Speedometer calibration for 2014

ScalerFab · Post by **ScalerFab** » Fri Oct 03, 2014 1:21 am

I'm looking to put some 285/75/17's on and will need to re-calibrate the computer to the new size. Anyone know what products are available for the 2014 - 6.4L?

Thanks in advance,

Troy

SheepdogOutdoorsman · Post by **SheepdogOutdoorsman** » Fri Oct 03, 2014 7:12 am

The 2014 PW comes with 285's on it already ... You wouldn't need to recalibrate the speedo ...

JBM Power Wagon · Post by **JBM Power Wagon** » Fri Oct 03, 2014 7:27 am

When I got my 2014 I went straight to 315/70/17 tires and the dealer bought a Hypertech speedo calibrator that they used. Good news is when I picked up the truck, for some really odd reason, the salesman gave me the Hypertech speedo calibrator and said "I guess this is yours".

ScalerFab · Post by **ScalerFab** » Fri Oct 03, 2014 8:08 am

SheepdogOutdoorsman wrote:The 2014 PW comes with 285's on it already ... You wouldn't need to recalibrate the speedo ...

The aspect ratio is different 75 vs 70. 285 is the width. 285/75/17' are 34". The stock 285/70/17's are 33"

ScalerFab · Post by **ScalerFab** » Fri Oct 03, 2014 8:09 am

JBM Power Wagon wrote:When I got my 2014 I went straight to 315/70/17 tires and the dealer bought a Hypertech speedo calibrator that they used. Good news is when I picked up the truck, for some really odd reason, the salesman gave me the Hypertech speedo calibrator and said "I guess this is yours".

Do you know the hypertech part#? They gave it to you because it can only be used on (1) VIN at a time...

SheepdogOutdoorsman · Post by **SheepdogOutdoorsman** » Fri Oct 03, 2014 8:12 am

It's only a 14mm difference, which is about a half an inch. 5% of 285 is roughly 14mm. There's roughly 25mm in an inch. I don't think that half an inch is going to throw your speedo off that much.

JBM Power Wagon · Post by **JBM Power Wagon** » Fri Oct 03, 2014 10:58 am

ScalerFab wrote:
JBM Power Wagon wrote:When I got my 2014 I went straight to 315/70/17 tires and the dealer bought a Hypertech speedo calibrator that they used. Good news is when I picked up the truck, for some really odd reason, the salesman gave me the Hypertech speedo calibrator and said "I guess this is yours".
Do you know the hypertech part#? They gave it to you because it can only be used on (1) VIN at a time...

I have it at home so will post it up later.

Bill2014 · Post by **Bill2014** » Fri Oct 03, 2014 1:54 pm

SheepdogOutdoorsman wrote:It's only a 14mm difference, which is about a half an inch. 5% of 285 is roughly 14mm. There's roughly 25mm in an inch. I don't think that half an inch is going to throw your speedo off that much.
ImageUploadedByTapatalk1412339146.805217.jpg

In this case the speedometer would be off by 2.23 mph at 65

Bill2014 · Post by **Bill2014** » Fri Oct 03, 2014 2:06 pm

These trucks all have GPS capability... Ram should take advantage of that and automatically apply a speedometer compensation periodically. This would keep the speedo's accurate as tire treads wear down AND reset the compensation factor for all the masses that change tire sizes.

After all, the trucks already adjust their engine and shifting tuning based on how it's being driven.

coder · Post by **coder** » Fri Oct 03, 2014 3:57 pm

I got my speedometer calibrator from Hypertech I would give them a call and see if they have one for the 6.4 Hemi.

adeluca73 · Post by **adeluca73** » Fri Oct 03, 2014 8:35 pm

Bill2014 wrote:These trucks all have GPS capability... Ram should take advantage of that and automatically apply a speedometer compensation periodically. This would keep the speedo's accurate as tire treads wear down AND reset the compensation factor for all the masses that change tire sizes. After all, the trucks already adjust their engine and shifting tuning based on how it's being driven.

EXACTLY...x2. This is so easy, it should be a built in user feature you can input in the "settings" menu.

JBM Power Wagon · Post by **JBM Power Wagon** » Fri Oct 03, 2014 10:20 pm

adeluca73 wrote:
Bill2014 wrote:These trucks all have GPS capability... Ram should take advantage of that and automatically apply a speedometer compensation periodically. This would keep the speedo's accurate as tire treads wear down AND reset the compensation factor for all the masses that change tire sizes. After all, the trucks already adjust their engine and shifting tuning based on how it's being driven.
EXACTLY...x2. This is so easy, it should be a built in user feature you can input in the "settings" menu.

X3!!! That is a GREAT idea!!!

loveracing1988 · Post by **loveracing1988** » Sat Oct 04, 2014 2:13 pm

JBM Power Wagon wrote:When I got my 2014 I went straight to 315/70/17 tires and the dealer bought a Hypertech speedo calibrator that they used. Good news is when I picked up the truck, for some really odd reason, the salesman gave me the Hypertech speedo calibrator and said "I guess this is yours".

