I have a F150 with the 5.0 with the automatic transmission and 3.55 limited slip gears.

I have the original tires, 235 75 R15.

I want to upgrade to 235 80 R15 or 235 85 R15 tires if possible.

Is it possible to put these tires without having to regear or any other major work needed?

I know this would affect performance, but would it do more damage to the tranny than stock if I am carefull?

Would this create a siginificatly more engine wear too?

What other modifications should I do to make these bigger tires run properly and without significant driveline damage?

Thank you,
Rob

 

I also have the 5.0 and 3.55 gears, the previus tires i had were 31 x 10.5, I just bought this weekend a set of 265/75/R15, they are both very close in size and they fit exelent, i like the look of them on a stock truck, that could be another option for you.
235/75 tires are about a 30" x 9.5 and 235/85 would be about half inch taller
there really isn't a big difference in tire size so everything should work just fine, minimal wear, you might feel it a little slugginsh with the 3.55 gears but it won't be much different.

 

What are you trying to gain by running a taller tire that is no wider?

I HIGHLY recommend going to a 265/75/15 or 31x10.50x15 which are nearly the same, just measured differently and different brands offer their tires in either metric or standard measurments.

At minimum, run a 255/70/15.

Going to a 235/85 from a 235/75 will adversely affect handling...tall narrow tires will cut through mud and snow well but will not handle great on the street, especially with the soft F150 suspension.

A 245/75 is closest to a 30x9.5 but that size is rarely available in 15 inch rim size

I have 31x10.50x15 and they are absolutely perfect.

Here is my 92 with 265/75/15's


Here is my 95 with 31x10.50x15

 

Nice trucks My friend has 31 on his f150 too, but on his truck, they look crammed into the wheel well and I do not like that look too much.

I wanted the taller tire because I go on a lot of dirt roads that sometimes have mud. I have yet to get stuck, but want the tires as a preventive measure.

I was told that taller tires cut through the mud better, but I didnt know that they would have a harsher ride. But about a comprimise of 245 80 R15 wheels? I dont know much about wheels, is this possible, or easy to find?

Thanks again for all the help, I want to make this truck into a reliable and cabaple truck for the next 100,000 miles.

 

I used to have 33/9.5-15 BFG All-terrain on my stock F150. Looked big and cool, and had great traction/off-road capability. But I also have 4:10 gears. They fit fine, only BFG All-terrains could pull this size off.

 

Is your truck 2 or 4 wheel drive? The 4x4 sits high enough that the crammed look isnt an issue, as you can see with my trucks which are both at stock height. 2 wheel drives do have that crammed look, though they wont rub.

The problem now will be to find a taller but not much wider size that is made. 235/80/15 is not made, but a 235/85/16 was OEM on F350's of this generation. If you can find a simple 5-lug 16 inch rim, you can run this size and accomplish what you are going for, but it will be a very tall tire.

For good overall performance on the street, in the mud, on the dirt, in the snow, etc. I'd say a 30x9.50x15 is perfect for you. If it were to be sized in metric, it would be a 245/80/15 or thereabouts. Not too tall, not too wide and will go right on your stock wheels without an issue.

If you are on a bit of a budget, I recommend the General Grabber AT2 or Firestone Destination A/T, if you can spend a bit more, the Bridgestone Dueler A/T Revo is excellent and of course the old standby BFG All Terrain T/A KO. Also a tire with spectacular traction off road even on a 2 wheel drive truck is the Cooper Destination Radial LT. These tires all have great prices online, but I recommend shopping around your local tire shops and get an estimate with all 4 tires mounted, balanced with valves, tax, disposal fee and all. They will often quote you the tire with mounting but balancing and other things extra. I ended up finding an overall deal locally that was better than getting the tires online for cheap and then bringing them someplace to be installed.

Good luck!

 

Yeah, mine is a 1989 F150 4x4, so the BFG All-terrain T/A KO's filled the wells, but I wouldn't call it cramped. Plus, I had them siped, they stuck to snow/ice like glue. I'd like to have one set of those for off-raod/winter, then a more moderate size like you suggest for summer touring.

BTW: even with 4:10 gearing, there is a noticable increase in power on the stock tires 235/75-15, but that size looks and performs quite small.

 

I agree that the 235 75 15 tires look puny. I have 255 70 15 on mine and it looks great. I had 31 10.50 15 on it before but the front is a bit low for that size tire. If my truck was 4wd it would definitely have 31 10.50 15 on it. Thats the perfect size for a 4x4.

 

if you ask most tire guys and old timers they will tell you that ya want a wider tire for mud-and a less wider tire for snow-wide rides on top the mud and snow narrower cuts through it-why a less wide tire is usually better in snow go through the snow down to the pavement makes sense though-I like the 31-10.50 size on mine a good all around tire

 

Thanks for the help My stock tires are getting worn and will be getting some newer tires soon. I ll probally get the 245 80 R15 so that way the truck wont feel as sluggish.

Thanks again, I will post pics once I install the tires

 

I don't see why you would want 80 series tires. Tall skinny tires look cheesy. The 265 75 15 would look a hell of a lot better and is close in size. I have actually been thinking about putting 31 10.50 15 Michelin LTX MS on mine.

 

These are the tires I have on my truck. I don't do off road, and I love these tires.
My rims had the Michelins on when I got them, but one size down. I have forgotten what size it was. They drove and rode fine, but looked a little small on the 4 wheel drive. When it was time to replace them, I moved up to the 31 x 10.50. Sam's club beat the local Michelin dealer by $100.
Truck had stock rims and BFG AT in 31x 10.50, when I purchased it. They were extremely noisey, and the truck wandered all over the road. Swiching to the Michelins reduced the wandering by 80%. A steering stabilizer got the other 20%.
Frank

 

You cant get a 245/80/15 because they dont exist

You can however get a 30x9.50x15 which is of comparable size to what a hypothetical 245/80/15 would be.

 

Thank you I know nothing about tire sizes.

Again thank you all for your help

 

Here is a pic of my truck if it helps. It currently has 235 75 R15.