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P Metric vs. LT Metric- which one for a pickup truck?

I have a 2004 Chevy Silverado Ext. Cab with 4WD. I still have the original tires on it- they are Firestone Steeltex LT245 75 R16's. The sticker in the cab (in the door frame) states that I should use LT245 75 R16s inflated to 50 PSI cold. I have 60,000 plus miles on these tires and will need a new set for winter. I have been pricing out some new tires and noticed that their P Metric counterparts are less expensive. I do not tow anything (even though I have a towing package), and I rarely haul heavy loads. I understand the differences between P Metric and LT, however I am not sure if a truck set up for a LT tire could use a P Metric. I have been told that the factory setup for my truck is made for an LT tire and it would handle differenly with P Metric tires. Any suggestions as to what type of tire I should purchase?

P.S.- I do not care about the ride quality of the truck- its a truck! BUT I do care about safety and I will not put P Metric tires on if they will compromise safety! Thanks for any suggestions.
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Comments

  • Actually, the handling's not the big issue, it's probably the load capacity. Go to tirerack.com and see which tires work for your truck. I bet P metrics have insufficient load capacity and lower than specified inflation pressures.
  • P= Passenger Car tire.

    LT=Light Truck tire.

    Tester
  • I like the tirerack site... its great for getting customer feedback on tires. I will have to check on the load capacity and get back to you on that one. This may be a moot point if P metrics will not safely work for my pickup. However, I guess that the only reason I am even REMOTELY thinking about this question is that all major tire companies make a P metric size for my truck, as well as many other pickups. Now if they were only made for passenger cars, then why do I even have the option to buy a P metric tire? My father's Ford F 150 calls for P255 70 R16s as well. His pickup is set up for towing too. Also, I have talked to others that run P metric on tires on their pickup trucks- regardless of what the OEM sticker tells them to do. I have researched this online and have found that load issues can arise when mounting a tire with insufficient load capacity. But they cited F-350s and heavy duty 1 ton pickups. I have a 1/2 ton that doesn't tow or haul heavy loads. If I can buy a P metric tire that will sufficient load capacity, what else should sway me from doing this? Any thoughts? Thanks for all of your suggestions.
  • Glad you mentioned the half ton pickup part. You can safely use P rated tires. I have a 2002 4WD extended cab GMC Sierra with automatic transmission and the door sticker says P 245 75 R16. If you have the Z71 or whatever the number is, The truck is set up for off-road use too. It may have a LT rated tire specified and there may be a reason, but I don't see a reason.
  • sjd81,

    Don't worry about the load capacity on your truck. If it came with LT metric tires, you should stay with LT metric tires. P metric tires will not have enough load carrying capacity.

    Yes, there is some confusion about tire sizing - and officially, the size includes the letters before and after the numbers. Lt metric tires are built different than P metric tires. Yes, I know you may have some friends who used P metric tires without problems, but I can show you tons of folks who have had problems.

    Remember, you said safety is most important! Stick with the LT metrics.
  • edited July 2011
    With the mileage you have gotten from your tires (60K) you might consider sticking to the same tire. That is awesomely good for a truck tire. Most folks are replacing truck tires every 30K miles. The rubber in the LT tire could be harder and the sidewall stiffer than an equivalent size of P metric. I'm not sure about running a P metric tire at 50 psi; sounds high for a passanger car tire.

    You might save a few bucks on the P tires and give it back if they wear out in 30K miles.
  • @CapriRacer - I'm confused by your 'don't worry about load capacity' comment. Why not? Are you saying it's OK to get tires that don't meet the load capacity spec?
  • Thanks for all the advice. I think that I will stay with LT tires for a few of the reasons stated above. Now if I can find some good deals before winter gets here...
  • texases,

    No, my comment was that a neophite can get easily confused about load carrying capacity as there are a couple of quirks in there - one of them being that P metric tires have to be derated 10% when used on light trucks, vans, and trailers. For someone who hasn't figured out how tires work, it's best that they ignore the business of load carrying capacity and follow the vehicle tire placard.
  • edited July 2011
    OK, as a former shop head technician and service manager who has endured corporate product sales training of several large brand tire manufacturers, let me chime in on the subject for the OP. I have a '97 Ford F-250 loaded with an engine driven welder and other large paperweights... recently outfitted with D load range 285/75R16 rubber.

    I think Tirerack has a great writeup and explanation of load ratings and inflation pressures. Check it out... you can learn a lot from their writeups.

    First thing to think of is the load capacity of the tire, as opposed to its inflation pressure. A tour de France cyclist has over 100 PSI in his rail-thin bike tires, whilst my buddy who has a street-legal monster truck resting upon HUGE 5-foot high tires has only 6 PSI in his tires. 150 lb cyclist vs 6000 lb diesel truck.

    Can you put passenger tires on your what I assume to be a 2500 Silverado (I don't recall 1500 Silverados coming with the Steeltex). If you go with a P tire, your max inflation pressure will drop from the 80 PSI that Chevy chose to use 50 of, to 44 PSI on a Passenger tire (I don't know of any P tires that have higher max pressures). Can you get down the road safely doing this? Probably, but don't plan on carrying anything heavier than a paperclip in the bed, half a tank of fuel, and no passengers.

    The Steeltex was an AWESOME product. Some bean-counters at Bridgestone are probably to blame as to why Firestone discontinued this product. I serviced a lot of vans and trucks with the newer Transforce AT product... and I have to say they wear quite well. Currently I'm running Cooper Discoverer ATRs that are wearing QUITE well after 12K miles. Now, you might be wondering why I dropped from an E load range tire which came on the truck originally to a D load range tire. My truck is a turd without 4x4 engaged, and isn't that great with it. I hated getting stuck on flat muddy ground because the sheer heft of the vehicle (almost 7000 lbs empty), so I decided to go with something wider and a bit taller both for off-road handling and looks. The 285/75R16 D load range Coopers have nearly three hundred pounds MORE load carrying capability at its max pressure of 65 PSI than the E load range 235/85R16 tires did at 80 PSI.

    Also, a lot of trucks list a higher pressure on the placard for the rear tires. This is because they assume the rear is loaded. A good trick to do is to inflate all-around to whatever you like, but then draw a few lines of chalk across your tread. Go drive around for a few miles, and see if the chalk is wearing evenly. If the chalk disappears on the outside, you're underinflated for that SPECIFIC load configuration (you, the angry girlfriend, the dog, and a full tank of fuel etc), or overinflated if the chalk is rubbing off in the middle of the mark. Adjust accordingly for your everyday configuration to find that sweet spot (both front and rear pressures) that allows the load to be distributed evenly across the entire tread footprint.
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