Whats up guys, Im new to the truck scene and i got a few questions. I just recently bought a 07 FX4 with factory 18's. I already have a Rough country 2.5 leveling kit on order for christmas. :santa:

A. What are the largest tires i can put on BEFORE i have to recalibrate the speedometer?

B. Which all terrain or mud terrain should i go? ( i mostly just want a good looking tire. nothin to extreme like a super swamper and such)

 

i have 35's and it throws the speedo off a few mph but i have a tuner so i can change it....

 

So 33's would be the safe bet?

 

i can't say for sure...but if noone responds in this forum then post it in the wheel/tires section...im pretty sure tho that if you go with 33's it will still throw the speedo off a little. but granted its only a few mph...i wouldn't personally worry about it...but if you want to be safe wait for a few more answers

 

the mileage thing aint a big deal, you dealer can recailbrate your speedo for about 50 bucks, thats they wanna charge me at my dealer. you can stuff some 35x12.50-18's on it, many guys on here have that setup, they WILL rub your upper control a tiny bit but nothing too bad. or another option is running 305/65/18 which is around a 34" tall tire, several guys on here are running those in the BFG AT on their trucks. either way its better than those crappy stock tires, real offroad tires

 

thanx for your input guys

 

i have 32s and the speedo reads 2 mph faster than my actual speed.

 

Hey, welcome to forum.

To help answer your question about speed correction go to the following website and type in your specific info.

http://pw1.netcom.com/~sgalaba/tiresize.htm

Its important to remember that your change in tire size results in a percentage (%) change in your speedodometer. Not very noticeable at low speeds, however at faster highway speeds it could get you in trouble. After upsizing my tires my speedo was off by 11%. That is, the speedo was showing that I was going 11% slower than I actually was. So 65mph was actually 72mph. I invested in an engine programmer that allows me to adjust tire size anytime to correct for this discrepancy.

I have a 4x2 with a 2.5" leveling kit. I am able to run 33's with no problem. I would think that the factory clearance of the FX4 coupled with a 2.5" leveling kit should allow you to run 35's. I have read in this forum and others that mud terrain tires with large outer lugs tend to rub heavily on the upper control arm.

Lots of great choices in All Terrain including BF Goodrich, Nitto, Toyo, Cooper, Dunlop, ProComp, just to name a few.

Its important to consider the wheel that the tire will be mounted on. Not enough backspace and offset could put the tire in contact with suspension and thus rubbing.

 

When I have my 325/60/18 (33X13X18) Nittos on vs. the stock Goodyear 275/65/18 my speedo is only off by 2-2.5 mph. With a 35" tire your wold probably be off by 4-5 mph.

 

http://http://www.1010tires.com/TireSizeCalculator.asp
heres a good tire calculator ive used. they let you input the stock tire size and what tires you want to run, it tells you sizes and what not and then it also shows what the speedo shows at 60mph and how fast you are REALLY going.