I'm replacing the tires on my 01 Lariat Screw and am getting feedback from my tire guy that has caused me to inquire here at the fountain of knowledge and get second opinions from actual F150 owners regarding tire selection. What I would like to do is put a wider tire on my truck....let's say a 255/50/17, keeping the 17" wheels and adding a stockier look to the truck. I'm not stuck on that exact size but have seen that tire on similar trucks.

Here's what I've heard:

1. I can't put that tire on my truck due to it throwing off my speedometer and ABS system, unless I want to have both recalibrated.

2. The load carying capacity will severely diminish? All I want to do is pull a 24' boat. Can I add shocks to help with that?

3. I am lowering my truck 2" in the rear, hence the desire to give the truck a stockier appearance.

I would like to avoid moving up into new wheels at the moment. 20's are in the plans, but I've got to feed the kids and keep the wife happy.

Help!

 

As long as the overall diameter remains the same, it's no problem.
Even if you go up an inch or so, it's not that big of a deal. You have plenty of torque to handle it.

 

I agree with frog. Your speedometer error will show the difference between the old and new tire circumferences (there is a link to a tire calculator elsewhere on this forum). 5% or less should not be significant. I believe the tire guy about the towing and load carrying capability, but you should be able to check the load specifications on the tires yourself. Don't forget to check the tire ratings against your published vehicle ratings (inside the driver door). I've never heard the ABS story before, it sounds like bunk to me. I have always heard that ABS works on a computer "clock", not on wheel revolutions.

 

The tire size you list is not a wider tire than what you have stock. You have either 265/70R17 or 275/60R17 stock depending on what group you got.

In order for me to keep from having to recalibrate the speedo, I had to get 285/50R18's for my truck, which replaced my stock 275/60R17's. I assume you are more set about the 50 dimension, as this is a lower profile tire. The overall diameter of these two stock tires is 30 inches (275) and 31.6 inches (265). Ideally you should stay within these two overall diameters to avoid having any problems.

A 285/50R17 will only have an overall diameter of 28.22 inches, which is considerably less. Your speedometer would say you are going faster than you actually are (which may be beneficial because you are less likely to get pulled over).

Also keep in mind that you can't put much more than a 275 on a stock rim, since it is only 7.5" wide, especially in a 50 series tire. I'm afraid that in order to avoid too many problems, you should consider new wheels as well.

 

CAREFUL, CAREFUL, CAREFUL!

I put the Lightning wheels on my 2wd SCREW. Looks great..however...the new tires were 1.5" larger in diameter. No big deal right? Wrong! Threw off the computer BIG TIME! Tranny shifting was way too early. Truck was in 3rd gear and overdrive at 15-20 mph.

Only fix was a SuperChip which reprogrammed the shift points. Speak to Mike Troyer at Superchips. He'll explain it to you.

 

Dan - what size tires did you go with?? I used 285/60/18 on mine (which are larger than stock) and I did not notice a difference.

 

I swapped the factory 17 inch Goodyears on my 4x4 for same size BF Goodrich All Terrain T/A kos. What a difference. The BFG is a much heavier tire, the ride is better and they are a true truck tire. No problems with tranny, speedo, or clearance.

 

Good Morning ScrewHeads !

Santa, what a guy, bought me some 16" aluminum wheels from
Discount Tires. Goodyear AT/S (305-70-16") completed the package.
This combo works well on a stock (no cutting or spacers) 4 X 4 SuperCrew at 30psi, and I can air'em up to 50psi if needed.



NordicBastard