P-rated tires vs LT-rated tires for TV

[rlocicero]

Originally Posted by Happy Vibe

so rlocicero the manufactures are putting trucks on the road that the tires are going to blow if you load them to there max. In my case I do not have a choice but to run P tires as no one makes a tire in my size that is LT rated. So I guess I will not tow my trailer until someone comes up with an LT tire. I have also towed thousands of miles and not had a blowout does that prove that the P rated tires are ok?

In your case you may be ok. Your vibe is a 4700 lb trailer with a 340 lb tongue weight. We have towed tens of thousands of miles without a single tire issue. If I were towing something as small as yours, I wouldn't worry either. All of our trailers have been in the 28' to 32' range and between 6500 and 7800 lbs. All but 2 trucks have been 1/2 ton Fords. I did switch to 3/4 ton Fords for our 5th wheels.
I have also been in the automotive business since 1967 and have dealt with all kinds of tire issues. I still recommend that your factory tires should be upgraded if you are going to be doing some serious towing. That includes thye marginally rated tires that trailer manufacturers use. Both my truck and trailer are equipped with 10 ply rated tires. Trailer sway is nonexistent.

[Happy Vibe]

Well I have been towing the vibe with a minivan for the last two years and I had know sway with that so I KNOW that I will not have an issue with the truck. But as I said with the 20 inch tires on my truck no one makes an LT in that size. I have already up graded the tires on the trailer.

[Tireman9]

Originally Posted by f5moab

Look at the tire placard on the driver side door pillar and that is the recommended tire. And that is the size and type that is safe for up to the maximum load of the vehicle.

P tires can be a somewhat squirmy with a trailer on the back, but that depends on the size of the trailer and if they are SL or XL rated.

MY 2013 Silverado came with SL rated P-rated 275x55 20 tires. I replaced them the first month with a AT tire, same size, P-rated but XL load rating. The SL tires were squirmy, but the XL I have on there now are not squirmy even with a 50 mph cross wind while traveling at about 70 mph on I70.

XL rating also give you a higher load range on the tire and a rougher ride, but not terrible.

I trust you are not towing when driving 70 or that your TT has LT type tires not ST type.

[Tireman9]

JWHybrid2B It would have helped if you had provided the GVWR and the max CGVWR so we would know the weights on your combination.

"P" type vs "LT" type. What are the letters before the numbers in the size? P?, LT? or no letter. If P or no letter they are passenger type. The no letter being European sizing.

If you have P type and there is no "XL" or "Extra Load" they are by default Standard Load.

LT type can be LR-C, LR-D, LR-E etc. with increasing pressure and load capacity.

If a P type tire is used on a "Multi purpose vehicle" (Truck, SUV) or trailer The load capacity is to be reduced by 9%.

I have never heard of anyone being able to "look" at a vehicle and know its weight so you need to get the TV and TT when fully loaded on a scale to know the facts and real numbers. The "Rating" is more than likely been exceeded by 50% of users based on actual data collected in the field.

mlong did you figure out how to read the size & type of your tires?

"I do have P rated tires" P or LT is not a "rating" but a "type"

IMO very few large(18 and up) rim diameters are needed unless you have large diameter brakes ie Corvette. This is all marketing.

[chriscowles]

If I'm reading this correctly my plan to put P265/65R17 tires on my Durango having a load rating of 112 only gets me the equivalent of the current 108s that are mounted on it now. That's with consideration that the 108s are used only for passengers and the 112s being intended for towing. Obviously I should ditch the 108s but the 112s don't seem much better when the capacity reduction is taken into account.

Finding a 245/70 tire with a rating higher than 112 is pretty much impossible without jumping to an LT, load range E. For ride purposes I'd prefer a C or D but I'll do what I must do. The circumference-equivalent 265/65 isn't much better.

What variant of tire size should I consider, to increase the choices available while minimizing the circumference difference? (Changing wheels is not an option.)

[Tireman9]

Originally Posted by chriscowles

If I'm reading this correctly my plan to put P265/65R17 tires on my Durango having a load rating of 112 only gets me the equivalent of the current 108s that are mounted on it now. That's with consideration that the 108s are used only for passengers and the 112s being intended for towing. Obviously I should ditch the 108s but the 112s don't seem much better when the capacity reduction is taken into account.

