P instead of LT for K1500 GMT400 Silverado

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2,131
Location
Maryland
I've recently bought a 1991 Silverado Extended Cab, Long Bed to use for Home Depot runs and to load stuff into this truck for transport that I would not like to put into my nicer SUV or sedan. The truck came with LT tires from the factory in size 245/75-16. The previous owner upgraded the size to 265/75-16 which many upgrade to for a slightly taller and beefier tire. The truck has two Dunlop A/T Radial Rover on the front and two Jetzon Revenger A/T in the back. Both axles have plenty of tread. However, from my understanding both of these tires don't perform well in the rain or snow, something that's important for me in a full size truck with weak brakes during inclement conditions. DTD is having their Presidents Day promotions on tires and I thought about buying four new ones for this rig. I don't want to spend a lot but at the same time want the performance. I have decided to downgrade from the LT tire to a regular P tire for a smoother ride. From my research many people put the P rated tires on their trucks and many trucks come from the factory with P rated tires. The LT tires have reinforced sidewall with more ply to carry heavier loads and for towing. I do not intend to carry any heavy loads or will I ever tow anything. I also want to go back to the stock size of 245/75-16 to perhaps get a slight bump in gas mileage and to reduce some sluggishness. I'm not sure these things will be achieved but it's worth a shot. The P tires are less expensive than the LT tires so I've narrowed it down to the General HTS60 which are selling for $105.50 per tire with a combined rebate of $135, meaning these will be shipped to my door for $287 after rebate in size 245/75-16. The reviews are great and these will probably perform better and ride better than the tires that are on the truck now. One thing that bothers me is that the door jamb sticker on the truck recommends a 45 cold pressure psi on the factory LT rated tires which have a capacity of 80psi if needed. The P rated tires have a maximum recommended pressure of 44psi on the sidewall as many of you know. If I run these at 44psi cold pressure or close to it, I'd be running them at the maximum recommended pressure of the tire but slightly lower than what GM recommends at 45psi for the LT tires. Would this be okay to run the P rated tires at their maximum mfg. recommended tire pressure - to be as close to the 45psi GM recommended pressure or is it simply too dangerous especially for the summertime as the pressure will rise with temperature on this heavy rig? I intend to recoup some of the cost of the new tires by selling the old tires on Craigslist as they all have a lot of tread left. Is my logic about the tire size, performance of the Grabber HTS60, downgrading to a P rated tire that has a maximum allowable mfg recommended pressure of 44psi skewed for my needs? Should I pay an extra $51 and get the LT rated HTS60 with the lower 50k mile treadwear rating and settle for a harsher ride? The Continental Contact LX20 also have rebates on them and from some reviews look to be good tires but the reviews for the HTS60 seem to be better suited for a full size truck. Thanks in advance!
 
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Nick1994

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13,421
Location
Phoenix, AZ
I'd just spend a couple extra bucks and put the tires it calls for on it and not worry. LT tires don't make that big of a difference. I've got LT tires on my Jeep and upgraded to them on my 96' C1500 and never noticed a difference. On an old truck, a 1% slightly less bumpy ride to Home Depot really shouldn't matter.
 
Messages
768
Location
South Carolina
LT tires need more pressure by design. Run your P tires at a lower pressure. It's up to you what that lower pressure is, but I would guess roughly 10 PSI less. You should be able to find a load vs. pressure chart for your new P tire. Also realize that any P tire's advertised load rating is reduced by a factor of 1.1 when it is installed on a light truck.
 
Messages
216
Location
South Louisiana
I find it odd that a 1991 K1500 would call for lt tires. Maybe in 1991 a 16" sizes were only available in 6 ply lt? Another size to consider might be 265/70-16. Likely hard to find in LT form but just a little wider. When shopping for tires for my moms sequoia the price between the 245/75s and the 265/70s could be as different as $25 a tire.
 
Messages
13,378
Location
ROCHESTER, NY
Through your own research, I would get a really nice set of 4 tires from DTD for exactly what you need/want in the SIZE that you want(even if you stay with the 265s). Get tires that will perform for you in the foul weather that you will encounter. And sell off your current tires on the truck to recoup some of your money back. My buddy put on his '97 Dodge RAM(OE were 245mm), "P" tires(in 265mm) because he used the truck like a car. The "P" were OK however due to the weight of the truck all by itself, these tires didn't perform as well and wore out fast compared to an "LT" in everyday-ness. The "P" were a bit sloppy. The "LT" tires were just better suited for this RAM. On the next set of tires(he stayed with 265mm) however he went with a more appropriate "LT" tire more suited to the truck. A NICE HIWY TIRE(I can't remember) like Firestone Destination LE2 or Michelin LTX MS/2. NOT a full blown knobby truck tire designed for weight & construction sites. But in these new "LT" tires, he ran a lower PSI for comfort(didn't affect MPG) and the fact that this truck never had any weight in the box to speak of except for the occasional sheet of plywood or a few 2x4/2x6's. My buddy didn't run the high PSI in the tires, that the truck required(for heavy loads) as he never loaded up the truck. You can probably run a PSI that is more suitable for your normal type driving.
 
