The 2003 Expy calls for P265/70R17 tires. What would be the pros and cons of running a LT265/70R17 instead?

 

nothing a lt tire may have more plys and can be pressurized up to 50 psi but you sometimes lose weight rating. i almost went with a lt tire on mine but the bf goodrich rugged trail are 5 ply and rated at 2,601 lbs the lt tire was 900 lbs less

 

Using a LT tire is in my opinion the smart way to go if you plan on actually using your truck like a truck. I put BFG all terrain on my 03. I love them. They have 6 ply on the face and 3 ply on the sidewall. as opposed to the stock Generals which have 3 ply on the face and only one ply on the side wall. The BFG are alot more forgiving if you hit a pot hole. They are quiet and are rated for ice and snow.

 

Unfortunately Michelin doesn't make an LT265/70R17 tire yet. Hopefully they'll come out with the LTX in that size by the time I need to replace the stock tires on my 04.

 

Light Truck versus Passenger tire. Having sold tires right after high school at Sears I have had the same question asked a couple of times. The "P" tire will usually come in just black was or if it is a 75 series a white wall which you can mount to the inside. The "LT" will come in the RWL/OWL which is the Raised White Letter or the Outlined White Letter. Usually the "P" has a less aggresive pattern on it. The Michelin P235/75R15 in the "P" and the "LT" both had the exact same specs at the time and warranty but the "P" had a much better milage warranty. Even the Michelein rep could not give ma a solid answer as to why some one who wanted black wall tires should not buy the "P".

If you plan on using this vehicle more as a people puller than a boat puller then I would recommend going with the "P" rated tire just for the ride. The "LT" usually has a stiffer sidewall which transfer more energy to the vehicle.

Geo!

 

I called two tire stores this morning and asked them. Both of them said they would go with an LT because of the weight of the Expy. "It's a very heavy veihicle" they said. Other than that, they couldn't give me an "answer" as to the pros and cons. One guy actually wouldn't believe me that the truck came with P tires from the factory, and the other one was dumbfounded when I brought up the fact that the LT actually had a lower weight capacity. So, why would I want to put a tire with a lower weight capacity on such a "heavy vehicle"?! He told me to call back tomorrow to talk to his manager who's been selling tires for thirty years.

I think I'm gonna go with an LT for the couple extra plies and stiffer sidewall, because I think it should be more stabile when towing. The truck is mostly used around town as a "people puller", but we do frequently pull a trailer for 100 miles between mine and my parents house. And I also want to be able to throw the mud truck on the dolly behind the Expy and not have to worry about gettin a little squirrley cruisin down I-95.

I'd still like to know why the LT has a lower weight capacity if anyone knows.

 

LT tires are for men's 4x4 trucks while P tires are for boy's 4x2 trucks.

 

Well in that case I have to go with the LT!

 

Bump... Still wanted to know why the higher ply sidewalls would have a lower weight rating

 

It might be the rating system that causes the differene. My understanding is that LT tires are load rated for the specified value but with P tires you need to derate them by 9% for use on an SUV or trucks. I noticed that most manufacturers do not do the derating in their spec charts however I did notice that Michelin derates the P tires on their web site for truck/suv uses.
I don't know if that explains the difference or not.

 

So by the time it is all said and done they are +/- the same...

 

by the numbers they are the same. by the seat of your pants driving, they are different.

 

I wouldn't say they are the same. They could be the same however I noticed that many LT tires in the same size are a bit heavier that a P tire in the same size due to additional sidewall support.

 

I can't make any sense of it, but this is from Tirerack

Maximum Load

A tire's maximum load is the most weight the tire is designed to carry. Since a tire's load carrying capacity is related to the tire's size and how much inflation pressure is actually used, maximum loads are rated with the tire inflated to an industry assigned inflation pressure.

Additionally, load ranges are used to separate tires that share the same physical size, but differ in strength due to their internal construction. "Higher" load ranges are used to identify tires that have a stronger internal construction, and therefore can hold more air pressure and carry more weight.

