivalent load capacity.

But by doing so will it be under inflated or become too draggy. Only index different same size and profile right?

 

My new Goodyear also has higher rating than stock Dunlop. Although manual recommend 33, I have been doing 35.

[Kklee]

Load index indicates potential max load capacity when higher pressures are used. It doesn't magically increase load capacity if you maintain the same tyre pressure, assuming same tyre type and size with the only variable being load rating.

 

Standard or extra load tyres?

Maybe you have an example to illustrate?

[inlinesix]

Afaik, for the same tyre type and size (diameter and width), tyres with lower and higher load ratings can only handle the same load. Only at higher tyre pressures will the additional load rating be utilised. If you upgrade to a totally different tyre type, different story lah.

 

This article explains why, and I've excerpted the relevant section: "The above chart correctly shows that an extra load tire is not rated to carry any more load than a standard load tire when both are inflated to the same pressure (up to the standard load tire's "maximum load" pressure of 35 psi). This is because a tire's load capacity is a function of its size (which determines the size of the "air chamber"), its construction (which determines how much pressure can be held) and the actual air pressure used (which determines how many air molecules are forced inside the chamber). Tires with equivalent physical dimensions typically carry equivalent loads (until they reach their maximum load pressure)." - https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=195

 

 

Load index indicates potential max load capacity when higher pressures are used. It doesn't magically increase load capacity if you maintain the same tyre pressure, assuming same tyre type and size with the only variable being load rating.

 

Why do my stock tyre has load index of 84 while MIchelin PSS has load index of 88?

But by doing so will it be under inflated or become too draggy. Only index different same size and profile right?

 

My new Goodyear also has higher rating than stock Dunlop. Although manual recommend 33, I have been doing 35.

 

It is not draggy at all.

 

If pump till 38, the ride will be bumpy.

 

[Muser]

Standard or extra load tyres?

Maybe you have an example to illustrate?

This applies to both standard (SL) and extra load (XL) tyres. It's the air that supports the car's weight. The construction of XL tyres merely allows them to support higher pressure (ie, more air) and therefore carry heavier loads.

 

So, all other things remaining equal, an SL and XL tyre can handle the same max load at the same tyre pressure. But the SL load ability maxes out at 36 psi (250 kpa) whereas the XL load ability only maxes out at 42 psi (290 kpa), so even if you inflate an SL tyre to 42 psi, it won't tahan more weight. But if you inflate the XL tyre to 42 psi, it will be able tahan much more weight than an SL tyre of the same type/size.

 

Why do my stock tyre has load index of 84 while MIchelin PSS has load index of 88?

I'm not sure what your question is, bro. Different manufacturers and different tyre models lor. But unless you pump till damn hard (eg, 38 psi in your example), you won't be maximising that load capacity. And at lower pressure, the load capacity of your stock tyres and PSS are identical, assuming they are of the same size.

Edited June 24, 2017 by Muser

[Kklee]

This applies to both standard (SL) and extra load (XL) tyres. It's the air that supports the car's weight. The construction of XL tyres merely allows them to support higher pressure (ie, more air) and therefore carry heavier loads.

 

So, all other things remaining equal, an SL and XL tyre can handle the same max load at the same tyre pressure. But the SL load ability maxes out at 36 psi (250 kpa) whereas the XL load ability only maxes out at 42 psi (290 kpa), so even if you inflate an SL tyre to 42 psi, it won't tahan more weight. But if you inflate the XL tyre to 42 psi, it will be able tahan much more weight than an SL tyre of the same type/size.

 

This is the unconfusing part.  

The confusing part is 

 

Load index indicates potential max load capacity when higher pressures are used. It doesn't magically increase load capacity if you maintain the same tyre pressure, assuming same tyre type and size with the only variable being load rating.

 

Example,

Two Standard tyres

Same size

Same pressure (e.g. 32 psi)

One load index is 91 and the other 94.

The load capacity the same?