Tire Pressure?

[illbenooneelse]

Beach Sand at 30/30 seems higher than suggestions I've seen (closer to 20) but I suppose it depends on the type of sand (wet, packed, hard vs deep dry soft).

You’re right, most seem to run 20psi with some even saying they go as low as 15psi. We load pretty heavy (2 adults, 3 kids, dog, loaded roof and hitch platform) so I’m running really conservative at 30/30 and do my best to stay in the damp pack. For proper suger-sand i’d absolultly consider airing down more... interested in what others think is doable with all the added weight. Rolling a tire off the rim seems like a real possibility.

 

[manoftaste]

...or Americans are so fat that they achieve full load just by being in it...

Ha.

Yeah I vaguely remember the Firestone issue on the media etc.

 

[manoftaste]

Lawyers in the US. The LR rear spec assumes full load. I have noticed this with other European cars. We usead to get a half load and full load air pressure spec. Now? It seems the NA market gets the full load spec only. For me any more than 38 psi in rear results in premature centre wear.

So as far as engineering and optimum driving comfort and safety, how does then LR get away with the difference in the front to rear contact patches size due to the full load spec PSI on the rears but with normal load inside the truck, hence causing varying traction levels between front and rear?

Do they just not care and let that stress on the driveline be whatever amount that may be? Or is it that when they moved to the full spec (to satisfy the lawyers or regulations) they actually made engineering or coding adjustments to compensate?

I mean, I would not even want to waste my time asking any LR Service dept in my area because, I am sorry to say this, they pretty much all are just inept, with interest in only making money. So I doubt they would actually be able to offer any insight in this matter. The only thing I expect from them is them saying that stick to the LR recommendations, so they dont get themselves tangled into any liability issues.

 

[iconoclast]

i dont think one could create a 4%+ difference in overall circumference from rear to front with air pressure. i would not worry about drive train damage because you have x amount in the rear and y amount in the front. if anything you would notice uneven tire wear before you have damage to the diff.

 

[manoftaste]

In my case the ride of the LR4 is much better at "proper" spec than when having the tires inflated as if it was fully loaded (ie. towing).

For me the goal is ride/tread wear. I keep airing down until I get a nice consistent wear pattern across all four tires. In the odd scenario where I am fully loaded (7 people, and ski box and/or towing then I air up to 42 in the rear and leave front at 36.

Curious what year is yours?

 

[manoftaste]

i dont think one could create a 4%+ difference in overall circumference from rear to front with air pressure. i would not worry about drive train damage because you have x amount in the rear and y amount in the front. if anything you would notice uneven tire wear before you have damage to the diff.

Sure. But I was more curious about the size of the contact patch than the circumference.

I have aired my rears down to 41.5, but judging by the fine dust in my parking area picked up by the tread, there is still quite a bit of difference between the fronts and the rear. The dust hasn't fully covered the entire tread edge to edge yet, the way the fronts do. I will keep airing them down step by step till I get the dust to cover the entire tread inside to outside edge, mimicking their edge to edge reach on the fronts, and then see what that PSI number comes up to.

The above process of matching fronts and rears contact patches with dust would be sort of my layman's way of figuring out the correct rear PSI for the Normal load.

And could it be that the Normal and Full load is now being referred to as the "Light load" and "heavy load" that my MY16 handbook is talking about on its page 240, under a Warning heading:

So tell us Tata/LR, what is that "Light load" setting that you are referring to here? Do you have a recommended PSI number? Or is it that the 43 PSI is your Light load setting? Is it? No? If it is not then what would be your recommended light load setting? And if it is, then what would be your Heavy load setting?

Would your lawyers have the answer, Tata/LR?

Or could it be that being as lazy as you have become over these last few years, this warning paragraph is a carryover by mistake from the older model years and you just did not bother taking it out from your documentation much like you did not bother to update/correct other sections of the handbook like the Tow Hitch/towing section which still carries a few versions old, outdated but "required" measurements for the tow bar, confusing the hell out of your inexperienced customers who actually are trying to stick to your recommendations by purchasing your "Land Rover Approved" overpriced but very cheaply packaged tow bar with a leaflet in its box referring to a different set of measurements. ha. And no supplements with handbook or any other attempts or means to clarify things either.

