This is into regards of changing tire and gear size. If you have a 98 and newer truck you do not have a speedo gear in your transmission. You have to get your speedo reprogrammed in the vehicle computer. The only people who have the software to do this are your Ford dealership. They can only go 2 sizes up or down. So if you have say 33’s, 35’s Ect, they can not do it. Now if you are like the most of us who get gear changes to, then you are screwed. They can not do a speedo recalibrate with any gear or tire combination. So you ask, how can we fix this? You can make sure that when you change the tire size you also get the exact gear change to compensate. This is not always achieved. Take me for instance. I have 4.10 gears and 33/12.5/17 my speedo is off 6mph. Here is the other solution. You have to get a Superchip with a custom program. I have Mike T working on one for me right now. This will be the aspirin to my headache from all of this. They can recalibrate the speedo for you. This is a post to give other people a heads up and help people with this problem. I made a lot of phone call and trips to local shops and was not able to get anything done. I also took it to Ford and like I previously stated they could not do anything either. Well anyway, I hope this helps someone. If anybody know of any other fixes to this problem please post them. Thanks

 

If I understand correctly. If I go from 331 to 410 ford cannot recalibrate my speedo even if I keep same size tires.I have a 2000 f150 w/16 inch tires.

 

Rus, I know it sucks but yes you are right. They can not do anything about gear changes. I posted the same topic in the "Wheels and Tires" thread. There seems to be reply's over there. Maybe you can get some more answers.

 

Well, I guess I'll have to go out there and tell my truck that the speedo drive gear I put in when I had the 4.10's installed and again when I put 33" tires on, really didn't change anything. She'll be sooo disappointed!

I think you mean '99 and newer.

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98 F-150 XLT 4X4 ORP Super Cab Short Bed, 4.6, Auto, 4.10's, Mag-Hytec diff. cover, Magnacharger supercharger, K&N FIPK, Superchip, Gibson single cat-back, 80/100w German head lamps, 80w amber fog lamps, Warn HS9500i winch with semi hidden mount, Wrangler dual battery kit with red & yellow top Optima batteries, 285/75R16 Goodyear MT/R's, 16x8 Center Line Hell Cats (JUNK WHEELS), Rancho RSX shocks, B&M deep aluminum trans pan, Rhino bedliner. Needs one more door.
http://hometown.aol.com/ninetyeightfword

[This message has been edited by 98fword (edited 03-03-2001).]

 

Yes I know. Someone stated that in the same post on the tires and wheel thread. I believe they started to do this in late 98. But anyhow, if you have a new truck you are going to run into this problem. Oh, by the way, Ford gave me that info. What the he!! do they know anyway. lol

 

Yes it was me, regarding the year. Sometimes there is people working for Ford that do not know enough to be taking care of customers concerns and questions. And sometimes they just answer whatever it comes to their mind so they don't look like they don't know. What the heck!!!, the customer is not suppose to know anyway.

That's one of the reasons I like this site. Lot of information that I can take, leave, compare, analyze with no cost or headaches, and from the real experience of working with our trucks.

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My Ride: 1998 F150 4x4 Lariat Supercab Flareside 5.4L in Oxford White/gold, ORP, Tow Package, 3.55 Gears.

Modifications:
Optima Red Top Battery
Split Fire Spark Plugs
K&N FIPK
Gibson Supertruck Exhaust System
Stepshield door sill protectors
Performance Accesories 3" Body Lift
Performance Accesories Lift Lips by Mountain Enterprises
Superlift 3" lift blocks
Gabriel Gas Ryder LT VST Shocks
Daystar Front Anti-sway Bar Polyurethane Bushings
Heckethorn Steering Stabilizer
35x12.5R16.5LT BFG All Terrain KO's
16.5x9.75 American Eagle 589's.
McGard Premium Wheel Locks

Photos at: http://www.communicomgroup.com/jmtruck

 

Just curious... what would be the advantage? If you swap gears, and then size new tires to match the original final drive ratio, are you gaining anything in terms of performance or power?



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98 Explorer (Lemon Law Case in Progress)

'00 F-150, X-cab, 4x4, Lariat, Off-road, Trailer Tow, Holandia Sunroof, built 11/99 picked up 10/00!Clear Corners, Manik Stainless Steel 1-piece brush guard, Custom CB wiring, Uniden PC76-XLW CB radio with K-40 Magna-Mount antenna (for now), 1 set of 165 watt KC Daylighters (for now... more on the way) Custom switch mounting plate and overhead console, Bully Stainless Steel Trailer hitch drawbarw/ 2" stainless steel ball.
List of planned mods: Clear tails, torsion bar tweak, bug deflector, spray in liner, and a tonneau of some sort...

