I am finally getting rid of the 255 70R16 Goodyears that came on my truck. I would like to go to a 265 75R16 in a Bridgestone Dueler AT. What are the consequences of going to the larger size tire. I know speedometer and odometer will be off. I think truck will show less miles than actually traveled with bigger tires. How far off will the speedo be? What about the bridgestone tires (good,bad). My truck is a 97 F150 4x4 SC 3.55 rear automatic. Thanks in advance.

 

Check out www.tirerack.com They have a wealth of information on sizing and performance of brands.

 

Larger diameter tires has the same effect as lowering your gear ratio too. It would be like going from a 3.55 to a 3.08 or close to it. I did not do the math. I plan to go with a 265/70/16. A little taller and a little wider. The 265/75/16 is much taller than stock.


------------------
97 F-150, 2WD, Reg Cab,Flareside,Dk Toreador Red, Windsor 4.6, Magnecor 8.5mm wires, Bosch Plat +4s, 3.55 LS, EGR Bug Deflector, ******* Bed Cover, Bed Liner, XL Full Length Running Boards, Air Aid Kit, Gibson Single Out Cat Back, Superchips, TransGo Shift Kit, Hellwig Rear Sway Bar, Hellwig 2500# Overload Springs

 

More like going from 3.55:1 to 3.38:1 if I remember correctly and about 3-4% off on the speedo to go from 255/70's to 265/75's. Again, If I remember correctly. I am over 40!

------------------
97 F-150 SC Lariat, Styleside, White over Gold, 4.6L (Windsor), Automatic, 3.55 rear end, electronic 4X4, w/ every option of Lariat and ORP packages except the 17" wheels (I even got the OR decals now!) MOD's so far: K&N air box mod, Gibson Super Truck, clear Bugflector II, Leer TSC 600 hard cover, Bridgestone Dueler OWL ATP 265/75 R-16's, TrailMaster Invader N7 shocks, Smittybilt step bars, Ford moulded mud guards, "White-white" head lamps, Cloud Rider Design's SS Grill and bumper opening, Bosch Platinum + 4's, Hayden 30K+ Tranny Cooler,Class III Reece load distributing hitch system, full wiring including trailer battery charging system, Escort Sensor II Brake controller, Superchip

 

I agree the 265 75R16 might be a little big. What about the 245 75 R16 in the Bridgestone AT. How much difference will that make in the look of the vehicle from the stock 255 70R16's. From what I've read it will not effect the speedo much.

 

I went with the 265/75 R16's. I like them and do not consider it too big. Not having any problems with them judt have to keep an eye on the speedo cause when I am doing 55 I am really doing 57 and so on. No one will tell you that going up one size will hurt even the dealer will agree with this and did. Everyone is just trying to make you aware of the other changes that happen.

 

I am hoping to upgrade my 265/70/17's to 285/75/16's, and am going to stick with the 3.55's (for now anyway). I would not worry about 265/75/16's. They are actually the same diameter as my 265/70/17's. It will throw your speedo off a little, but I wouldn't worry about loss of power.

As for your question about the 245's...that is very little difference from your stock tires. The 245's are a little more narrow (about .3" narrower), and just a little taller (.4" taller) than the stock 255's.

------------------
'97 F150 4x4 Off-Road Extended Cab Lariat Flareside white/tan, tan leather, 4.6, 3.55

Duraliner bedliner, Husky floormats, Custom seatcovers (I only cover the leather when I'm really dirty, though), Premier single-lid toolbox

Gibson 2.5" split-rear exit cat-back exhaust, K&N Air Filter

Many more modifications to come

http://ocu-stars.okcu.edu/cvenable.stu/index.htm#b

 

i just had BFG A/T 265/75r/16's put on my truck a few days ago. What a difference, i love them. I noticed a little drag going up a hill but i just down shifted and that took care of it. What i really like is the look, they improved the look of my truck 100%.
mel

------------------
99' Black F150 ext-cab
V6-Manual 4x2
Mods:
Tinted Windows
Awia CD Player
Pioneer Spkrs
Flowmaster Exhaust
Rear exit/18" Chrome Tips
K&N Filter
Stainless Steel Nerf Bars
BFG A/T 265/75R/16's

 

The tire sizes are as follows:
255/70/16 = 30"
265/75/16 = 31.6"
285/75/16 = 32.8"
265/75/17 = 32.6"

wouldn't it be easiest to put 285/75/16's on and go to Ford and get the necessary parts to have the speedo and computer calibrated from a F-150 with the ORP? The two sizes are only .2" different in height.
I have been pondering getting bigger tires myself and I have been trying to figure out how to keep the speedo as accurate as possible.
I'm not so worried about the gearing because trucks with the ORP package come with 3.55's too, so the difference shouldn't be enough to cause problems with shift points etc.
Any input??

------------------
2000 F-150 XLT, 5.4L, 4x4, auto, Extended Cab, Deep Wedgewood Blue, 3.55, Towing Package, Sliding window, CD player, 4 wheel abs/discs, 255/70/16's, build date 11/99, no mods...yet

 

Nice try Blue but the ORP comes with 265/*70* R17's not 265/*75* R17's like you used in your calculation. You will find that the 265/75R16 and the OEM ORP tire (265/70R17) is about the same diameter. 31.6 vs 31.5 inches. If you go to 286/75 R16's you will need a bigger reclibration than just using the gear out of an ORP.

 

Just a reminder,

There are no gears for recalibration of '99 and '00 speedos, it has to be done in the computer.

------------------
BLK 2000 F150 XLT 4X4 SuperCab SB, Shift-on-the-fly, 5.4L, 4R70W, 3.55 LS, 4-Wheel disc/ABS, ORP, Keyless, PWR Seat, Slider, Soft tonneau, Cab steps.
MODS: Rhino, Molded flaps, Mobil1 0W-30

 

cphilip..my bad thanks or correcting me on that one.
So if 99 and 00 models have to use a computer to recalibrate, who can do it? Dealership?? Aftermarket??

------------------
2000 F-150 XLT, 5.4L, 4x4, auto, Extended Cab, Deep Wedgewood Blue, 3.55, Towing Package, Sliding window, CD player, 4 wheel abs/discs, 255/70/16's, build date 11/99, no mods...yet

 

Boy all this talk about tire sizes and caliberation is making my head spin. I went from stock 255-75(70?)-16 to Bridgestone Dueller 265-75-16 and never even thought about the gears. Now I'm going to 285-70(75?)-16 and wonder if I need to do something about the gears? As for the Duellers they ride great, especially in the rain.

 

Yes highground, you are now at 3.38:1 effective gear ratio and your speedo is off by about 3 to 4%. Same as me! Oh!.. another thing I just learned: you lost about 500 pounds of trailer weight towing capacity as well.

[This message has been edited by cphilip (edited 02-28-2000).]

 

Just in case all were wondering, you can get your trucks speedo calibrated by a company for about 10$, and that'll tell you EXACTLY how much you are off. In Pa, the company my p.d. uses to do our cruisers is called DAVIDHEISER's INC. If you want to know exactly, you can contact your local Police Dept. and ask them who calibrates there machines and cruisers. Anybody that may want the number to DAVIDHEISER's send me an E-mail, maybe they know other companies that do this. But hey, $10.00 would surely beat out a speeding ticket. Also I had 245'70r16's on my Trooper and thought they were allright, am swapping my 255/70R16' to a higher size (265,285) in the near future.
P.S. Had Firestone Firehawks (now called wilderness AT III) on my Jeep and have them on my girlfriends Rodeo (31x10.50-15). LOVE EM' Excellent wear both on and OFF ROAD and great warranty.