i have a 2004 FX4 supercrew with a 2.5 AS. i just put on a set of BFG 35 MTs on my factory 18" wheels.

my speedo is off (obviously) and i wanted to know if others with this tire combo are doing anything to correct it or just dealing with it being off? if so, what are you guys doing to correct it?

also, i've read where there is no need to change the gears with this tire combo. is this true? if not, how much work and money is it to change the gears? is running this combo without any changes harsh on the transmission?

i appreciate your help a lot!

 

Sounds like you need an Edge Evo. I bought one through 4wheelparts for about 400. You can change tire sizes in your computer to recalibrate your speedo and it helps with the power loss due to the extra tire height. I still haven't received mine yet to atest to the hype, but I'll let you know how it goes in a week or so. About the gear change, I have only seen a few members that have changed out the gears while running 35's. The cost of installation for the front and rear gear and pinion is more than the Edge Evo itself. Hope it helps, aloha.

 

I don't think the Edge will actually change your speedometer it just gives you an accurate reading on it's display. If you want your odometer to reflect accurate mileage on your truck as well you need to get your speedometer recalibrated. Dealer did mine for $85 which wasn't much for me considering the cost of tires/wheels. Also if you are under warranty you could run into problems if you don't have verification that the odemeter was corrected for tire size change.

 

I believe most aftermarket computer tuners allow you to correct the speedometer/odometer. You can check the manufactuerer's websites and they will tell you.

 

I have the Edge and it helps I recommend it or the xcal2.

 

When I changed both gearing and tire diameter my speedo was off huge. The Diablo tuner fixed it dead nuts on. Just go to Toyo or Tires.com and get the revolutions per mile for the size tire you have and the programmer. Hopefully Diablo has one for your year as mine is a 2003.

 

I'm running 35's with 4.56 gears,Got most of my low end back, I recomend 4.56's but its all up to you... I also got an EDGE Evo II , mainly to change tire size and gear ratio for the speedo.... But It doesnt work on my 98 F150 ... A little bummed my speedo reads 80 when Im sure the traffic around me is only doing 65 not sure how to fix it...So I set my EDGE on level 3 here are my settings:

WOT 1-2 5250rpm
WOT 2-3 5250rpm
WOT 3-4 4800rpm
REV. LIM. 5650
STD SHIFT +1 on all shift points ( 1-2, 2-3, 3-4 ) might change (1-2) +2 and (2-3)+3 and (3-4)+3
SHIFT FIRMNESS +12 on all ( 1-2, 2-3, 3-4 )

I run 91 octane so I dont mess with timing settings.... I might mess with my WOT fuel levels because when I'm on the gas hard I get a tiny lag between the 2-3 shift, not sure what causes this I'm guessing it is because the WOT rpm are up there,...

thank's

Robert Currie
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1998 F150 Supercab Flareside Lariat, 5.4, 4.56 gears, Truetrac, 35'' Pro-Comps W/ Pro-Comp Wheels, 7.5 Fabtech Lift, Fiberglass Front Fenders, K&N Intake, Flowmaster, Expy Center Console, 7000K headlights W/ Clear lenses, Clear Corners, Tint all around, Edge Evolution II ...

NEXT MOD: Kenwood 717DVD, 2 Kenwood Amp's - Mono 1100 Watt and 4ch. 850 Watt, 2 Pioneer Shallow Mount 10'' subs, Music Moose Box, Pioneer 6x8 Door and Rear Speakers-All this stereo stuff is in my room waiting to get installed, no time right now to install it myself...