Hi Zeng,
1) 185/55/15 82V. Front 220 kpa Rear 220 kpa

2) 175/70/13 82H. Front 210 kpa Rear 210 kpa Now using 175/65/14 82H

3) 185/65/15. 88H Front 230 kpa for up to 3 persons, 230 kpa for 4 persons or more. Rear 210 for up to 3 persons, 300 kpa for 4 or more persons.

Brand of tyres: GY

How much can I inflate those tyres above? Hope to hear from you.

This post has been edited by BravoZeroTwo: Apr 4 2019, 12:38 PM

300kpa? Those 4 person hulk ka?

It was stated at the sidebar of the door.

First the tables for Load Index 82/88 and speed rating H/V :




Car 1) 185/55/15 82V. Front 220 kpa Rear 220 kpa
Reading from Table 1,Load Index 82 at 220 kpa : load is 430 kg per tire.
Front axle:860 kg
Rear axle :860 kg
Total load on all 4 tyres :1720 kg ...... as designed by car OEM.

Now , from the perspective of GY manufacturer, this 82V tyre can carry up to 475 kg per tyre at a pressure of 250 kpa.
Maximum load on all 4 tyres would be 1900 kg.

Now, refer to Table 3:
This 82V tyre at a pressure of 280 kpa allows you to drive at higher road speed up to 210 km/hr and, reduced load from 220 - 240 km/hr.

In conclusion , IMHO, GY manufacturer is allowing you higher pressure of 280 kpa carrying full load of 475 kg per tyre up to a max road speed of 210 km/hr.Reduced load thereafter from 220 to 240 km/hr.

Car 2) 175/70/13 82H. Front 210 kpa Rear 210 kpa Now using 175/65/14 82H
At 210 kpa, these 2 tyres (82H) allows for 415 kg per tyre.
Hence total load on 4 tyres as designed by car OEM is 415 x 4 equals 1660 kg.
Maximum tyre load permitted by GY at 250 kpa is 475 kg per tyre.

Again, GY allows tyre pressure of up to 280 kpa at a road speed of 210 km/hr, not beyond please note.

Car 3) 185/65/15. 88H Front 230 kpa for up to 3 persons, 230 kpa for 4 persons or more. Rear 210 for up to 3 persons, 300 kpa for 4 or more persons.

Now this is interesting as there is discrepancy here.
With a recommended 300 kpa for 4 or more persons at rear axle , you are not supposed to use 88H tyres as it's limited to 280 kpa.
This is based on the assumption that the car OEM has correctly recommended 300 kpa on it OEM tyres , which are probably rated at W or Y.
If my assumption is correct, then you have wrongly swapped W or Y tyre of OEM to a H replacement tyre.
Can you clarify this ?

This post has been edited by zeng: Apr 4 2019, 03:01 PM

Can you snap a picture whether W or Y is indicated and upload here please ?

Hi Zeng,
For tyre no.3, the original tyre was Continental CC5. I rechecked again for tyre pressure at the rear is 300 kpa, 3 bar or 44 psi. Don't know why so high.

If your car OEM has correctly specify 300 kpa for rear tyre, then the OEM rear tyre (that comes with the new car) could not be 88H 185/65/15 ..... as H has a manufacturer limit of 280 kpa.
Can you kindly check your door side pillar sticker or owner manuals where W or Y tyre is specified and not H tyre ?

However, if the original rear tyre was 185/65/15 88H, then I am afraid OEM has not complied with tyre Standards with its recommendation of 300 kpa on an 88H tyre, IDK.

This post has been edited by zeng: Apr 4 2019, 03:24 PM

Pillar sticker stated as above. Will refer to user manual for reconfirmation and let you know.

In this event, I hate to say 300 kpa recommendation is a blunder, big time from car OEM.
User manual may or may not have such details.
Generally pillar sticker should be reliable on recommended tyre pressure and tyre specifications.

Just checked the user manual, no information on tyre pressure. Asked to refer to tyre placard at door pillar for technical details. In this case, how much kpa should I inflate my rear tyres ? Thanks.

Hi bro, may i know which car ? Or lorry ? Please share =)

Does the user manual or placard shows tyres being H, W or Y tyre AND is the Load Index 88 or higher?
What about a picture of your pillar placard ?

This post has been edited by zeng: Apr 4 2019, 10:31 PM

It says 88H on both user manual as well as placard at pillar.

Please find attachment. Thanks.


Attached thumbnail(s)

So it says 88H tyres clearly on pillar placard.
Hence, you'd correctly used the 88H tyres here.
As to recommended tyre air pressure:
280 kpa would be in compliance with tyre manufacturers/Standards Organisation, OR
300 kpa would comply with car OEM (???*which had no professional basis ,in a way) but non-compliance with tyre Standards Organisation.

This post has been edited by zeng: Apr 6 2019, 10:15 AM

IMHO, 280 kpa in compliance with tyre Standards Organisation at maximum load of 560 kg/tyre.
At 300 kps- it's non-compliance with tyre manufacturer/Standards Organisation AND it isn't designed for loads higher than 560 kg.

This post has been edited by zeng: Apr 6 2019, 10:15 AM

Deleted

This post has been edited by coolkwc: Apr 6 2019, 10:58 AM

What is this tyre Standards Organisation??
BMW engineer cannot be that wrong to specify such pressures.




As long as whatever you put within acceptable range of ABOVE minimum pressure (of car maker's door pillar sticker) and BELOW the maximum tyre can take (on tyre sidewall) is OK
Just that the car maker's sticker is GENERALLY on the SOFT (COMFY) side and NOT FUEL SAVING
For high speed wangan runs or full load (cargo/human) GENERALLY one can go higher pressure for LOAD (and side benefit of FUEL SAVING).


This post has been edited by ceo684: Apr 6 2019, 11:10 AM

https://www.etrto.org/Publications/Available/Standards-Manual


BMW engineer may not be wrong, only IF BMW of appropriate department in Germany/UK/Malaysia.... had consulted it's OEM tyre manufacturer, is it Michelin, or Dunlop .... or Goodyear .... and is it from Europe or UK or Japan or Malaysia or ... ???
Next question: is that OEM tyre manufacturer factory is based from Europe, or Malaysia.... or Singapore ????

What if OP current Goodyear is not the same manufacturer as OEM tyre manufacturer say, from Europe/Japan ....Does this GY manufacturer (from Indon or Thai or Vietnam) gave similar clearance on say 3.0 bar or 3.1 bar .... as from OEM tyre manufacturer from Europe/Japan ?????? Any guarantee saying so ??????IDK.

Edit:Btw, we are here talking strictly about OP's passenger car standard load summer tyres. It's not about XL/Winter/temporary T/run flat/LT etc tyres..... if you know what I mean.

Edit2:Is it mentioned somewhere in user/owner manual that this is for "high speed or competition use only" or something to that effect ?
I'm curious on this vis-a-vis tyre manufacturer 'agreements/approvals' or whatever .(.... where summer tyres W/Y is rated at 310 kpa and above?)

This post has been edited by zeng: Apr 7 2019, 09:53 AM

Should I highlight this 300 kpa issue to the our local distributor ? Not sure if I will get an answer as so far no one has ever brought this up.