Messages
1,869
Location
Texas
Originally Posted By: Spartuss
I've recently bought a 1991 Silverado Extended Cab, Long Bed to use for Home Depot runs and to load stuff into this truck for transport that I would not like to put into my nicer SUV or sedan. The truck came with LT tires from the factory in size 245/75-16. The previous owner upgraded the size to 265/75-16 which many upgrade to for a slightly taller and beefier tire. The truck has two Dunlop A/T Radial Rover on the front and two Jetzon Revenger A/T in the back. Both axles have plenty of tread. However, from my understanding both of these tires don't perform well in the rain or snow, something that's important for me in a full size truck with weak brakes during inclement conditions. DTD is having their Presidents Day promotions on tires and I thought about buying four new ones for this rig. I don't want to spend a lot but at the same time want the performance. I have decided to downgrade from the LT tire to a regular P tire for a smoother ride. From my research many people put the P rated tires on their trucks and many trucks come from the factory with P rated tires. The LT tires have reinforced sidewall with more ply to carry heavier loads and for towing. I do not intend to carry any heavy loads or will I ever tow anything. I also want to go back to the stock size of 245/75-16 to perhaps get a slight bump in gas mileage and to reduce some sluggishness. I'm not sure these things will be achieved but it's worth a shot. The P tires are less expensive than the LT tires so I've narrowed it down to the General HTS60 which are selling for $105.50 per tire with a combined rebate of $135, meaning these will be shipped to my door for $287 after rebate in size 245/75-16. The reviews are great and these will probably perform better and ride better than the tires that are on the truck now. One thing that bothers me is that the door jamb sticker on the truck recommends a 45 cold pressure psi on the factory LT rated tires which have a capacity of 80psi if needed. The P rated tires have a maximum recommended pressure of 44psi on the sidewall as many of you know. If I run these at 44psi cold pressure or close to it, I'd be running them at the maximum recommended pressure of the tire but slightly lower than what GM recommends at 45psi for the LT tires. Would this be okay to run the P rated tires at their maximum mfg. recommended tire pressure - to be as close to the 45psi GM recommended pressure or is it simply too dangerous especially for the summertime as the pressure will rise with temperature on this heavy rig? I intend to recoup some of the cost of the new tires by selling the old tires on Craigslist as they all have a lot of tread left. Is my logic about the tire size, performance of the Grabber HTS60, downgrading to a P rated tire that has a maximum allowable mfg recommended pressure of 44psi skewed for my needs? Should I pay an extra $51 and get the LT rated HTS60 with the lower 50k mile treadwear rating and settle for a harsher ride? The Continental Contact LX20 also have rebates on them and from some reviews look to be good tires but the reviews for the HTS60 seem to be better suited for a full size truck. Thanks in advance!
So you have a truck but you want to run passenger car tires on cause you don't want it to ride like a truck? Sounds like you need one of the newer trucks with all the comforts of home and buttons for each.
 
Messages
1,537
Location
iowa
Starting in 1996 on the K1500 they went to a P245/75-16 109 load index at 35 psi, or the P265/75-16 114 load index tire at 35 psi. The LT was the 3rd option. I think that the P tires at 35psi would work fine, since they are still using P tires even on the new heavier trucks at 35psi. I have never used, or needed an LT tire on any of my 1/2 ton trucks.
 
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3,964
Location
Somewhere in the US
OK, let's do some math: An LT245/75R16 has a load carrying capacity at 45 psi of 1985#. A P245/75R16 has a load carrying capacity of 2065# at 35 psi (after derating for LT service) - and 2004# at 33 psi (after derating), but 1975# at 32 psi (after derating). So there is enough load carrying capacity. While I don't think this is a good idea, my fundamental argument is moot. The only thing I can object to is the difference in spring rate caused by the pressure - AND - I think you are going to have trouble getting most tire shops to agree to the swap.
 