Finding a 245/70 tire with a rating higher than 112 is pretty much impossible without jumping to an LT, load range E. For ride purposes I'd prefer a C or D but I'll do what I must do. The circumference-equivalent 265/65 isn't much better.

What variant of tire size should I consider, to increase the choices available while minimizing the circumference difference? (Changing wheels is not an option.)

Rather than talking about Load Index maybe it would be better if you talked about the actual load capacity rating for the tires under consideration and the actual loads on the TV with the TT hooked up and loaded.

Don't forget to De-Rate the P type tires by 9% but use the tire max pressure.

Where did you get the 112 is for towing information?

I find a P265/65R17 is rated for 2126# @ 35 psi (2337# derated) and has a Load Index of 110 according to TRA yearbook. Maybe the brand you are considering has an Extra load version.

[chriscowles]

Originally Posted by Tireman9

Rather than talking about Load Index maybe it would be better if you talked about the actual load capacity rating for the tires under consideration and the actual loads on the TV with the TT hooked up and loaded.

Don't forget to De-Rate the P type tires by 9% but use the tire max pressure.

Where did you get the 112 is for towing information?

I find a P265/65R17 is rated for 2126# @ 35 psi (2337# derated) and has a Load Index of 110 according to TRA yearbook. Maybe the brand you are considering has an Extra load version.

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?

[OldCoot]

I would go with at least a LT LR D and lower the pressure when not towing. I use LR E and lower the pressure to 35 front, 30 rear.

[chriscowles]

Originally Posted by OldCoot

I would go with at least a LT LR D and lower the pressure when not towing. I use LR E and lower the pressure to 35 front, 30 rear.

Do you have a specific recommendation for a 265/65 or 245/70, R17? I live in Florida so wet stopping and hydroplaning matter, while ice and snow ratings are meaningless. I do expect to go off paved roads occasionally but the worst will be poorly maintained campground roads, pulling the trailer. I'd like to minimize road noise if practical but I can't have everything.

Do you use an information source to determine that 30# and 35# are the right inflation for your tires when unloaded? Or is that a matter of feel?

Thanks

Chris

[OldCoot]

Originally Posted by chriscowles

Do you have a specific recommendation for a 265/65 or 245/70, R17? I live in Florida so wet stopping and hydroplaning matter, while ice and snow ratings are meaningless. I do expect to go off paved roads occasionally but the worst will be poorly maintained campground roads, pulling the trailer. I'd like to minimize road noise if practical but I can't have everything.

Do you use an information source to determine that 30# and 35# are the right inflation for your tires when unloaded? Or is that a matter of feel?

Thanks

Chris

I use LT245/70 R17 119/116R E WRL SR A OWL TL on my 05 Silverado. The 35-30 is just my preference. I don't drive it much unless it's towing and then they go to 55 front and 60 rear. Truck sits for weeks and sometime months. We snowbird in Davenport, FL from late Nov to mid Mar so we are aware of the wet conditions. No problem.

[JWHybrid2B]

Originally Posted by Tireman9

JWHybrid2B It would have helped if you had provided the GVWR and the max CGVWR so we would know the weights on your combination.

"P" type vs "LT" type. What are the letters before the numbers in the size? P?, LT? or no letter. If P or no letter they are passenger type. The no letter being European sizing.

If you have P type and there is no "XL" or "Extra Load" they are by default Standard Load.

LT type can be LR-C, LR-D, LR-E etc. with increasing pressure and load capacity.

If a P type tire is used on a "Multi purpose vehicle" (Truck, SUV) or trailer The load capacity is to be reduced by 9%.

I have never heard of anyone being able to "look" at a vehicle and know its weight so you need to get the TV and TT when fully loaded on a scale to know the facts and real numbers. The "Rating" is more than likely been exceeded by 50% of users based on actual data collected in the field.

mlong did you figure out how to read the size & type of your tires?

"I do have P rated tires" P or LT is not a "rating" but a "type"

IMO very few large(18 and up) rim diameters are needed unless you have large diameter brakes ie Corvette. This is all marketing.

My tow vehicle GVWR is 5,710 lbs. My towing capacity is 7,000 lbs, but I am not sure what my CGVWR is unless you add the GVWR to the towing capacity which would be 12,710 lbs. I just weighed both TV and trailer and came out to 10,220 lbs with me in the vehicle. I am planning on adding about another 500-600 lbs max. Taking the 9% off the total CGVWR my maximum is 11,556 lbs which I would fall under.

