Help Me Pick the Best Tire Size

[crawdad]

Hey guys, I've got to put new tires on my LWB 86 next week. The stock size is 235/75/15. Thing is I recently picked up some 8 inch Rally wheels and I'm not sure an 8" rim is best for the stock size. I'm thinking of going up a size to maybe 265/75/15. What do you think, or suggest. I'm not looking for that "low-wide" look, just a good size tire to fill in the wheel well and look good on the 8" rim.
Appreciate your comments.

[ont_guy_38]

I have 255/70/15 on my truck,they fill up the wheel well pretty good and they are just a little bit wider then the 235/75. I have attached a picture to give you some idea what they look like

[Jonboy]

I would say either the 255/70 or a 275/60.

[slugish]

think you would be pleased with the 275x 60 x15. Just a little fatter than 255x70

[ont_guy_38]

Originally Posted by slugish

think you would be pleased with the 275x 60 x15. Just a little fatter than 255x70

Yes they are a little fatter but they are 60 series which makes them a smaller radius which is fine if your truck is lowered a bit

[jokersbowtie]

this might help

http://www.net-comber.com/tirecalc.html

[Ivan D.]

This is with 32x11.5x15 in the front and 33x12.4x15 in the rear. Actual diameters tho ain't really 32 and 33, but more like 30.5" and 31". These tires are mounted on 15x8 wheels, which are a bit narrow but that's what I have so that's what I used. If you wanna match tire width to wheel width you may be best off with 10.5-wide tires - those can usually be had in 31-33" diameter. The wheel wells of yer 86 are slightly smaller than those of my '79 so I'd probably go with the LT31x10.5x15 if I were you, and if the truck don't go offroading a whole lot I'd get them tires in a more street-friendly tread design. So overall maybe something like this:
http://www.tirerack.com/tires/tires....e1=yes&place=0

Oh, if you're wondering why I'm not going with 275s and such - yer truck is a truck, and as such requires truck tires, unless you plan on not using it as a truck a whole lot. IIRC there was a problem some time back with F150 owners replacing the LT tires with P ones then hauling heavy stuff and blowing them, I believe Ford now has a policy that if an originally LT-equipped truck has the tires replaced with P-rated ones and as a result of that gets into an accident the company will not pay the onwer any compensations - P-rated tires have less payload carrying capabilities than LT-rated tires, and it is therefore the owner's fault for not using the right tires and consequently overloading the passenger ones and damaging his vehilce. I know many people run P-rated tires on their trucks and are doing just fine, however I'd rather be safe than sorry - heck even my full-size car now has LT tires as during winter it can easily reach 5000lb LVW and last thing I want in a MI winter is getting stranded in the middle of nowhere for running over a road debris or something.

[killthewabbit]

I'm rocking 255/70-15 on mine. I think it looks great on stock height half ton 2WD trucks. If I were going to lower it, I'd go with a 60 series tire if I were sticking with 15s. I like 275/60-15s on our trucks, but they leave a bit of a gap if used at stock height. There's only an inch or so difference in height between the 275/60 and the 255-70, but the 255 looks a bit better on an 8" wheel, IMHO.

[Pyrotechnic]

Good point about the P and LT ratings. I rarely think about it as my truck is just a half ton and while I do haul things, it's more of bulky things rather than sheer mass. I run 275/60/15's on 8 inch rims all around.

[crawdad]

Well the truck is not a 4X4 so there is no off roading planned, however, I do eventually plan to use this truck to pull my car trailer. I've heard what you said about the P metric tires used on trucks before. I know that some tire manufacturers want honor their warranty if using P metric on a truck, so that is something to think about. I was wanting to stay pretty much the same tire diameter or maybe a little taller and something just a little wider than the 235's. What do yall think about the 30/9.50/15 tire size?

[streetstar]

i inherited my dad's 84 GMC in 1988 when i was still in high school. It had stock 8" Rallyes with 235/75's stock.

