new 32's,-speedo recal.

[William Schumacher]

well:, with the 265/75/16 ko's,up from 255 70's,my speedo has got to be off,how can I have it recalibrated with the new tires,is it computer changeable,or a needle gear.

p.s. : my dealer tells me it can't be done on my '99 ???,

I don't beleive them.

thanks,

 

[William Schumacher]

thought I would mention this, my dealer now say's that if the ABS light don't come on,then theres nothing wrong with the speedo cal. ,he said the light would come on if the speed was off ????????

anyone know for sure thought this was adjusted by computer,rabs or something.
thanks,

 

[Keach]

Speedo Cali.

Bill

Yes your speedo is off. Grab a gps unit and double check to see how far your off. I went to 31x10.5's and it was off about 3-4 mph. My dealer sd it couldn't be done either. I went to Grande Ford in San Antonio (where i live) and the tech put it on a computer and made the adjustment, took 10 mins and cost 30.00 bucks. Call them and ask for a service advisor and he will tell you whats up. Here's the # (210)661-4121. All they sell Ford Trucks and they have handled this on Explorers - F350's. Hope this helps.

 

[Tom Wilk]

Well, the computer has no clue as to what size tires you have on the car without telling it. The ABS will only have problems if the tires are different sized between the two axles (or possibly between two sides of the same axle). The dealer is not correct.

I made the same tire size switch as you, I think I posted the results in another thread. I chose to leave it as is, with the speedometer reading correctly and the odometer reading 5% low (speedometer was reading high before the tire switch). So, I don't know the procedure for a 99. I suspect still that it has to be programmed into the computer.

I recall reading on the F150 web site that someone had to reprogram his truck for 33 inch tires and 4.56 gears, but the dealer didn't have those sizes listed in their computer. It seems that they only listed tire sizes that Ford offered as well as axle ratios that Ford offered. So, they did some calculations and came up with an equavalent tire size/gear ratio that matched something Ford offered to get the correct calibration.

Try to talk to an actual mechanic if you can. My guess is that you talked to one of the service "manager" people and they aren't mechanics. They are more like salespeople for the service department.

 

[William Schumacher]

thanks guy's,I'll give the Grande Ford guy's a call to explain what has to be done,my dealer is pretty big for the area too(Smith Cairns Ford),makes you wonder cause I went in not asking if it could be done, I went and said do it via the computer,
I'll let you guy's know how I make out,

 

[William Schumacher]

against the law to change computer ????

I phoned grande ford and they said to change the parameters in the computer using the NGS system that my dealer may not have,so I phoned my dealer again and now they tell me,it's against NY state law to change the computer,a few minutes more of screaming back and forth,then he tells me against federal law to change it,and keeps saying we could discusds this all morning but he aint going to do it, ,

 

[GJarrett]

Find another dealer

Mine did it no problem. All you are having them do is recalibrate the computer to accurately reflect your speed. It has nothing to do with the emissions calibrations, etc.


Some dealerships say it cannot be done but I figure that's because they do not have a tech trained recently enough to know how to do it. We've been through this before; I cannot remember who but someone in San Antonio (was it you, Keach?)had a dealer tell him it cannot be done but he went somewhere else and got it done once he found out my dealership in Dallas could do it.

 

[William Schumacher]

HI Jerold:,a phoned a few dewlerships,but everyone say's the same thing,I beleive they just don't understand how to do it.and by saying what he's saying,he's off the hook,
I phoned grande ford again, and he said I would only be off 2 or 3 miles,I may just leave it. .one thing my dealer said was that when we were shouting at one another,he said that this changes the way the truck burns gas,emisions, etc.
not more I could have said. he's an idiot
thanks,

 

[Maniak]

You went from a 30.1" tire to a 32.6" tire.. (big 30" to a small 32").. Assuming your speedo was dead on before.. you speedo is now 5% off.. (reading slow). It is easy to figure out.. If you doing 55.. just take 10% of it.. (5.5mph) and then take 1/2 of that... so at 55 you are doing 52ish... Your speedo is analog so being exact isn't important.. After you do this for a short while it will become 2nd nature.. Our speedo is currently 18% high (reads high) from gearing to 4.10's with 32" tires.. after adjusting it for 30" tires with 3.27 gears. I personally wouldn't worry about being 5% off. Once you get farther off then worry..

for future reference... To figure this out you do the following...

265/75/16 tire size...
265/10 (change mm to cm) = 26.5cm
26.5/2.54 (to convert to inches) = 10.43" This is the width
10.43*.75 (height is 75% of width) = 7.8"
7.8+7.8 (you have two side of the tire) = 15.6"
16+15.6 (add the rim diamter to the tire height) = 31.6"

The old tire (255/70/16) is 30.1"

The difference between 30.1 and 31.6 is 5% (31.6 is 105% of 30.1)

I hope this is of use...

 

[William Schumacher]

ok guys,this is what I found out,
1'st,measure the diameter of the tires,divide that by (63360)you should get a 3 digit #
the dealer should use what is called an NGS scanner,
with the scanner,he would take out the red card,and insert the green card,on the screen go to service bay,from service bay,go to ABS,from ABS,go to tire size change,this requires a 5 digit #,start with 00 then add the 3 digit # so it's 5 digits long, then hit done, do it over again to make sure it took the change.

now does this sound illegal to you ????

 

[CBoug76]

Guys,
What ever happen to just changing the Speedo Gear like "Robert" Suggests in this post??? =
Dead Link Removed


Chris

 

[William Schumacher]

computer driven now

Chris:, it's not the same type of system anymore,they are making it harder to do,it's done by computer now,a few guy's have gotten their dealers to do it,mine won't. I have found one willing to try,even though they have never done it before.the procedure is in the above post.
but thanks for the reply,

 

[CBoug76]

Ahh ok, I Guess i would be all set either way, since i have a friend and his son who own a NGS tester who work as Ford Mech's. =)

 

[Robert]

Re: computer driven now

Originally posted by William Schumacher
Chris:, it's not the same type of system anymore,they are making it harder to do,it's done by computer now,a few guy's have gotten their dealers to do it,mine won't. I have found one willing to try,even though they have never done it before.the procedure is in the above post.
but thanks for the reply,

Keep us up to date if your dealer is successful. I am curious. It has been reported in another thread by I think JGarret that a dealer reprogrammed his for $75. I would certainly remember which dealers were helpful and which were not. For curiosity, have you looked under your '99? The poster that I mentioned had a 4-speed Auto so if you have a 5-speed automatic like my '97, see if you have the gear. When I made the same tire change as you, my speedometer read about 3-4 MPH low at 60 MPH. Not much, but I wanted it to be right. Changing my gear did just that.

 

[William Schumacher]

Robert:, I spoke to Grande Ford in texas,they come recomended by Gerold and Keach,they seemed to know what they were doing,they only sell ford trucks,they said it's not done by gear replacement anymore,it's done via the abs system,through the NGS scanner.not sure what year this started though ????,
but thanks,

 

[Robert]

Originally posted by William Schumacher
Robert:, I spoke to Grande Ford in texas,they come recomended by Gerold and Keach,they seemed to know what they were doing,they only sell ford trucks,they said it's not done by gear replacement anymore,it's done via the abs system,through the NGS scanner.not sure what year this started though ????,
but thanks,

Gerald was the one I meant in my other post. I noticed in his tag that he has the SOHC V6 which would have the 5-speed auto as well. Therefore, your dealer is correct (as Gerald pointed out to me) your '99 does not have a speedometer gear, but can be reprogrammed through the computer port. Since the '99 don't have a gear and my '97 does, it leaves only the '98s in question.