93 Probe GT teal, OE rims painted to match, bone stock drivetrain.

 

Since the speed is determined by the hall-effect sensor at the transmission, a circuit could be designed to be placed between the sensor and the computer. This circuit would intercept the incoming signals and trigger a calibratable, output signal stream to give the computer the desired speed rate. I haven't looked at the schematics, but it doesn't sound like it would take too much to design the circuit (maybe a couple of chips and some interface connectors). I'll try and get more information and see about designing a "little black box". Who knows, maybe I can sell it!

 

I'd buy one

 

Check out this web site: http://www.autotransinc.com/recal.htm - they have a device that will do what you are talking about.

I have an 99 Expedition that I changed to 4.10's but the problem is that I don't know which hall effect sensor is sending signal to the speedo. On the Torque on Demand (TOD) system there are two hall effect sensors one for the front and the one for the rear driveshaft and if they read differently, it engages the 4x4 clutches.

This would mean that the box wouldn't work for me but if you have a 4X2 it probably would work (and it is cheap).

I have been talking to Mike at Supechips and he has confirmed that he can provide correction to my speedo through the chip. I have ordered the chip and will post the results.

BTW, I would make the change to 4.10's again in a heartbeat - Ford should make them available from the factory.

Ian


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99 Expedition EB
5.4l, 4x4, 4.10'S
WMS Tube, Bassani Cat Back Exhaust.
Superchip Flipchip on Order

 

Gijoe,if you put on bigger tires it changes your gear ratio. If you change your gears you can get it back to stock. If you just go big in tires it will feel like you have a 4 banger. If you just change your gears then yes, you will feel a major differance in perceived power. I hope I helped. I am sure someone here will have a clearer answer. I love this site.

 

Ian, great link. I am going to call to see what they tell me. I hope someone in Tucson can install it for me. I'm not good with electrical stuff. It all seems to catch on fire. lol

 

TucsonTruck help me out I just went to 285/75/16's from 235/75/16's .The other day one of the local cops had his radar set up and I thought this might be a good time to check to see how much the speedo was off . I held my speed at 30 mph and to my surprise he said I was doing 30-31.

Now I want to change the rear ratio to match the 285's like the present ratio matched the 235's. Can you tell me how and what the problems might be?

99 F-150 2wd Ex-cab WS
Kenwood MP3 player
Kenwood electronic EQ/Crossover
Kicker component 5x7's
Pioneer 50x4 amp
Chassis Tech upper control arms
Lift springs
285/75/16 Mickey Thompson MTX
Elite alum wheels
Painted grille and shell
Painted bumper
Custom graphics
Tow package

Future mods
Subwoofer
Chassis tech lift spindles

[This message has been edited by dwdodd (edited 04-01-2001).]

 

If you are only 1-2 mph off I would just leave it alone. You probably have 3.55 gears. If you got 3.73 you would probably be back to normal. The difference between 3.73 and 3.55 is not much at all. If you ask me it would be a waste of money to change your gears if you are only off that much. Gear changes cost a lot off money. If you start to get bigger tires you can go to 4.10. Now that is worth the money. If you just want to have your speedo read correct you can do other things. If you have a speedo gear in you truck you can just change that out for like 15 bucks. If you dont then you will have to get a superchip from Mike T. He can correct it for you. There is not a lot of problems with gear changes if you have them done right. I even got better MPH with mine about 1 1/2 MPG better. Usually though you will get a little less MPG. All depends on your set up. Well I hope I helped you out.

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2000 F-150 2wd sport 4.2 V6
XLT, Ext cab, auto transmission

(Performance)
JBA Headers:Jacobs Ignition:K&N:Superchip
Throttle body spacer: Cat back exaust
4.10 gears (had 3.55)

(Appearance)
Custom Seat Covers: Dash Mat
Floor Mats: Cd player: Pioneer Speakers
Rockford Amp: Truck box: Rhino Liner
Grill Guard: Nerf Bars: Fender flares
Custom graphics: Tail light covers
Vent Visors: Driving Lights
Tinted windows
3 inch spindle lift: 3 inch body lift: lift lips
33/12.5/17 Procomp A/T