But i agree with the 255-70 answers for what you want

[crawdad]

I think I'm going to go with the 255/70/15's. I just called and talked to the Cooper tire dealer here in town and he said that although the "P" designation means it is a Passenger type tire, it doesn't mean it is not meant for light truck applications as well since most light trucks are passenger type vehicles too. He said the warranty issue comes into play when mounting P type tires on commercial truck applications. I don't know if he knew what he was talking about, but he sounded convincing. He said there would not be a warranty issue if mounting the Cooper Discoverer tires on my truck, and that they are designed for light truck/SUV applications. Most all of the sizes begin with a "P" too.

[Ivan D.]

I've seen many new half-tons roll off the dealership floor with P-rated tires - really it becomes an issue when the original tires were LTs, which is usually on half-tons intended as bare bones plain Jane fleet work trucks. You should be fine with P tires the way you plan on using them, with my last post I was making more a general warning than anything else.

As for the 30/9.5/15s - yer current 235/75-15s are most likely 28" in diameter, so imagine something slightly wide and about 1" larger in radius - really look at yer current wheels wells and picture the gap around the tires 3/4-1" smaller, that should get you in the ballpark.

[dhughins]

i cant decide myself. i thought i wanted 275/60r15 but i really would like to see some 70 series. i like tires with more meat on them. does anyone have pics with 70 series tires?

[BaddBusa2005]

I am going to put 275/60/15's on my rallies next. I have 295/50's on it now with the 8" rallies.

I will attach a pic with the 295's

[killthewabbit]

Originally Posted by dhughins

i cant decide myself. i thought i wanted 275/60r15 but i really would like to see some 70 series. i like tires with more meat on them. does anyone have pics with 70 series tires?

You can check out pics of mine with mismatched 255/70-15 in my signature. Slonaker also has 255/70-15 on his, if I recall correctly.

[crawdad]

I went with the 255/70/15's on the truck. They look really nice, fill up the wheel well pretty good and I've maintained the stock height which is what I wanted. I'm glad you guys suggested those. I was going to post some pics but I had to put the truck in the body shop to have the frame aligned. When I had the new tires put on, I also had them do an alignment. There was some damage to the lower right A arm and I had to replace it. Then found out the frame had been tweaked to the point that they couldn't align it. Hopefully the body shop will be able to remedy that and I'll post some pics of the tires then. Thanks again for your help and ideas.

[streetmaster42]

Cool truck (BaddBusa2005) were you get the tri-bar spinners that you have on the Rallies. Im planning on a set for mine.

[Duro5341]

Originally Posted by crawdad

Well the truck is not a 4X4 so there is no off roading planned, however, I do eventually plan to use this truck to pull my car trailer. I've heard what you said about the P metric tires used on trucks before. I know that some tire manufacturers want honor their warranty if using P metric on a truck, so that is something to think about. I was wanting to stay pretty much the same tire diameter or maybe a little taller and something just a little wider than the 235's. What do yall think about the 30/9.50/15 tire size?

If you plan on pulling a car trailer, which becomes really heavy with a car on it....probably around 7000-8000lbs easily. I would stick with the stock 235/75R15. If you go with a taller tire, you can kiss your towing ability good buy, unless you have a 454, or a diesel. I have a car trailer, and with my 79 monte carlo on it, it becomes a real dog. I have LT31X10.5R15 tires, or LT265/75R15 for you metric guys. If I knew I was going to pull a car trailer, when I baught the tires, I would have sticked with stock, and saved about $200 aswell

Duro

[MylilBowTie]

That is where gearing comes into play. Bigger tires reduce your rear end ratio, smaller raise it. This is a small percent of change though. You will really notice it pulling with bigger tires. If you are used to pulling with stockish type gears 2.73-3.08 and then try it with some 4.10 3.73 or even 3.42 gears. It will be like night and day when towing. Most get scared off by gas mileage.