Tire sizes

[Pickle]

I have a 75' c20 and I need new tires. I bought 16 inch rims that are 8 inch wide and have been getting mixed answers from local tire shops. Some say that P rated tires will work fine, just not with a large load. Some say that it is illegal to run less than an 8ply rated tire on a 3/4 ton truck. Most that say I cannot go to a P rated tire are suggesting a 265/75 tire but I wasn't sure if that would give me any issues as far as turn radius and brakes. Right now not including lack of tread I am running 29x9.5x16.5 tires. The price difference between the 245/75 or 245/70 tires and LT265/75 tires are quite significant and if I can get away with the smaller tires would make my life a lot easier. I only have one 600 mile trip with a light load (my bed, dresser and a few boxes. i might possibly haul a small rented trailer) and then it will be city driving for quite a while. Would it be okay to stick with the smaller tires and just get what I can out of them and buy new tires after I move? Or would it be too dangerous and more worth it to get the bigger 8-10 ply rated tires and pay the extra $200?

[GCncsuHD]

Unless it varies by state I do not believe there is any law preventing you from running a P rated tire on a 3/4 ton truck. But, in the event that there is an accident, that involved a tire failure, you may potentially be more liable in the event.

Keep in mind that when you mount a P rated tire onto any load carrying truck, 1/2, 3/4, etc it is industry standard to reduce the load rating printed on the tire by an additional 10%. So those P rated 245/70R16s with a load rating of 2094lbs are actually only good for 1884lbs.

Still enough to cover a the curb weight of your truck and a light load, but keep in mind there is more to a LT tire than just the additional weight. An LT tire and a P rated tire of equal weight capacity (such as an XL rated P tire), the LT tire still has more/stiffer sidewall plies and generally a harder compound. Under the same load the sidewall of the P rated tire will flex more, producing more heat which breaks down the rubber quicker, a detriment to tread life. For short trips, this isn't a big issue, but for your upcoming 600mi trip, it could seriously affect the tread life of those tires.

Can you put P rated tires on? Notwithstanding Komifornia state laws I am unaware of, yes you can.
Would I? Not likely.




Addressing a few other questions, the tire size has no effect on turning radius one way or another, unless the larger tire rubs and prevents you from turning the wheel as far. On the other hand, shallower backspaced wheels will increase your turning radius. Why are you looking at P rated 245s and LT rated 265s? There are P rated 265s, and LT rated 245s. Listen less to your tire guy, and do a little research on your own. The LT245/75R16 (30.5x9.6x16) will be closer to what you are running currently (29x9.5x16.5s). A LT225/75R16 will be 29x9x16. Do you want to stay close to the same size? Larger? Smaller? As far as brakes, larger diameter, and increased weight of the tire will both decrease the braking ability, so keep that in mind, though with 3/4 ton disc brakes, as long as you don't go crazy, that shouldn't be an issue.

[Pickle]

I'm trying to stay as close to the same size as possible. I'm just trying to be cheap and spend as little money as possible until I make this trip and get a new job and so on. The 16" rims I bought have 265/75s on them and are mud terrain tires. Only two have any amount of tread left and I just felt it was a bit bigger than I wanted to move to. Since I'm shopping online for tires I found a local place that will switch them out for me and take the two good tires for payment making the tires + shipping (unless I go with discount tire direct which will ship for free) the only expense I have. I used a size calculator and 245/75 was a closer fit to my current set up, and websites are loaded with cheap P rated versions of that size. I'm getting prices as low as $90 a tire compared to $113 for XL and $135 for LT. The LTs I can only find on websites that either charge shipping or aren't as cheap as discount tire direct so I guess I'm just wondering if it's worth the $100-200 savings and will last me the trip and maybe a year of light use versus just forking over the money now and making my budget a bit more uncomfortable for the move. The only other mixed answer I've been getting is weather or not 245/70 or 245/75 will fit on the rims I bought that are 8" wide. some say its too wide, others say its at the end of the recommended range.

[GCncsuHD]

To me, it would be more than worth it to spring the extra cash for the correct tires. Do it once, do it right. If you are on that much of a budget, consider finding used tires of the correct size and rating, or keep the two good, put them on the back, buy two LT245s for the front, run that for the trip, then once you are there, and your budget is in better shape, buy the other two.

As far as 245 fitment on a 8" wheel, 8" is the upper range of the "recommended" fitment for most 245s, but is still in the range. It will be perfectly fine, the guy setting the beads on the tire may cuss you for a bit, but other than that there will be no issues. My wife's car has been running 245/75R16s on a 16x8 for almost 50k miles now.

[Pickle]

You've convinced me. Now the only thing to decide is which tire. I have four that I have picked out, one of which I also have the option of buying from a shop in town for a little bit more.

GT Radial Adventuro AT3 - 120s 10 ply $499.88
http://www.discounttiredirect.com/di...5&rd=16&cs=245

GT Radial Savero HT2 - 120r 10 ply $499.88
http://www.discounttiredirect.com/di...5&rd=16&cs=245

Nankang FT-7 - 120r 10 ply $523.92
http://www.discounttiredirect.com/di...5&rd=16&cs=245

West lake SL309 - 120q 10 ply $536 online $560 in town (includes all the bells and whistles shops usually offer)
http://www.discounttiredirect.com/di...5&rd=16&cs=245

I'm not sure which brand would be better. I'd like a second opinion on them but if you don't feel like looking through them I understand. I appreciate all your help, it has made this a whole lot easier. I've been using this truck to learn more about working on vehicles and teaching myself along the way, but this is the first time I'll change the tires since buying it.

[GCncsuHD]

The first three are Chinese tires, I've never owned any of the three, but I do see the GT radials around more so than the Nankangs. From there it's your preference of which tread style you prefer. I've never heard of the last ones at all, but a quick google search, also Chinese.

If you could swing a little more, the Falkens and the Coopers just a few down from those you listed are proven good tires.

Also, I wouldn't rule out finding some very nice used LT245s on craigslist or such. They are OEM size for several trucks and many are swapped off in favor of larger tires very early.

[Pickle]

Craigslist in my area doesn't really have anything. Isn't Eldorado a branch off of cooper? A small tire shop near me just quoted me $511.70 out the door for four new ELDORADO HI FLY VIGOROUS HT601 10 ply tires with a possible credit for my two good tires.

[Stocker]

You really don't need 10PR tires.... in fact 8PR (LR-D) are OK but still a bit overkill for how you say you'll be using your truck. Remember, the higher the rating, the stiffer & heavier the tire is (in general) and you'll see negative impact on fuel mileage. P-metrics are legal but I probably wouldn't run 'em. Keeping in mind your anticipated max load + a bit of safety factor, look into 6PR (LR-C) tires.

As to acceptable rim width for any tire size, a good resource is http://www.tirerack.com/index.jsp and search for Tires by Size. If you can run a 265/70-16 (same diameter as 245/75-16), there's a wide variety to choose from, and they fit perfectly on an 8" wide wheel.

[RichardJ]

You quoted a couple of tires from "Discount tire". The shop in town (Redding, CA) wouldn't happen to be "America's Tire" would it?

Same company.