Speedometer recalibration

  • Welcome to EcoDieselRam.com We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your EcoDiesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • We believe in quality OVER quantity, and a family friendly place for your #EcoDiesel home!
    CLICK HERE TO REGISTER! Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

bobcat67

Active Member
May 19, 2016
223
86
28
Montana
Truck Year
2016
put some 275-65R20s on the 2016, has anyone had a reflash so the speedometer is accurate? I talked to a service writer that I know yesterday and they were unsure if they were able to adjust for larger tires, something about how the emissions system might be designed around the stock tire size. I'm used to the emissions systems falling off, but don't really want to go that route with this pickup
 

Brady

Well-Known Member
Jun 7, 2015
991
392
63
OHIO
Truck Year
2015
A monitor such as the Edge CS2 can recalibrate your ECM for the tire size difference. It has other benefits as well.


-Brady
 

flying7

Active Member
Jul 15, 2014
175
41
28
CALI
Truck Year
2014
Emissions isn't designed around the tire size, that's for sure. It sounds like they didn't want to mess with it. But ya, I would do a CTS 2 if you don't want to run a tune.
 

bobcat67

Active Member
May 19, 2016
223
86
28
Montana
Truck Year
2016
Emissions isn't designed around the tire size, that's for sure. It sounds like they didn't want to mess with it. But ya, I would do a CTS 2 if you don't want to run a tune.
Yeah I thought that sounded pretty fishy that the emissions system would be designed around the tire size. I can understand a transmission being affected by a considerably larger tire, but not the emissions system and I only went up one size taller to get a 10 ply tire. I'm not against running a tune, but I am also leery on the overall reliability of the motor. I love the pickup though and work at a diesel shop when I'm not on a drilling rig so I have a feeling the emissions junk will fall off someday
 

Retired Bones

Member
Jun 15, 2016
33
7
8
Truck Year
2015
Your service writter is a twit. I bought the smaller 17" rims on my '15 and it was on 20's new that I didn't want. They re-flashed the Speedo in five minutes and five miles of city/highway driving. They did it at delivery. I wanted the 195-70r17's with the 392 axle for towing. Other than high engine oil temperatures, it tows well. (274 degrees) is as high as I have seen.
 

bobcat67

Active Member
May 19, 2016
223
86
28
Montana
Truck Year
2016
Yeah I think he just didn't want to reflash it. Lazy pricks, probably just order an insight cs, can't really decide on if in gonna tune it or not. 274 degree oil temp is relatively insane!
 

jdn112011

Well-Known Member
Oct 18, 2015
1,202
310
83
27
Roseau, MN
Truck Year
2015
Yeah I think he just didn't want to reflash it. Lazy pricks, probably just order an insight cs, can't really decide on if in gonna tune it or not. 274 degree oil temp is relatively insane!
You have some pictures close and far with the 65 series tires on to share?
 

ed fisfer

New Member
Jan 25, 2016
1
2
3
Truck Year
2015
put some 275-65R20s on the 2016, has anyone had a reflash so the speedometer is accurate? I talked to a service writer that I know yesterday and they were unsure if they were able to adjust for larger tires, something about how the emissions system might be designed around the stock tire size. I'm used to the emissions systems falling off, but don't really want to go that route with this pickup
Run A Hypertech Speedometer Calibrator - Part #752501 Works great,
 

jdn112011

Well-Known Member
Oct 18, 2015
1,202
310
83
27
Roseau, MN
Truck Year
2015
Excuse it because it's a mess right now, but I hope that gives you an idea what they'll look like
You have no leveling kit, no spacers, factory rims and you don't get any rubbing correct? Factory coil suspension?

What specifically is the brand tire you have out of curiosity?
 

bobcat67

Active Member
May 19, 2016
223
86
28
Montana
Truck Year
2016
You have no leveling kit, no spacers, factory rims and you don't get any rubbing correct? Factory coil suspension?

What specifically is the brand tire you have out of curiosity?
Factory wheels and factory coil suspension and no spacers, with no rubbing; even with suspension compression and turning.
The tire brand and style is Hankook Dynapro ATM, had a few sets of these on multiple 3/4-1 ton pickups and had great luck with them, figured I'd give them a shot on the half ton.
 
  • Like
Reactions: jdn112011

jdn112011

Well-Known Member
Oct 18, 2015
1,202
310
83
27
Roseau, MN
Truck Year
2015
Thanks for the information
 
  • Like
Reactions: bobcat67

bobcat67

Active Member
May 19, 2016
223
86
28
Montana
Truck Year
2016
I had a set of the dynopro's to and loved them for the money. It was on a 06 Duramax.
Yeah they seem to be nice tires, I need to figure out how big of a spare a person can fit underneath with dual exhaust, the factory donut leaves a lot to be desired
 

Frank MAtiella

New Member
Jun 23, 2016
4
1
3
Truck Year
2015
put some 275-65R20s on the 2016, has anyone had a reflash so the speedometer is accurate? I talked to a service writer that I know yesterday and they were unsure if they were able to adjust for larger tires, something about how the emissions system might be designed around the stock tire size. I'm used to the emissions systems falling off, but don't really want to go that route with this pickup
They can adjust for just about anything. You probably have a lazy service writer or dealer. I ran into the same thing at Larry Miller Dodge in Tucson. They wanted almost $199.00 to do it. Sometimes dealers will offer a truck with lift kits and bigger tires already installed. By law a speedometer has to be accurate on a new vehicle. When they put oversize tires they will recalibrate the speedo. All they have to do is enter the revolutions per mile that tire will rotate. It takes about 10 minutes. They just want to hit you up for more money and make you think they know everything and you don't know squat. It is such a simple and easy operation that dealers should offer it for free just to build good will. Fat Chance right?
 

jdn112011

Well-Known Member
Oct 18, 2015
1,202
310
83
27
Roseau, MN
Truck Year
2015
They can adjust for just about anything. You probably have a lazy service writer or dealer. I ran into the same thing at Larry Miller Dodge in Tucson. They wanted almost $199.00 to do it. Sometimes dealers will offer a truck with lift kits and bigger tires already installed. By law a speedometer has to be accurate on a new vehicle. When they put oversize tires they will recalibrate the speedo. All they have to do is enter the revolutions per mile that tire will rotate. It takes about 10 minutes. They just want to hit you up for more money and make you think they know everything and you don't know squat. It is such a simple and easy operation that dealers should offer it for free just to build good will. Fat Chance right?
Dealers here for ram have the programmer in the truck for any modified vehicles. Rams computer module only houses speed calibrations for the various different tire dimensions offered on various trim levels of ram