P-rated tires vs LT-rated tires for TV

[ChooChooMan74]

When buying my latest tires, I was in the hunt for LTs, but there were VERY FEW 245/70R16 LTs on the market (slightly oversized tire for my vehicles stock tire of 225/75R16). I decided to go with XL P rated tires. Big difference over the stock "economy" tires. Still got a little jello feeling, but towing less than 10% of the miles that I put on yearly, I didn't feel the need to get the LTs.

[Tireman9]

Originally Posted by chriscowles

In switching from P tires to LT LR E, should I having any concerns about the capacity of the 17" alloy wheel to withstand the max inflation pressure of the LR E tire? The only guidance I can find is the door sticker which, of course, recommends pressures intended for a soft ride in a passenger vehicle.

I looked on the wheel itself but found nothing. Web searches also are fruitless. Is anything stamped on the inside of the rim, typically?

Chris Cowles
Gainesville, FL
Former pop-up owner
Hybrid owner wannabe

Many times Aluminum wheels have the load and inflation limits cast on the back side of the spokes. Probably nothing in the air chamber. You should be able to get the specs from company that sold you the wheels.

[chriscowles]

The wheels are OEM. I can't find anything from Dodge, except the inflation recommendations on the door jamb.

I already dismounted one of the wheels, washed off the road grime, and inspected it closely. I found nothing. I guess I can look again on a different wheel but I don't expect to find anything.

Chris Cowles
Gainesville, FL
Former pop-up owner
Hybrid owner wannabe

[Tireman9]

Originally Posted by chriscowles

The load ratings I cited are from a retail web site listing the rating of specific tires they have available at prices that don't give me angina. Some are 110, others are 112. I got the capacity attributed to the load rating from a table on another retail site, probably TireRack.

I didn't get anywhere that a 112 is rated for towing, but the tow ratings specified by Dodge on the door sticker and replicated here assume OEM Goodyear rated at 108. For me to upgrade to 112 can only be an improvement. No, I don't think Dodge has my best interests at heart.

The bottom line is that I need/want to upgrade the tires on my Durango which, for now, is my daily driver. I'd rather not ride on tank treads but will do what is necessary to tow safely. If that means Load Range E truck tires, so be it.

The OEM tires are 245/70. I can change to 265/65 without affecting the speedometer or ignoring the design assumptions of the differential.

I won't be dragging the Queen Mary behind me. I plan to buy a trailer having GVWR < 5000# which means the tongue weight would be 750# at worst.

Advice?

Tire load capacity (either in pounds as found on tire sidewall and in tables or the Load Index) is not a tow rating. It is the load you would get when you are on a scale.

If you have a 5th wheel that puts extra load on the pickup then you need to measure the load on the tires while hooked up with your fully loaded trailer.

For ballpark what is your actual rear axle load with full tank of fuel? Add 750# to that and that is the total load your rear tires must carry. A recommendation is to have at least 15% more load capacity than you expect to need.

[JWHybrid2B]

Originally Posted by chriscowles

What is your TV?

Chris Cowles
Gainesville, FL
Former pop-up owner
Hybrid owner wannabe

2004 Toyota 4Runner Limited 4x4 4.7 liter V8 w/tow package 7,000lbs tow capacity.

[chriscowles]

It's unusual, but they list neither the GVWR nor the GCVWR in the manual. They do list the cargo capacity.

[JWHybrid2B]

Originally Posted by chriscowles

It's unusual, but they list neither the GVWR nor the GCVWR in the manual. They do list the cargo capacity.

Weights and Capacities
MAXIMUM TOWING CAPACITY** 7000 lbs. MAXIMUM PAYLOAD** 1215 lbs.
GROSS WEIGHT 5710 lbs. CURB WEIGHT 4495 lbs.

** When adequately equipped, which may require engine and/or other drivetrain upgrades.

[JWHybrid2B]

I finally found the GCVWR for my vehicle. Says 12,000 lbs. I just weighed both TV and TT and it was 10,220 lbs, so I don't have much left to hit the limits. I am supposed to deduct 9% from the 12,000 =10,920 lbs because I have "P" rated tires.

[Tireman9]

Yes, whenever P type tires are used on trucks, SUV or trailers they MUST be de-rated by 9%.

[Happy Vibe]

If the SUV came stock with P rated tires and the manufacturer says what the GCVWR is why do you need to reduce it by 9%?

[Tireman9]

Originally Posted by Happy Vibe

If the SUV came stock with P rated tires and the manufacturer says what the GCVWR is why do you need to reduce it by 9%?

It's not the vehicle capacity or GVWR that is to be reduced. It is the tire load capacity you see in tables or molded on the tire sidewall that is reduced.

Tire capacity should exceed the actual load so in your case the actual load needs to be less than (tire capacity-9%).
This is by axle when you have GAWR which should be on a certification label or you should be able to get this from your vehicle dealer.

You cannot take the total capacity of all 4 tires and compare with the total vehicle weight as the weight is not equally distributed F&R r & L

[Happy Vibe]

But jwhybrid2b just took the GVWR and reduced it by 9% I don't see were he states his max tire load? If his tires are rated for 9% over his GVWR or GAWR which ever is closer to the max tire load, than he does not need to reduce his GVWR.

[Old Bones]

Just had LT 'E' load range tires put on today. Truck definitely feels more solid to the ground in comparison to the P rated tires that were on there originally.

Looking forward to feeling the difference when hauling the TT.