Air Pressure for better fuel efficiency

[SuperSafari]

Hi All,

I have a 2021 Y61 Patrol; the advised air pressure for each of my tires as printed on the driver's door are 29/32 psi for front/rear tires. This is my first off-roader/4x4 vehicle, so Im trying to understand how to get the best fuel efficiency from it.

When looking at the front and rear tyres, they look like they could use some air as the bottom portion of the tyre is a bit flattened out (similar to a tyre lacking air). Is this normal for such offroaders, and since I mostly use it as a daily for highway driving 99% of the time, should I try to increase the pressure for both front and rear tyres?

Cheers.

 

[CTL]

29/32 is for comfort and NVH levels.
Try going up to 34/36 and see if you can deal with the slightly harsher ride. Tyres will wear better

 

[SuperSafari]

29/32 is for comfort and NVH levels.
Try going up to 34/36 and see if you can deal with the slightly harsher ride. Tyres will wear better

Thanks for the info; how can I be sure that the tyres will wear better at 34/36? Is there an upper limit for air pressure on those tyres? Im just a bit reluctant because that will be going against the recommended pressures by Nissan.

Moreover, is there an upper limit of pressure where there will be some sort of diminishing returns when it comes to tyre wear (the higher you go the more the Tyres will wear?)

Thanks in advance.

 

[Triton14]

For on road as your vehicle weight increases so should your tyre pressure incrementally.
If your unladen & running higher pressures you will have less contact with the bitumen which can be dangerous & cause uneven wear in the middle of the tread, to low a pressure & you will again have uneven wear on the outside of the tread.


What is on your driver's door is a standard/guide for the vehicle off the factory floor.

From there the user needs to adjust accordingly.

 

[cam04]

Look up your tyres on the tyre and rim association inflation tables and you’ll see how pressure varies according to load state. Tyres will wear better at anything up to 40 psi for your owners p metrics - and use much less fuel.

 

[dabbler]

The advice above is good and sometimes it takes a few runs under similar conditions to work out a new vehicle's foibles.

Don't forget your right foot controls fuel consumption. Moving to a heavy 4x4 will almost certainly need a change in driving style if you want to manage fuel consumption.

 

[Les PK Ranger]

It's quite normal for the bottom tyre profile to look a little less than the top, gravity
A lot depends on brand too, sidewall height, and stiffness of the sidewall (LT tyres etc can vary in ply # and build strength).

If your wheels are stock size rims and tyres, as per the placard is usually about right for general driving.
You can put a few extra PSI in for bitumen driving, especially if the tyres look a little arched upward in the middle, or the rears if under any sort of great extra load can also have more put in, maybe 4 or 5 PSI extra for a start ?

You don't want them overinflated (wear in centre) or underinflated (wear on the inside and outside edges).

If you wheels have been upgraded in dia, maybe wider tyres, the placard info is no longer right for your setup.
You need to talk to the tyre maker perhaps, and ask their opinion.

Or, maybe try the 4PSI rule.
This is something 4WDrs (and general auto owners) either believe helpful or not, but it was pretty accurate for my Ranger stock rims and tyres when I had it . . . monitored with a TPMS on trips with various pressures on bitumen, gravel etc.

the 4PSI Rule

While some people do not believe in the 4psi rule it seems in recent times there are a growing number of companies who use the method.

www.tyrereview.com.au

 

[SuperSafari]

Cheers for all the input guys, much appreciated!

 

[G_ute]

I guess the chalk test is not the best for economy but is is about tyre wear and comfort.

E.g.

99% highway in a thirsty 4x4 Patrol. There's your problem.

 

[aaDam2789]

Best advice i got was fill it up cold and take it for a drive. the tyre pressure is perfect if the warm pressure is 3-5psi more than the cold pressure. More than 5psi change means they're a little flat and need a top up. Less than 3psi change means they're too full

 

[Gracowha]

Similar to above, the 4psi trick is how I work. I heard that is more of a truckie thing but works well for whatever load, or lack of, you are carrying. https://www.tyrereview.com.au/tyre-advice/the-4PSI-Rule I also run a OBD2 tyre pressure monitoring system which makes it easier to track.

 

[Albynsw]

Similar to above, the 4psi trick is how I work. I heard that is more of a truckie thing but works well for whatever load, or lack of, you are carrying. https://www.tyrereview.com.au/tyre-advice/the-4PSI-Rule I also run a OBD2 tyre pressure monitoring system which makes it easier to track.

That tyre review article is wrong. Your tyres can go up that much just sitting in the sun stationary. As I understand it you are meant to use warmed up tyres as your baseline ie drive for 10-15 minutes and then record the pressures as your baseline

 

[aaDam2789]

That tyre review article is wrong. Your tyres can go up that much just sitting in the sun stationary. As I understand it you are meant to use warmed up tyres as your baseline ie drive for 10-15 minutes and then record the pressures as your baseline

nah mate baseline is cold psi. So it's good to measure first thing in the morning. Also, they will heat up a whole lot more in 30-60 mins of driving than in 10-15 mins of sun. Besides, the sun is going to be significantly blocked because its under a car

 

[aaDam2789]

Hi All,

I have a 2021 Y61 Patrol; the advised air pressure for each of my tires as printed on the driver's door are 29/32 psi for front/rear tires. This is my first off-roader/4x4 vehicle, so Im trying to understand how to get the best fuel efficiency from it.

