Understanding Tyre Pressure Table

[ali.mkhm]

Hi guys,

I am trying to understand the suitable tyre pressure for my Qashqai (2018 ST-L). But I don't quite understand the table, it varies based on the code on the left like 215/65R16 98H, what does it mean? How do I find out which one is mine?

Thank you.

[Zooksport]

look at the tyres fitted to the car, the size should match 1 of the choices on the label.

Then the top section is for light loading, 1 or 2 people, and the lower section is for when you're off on holidays with lots of suitcases and 4 or more souls in car.

Check pressures once per month, should be fine, although some do the check weekly, or every tank of fuel. If you have pressure monitoring, you can wait till an indicator says they are low, but I always have recommended monthly.

Don't neglect the Spare. It will lose air too, and probably doesn't have a monitor.
.

[ali.mkhm]

Hi Zooksport,

Thanks for your reply. Can't believe I missed that lol. Just to confirm, attached are from my tyres, so it means they are "215/55 R18 XL" right?

[ali.mkhm]

Just wondering why there's a significant difference between light load ({30}) and heavy load ({38})..

[Zooksport]

Yes, 215/55R18, after that should be 99V. 99 is the load carrying capacity of the tyre, (in this case 775Kg per tyre) and 240Km/hour max speed. Don't throw it off a cliff to test this, just take our word for it, OK?

Xtra Load tyres have stiffer sidewalls. By suggesting a lower pressure, they attempt to retain a comfortable ride. I personally, if it were my car, be running 35psi all round, along with tyre rotations every 5000 miles or so.

Shoulder wear due to under inflation, never resolves itself simply by over inflating the tyres, but centre tyre wear, due to over inflation, can be stopped, by running the tyres at lower subsequent pressures. (never below recommendations.)

Best result, and maximum tyre life, can be achieved through diligence. Regularly inspect your tyres for unusual wear. Use a ruler, or buy a Tread depth indicator, (a couple dollars) to monitor tread depth in each groove across the tyre, in at least 2 places.
Unusual is anything differing from a new tyre. Rotating the affected tyres away to the opposite corner, or the other end, MAY resolve the unusual wear. (directional tyres will have to be remounted to suit opposite side of car)

Consider applying the 4psi rule, although difficult to determine in very cold climates. https://www.tyrereview.com.au/tyre-advice/the-4psi-rule, The process is quite reliable.

Generally, a tyre that looks visually under inflated is likely to be less than half its ideal pressure, and that can seriously affect the durability of the tyre.



.

[ali.mkhm]

That was a lot of useful information buddy, thanks a lot. Yea, going 35 makes sense. I bought this car new and has ran for 5000km so far (for 8 months), perhaps I should soon perform a tyre rotation.

I'm really a newbie with car technical, and there were many concepts in your reply that I am not familiar with. Will study them all and ask you guys again if I have questions.

Thanks again

[DaveBerlin]

Zooksport, it Looks like you were or are in the Tyre Game, nice Information ! - Thanks also Dave

[Zooksport]

Experience: 12 years retreading, then 5 years selling and fitting for other blokes, then 14 years in my own tyreshop, selling and fitting. Tyre repairs in car and truck and OTR all the way through. Me and only 1 other person in the state at the time (2001), were certified to repair Michelin UHP tyres.

Still in the game. Doing TyreFill now. Puncture proofing tyres for mining.