[foghelmut]

On the fence here. I think I've read every thread on the subject, but thought I would start my own. Since I got bigger tires, I really just want to fix my speedometer/odometer, but also wanted to see what the options were.

Rough Country Inline Speedometer Calibrator

• this technically doesn't ship to California
• does the truck adjust the shift points and RPMs to the corrected speed information? Or is all of that still mechanical gearing?

Trifecta Tune

• everything about Sport mode just really doesn't interest me and it would probably just live in Eco mode
• Is the power increase only with 91 gas? Or do you also get it with 87?
• Does it update the odometer as well or just the speedometer?
• Is there an MPG increase?

 

[_Leo_]

i noticed an MPG increase and there is also an increase in power on 87 octane. where you'll notice the power the most is lower down, its not a huge increase but its better then stock, and will lug a bit more then stock does. i rarely ever use sport mode, the higher revs annoy me, i wouldn't mind the throttle mapping but i dislike the over revving, it makes accelerating out of turns more annoying and normal city or traffic driving annoying

i'm pretty happy with my trifecta tune, now i just want to turn off AFM, that **** annoys me and i think its starting to play some games with shifting

 

[93Duc]

On the fence here. I think I've read every thread on the subject, but thought I would start my own. Since I got bigger tires, I really just want to fix my speedometer/odometer, but also wanted to see what the options were.

Rough Country Inline Speedometer Calibrator

• this technically doesn't ship to California
• does the truck adjust the shift points and RPMs to the corrected speed information? Or is all of that still mechanical gearing?

Here is information I've gathered from personal experience with my truck and exposure with a friends truck, a lengthy conversation with my local tire (DT) store manager and this forum:

Tire sizes can vary within a manufacture on a specific tire.
The twins have (what is considered by those I have spoken with) a sensitive Traction Control System.

The Rough Country (RC) inline speedometer calibrator worked perfectly on my truck when I up-sized tires from OEM 265/65 17 to 265/70 17.
By worked perfectly is meant: noticed the change in RPM at given speeds were back to what they had been with OEM tire size, and shift points were back to what they had been with the OEM tires.
When I setup the RC spedo calibrator I input the specific size rather than what I have come to realize is the generic value. Generic Value example: 265/70 R17 / Specific Value example: 31.65 / 17
Also what is meant by worked perfectly: can set the cruse control to any speed value and it holds and performs as it should, traction control works in slippery conditions, all off-road settings work.

A friend has a 2020 Bison - he went directly from OEM size tires to KM3 35" and used the RC speedometer calibrator. Same experience that I had above - worked as advertised, cruse control, shift points, etc. I have driven his truck about half dozen times.
He recently re-geared to 4:10's and went with Duramax Tuner engine and transmission tune. He removed the RC inline speedometer calibrator. The shop that did the tune had to work with his truck a few times to get the calibration performing correctly for the speedometer (including using a GPS speed monitor). This shop is one of the sources for the Traction Control being sensitive. I have driven his truck a few times since (even as recent as last week) and it is performing extremely well - I am confident his speedometer is correct.

I also read the post on here questioning that the speedometer correction is not correcting the odometer. After a period of consideration and cross referencing what I have observed (not perfectly scientific) I am of the point of view that the speedometer correction also corrects the odometer. Until sufficient evidence is discovered that the odometer is not corrected I maintain the point of view that it is.

I suspect that with a re-gear and change in tire size that more than the inline calibration is needed.

 

[Hunter62]

I have the RC Calibrator, It corrected the shift points and the odometer is correct now
I posted several months ago that for some reason it had lost it's programming. On a long trip the truck did not seem to be shifting like it had been, so using the GPS on my phone, I found out the speedometer was off, I re-programmed it and no problems since then
I used the tire size, put in 265/65/70 to 285/70/17 and it is almost perfect on a 425 mile trip that I had my gps running at the same time.

 

[foghelmut]

Which model Rough Country calibrator?

The 90005 says it works for the 2017-2018 models, but I've read that people are using it successfully on 2019 trucks.

Rough Country website says to their 90045t model is for 2019+ trucks.

I'm not sure if there's a difference if the old model still works?

 

[Hunter62]

I have the 90005 in my 2017...

 

[littleblazer]

Another happy rough country user here. I didn't drive the truck at all without it so I can't comment on that aspect. I can say I noticed no difference after with larger tires vs stock.

 

[Beadblaster]

I know there was a post a while back where trifecta said that they only correct the speedo and not the odometer . They also said that screwing around with the odometer is illegal.

 

[littleblazer]

I know there was a post a while back where trifecta said that they only correct the speedo and not the odometer . They also said that screwing around with the odometer is illegal.

I took that as the reading is correct from that point in time, as in they don't put on the miles lost on the odometer but from the second the tune is on onward it'll count correctly. Not entirely sure though.

 

[93Duc]

I know there was a post a while back where trifecta said that they only correct the speedo and not the odometer . They also said that screwing around with the odometer is illegal.

That was the post I was thinking of. Thanks.

Without full context of the conversation it’s unclear.

 

[Beadblaster]

I found the post over on the zr2 forum. Here is trifectas response.

 

[Hunter62]

Okay, they are saying they do not "adjust" the odometer, which would be fraudulent.

To me "correcting" means it is now reading that when you drive a mile it shows you drove that mile

beffore I installed the RC unit, when I drove a mile the odometer showed I drove 7/10th's of a mile...the RC unit corrected the odometer so now when I drive a mile it shows I drove a mile

 

[foghelmut]

That's what I'm looking for: driving a mile = driving a mile.

I mean, technically using a non-stock tire size is committing odometer fraud.