Do I need to program Speedo

[QuasarZ]

Have a 22 Laramie off-road with the 18” wheels and wild peaks. I’m looking to get the factory 20” wheels and get some 275/60/20 all terrains. Is that enough of a jump to need to recalibrate the Speedo?
Thanks.

 

[Eighty]

Have a 22 Laramie off-road with the 18” wheels and wild peaks. I’m looking to get the factory 20” wheels and get some 275/60/20 all terrains. Is that enough of a jump to need to recalibrate the Speedo?
Thanks.

What size tires are your factory Wildpeaks?
The new size you’re listing is theoretically a 33” tire. So it depends on what your original theoretical tire diameter is.

 

[QuasarZ]

What size tires are your factory Wildpeaks?
The new size you’re listing is theoretically a 33” tire. So it depends on what your original theoretical tire diameter is.

275/65/18. Basically 32”

 

[Eighty]

275/65/18. Basically 32”

It’s a 3.125% difference. So 2 mph off at 70mph. Up to you, I’d say.

 

[QuasarZ]

It’s a 3.125% difference. So 2 mph off at 70mph. Up to you, I’d say.

Does it mess up shift points or anything else?

 

[Eighty]

Does it mess up shift points or anything else?

If your truck wants to shift at 2000 rpm, then it’s going to shift at 2000 rpm. It doesn’t know or care that the vehicle is traveling 3% faster at that time.

 

[firemedic10584]

if you've got AlfaOBD, it's a 5 minute process (if that) to change the tire size. I've done a few trucks now to change them and they are all back to being dead on again.

 

[theblet]

I didn’t

 

[kdoublep]

I'm about to change mine with Alfa. I'm off about 1.8 mph at 65 from stock Bridgestones. Running 275/60 20 Scorpions now.

 

[Darksteel165]

If you don't change it, also know your recorded milage will be incorrect. Most if not all states require you to disclose during a sale if you know the milage reading on the odometer is incorrect.
If you changed tire size the only way someone would know is if they checked the speedo themself since the truck will think it's legit miles.

Just something to keep in mind, you might be putting more or less miles logically on your truck for the better or worse.

 

[kdoublep]

Exactly. I would be actually over what my odometer reads and would only be able to guesstimate. It wouldn't be crazy mileage but will add up over time. Thank you Alfa.

 

[theblet]

If you don't change it, also know your recorded milage will be incorrect. Most if not all states require you to disclose during a sale if you know the milage reading on the odometer is incorrect.
If you changed tire size the only way someone would know is if they checked the speedo themself since the truck will think it's legit miles.

Just something to keep in mind, you might be putting more or less miles logically on your truck for the better or worse.

Yup. I’ll prob change it with jscan when I get all the pieces. Sometime this year I hope

 

[djants]

Can anyone link device and instructions to change speedo?

 

[theblet]

Can anyone link device and instructions to change speedo?

You'll need the jscan app, and a VIn license. Here's the hardware:

What code reader do you love?

Mine disappeared today. Which one are you guys using? Had a good recommendation from a friend, however it was android only and I have iOS.

5thgenrams.com

Not sure how to actually do it yet, as I still didnt purchase this, but heres a video

 

[Rodger1966]

if you've got AlfaOBD, it's a 5 minute process (if that) to change the tire size. I've done a few trucks now to change them and they are all back to being dead on again.

What is the maximum circumference allowable without screwing up the park sense, and or anything else? I put 295/65-20's on this morning, going to mess with it when I get out of work.

 

[firemedic10584]

What is the maximum circumference allowable without screwing up the park sense, and or anything else? I put 295/65-20's on this morning, going to mess with it when I get out of work.

That specific size may already be one of the pre-programmed sizes in Alfa, if so, simple as selecting that. If it's not, you have to enter the millimeter size instead. As far as park sense, I don't believe changing the tire size will affect that at all? I could be wrong though.

 

[theblet]

What is the maximum circumference allowable without screwing up the park sense, and or anything else? I put 295/65-20's on this morning, going to mess with it when I get out of work.

I wanna say 35". Here's your size. 35" should do it

 

[Rodger1966]

That specific size may already be one of the pre-programmed sizes in Alfa, if so, simple as selecting that. If it's not, you have to enter the millimeter size instead. As far as park sense, I don't believe changing the tire size will affect that at all? I could be wrong though.

I poked 2800 in it and it did not like it.

That specific size may already be one of the pre-programmed sizes in Alfa, if so, simple as selecting that. If it's not, you have to enter the millimeter size instead. As far as park sense, I don't believe changing the tire size will affect that at all? I could be wrong though.

 

[Rodger1966]

110.2" x 25.4mm = 2799.08mm. I Guess I will play with it and see what works.

 

[skyhawk42]

I have 35s on mine and started at 2710 and park sense went out. Tried 2700 and park sense came back, but speedo was still off. 2670 ended up working for park sense and is pretty much right on with the gps for speed now.