2nd Gen Non-Engine/Transmission Bigger tires vs. speedo/miles

[SWEdholm]

Hay guys,



Just put 285's on my truck. Got 59,000 turns on my first set of BTG KO's (265's). My problen seems to be a difference in speed when I compare it to a GPS while going down the road. GPS says I am going 2. 8 miles per hour faster than my speedo. shows. Also, during a mile marker comparrison I showed approx. six miles short of the mile markers (in 100 miles of mile markers).



Question, is there a way of adjusting the speedometer to accomadate the larger tires? The Dodge Boys say that the tire is larger the the Manufactures recommended 245 size and they would not adjust. A friend said he looked up some stats for adj. the computer input and the Dodge Boys he went to "rolled back" and made an adj. that has seemed to work.



Any ideas out there?

 

[carson6]

my 315's ...

... throw mine off 15 mile@ 100 mile marker's (when new)stock tire's were 30. 5" and my 315's are 35. 5" but i like it

 

[Mundgyver]

What you want is an Abbot Ration Controller. I put one on my truck and it works like a dream. Tire size is not a problem.



http://www.abbott-tach.com/era.htm



Check this site out.

 

[243]

Will the ERA work correctly with 4-WABS?

 

[elamb]

I just talked to my dealer about doing this last week. I have 265/75/16 and I want to go to 285/75/16. They told me no problem that they could go up 1 size from factory. Costs was $65. I am not ready for tires yet, I was just curious.



Goodluck

Eric

 

[tcourse]

The upside

is you can add extra miles to your warranty.

 

[WadePatton]

Originally posted by elamb

I just talked to my dealer about doing this last week. I have 265/75/16 and I want to go to 285/75/16. They told me no problem that they could go up 1 size from factory. Costs was $65. I am not ready for tires yet, I was just curious.

Goodluck

Eric

There's a limit to how far the dealer can correct the speedo, I think it is 305's or so. After that you'll have to use an aftermarket correction device.

 

[KevinO]

go to www.superlift.com and they have a true speed sensor you can wire in. I have 315's and it is keeping the miles off my truck I wouldn't want to know how much i've saved in the two and a half years the tires been on.

 

[C. Harlan]

Why would you want to correct your speedo?? That's kind of dumb, if you really want to log more miles on it... Think about it. you are saving miles on the clock, but to each his/her own. . Oh well... .



-Chris-

 

[Loren]

I have the TruSpeed from Superlift. I bought it from Rickson.



Great service from Rickson and great service from Superlift. The computer failed a couple of months back and I called Superlift. On their instructions I returned it. I got back a brand new one free of charge.



Superlift never asked for a receipt, nor any other warranty proof. The original unit had been on my truck for 25 months. It comes with a one year warranty, but obviously Superlift will back it up for much longer.



The TruSpeed has a two-position switch so you can have adjustments for two different tires. This is handy if you use winter tires, or switch for any other reason. It's very easy to calibrate by using the percentage method. One turn of the adjusting screw equals a 4% change in mileage recorded. There are also charts showing tire sizes and required adjustments, but they don't cover 19. 5" wheels.



I'd buy another one in a heartbeat.



Loren

 

[BudW]

Anybody have prices for the electronic calibrators they purchased.



I want taller tires but can't afford the consequences of having an inaccurate speedometer (i. e. I bought this truck to carry my lead foot).

 

[Mundgyver]

BudW



Look at my post earlier in this disscussion for the Abbott Ratio Controller. It will do what you want and will alow you to switch to any size you want at any time. As I remember, mine was around $130

 

[243]

Okay, lets try something different...



anybody using the ERA with 4 wheel ABS?

 

[Mundgyver]

243





What do you need to know about ERA and 4 wheel ABS?

 

[MDale]

I work at a Jeep dealership and just adjusted my speedo about a month ago for my 285/75/16, with the DRB3 which is the same scan tool for all chryslers. The dealership can adjust for any size tire but you must know how many revs per a mile your tire size is. You can find revs/mile at the tire's manufacture website.