4WD

Messages
17,052
Location
Texas
Originally Posted By: CapriRacer
OK, let's do some math: An LT245/75R16 has a load carrying capacity at 45 psi of 1985#. A P245/75R16 has a load carrying capacity of 2065# at 35 psi (after derating for LT service) - and 2004# at 33 psi (after derating), but 1975# at 32 psi (after derating). So there is enough load carrying capacity. While I don't think this is a good idea, my fundamental argument is moot. The only thing I can object to is the difference in spring rate caused by the pressure - AND - I think you are going to have trouble getting most tire shops to agree to the swap.
Some US tire shops give good advice on this and some don’t … I trusted a 30 year guy on the subject as did my son. Both rode like tanks and really did not need LT … it was a desired tread design mainly … Many, many 1500 trucks leaving the factory with P metric over the last few years … Unless there is just a technical or preference for LT … P metric are doing lots of light truck work … And any P245/P265 are not small tires compared to when I got my 1st W150 Some folks might be best off with a 2500 truck on LT’s … I know two guys incredibly pleased with that switch …
 
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5,016
Location
Southeast
My truck came with P tires stock and a 6900 lb tow rating. We, and the previous owner, both tow/ed with it. My first trailer was about 6500 wet with stuff in the bed. While that was really too much for the truck, we didn't have any issues with P tires, aired up to the max. We've got a smaller TT now at about 4500 wet. P tires are fine. So if you're just driving around town in an unloaded truck carrying the occassional plywood and drywall run, it's not even worth another thought. P tires at 30-35 PSI will be just fine.
 
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Messages
2,584
Location
wv
Sounds like this truck is a beater for when you dont want to use your SUV. With that said I wouldnt spend that kind of money on tires when you say that the tires on it have plenty of tread. Since you sound like a frugal and educated person with an eye to detail.. I would sell the truck and get a small utility trailer. (no maintenance, no insurance, taxes, inspections etc etc) The trailer will haul much more than any pickup will and it doesnt need any attention.
 
Messages
10,910
Location
Cincinnati, OH, USA
Originally Posted By: AZjeff
What's the deal of an LT tire of the same size with lower rating than a P tire?
The LT has full rating at 80 PSI, the P is usually around 44 PSI or so. If you're never, ever going to haul anything heavy or tow anything, go with the P-I personally use LTs and run them at 45-50. If I wanted a Cadillac, I would buy one...whoops, Escalades are "trucks", aren't they??
 

4WD

Messages
17,052
Location
Texas
Originally Posted By: krismoriah72
Sounds like this truck is a beater for when you dont want to use your SUV. With that said I wouldnt spend that kind of money on tires when you say that the tires on it have plenty of tread. Since you sound like a frugal and educated person with an eye to detail.. I would sell the truck and get a small utility trailer. (no maintenance, no insurance, taxes, inspections etc etc) The trailer will haul much more than any pickup will and it doesnt need any attention. Had one for 20 years = also like how much lower they are for loading/unloading … especially compared to 4WD vehicles …
 
Messages
1,797
Location
TX, USA
LT tires are needed when you are hauling and towing heavy items. The LT tires will also potentially last longer since it usually have around 2x thickness compare to a P tires. Then it also depends on the truck itself. Those old trucks are built like a tank with metal not plastic like the new one. So, that is why it requires LT tires especially that is the K truck which is a 4x4. So the P tires may not be sufficient to carry the empty weight.
 
Originally Posted By: JMJNet
Those old trucks are built like a tank with metal not plastic like the new one. So, that is why it requires LT tires especially that is the K truck which is a 4x4. So the P tires may not be sufficient to carry the empty weight.
I wondered about this and tried to do some searching and it's hard to find specs of the exact truck but it looks like if anything a similar 2017 4wd Chevy weighs more that this old gal. Surprising. It doesn't sound like the OP is going to put many miles on the truck so he'll probably never wear out a set of anything he buys.
 
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7,545
Location
California
The LT rated tires will let you carry and tow more, but unless you're hauling sacks of concrete/sand/gravel and other flotsam until the rear end sags it might not be worth the expense. The truck will definitely ride different with an LT tire - if you have P-rated tires, you also need to derate the load capacity from the sidewalls about 10%. A LT-rated tire might be built like a P-rated tire, I think the LT-rated tires have thicker plies/body cord and steel belts for it to get a 6/8PR equivalent to a bias-ply tire. A buddy has a GMT400 2-door Tahoe(C/K Blazer) and I told him to stay with P-rated tires. I doubt his truck will see anything more than a few hundred pounds in the cargo bay at a given time.
 

Spartuss

Thread starter
Messages
2,131
Location
Maryland
Installed the P rated General Grabber HTS60 and couldn't be happier. Rides smoother, quieter with less rolling resistance.
 
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