hello all, Im getting ready to lift my 2 wheel drive truck that has the stock 30 inch tires to 35 12.50's do i need to redo the computer chip if I change the gears to 4:56 from the stock 3:55's any help would be greatly app.

Thanks
Dale

 

Hi Dale,

For future reference, it helps greatly if you'll please include your model year in addition to the other info you provided (2WD, tires, gears, etc.), as the answer to that question & many other questions varies greatly depending on what model year truck you have there. Just FYI..............

If it's a 1999 or newer F-150, yes, you will need to have custom programming done in the Superchip to correct the speedometer, odometer & the shift points if it's an automatic.

If it's a 1998 or 1997, then you'll need to change the speedo gear in the tailshaft of the transmission.

For pre-1997's, and I don't remember how far back this goes, they have a dash cluster that will allow the speedo to be recalibrated a certain number of times, I think it's 5 or 6 times, over the life of the vehicle.

If yours is a '99 or newer, give us a call & we'll be happy to take care of the custom propgramming needed in the Superchip.

Good luck!

 

Its a 2001 2 wheel drive 5 spd. v6, besides the speedo being off will it mess with any thing till i get the chip?? or can I wait and put the chip in when I do the gears in a couple of weeks.

Dale

 

Driving it will be sluggish but it will still drive. Your anti-lock will not work properly and possibly set off a code. Either way, you can still drive the vehicle.
-Tom

 

Hi Dale,

OK, since it's a 2001, yes, you do need to have us do a custom program to update your Superchip for the tire size & gear ratio change.

The way these OBD-II Ford F-150's are set up, you can drive the vehicle with the speedometer being off, even if you have an automatic transmission instead of a manual. You will still have your normal braking functions, the PCM looks at numerous data streams to confirm VSS (vehicle speed sensor) data. Though they are what some refer to as VSS dependent (vehicle speed sensor) systems, you will still have normal braking functions, though braking *effectiveness* will certainly be decreased somewhat from adding that much additional weight & load and shifting the polar moment of inertia higher, etc.

You definitely do need to change those 3.55's to 4.56's with 35" tires, that is the correct gear ratio to use. You do not want to drive it around on 35" tires with the stock 3.55 gearing for any length of time, your clutch sure won't like it and the performance & fuel mileage will be in the toilet.

Using 4.56's with the 35's will allow the engine to turn very close to the same rpms for a given speed & gear with the 35" tires as it does with 3.55's & the original factory tires, so that will take care of allowing the engine to operate up in it's power band. You will still need correct speedometer calibration, both the gear ratio and the tire size will need to be corrected for in the powertrain program, and that can certainly be done in the Superchip, not a problem.

Just give us a shout & we can take care of that for you whenever you want that taken care of, & good luck with your tires & gears!

 

Thanks mike, Ill give you a call when Im done putting everything on.
Dale Balser

 

You're very welcome!

By the way, our web site is being built currently (troyerperformance.com), so if you happen to take any photos of that truck with the big tires, lifted, or what have you, etc., that you'd like others to see, feel free to send them our way for inclusion in our customer gallery on our web site.