It is probably like the tuners and it is Vin locked to your truck.

loveracing1988 · Post by **loveracing1988** » Sat Oct 04, 2014 2:14 pm

ScalerFab wrote:I'm looking to put some 285/75/17's on and will need to re-calibrate the computer to the new size. Anyone know what products are available for the 2014 - 6.4L?

Thanks in advance,

Troy

Diablosport has the intune and Trinity for the 6.4, you can use that to reset the tire size and tune the engine if you want.

ScalerFab · Post by **ScalerFab** » Thu Dec 04, 2014 1:10 am

Just installed 315/70/17's and have a message in to Hypertech. The speedo is off a little less than 5%...

If anyone has the part# of the recalibration unit I need, that would be great.

No rub with the 315's on stock wheels...

ScalerFab · Post by **ScalerFab** » Thu Dec 04, 2014 4:23 pm

Well, this is the message I sent to Hypertech:

To whom it may concern,

I'm looking to purchase a speedometer re-calibration unit for my 2014 Ram 2500 Power Wagon with the 6.4 Hemi. I just mounted bigger tires and would like the compter to be in sync again.

Please let me know the part# of the product that I need.

Thanks,

Troy Loftus

And, this is the response I received:

Troy

We do not have a tuning device for this make and model, we may eventually but no word as to when at this time. We will not know the availability for a new application until a week or so prior to the release. I've entered your contact information so you'll be notified once ready. Thanks

Jim

So, if anyone knows the part# of the unit that folks have used to recal a speedo on a 2014 with 6.4, that would be greatly appreciated

JBM Power Wagon · Post by **JBM Power Wagon** » Thu Dec 04, 2014 11:22 pm

Hi Scaler, when I bought my truck the dealer used a Hypertech speedo calibrator and it worked. I did get your email so when I get a chance I will find it and pull the part number.

ScalerFab · Post by **ScalerFab** » Tue Dec 09, 2014 9:24 pm

I found and purchased Hypertech part# 752501 for $163 w/ free shipping, and after updating the unit via the internet, it worked flawlessly. I had to try a few different tire heights to get the speedo corrected according to my phone gps. I actually am using 33.5". The tires I have measure about 34-ish", but when I used those numbers, the speedo was over the correct speed...

JBM Power Wagon · Post by **JBM Power Wagon** » Tue Dec 09, 2014 10:01 pm

Glad to hear it worked!!!

ScalerFab · Post by **ScalerFab** » Tue Dec 09, 2014 10:15 pm

JBM Power Wagon wrote:Glad to hear it worked!!!

Thanks, man... I appreciate you taking the time to look that up for me. I can't believe that the folks at Hypertech stated that they didn't offer a unit that would work with my truck...

adeluca73 · Post by **adeluca73** » Tue Dec 09, 2014 11:02 pm

Question, is the Hypertech good for anything other than reprogramming the speedometer? If not, $163 is awfully expensive to adjust just that one parameter, right?

ScalerFab · Post by **ScalerFab** » Wed Dec 10, 2014 2:19 pm

adeluca73 wrote:Question, is the Hypertech good for anything other than reprogramming the speedometer? If not, $163 is awfully expensive to adjust just that one parameter, right?

Just good for gear changes, tire size changes, and reading/clearing DTC's... That's all I needed, so spending $400-$500 on a tuner that I don't want would have been wasting my money in my opinion.

olyelr · Post by **olyelr** » Thu Dec 11, 2014 9:19 am

SheepdogOutdoorsman wrote:It's only a 14mm difference, which is about a half an inch. 5% of 285 is roughly 14mm. There's roughly 25mm in an inch. I don't think that half an inch is going to throw your speedo off that much.
ImageUploadedByTapatalk1412339146.805217.jpg

I know this does not pertain anymore really as the OP got a set of 315's, but anyway. Your numbers a re a bit off. Your "about a half inch" number should have been doubled, as it is only the sidewall height number (and there are 2 sidewalls in the overall height of the tire). Your picture clearly shows the overall tire height is over 1" taller. Certainly not a big changing factor, but...

SheepdogOutdoorsman · Post by **SheepdogOutdoorsman** » Thu Dec 11, 2014 10:36 am

olyelr wrote:
SheepdogOutdoorsman wrote:It's only a 14mm difference, which is about a half an inch. 5% of 285 is roughly 14mm. There's roughly 25mm in an inch. I don't think that half an inch is going to throw your speedo off that much.
ImageUploadedByTapatalk1412339146.805217.jpg
I know this does not pertain anymore really as the OP got a set of 315's, but anyway. Your numbers a re a bit off. Your "about a half inch" number should have been doubled, as it is only the sidewall height number (and there are 2 sidewalls in the overall height of the tire). Your picture clearly shows the overall tire height is over 1" taller. Certainly not a big changing factor, but...

The extra height is determined by radius, not diameter. So, "about a half inch" would still be correct.

FirerescuePW · Post by **FirerescuePW** » Thu Dec 11, 2014 1:11 pm

The extra height of the truck is determined by the radius. The extra height of the tire is determined by the diameter, which is directly related to the circumference, which is what the speedo and related programming uses to determine the speed of the vehicle.

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