Thunder_God_69
Registered User
Hey guys, I'm new here. I am really curious as to what most of you will think in regard to my tire size question. I have a 1988 F350 with the 7.3 IDI.....it is stock, so no turbo. I have been restoring the truck, and am about to do some Alcan offroad leaf springs front and rear. They will be a 3" lift in the front, and a 2" lift in the back. The truck would easily fit 35's now with no issues, I am currently running 33's with LOADS of room to spare. The truck is a manual ZF5 with 3.55 gears. I have thought about changing the gears to something more aggressive, but honestly I don't use the truck to tow, and the most it ever hauls is a load of firewood. Also, the 3.55's make it really nice to drive on the road.....I can roll along at very respectable speeds, and the motor is not screaming. With even bigger tires.....it will be even nicer once cruising, in my opinion, cause the motor will be at even lower RPM's.....and if I hit a hill it can't pull, I can always just grab another gear. Now I have done the calculations, and going to 35's will lower my RPM's around 100, 37's will lower them around 200.....pretty much across the board. I did the calculations in 4th gear 1:1 and in 5th gear .77:1.....I honestly think that the truck would still be fine with 37's.....it still has a lot of low end torque, even with no turbo, and 1st gear is sooooo low, that I don't think it will affect it much off the line. I do have 150 acres of land, and that is where it would shine.....in first gear, and low range.....tire size will not be an issue, lolol.....it is unstoppable with the gear reduction it seems. Anyway, I would really like some input on this, as my leaf springs will be in soon.....and once I put them on, I'll be buying the new tires for it. Thanks in advance for any advice you can give me.
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