Taller tires...etc.

[GreenF350]

So I stopped at our local dealership today and wanted to know if 1) They could reprogram my computer for my larger tires (35" supposedly the biggest tire it can be calibrated to) and 2) To see if they could tell me whether any work had ever been done to it regarding the notorious cackle. I was told that they can't recalibrate for tires that size and that they "think" the records for that model year (2000) have dropped off of record. WTF? Everytime I go in there for something I get brushed off or told something I know is BS. I don't even know why I go there anymore. It's not like I am trying to get something for nothing, I figured they would charge the usual amount to hook up a computer to recalibrate the speedo. Ok, I'm done complaining now....

Anyway, I can get the computer recalibrated for 35" tires correct? Or do I need to buy the superchips recalibrator or whatever it is called? Thanks.

-Aaron

[ShawnCT450R]

Hey there Green

When I had my 99&1/2 done at 4 wheel parts, they told me that the only way to adjust the speedo on a 7.3 was to purchase what they called a "true speed" unit and use that to adjust the speedo for different tire sizes, gear ratios, etc. Hope your not as bummed as I was at the time.

[akduece50]

just go inside your speedo and re set your need how ever miles it off. Thats what i did.lol. when im not moving it says im running 11 miles a hour but hey atleast goin down the road its right

[akduece50]

Needle*******

[GreenF350]

Not a horrible idea actually, except that I can deal with the speedo being off. (Only about 4 mph at 65) I just keep reading that it messes with the transmission too. I don't know how bad, but I figure every thing I can do to help out the transmission is a good thing.
-Aaron

[akduece50]

i hope it dont........lol if u figure something out lemme know cause like u said anything to help the tranny is good

[Bizkitbroke]

I asked my collision teacher about this very thing to day. He said I could purchase a speedometer gear or servo to correct for taller tires. He said it was like every tooth on the gear was 3 mph. Maybe a tech can help with this.

[bigcountrysg]

The simpliest way to correct the speedometer, is to get true speed, or the speed correction computer from super lift. Those are the only two I know of. They plug into the wiring harness, and your done a simple plug and play unit. Also if you ever take them tires off and go to a smaller tire lets say as if you sell the truck. You can keep the speedometer corrective computer. This way if you get another truck you can hook it up to that one if you put bigger tires on it. It is the simpliest way I know to do what you are wanting to do.

Your teacher was correct on that one tooth is approximately 3 mphs. Bigger gear ( more teeth) means slower speeds, smaller gear ( less teeth) means faster speeds. I believe you would have to go to a bigger speedo gear for what you are trying to do as well. If you wanted to switch the speedo gear. being your stock tire size was 265x75xr16 or 31x11.50r16, now your going up to 35x?xr16, 315x?xr16, that is if you are keeping the stock tire size. I believe you would need to go up 2 teeth on the speedo gear to get the closest correction by switching out the gear.

[lilredpowerstroke]

First off the speedo on our trucks are electronic so there is no gear to change out. Second the Tru Speed is from Superlift and is the only aftermaket speedo recalibraion I know of. The tranny is out of whack but just because it is not shifting when its suppose to, also the ABS is also not 100% right either.

[Marty]

Originally Posted by lilredpowerstroke

First off the speedo on our trucks are electronic so there is no gear to change out. Second the Tru Speed is from Superlift and is the only aftermaket speedo recalibraion I know of. The tranny is out of whack but just because it is not shifting when its suppose to, also the ABS is also not 100% right either.

That kind of hurt just reading it.

I've heard there is a way you can override the speedo 5 times before needing a new one. There is a specific order in which you do something that sets it. If I find it Ill let you know.