[chriscowles]

Originally Posted by OldCoot

I use LT245/70 R17 119/116R E WRL SR A OWL TL on my 05 Silverado. The 35-30 is just my preference. I don't drive it much unless it's towing and then they go to 55 front and 60 rear. Truck sits for weeks and sometime months. We snowbird in Davenport, FL from late Nov to mid Mar so we are aware of the wet conditions. No problem.

I've searched for 245/70 and 265/65 R17 LR D and can't find any. I do find 245/70 LR E. Looks like that's what I'll be getting. Goodyear Wrangler SR-As and Michelin LTX M/S 2s both are well reviewed by Consumer Reports. They describe the Michelins as having slightly better handling but the Goodyears have better rolling resistance, and they're cheaper at Wally's.

Since I'll still have to drive it around town I suspect I should opt for the better rolling resistance in hopes of slightly better gas mileage. I had considered A/Ts but really can't justify the noise and loss of ride comfort.

[Herk7769]

Originally Posted by chriscowles

I've searched for 245/70 and 265/65 R17 LR D and can't find any. I do find 245/70 LR E. Looks like that's what I'll be getting. Goodyear Wrangler SR-As and Michelin LTX M/S 2s both are well reviewed by Consumer Reports. They describe the Michelins as having slightly better handling but the Goodyears have better rolling resistance, and they're cheaper at Wally's.

Since I'll still have to drive it around town I suspect I should opt for the better rolling resistance in hopes of slightly better gas mileage. I had considered A/Ts but really can't justify the noise and loss of ride comfort.

Love the LTX M/S2 I have had on my truck for the past 3 years. The gas mileage has been good to me and they wore like IRON until I got stuck a once in the Florida sand this winter and I ground off a couple of years worth of rubber trying to get out.

Will be replacing the rear tires with A/Ts this summer I think. The fronts will get them too I guess, eventually they are totally good now, (though I would like to keep the M/S2s there since it is 2x4). Need to look into that some more.

[Sgt. Schultz]

Originally Posted by chriscowles

I've searched for 245/70 and 265/65 R17 LR D and can't find any. I do find 245/70 LR E. Looks like that's what I'll be getting. Goodyear Wrangler SR-As and Michelin LTX M/S 2s both are well reviewed by Consumer Reports. They describe the Michelins as having slightly better handling but the Goodyears have better rolling resistance, and they're cheaper at Wally's.

Since I'll still have to drive it around town I suspect I should opt for the better rolling resistance in hopes of slightly better gas mileage. I had considered A/Ts but really can't justify the noise and loss of ride comfort.

Have you considered something like http://www.tirerack.com/tires/tires....omCompare1=yes

LT245/70R17
108/104Q C

[chriscowles]

I'm looking to upgrade the load range. Those Firestones are only LR C, the equivalent of the tires I have now.

I think D's would suffice and perhaps be a bit more comfortable but can't find any.

Thanks, anyway.

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

[Sgt. Schultz]

Tire Rack had these as well
http://www.tirerack.com/tires/tires....omCompare1=yes

LT245/70R17
114/110Q D

[Tireman9]

Originally Posted by JWHybrid2B

My tow vehicle GVWR is 5,710 lbs. My towing capacity is 7,000 lbs, but I am not sure what my CGVWR is unless you add the GVWR to the towing capacity which would be 12,710 lbs. I just weighed both TV and trailer and came out to 10,220 lbs with me in the vehicle. I am planning on adding about another 500-600 lbs max. Taking the 9% off the total CGVWR my maximum is 11,556 lbs which I would fall under.

GCVWR should be in your owners manual.

It looks like others have offered some suggestions.

[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

[JWHybrid2B]

Originally Posted by Tireman9

GCVWR should be in your owners manual.

It looks like others have offered some suggestions.

Couldn't find the GCVWR in my owners manual and tried googling that and couldn't find anything. All I could find is the vehicles GVWR.

[chriscowles]

Originally Posted by JWHybrid2B

Couldn't find the GCVWR in my owners manual and tried googling that and couldn't find anything. All I could find is the vehicles GVWR.

What is your TV?

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