Each load range has a assigned air pressure identified in pounds per square inch (psi) at which the tire's maximum load is rated. Listed below are the air pressures at which maximum load is rated for popular P-metric and LT tires:

<TABLE cellSpacing=2 cellPadding=2 width=392 border=1><TBODY><TR align=middle><TH colSpan=2>Tire Load Ranges</TH><TH width=188>Inflation Pressure Assigned

For "Maximum Load" Ratings


</TH></TR><TR><TH align=left colSpan=3>P-metric</TH></TR><TR><TD width=130>Standard Load</TD><TD align=middle width=44>(SL)</TD><TD align=middle width=188>35 psi</TD></TR><TR><TD width=130>Extra Load</TD><TD align=middle width=44>(XL)</TD><TD align=middle width=188>41 psi</TD></TR><TR><TH align=left colSpan=3>Light Truck</TH></TR><TR><TD width=130>Load Range C</TD><TD align=middle width=44>(LRC)</TD><TD align=middle width=188>50 psi</TD></TR><TR><TD width=130>Load Range D</TD><TD align=middle width=44>(LRD)</TD><TD align=middle width=188>65 psi</TD></TR><TR><TD width=130>Load Range E</TD><TD align=middle width=44>(LRE)</TD><TD align=middle width=188>80 psi</TD></TR></TBODY></TABLE>

P-metric tires used on passenger cars and station wagons are rated to carry 100% of the load indicated on the tire's sidewall (or listed for the tire in industry load/inflation charts). However, if the same P-metric tires are used on light trucks, (pickup trucks and sport utility vehicles for example), their carrying capacity is reduced to 91% of the load indicated on the tire's sidewall. This reduction in load results in causing light truck vehicle manufacturers to select proportionately larger P-metric sized tires for their vehicles to help offset the forces and loads resulting from a light truck's higher center of gravity and increased possibility of being occasionally "overloaded."

For example, P235/75R15 P-metric sized, standard load tires used on cars and light trucks would be rated to carry the following maximum loads at 35 psi:

<TABLE cellSpacing=2 cellPadding=2 width=255 border=1><TBODY><TR><TD>Cars</TD><TD>Full Value</TD><TD>2028 lbs.</TD></TR><TR><TD>Light Trucks</TD><TD>9% Reduced Value</TD><TD>1845 lbs.</TD></TR></TBODY></TABLE>

Additionally, while a tire's maximum load is the most weight the tire is designed to carry, its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used. For example, P235/75R15 P-metric sized, standard load (SL) and extra load (XL) tires used on cars would be rated to carry the following loads at the inflation pressures indicated:

<TABLE cellSpacing=2 cellPadding=2 width=437 border=1><TBODY><TR><TD width=134>Air Pressure (psi)</TD><TD align=middle>20</TD><TD align=middle>23</TD><TD align=middle>26</TD><TD align=middle>29</TD><TD align=middle>32</TD><TD align=middle>35</TD><TD align=middle>38</TD><TD align=middle>41</TD></TR><TR><TD width=134>P235/75R15 SL</TD><TD align=middle>1543</TD><TD align=middle>1635</TD><TD align=middle>1753</TD><TD align=middle>1852</TD><TD align=middle>1940</TD><TD align=middle>2028</TD><TD align=middle>


</TD><TD align=middle>


</TD></TR><TR><TD width=134>P235/75R15 XL</TD><TD align=middle>1543</TD><TD align=middle>1635</TD><TD align=middle>1753</TD><TD align=middle>1852</TD><TD align=middle>1940</TD><TD align=middle>2028</TD><TD align=middle>2105</TD><TD align=middle>2183</TD></TR></TBODY></TABLE>

Note: 35 psi is the assigned "maximum load" pressure for standard load tires and 41 psi is the assigned "maximum load" pressure for extra load tires.

The above chart correctly shows that an extra load tire is not rated to carry any more load than a standard load tire when both are inflated to the same pressure (up to the standard load tire's "maximum load" pressure of 35 psi). This is because a tire's load capacity is a function of its size (which determines the size of the "air chamber"), its construction (which determines how much pressure can be held) and the actual air pressure used (which determines how many air molecules are forced inside the chamber). All tires with equivalent physical dimensions carry equivalent loads (until they reach their maximum load pressure).

The tire's maximum load is indicated in relatively small sized print branded near the tire's bead (adjacent to the wheel) indicating the appropriate value. Because tires are global products, their maximum load capacity is branded on the tire in kilograms (kg) and pounds (lb.). These values can also be found in the industry's tire load & inflation charts.

NOTE: P-metric and Euro-metric sized tires' "maximum load" inflation pressure may be, and often are, different that the tire's "maximum inflation pressure".

 

That was very educational!

The way I understand it, an LT at 35 psi has the same load rating of a P at 35 psi (at 91% rating for an suv of course), because they are the same size "air chamber". Now I know I can run the LT's at 35 psi for an everyday better ride without sacrificing the integrity of the tire. Or air up for higher load capacity when hauling. Or even air down for better off road traction because I know I have a stronger sidewall due to the added plies of an LT.

I think buzzard summed it up just right, "LT tires are for men's 4x4 trucks while P tires are for boy's 4x2 trucks."