2nd Gen Non-Engine/Transmission changing tire size

[cmills]

I have a 99 4x4 that came with 245 75R 16 tires but would like to put 265 75R 16 on it to just fill up the wheel wells a little (I know it isn't much) But I want to know how much it will change the speedometer reading and if there is any negatives about changing tire sizes?



Thanks,

Cory

 

[SRadke]

I went from 245-75-16 to a set of 255-85-16 on my 96. This added from 8-9% to the ground speed (relative to the speedo). Your change should be about half that.



-Scott

 

[fkovalski]

I believe that the electronic speed sensor that is stock to your truck will allow you select the setting for the tires that you wish to use. The 265's were a factory option size and they incorporated that setting into the speed sensor. It has stock settings for either the 245 or 265 stock tire heights. I do not know if the adjustment can be done by the layman of if it is a dealer service option. Other here I'm sure will advise.

 

[DragonflyDriver]

Not sure if my '96 experience relates to a '99 model but I went with 265s and now my speedo is accurate. I was doing 55 when indicating 60 with the 245s. I'm putting less miles on it now because of this. Unfortunately for my false reality, the mpg became accurate also and dropped to about 19 unloaded from 21 which calculates out with the change in speed.



Never liked how the 245s looked, even on this 4x2.

It also rides a lot better now.

 

[cmills]

speed sensor

Can someone clarify the deal with the electronic speed sensor, do I have to take it somewhere to have it changed or can I do it myself?



Thanks,

Cory

 

[Bob4x4]

The dealers can once again reprogram the pinion factor using the Drb. They have taken that feature away and returned it a number of times in the past. If you need it to be done you might want to act now. There is no telling how long it will be available this time.



Bob

 

[cmills]

speed sensor

Thanks Bob, if they do this is it like a reflash where they can mess up a bunch of other things in the process? Also if they reset it, I assume it would make the odometer read correct also, right.



Thanks again,

Cory

 

[Bob4x4]

it is not a flash,just a change in the abs module to adjust tire revolutions per mile to make the speedo accurate for different tire sizes.



Bob

 

[cmills]

sensor

do they switch out a part or do they plug into the deal under the dash, Does this also Correct the odometer? How much do you thing they will charge me to do this?



Thanks,

Cory

 

[Bob4x4]

Cory,no parts are changed. The scanner is plugged into the dlc(data link connecter) under the dash and changes the tire revolution per mile setting. This will also make the odometer accurate.



Bob

 

[cmills]

thanks

Thanks for the info Bob, the worst thing is, they will probably charge me for a whole hour for a 10 min job.





thanks again,



Cory





Merry Christmas

 

[Partyat33]

You might be suprised. I went from 235's to 265's and now according to my GPS I am only off by one or two mile an hour. So now its actually right.



Dennis

 

[klenger]

Here's a link to an Excel calculator that will help.



http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls

 

[SRadke]

Dennis you're right, 235-86-16's are almost exactly the same height as 265-75-16's. This is due to the diffrent aspect ratio (the second number in the size).



-Scott

 

[dram99]

speedo reprogram

go to the tire manufacturer and get the revolutions per mile that the tire rolls. in the case of michilen it is on their web site, as with most tire manufacturers. then go to your nice, friendly, good, dodge dealer and have them plug in the odbII scan tool. they have three options for tire size----- 245x75, 265x75 (235x85), and 'other'. 'other' lets them program the revs per mile. i placed 285x75x16 mich ltx on mine and they programed the pcm to 815 res per mile. . dead on with a gps... i'm happy. .



hope this helps with all who think bigger tires look better... i do, 285's fill out the wheel well better that the 245 wheel barrel tires. .



duane 99 2500 105k and happy