When looking at the front and rear tyres, they look like they could use some air as the bottom portion of the tyre is a bit flattened out (similar to a tyre lacking air). Is this normal for such offroaders, and since I mostly use it as a daily for highway driving 99% of the time, should I try to increase the pressure for both front and rear tyres?

Cheers.

also you'll need different tyre pressures when you're loaded fully vs just doing city driving. It's not obvious to everyone. But city driving when you might have nothing in the boot you might even find front/rear pressures can be almost the same as each other. When you load it up for a trip though with possibly a couple hundred kilos including passengers, you'll want an extra 5-10psi in all your tyres especially the rear

 

[Hoyks]

Thanks for the info; how can I be sure that the tyres will wear better at 34/36? Is there an upper limit for air pressure on those tyres? Im just a bit reluctant because that will be going against the recommended pressures by Nissan.

Moreover, is there an upper limit of pressure where there will be some sort of diminishing returns when it comes to tyre wear (the higher you go the more the Tyres will wear?)

Keep in mind that Nissan are in the business of selling cars, not tyres.
The vehicle comes from the factory with a road biased tyre that handles reasonably well on road, but is too lightweight construction for off road work, will wear out pretty quickly (stuffed by 40000km isn't unusual) and is built to a price to keep production costs down.
The pressures indicated are to maintain reasonable handling and a comfortable ride, they don't give a rats if the tyres wear out and you get 25L/100km, as by that stage they have your $$ in the bank.

There is an upper limit, where the tyre is inflated to the point that the tread face isn't flat anymore and you get excessive wear in the middle of the tread (rather than even wear at optimum pressures or wear on the sides of the tread if a bit low) and the contact patch is reduced. The tyre will roll with a lot less resistance and generally be cooler, but get far less grip than it should, will be a handful in the wet and won't stop anywhere as well as it should.
Its finding that Goldilocks zone thats the fun bit.

The max inflation limit should be molded into the side wall and will depend on tyre construction, but is probably around the 50psi mark for passenger cars.

 

[Les PK Ranger]

I also run a OBD2 tyre pressure monitoring system which makes it easier to track.

Really some sort of TPMS is a must now to watch tyre health, particularly on 4WD trips.
Almost as required as a dashcam (or two) !

I had the heavy duty digoptions kit with extra sensors for the spares, so I didn't even have to wind down the spare underneath, or check the 2nd spare on trips strapped to the roof rack.

Also had an extra 2 sensors for the camper trailer I planned to build one day.
All my rims had 2 valves, one for the permanent TPMS sensors, another for the very common airing down and up on trips.

 

[Albynsw]

nah mate baseline is cold psi. So it's good to measure first thing in the morning. Also, they will heat up a whole lot more in 30-60 mins of driving than in 10-15 mins of sun. Besides, the sun is going to be significantly blocked because its under a car

I said drive for 10-15mins not sit in the sun
If you run a TPMS system you will see how flawed or overly simplistic the 4psi rule is. The ambient temperature from morning to the heat of the day can be easily 25 degrees plus which has a significant impact on your tyre pressure readings even if you don’t use the vehicle, I can record a 2 psi difference with my tyre pressures with the sun on one side of the vehicle in the afternoon western sun whilst driving
Further to that this 4 psi guide is a guide for passenger tyres.

https://www.coopertires.com.au/media/1400/cooper-drivers-guide-tyre-pressures.pdf

I have been using TPMS for about 400,000 Klms and you soon work out that whilst it is a nice guide the tyre pressures and temperatures are much more dynamic than you first realise

 

[SuperSafari]

Why do front tyres have pressure lower than the rear? Is there a reason for that? Can I fill all tyres equally?

 

[linuxfan66]

Why do front tyres have pressure lower than the rear? Is there a reason for that? Can I fill all tyres equally?

weight isnt same front and back. in some towing setups you put the caravan/camper, front tyres, and rear tyres on different pressures.
it may also be for ride quality

 

[Batts88]

Best advice i got was fill it up cold and take it for a drive. the tyre pressure is perfect if the warm pressure is 3-5psi more than the cold pressure. More than 5psi change means they're a little flat and need a top up. Less than 3psi change means they're too full

There's usually more to it like the ambient temp, rainy weather which also effects the road temp and tyre pressures. If Iwas in a cold climate and the temp went down or only rose 1 deg I'd be constantly stopping to pump them up then they would end up over inflated. Same can happen in hot weather in reverse so usually each vehicle has its own happy medium but not everyone cares about tyre pressure so quite often a tyre outlet can help a lot as well.