Dealer flashed my computer for my new 285 Toyo's 2 days ago.

Just finished a 250 mi. trip and checked against my GPS.

Speedo is reading 1.5 MPH high. This makes my odometer read high by the same amount also.

My question is - is this the closest they can get it or is their some other adjustment in the computer?

All they did was select the 285 tire size in the comp[uter.

I have heard the 06's are a little different compared to the earlier years. I had also read where some talked about setting the RPM's in the anti lock section I think.

 

at what speed is your speedo reading high?? Remeber the dealer calibration is using a generic tire size of 285/70/17, but each manufacturer makes the tire a slightly different size eg. toyo might be 617 revs/mile, but the dodge computer matches 285/70/17 up with 622 revs/mile. The older dodge models actually used a revs/mile technique but the 06's use generic tire sizes.

 

I noticed when the speedo was on 65mph the GPS was reading around 63mph.

At a distance travelled on the GPS of 100 miles the odometer was reading 101.5.

I did hear the guys discussing tire brand while doing the recalib., said they doubted Toyo was in there.

You are most likely correct about the brand making the difference. I wonder what brands are in the computer. I could compare to see if any are closer to mine.

 

You can set the tires in the ABS. Use revs per mile-the tire mfr can give you that number, OR you can set by tire height-also get from mfr. It is better to set tire size through the ABS as it controls your breaking, this becomes very important when towing. Just setting via the speedometer/tire size does not take breaking via the ABS into consideration. Your ABS will still be thinking your stock size tire.

I was just into my dealership for a flash/white smoke, and asked them to set my tire size-315's. I gave them instructions as to how to set via the ABS. When all was said and done, the ninnys set my tire size via the speedometer AND since the highest setting that was available was for 285's, that's what they set to. Stupid people that cannot read simple directions and do something right - I have NO tollerance for them. So anyway now my speedo is set for 285's my ABS thinks 265's and I am a very unhappy camper!

CD
CD

 

CD before you go postal on your shop know that the 06s are different and can not be done how you described this has been covered several timeon this board 285 70 17 is a stock size (power wagon) for oe equipment in the dc system that is why it is as big as you can have done. Trust me I have little tolerance for idiots as well but you gotta let this one slide. Save up for a smarty thats what I am doing besides runnin the 315s puts the odometer in our favor for the warranty you will actuall get around 3k more miles out of the 36k mile warranty.

 

nitis:

I have seen this covered in other threads on the 06 but I have not seen anything about the problem I am having.
Is there just the 285 size to choose from and nothing else?
If that is the cast then I guess I will just have to live with the 1.5+ error in the reading.

 

It is a generic number based on the actual math. If anything, it is based on the 285/70/17 BFG TA KO that comes stock on the Power Wagon. Since tires do vary slightly, it could be off based on the brand you bought. You cannot set it for a specific manufacturer's 285 tire.

Is there a setting that will work for you between 265 and 285? Possibly a setting for a larger diameter wheel? I would fix that or change it back to stock because your warranty based on mileage has just been reduced my 1.5% or 540 miles on a brand new vehicle.

My speedo is set for 285's. I have Nitto 295's. My speedo is 100% accurate when compared with the GPS.

 

I can believe that. I just had mine recalibrated to the 285/70R17 for my 285/65R18 Nittos. My speedo is now way off. I was showing 80mph at 1900RPMs!! Going back to the dealer to get it put back to stock. It was only about 2mph off at 70mph before they made the change. The 285 size in the computer must be pretty large!!