how do i tell my truck i changed tire size?

[Motorious]

2017 express. came with 17's, have 20's to put on. do i need to tell the truck? how?

 

[jmd4100]

2017 express. came with 17's, have 20's to put on. do i need to tell the truck? how?

Just tell it like u would tell your friend... "Dude, I put bigger wheels on you". In all seriousness, I don't think you can on the newer Rams. If there's a way, I don't know it. But as far as I know, just try to compensate a little on the speedo

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[JoshR104]

2017 express. came with 17's, have 20's to put on. do i need to tell the truck? how?

Alpha OBD will allow you to change your overall diameter of the tire. The wheels don't matter as long as the overall tire diameter is the same. A 32" tire is a 32" tire regardless if it is on a 15" wheel or a 20" wheel still has the same footprint size per say just one has more sidewall than the other. Its only if you went from a 32" tire to a 35" tire that you would need to adjust the speedo.

 

[Motorious]

websites say tranny and abs as well as speedo affected. i want to find the guy who said technology is going to make our lives easier and kill him.

 

[Elevated 2013]

You do have to tell the truck that you have different size tires or your speedometer will be off at least a little bit. It all depends on the overall size of the tire. If you went with the same size tire but different rim size (obviously the last number of the tire size changed) then I don’t think you’ll see any changes in the speedometer. Otherwise it will be off a certain amount. It’s up to you to decide if you want to spend the money on a programmer or an AlphaOBD and OBDLink and MX+ to make the changes. I think any way you go they’re over $100 for either option unless you find something used.

 

[jmd4100]

websites say tranny and abs as well as speedo affected. i want to find the guy who said technology is going to make our lives easier and kill him.

Yes that's why I said I don't think there's a solid way to do it without buying a whole tuner or OBD

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[Motorious]

what is alpha? i know obd is on board diagnostics.

 

[Elevated 2013]

AlphaOBD is an app for a Windows or Android device (aka cell phone, laptop, tablet) that can make changes to your truck’s settings but it needs a Bluetooth plugin device to plug into the OBD port in your truck. That’s where the OBDLink MX+ comes in as it is the Bluetooth plugin device that AlphaOBD works best with. You can buy it on Amazon for $79.

 

[Motorious]

thanks.

 

[Firetruck41]

I have used the Veepeak Bluetooth OBD adapter ($11) on my 2010 2500, with AlphaOBD ($50).
If your tire diameter is not much different than OEM, I wouldn't worry too much about it.

 

[brny67]

Good info to know.

 

[kurek]

websites say tranny and abs as well as speedo affected. i want to find the guy who said technology is going to make our lives easier and kill him.

None of that is in any way different from what happens if you change tire size on a 1960s truck, except the ABS part. On the 1960s truck you would have to swap in a different speedometer gear to correct your speedometer, and modify your transmission valve body if you wanted the transmission to operate properly against your new effective drive ratio.

I'd say plugging in a little electronic doodad and typing a couple numbers into it is a lot easier than dropping the valve body and manually reprogramming it with springs and a drill - that's just my opinion.

In response to OP's question, if the outer diameter of the tire stays the same (or really close to the same) you can change wheel size all you want. A 33" diameter tire is a 33" diameter tire whether it's on a 17 or 20 inch wheel. If you do change the tire diameter you can use alphaOBD or there are aftermarket tools specifically for this job like this one from Superchips that also lets you change your TPMS thresholds, speed limiter and read/clear check engine lights.

 

[BWL]

Just break it to it gently over an oil change maybe. Noboby likes to hear you need another 3 inches. Calculate the o.d of the original tire and the o.d of the new ones. 1" or less difference and I wouldn't worry about it.

 

[Graygoose]

Alpha works, but Rough Country makes a Speedometer corrector as well, and it can read codes.

https://www.roughcountry.com/speedometer-calibrator-90019.html

 

[gdawg55]

Alpha works, but Rough Country makes a Speedometer corrector as well, and it can read codes.

https://www.roughcountry.com/speedometer-calibrator-90019.html

Do you know if the Rough Country unit will work on 2018 without having to unlock the pcm? Their website is a bit vague on the matter.

 

[Graygoose]

Yes it will. I used one on my 2015, worked perfectly. Just plugs into OBII port
Took maybe 10-15 minutes driving, key on, key off, etc

 

[Jimmy07]

Alpha works, but Rough Country makes a Speedometer corrector as well, and it can read codes.

https://www.roughcountry.com/speedometer-calibrator-90019.html

All of the tools do the exact same thing- adjust the tire size to correct the speedometer. It’s just that AlfaOBD is cheaper and capable of far more features than the one trick pony programmers.

 

[Graygoose]

All of the tools do the exact same thing- adjust the tire size to correct the speedometer. It’s just that AlfaOBD is cheaper and capable of far more features than the one trick pony programmers.

Possibly, I was just offering options.
Me personally, id prefer not to go in and make changes other than what I need.

 

[Firetruck41]

With an OBD Bluetooth adapter and the alphaOBD app, you can just go in and change the one thing you like. You can also change one more thing or a bunch of other things if you like. The OBD adapter can also be used with hundreds of OBD apps, like Torque, to read trouble codes, create gauges you can look at while driving for almost any engine sensor, log data from sensors, clear trouble codes, and more. That is why I would rather go that route, than something that can only do one thing or a couple of things. Plus it's quite a bit cheaper.

 

[waynestractor]

Just tell it like u would tell your friend... "Dude, I put bigger wheels on you". In all seriousness, I don't think you can on the newer Rams. If there's a way, I don't know it. But as far as I know, just try to compensate a little on the speedo

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AlphaOBD works great on the Rams for changing many parameters...