Since you are pretty strict about your "required" specs in this case, with the fear of going off spec and causing possible damage, something that should have been as simple as going to the dealership and picking up the part, it took pretty much a couple of days of my time to research, online search looking at older version of your tow bar set and by physically measuring bars at U-Haul and at your dealership to figure things out as to why things are not matching up and who/what documentation to believe in and who/what is correct because you know what your dealer' response about towing was, Tata/LR?

Without the slightest exaggeration, this is exactly what your "well-trained and qualified" personnel at Parts and Service had to say: "I have no clue."

Just ridic.

 

[iconoclast]

I think you may be misunderstanding the statement they make. The way I read that image above is saying if you change your PSI you should reset the TPMS for accurate readings. I do not think they are referring to drivetrain damage.

 

[ktm525]

Curious what year is yours?

2010 and it has been really good for tire wear (even, no feathering of edges etc) compared to the LR3 it replaced.

Light Load? I would think about 1/2 payload. A couple people and lots of cargo or lots of people and no cargo. Full load mostly requires that extra 600lbs of tongue weigh unless you are hauling bricks or sand.

 

[manoftaste]

I think you may be misunderstanding the statement they make. The way I read that image above is saying if you change your PSI you should reset the TPMS for accurate readings. I do not think they are referring to drivetrain damage.

I dont think that they are referring to drivetrain damage either.

I totally understand why the TPMS would need to be reset, and they are wise to mention that. It sure does need to be reset if you set your rears PSI levels to 39 or 40 PSI vs the 43 PSI listed on the label.

What I am saying here is that there is no mention anywhere about the light load and the heavy load PSI levels. They just give us one value for fronts and rears. But by mentioning of inflating tires to "Light load" and "Heavy load" settings, they are leaving the owners a bit confused. Here is why:

If I am being told to set my PSI to 37 front and 43 rear, are these Light load settings or Heavy load settings?

And I were to guess on my own and assume the front's 37 PSI is High load setting, would the light load setting for the fronts be less than 37 PSI?

And if the 37/43 are Low/High load settings respectively, than during full pay load am I to increase the fronts PSI levels as well?

Now, coming from LR3 and then having owned '13 LR4, I and some of us here could understand that 43 PSI most likely is the High load value. And knowing the LR3' 33 front/36 rear for normal load and the 33 front/42 rear for high load math, we are kinda guessing that even under High/Full load we are not really to mess with the front PSI levels of 37 (36 incase of v8 models I guess) and leave the front value as is.

But when LR does not mention anything about the Normal/Full load anymore and then and the same time also tell us that TPMS may need to be adjusted if we are inflating tires to Normal/Full load settings, they are not only confusing the hell out of the owners, specially the new owners with no prior history with LR3/4, but more importantly they are only and only making sure that they have zero liabilities cuz "we told ya so". Hence the reasoning for this particular para in handbook.

And/or LR is simply making sure that if the informed long time owners are finally able to figure out that this 43 PSI (42 in case of v8) is actually a High/Full load value and if they ever decide to figure out and deflate their rear tires to a Normal/Low load setting, lets just make sure to leave that little paragraph in there reminding them to reset their TPMS so we dont have any liabilities since we are not giving them the correct Normal load value this time around to simplify things for the soccer moms.

 

[manoftaste]

Light Load? I would think about 1/2 payload. A couple people and lots of cargo or lots of people and no cargo. Full load mostly requires that extra 600lbs of tongue weigh unless you are hauling bricks or sand.

Interesting cuz I was thinking of Light/Normal load to be just the driver and a full tank of gas, and the Full/High load to be the maximum payload whatever it is for each model year, for my '16 its about 1488 Lb. And LR usually assumes the driver' weight to be 165 Lb (per their LR4 brochures).

And I am not quite sure if the 550 Lb tongue weight is really included in the maximum payload value of around 1488 Lb (lesser number if the truck is optioned up with more optional and production equipment if you want to maintain the total the Gross Vehicle Weight the same as standard equipped model).

Cuz if you take out 550 out of the 1488 Lb (1484 Lb incase of LR4), you are really left with only 938 Lb for all seven passengers with no luggage. Thats 134 Lb per passenger, doesn't make sense. So I am guessing that the 550 Lb of tongue weight has to be outside of the maximum payload.

Noticed that LR stopped mentioning Maximum Payload Weight value in their brochures starting from MY14 (SCV6 versions).