Just got back from a friend's who has the Dodge DRB 3 tool.

He hooked up the thing to the diagnostic port under the dash, scrolled down to the section on the ABS system, selected 'revs per mile'; I told him to plug in 600 (the range on the screen allowed anything between 400 - 900!!)

My GPS now agrees completely with the speedo & the overhead!!

SuperLift - ya waited too long!!

I don't know what was going on with nobody able to adjust their trucks - it took my buddy 2 minutes for the correction!! Go figure...

;D ;D ;D

Rene

 

Yeah, supplier, price, features, etc., etc !!

 

No, no, no!!!

This isn't something ya gotta buy!! ;D

This is the dang tool that every dealer has - it's the diagnostic thingy that connects to the port under the dash, & allows them to read & program the computers in the truck! :

My dealer had told me 'nope; can't put in anything but 235 or 265 for tire size'. In the DRB3 tool, those tire sizes were already in the menu, as choice #1 or #2, but choice #3 was 'Other'; selecting 'Other' allowed us to set the revs per mile, anywhere from 400 up to 900. That should pretty much take care of any size we might want to put on....if the 315 turns at about 600 revs per mile, I can't imagine what size would turn at 400!! Maybe a Monster Truck tire!

Rene

 

Wow, I was just looking at prices for the DRB III Scan Tool and that sucker is expensive!

http://miller.spx.com/data/DC02-07A.pdf

$6000 bucks is pretty darn steep. I wonder if there are any more cost effective alternatives?

 

RamDan3:

I'm not making myself clear --

This DRB3 is a DEALER TOOl; the dealerships have them; the service dept should be able to just hook this up & correct our speedos.

Rene

 

[quote author=gadgets link=board=7;threadid=21524;start=0#msg201995 date=1067265447]
RamDan3:

I'm not making myself clear --

This DRB3 is a DEALER TOOl; the dealerships have them; the service dept should be able to just hook this up & correct our speedos.

Rene

[/quote]

I understand completely what you are saying. The DRB III does a lot more than just recalibrate the speedo. Not all dealers are willing to work with their customers and are as competent as others.

I'm just saying that I've looked into purchasing one of these tools for myself, but right now they are not cost effective. There are many reasons why it would be beneficial for someone who does their own maintenance to have this tool.

 

RamDan03-

Oh, okay - gotcha; yeah, $6000 is a bit pricey for the average mechanic to get one....

At least now we can go to the dealership with knowledge; 'this is how you adjust the speedo for bigger tires...'

Rene

 

Yeah, i'd rather just ride around until I found a reputable dealer rather than spend $6000 bucks...lol.

Maybe eventually the price of these things will come down.

 

By using this tool to adjust the speedo setting for larger tires it re-adjusts the auto trans shift points to where they are supposed to be?

From what I have read here larger diameter tires screw up the shift points on the auto ???

thanks

Ron W.

 

[quote author=rjweiss link=board=7;threadid=21524;start=0#msg202136 date=1067281153]
By using this tool to adjust the speedo setting for larger tires it re-adjusts the auto trans shift points to where they are supposed to be?

From what I have read here larger diameter tires screw up the shift points on the auto ???

thanks

Ron W.
[/quote]

Great question. I have the same one. I have 245's and I want to go to 265's. I have an auto 48RE.

 

great info--chris

 

The speedo calibration affects everything; the abs, the automatic shifts; fuel; & everything else - it's all computer based, nowadays.

If you want the automatic to shift right, you've gotta have an accurate speedo...

Rene

 

[quote author=gadgets link=board=7;threadid=21524;start=0#msg201964 date=1067260876]
'Other'; selecting 'Other' allowed us to set the revs per mile, anywhere from 400 up to 900. That should pretty much take care of any size we might want to put on....if the 315 turns at about 600 revs per mile, I can't imagine what size would turn at 400!! Maybe a Monster Truck tire!

Rene
[/quote]

If I remember my 8th grade geometry?? Circumference (piD = C) ,,, if you divide 5280 by 400, you get 13.2. Then working backwards to solve for diameter, you divide 13.2 by 3.14 (value of pi). That gives you 4.2. That's the diamter of the circle with a circumference that would cover one mile with 400 revolutions. A tire 4.2 feet tall. Not quite a monster tire, but still pretty big!

 

I run 35s in the winter and 37s in the summer. I'm going to stop at Buzz Chew (our local dealer here on long Island) and see if they can do the speedo recal. tomorrow. Thanks for the info.

Jim Shaw