What is required to run 33s?

[CatBee]

I have a '93, 4x4, single cab, and it has the stock tire option of 235/75R15 which are 29s. They of course fit fine, but I want to try and get some bigger ones the next time I need to get tires. I know 31s (265/75R15) were the biggest stock size for my year of truck, but I want to know what modifications have to be done to fit 33s, specifically a 33x10.5R15. Currently the only suspension modifications is a front lift/leveling kit. I did not install it so I don't know how tall it is, but it is close to the height of the rear, maybe an inch lower the rear is, and the rear appears to be unmodified. How big of a lift, suspension or body, is required to run 33s without worry of rubbing?

 

[lil_Blue_Ford]

If you cut your fenders, then you don’t need any lift

3-4” of lift would probably work unless it never gets flexed up off-road.

Personally, suspension lifts are better than body lifts. You will want long arms for the front though, because flex and ride quality can be a thing.

The biggest question is what gear ratio do you have? 3.73 may be acceptable but not ideal. 4.10 is much better.

 

[CatBee]

I have a 3.73, but right now the gearing is kind of short imo. I did the gear ratio calculator stuff for cruising and I'm ok with the rpm a 33 inch tire would give me, that V6 makes good low down. Is that 3 or 4 inch measured from ground to frame rail? Or some other point?

 

[Curious Hound]

. Is that 3 or 4 inch measured from ground to frame rail? Or some other point?

That depends. Of you do a body lift, the distance from ground to frame won't change. If you do a suspension lift (highly recommended), it will. Of course, when talking about tires, you're interested in clearance from tire to body. Unless you are highly skilled and experienced, you will most likely buy a lift kit from an established manufacturer like Skyjacker. It will include everything you need and you just install it. You don't really need to worry about the measurements from ground to frame. You install the parts and it does what it does. If you have a good flat, level surface to park on, it is good to take before and after measurements of all kinds of things so you can make comparisons and know exactly what changed and how much.

One thing people often don't think about is that tire clearance is a dynamic thing. It changes in many ways. The front is the hardest part. When you turn the wheels left or right, the tires get closer to the fenders because the effective diameter for fender clearance gets bigger. You must actually measure diagonally across the tire. So it is bigger than 33" diameter. If one front tire climbs up on a rock and bears most of the front weight of the truck, it geys stuffed up higher in the fender and making a turn at the same time is the perfect storm - diagonal tire pushed up high. That is ideally the scenario you want to measure and plan for. If all you ever do is drive slowly on flat level pavement, much bigger tires fit without lift.