I just bought a used 1997 F150 regular cab 4.2L V6 from auction as-is. It did not have a spare tire/rim. I read the markings from the rim, 16x7. I went to a junk yard and bought a 16x7 with some rust that they say came off F150.

Now I went to tirerack.com and entered vehicle description. 235-70-16 is the OEM tire size. What's on it is LT235-85R16.

1) Does my truck have off-sized tires?
2) Did I buy the right rim?
3) What does "LT" in front of 235-85-16 mean? Is LT235 different from 235?
4) The truck did not come with Owner's Manual. Will someone kindly let me know what is the OEM tire size?

Thank you much for your help.


EDIT: I found the difference between LT and non-LT. Apparently, LT has a reserve capacity to take additional load, and has a load range designation, like LT235-85R-16/E on my truck.

 

Those trucks came with 235/70/16's. The XLT's and Lariats came with 255/70/16's.

 

Thanks for the reply. Mine is supposed to be Lariat according to the paper, but how can I tell it? Is it printed on the chassis or something?

Do rims go by the 2 numbers like 16x7? I read the marking (16x7) from the rim on the truck and bought from a junk yard with the same marking. Did I do the right thing?

 

The 2 numbers that you are looking at are two sizes for rims 16 is the how big, tall it is something like the diameter or circumfrence and the second number is the width tires have three measurements.

 

Not so fast...

Both my '97 2wd XLT and '99 4wd XLT came stock with the P235/70/16's. These were the standard size if no tire or wheel upgrades were selected.

If you check on the drivers door jamb, there should be sticker with the stock tire size listed.

To answer your questions:

Yes, your truck has "off sized" tires. No late model F150 came from the factory stock with LT235/85/16s on it period.

Yes, the base rim on the '97-03 F150 is a 16"x7". Check to make sure the lug nut spacing is correct though.

LT stands for Light Truck, as opposed to the P series tires. In general, an LT tire is a heavier duty tire with a higher weight rating (P series tires must be derated 10% from the listed cpacity when used in Light Truck Applications). LT tires generally have more belts and take higher inflation pressures.

If you have E series tires on your rig, they are wayyyy more tire than an F150 will likely ever need.

 

Thanks for the replies. On the door label I read 235-70-16. So what's on the truck (LT235-85-16) is way off, about 5-10% larger in diameter. So, actual mileage is also higher. Well, what can I do? After all, it was an as-is auction.

I will check the bolt hole spacing tomorrow.

Let me ask you two more questions.

1) I was going to buy a used tire (for spare) from the junk yard where I bought the spare rim. But their tire stock was not impressive. Do most tire dealers like Tire Kingdom or Pepboys (in Florida) sell used tires?

2) Since the truck is much heavier than any passenger car I have owned, I feel uncomfortable driving the chunk of steel without maintenance. I can think of engine oil/filter, transmission oil/filter, wheel alighment, fuel filter, brake pads/shoes. What else would you recommend? The truck is 97 F150 with 48K on odometer (or 52K miles actual).


Thanks.

 

should make sure to get the front end checked out (ball joints and tie rods) i know my ball joints have been bad on my 97 since about 55,000 miles....... i now have 130,000 miles. there just doesnt seem to be enough time in the day to get them done.

 

Check the wheels you got. The 92-97 F250HD and F350 used 235/85/16 for stock tires. The wheels were 16x7 and it wouldn't suprise me that junk yards can't tell the difference between an 8lug wheel and a 5lug wheel Check to see what the lug pattern is. If its 8 lug and from a 97 then its 8x6.5", if its a 5 lug from a 97 then its a 5x135mm which is what you want. What I would reccommend doing for a spare tire is walk the yard and try and find a 97-03 F150 and check them for spare tires instead of buying from the yards prepulled selection. Many of the trucks came with that size spare regardless of tire size being run. Mine came with 255/70/16 and my spare is a 235/70/16. For other things to check on the truck would be to check/change the gear oil in the differentials. It will use 75W140 synthetic oil which is kinda hard to find. Ford carries it and I've heard of a few parts stores now carrying it. Ford wants $14/qt here, cheapest I've seen it at a parts store is $10/qt. I would also get the coolant flushed and then I would install a remote filter kit for it. I've seen how much crud can be caught by the filters and there is no way I'll run a truck without it after seeing that. Also check the air filter and the maf for signs of buildup.

 

Thanks for the tips on maintenance. Guess what I found when I opened the hood! Engine oil, transmission oil, coolant, and air filter were absolutely clean. Apparently, they replaced/topped all fluids right before the auction in order to hide the real mechanical condition from prospective buyers. Way to sell a used car!

Both rims have 5 stud holes, and the hole center-to-hole center distance between neighboring holes was same on all. Though I could not measure the diameter of hole centers accurately, it appears to be 135 mm. So I guess I bought the right rim. I will hit a junk yard one more time to pick up a spare tire (and a emergency jack).

I am a little puzzled by the spare size being smaller than the regular size. Does it not affect driving? The smaller tire spinning faster than the regular one, especially, in the rear axle? Does the differential gear take care of this difference?

I could not find 75W140 from a local auto parts store. I will check internet. Ebay may have it.

Thanks a lot for your help.