Alfaobd tire size change instructions

[Ryancassidy]

All, I've been doing some searching but not having the luck I was hoping...

I'm looking for step by step instructions for AlfaObd to change the tire size on a 5th Gen RAM. Specifically I want to make sure I dont miss anything so the 2719mm number doesn't impact park sense or anything else as I understand there are several steps that need to be taken to ensure everything works. Not just changing one value. I've got loads of experience with VagCom and frankly I think that's easier to use.... (maybe because I'm most familiar with it.. lol )

Any instructions would be great. I found one VID on a 2500 MY18 but I'm not 100% sure it's the same.

Thanks for any guidance.

 

[2020Big4x4Horn]

Think I know the vid your referring to, its the same. Need to do the abs part after.

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[Ryancassidy]

Ohh.. I have the bluetooth OBDII and the security gateway dongle too. I was able to connect today using AlfaOBD free version. Installing the paid tonight.

 

[Ryancassidy]

Think I know the vid your referring to, its the same. Need to do the abs part after.

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Ohh OK cool. Good to know. Any issues with Parksense that you've experienced by chance?

 

[2020Big4x4Horn]

Ohh OK cool. Good to know. Any issues with Parksense that you've experienced by chance?

No everything worked as normal.

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[Ryancassidy]

So I did this earlier this morning. Maybe it's just breaking the seal and getting used to a new UI. But it seems to work ok. 2719 was the calculated circumference, but 2625 ended up being the best number to match GPS at cruise at 75mph.

Thanks for the guidance on it. Now In just waiting for my exhaust from BK to come in on Tuesday and the daystar spacers from santa apparently

 

[MayhemMOORE]

I just tried this on my ‘21 and it’s giving me issues saying it failed on the Rolls part of it. Park sense isn’t working and the brake and abs Iights flash briefly but go away and no codes are stored.

 

[TechDaddy3x]

I just tried this on my ‘21 and it’s giving me issues saying it failed on the Rolls part of it. Park sense isn’t working and the brake and abs Iights flash briefly but go away and no codes are stored.

I’m looking to update the tire size on my new 21 limited. Did you ever get park sense back working? Seemed to be a constant prob on the 21s. I upgraded to 34.5” tires

 

[MayhemMOORE]

I’m looking to update the tire size on my new 21 limited. Did you ever get park sense back working? Seemed to be a constant prob on the 21s. I upgraded to 34.5” tires

Everything works normal now. Just measure the actual diameter of the tire with it mounted and under the weight of the truck and use that to figure out the circumference you’ll need.


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[TechDaddy3x]

Everything works normal now. Just measure the actual diameter of the tire with it mounted and under the weight of the truck and use that to figure out the circumference you’ll need.


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With your issues with the failed rolls part and park sense...did that get resolved or does park sense still not work??

 

[MayhemMOORE]

Parksense work fine now. I thought I had explained it in this thread, but it was a different one. Here's my reply in that thread about it:

"I used AlfaOBD to do my calibration and found that while calibrating for the 285/55R22 (roughly 34.4") tires I put on, anything over 2710mm circumference caused parksense to freak out. The math works out to about 2740mm circumference for that tire size, but over multiple attempts to get the speed dialed in, I believe I ended up at 2670mm which put it dead on with gps at any speeds I drive and plays nice with parksense.

Try measuring the actual height of the tire as it sits on the truck using a level across the tread, then use that to figure up what size to actually calibrate for. This is what I ended up doing and it put me within a few mm of my end result which is within the limits of what allows parksense to work properly."

 

[TechDaddy3x]

Parksense work fine now. I thought I had explained it in this thread, but it was a different one. Here's my reply in that thread about it:

"I used AlfaOBD to do my calibration and found that while calibrating for the 285/55R22 (roughly 34.4") tires I put on, anything over 2710mm circumference caused parksense to freak out. The math works out to about 2740mm circumference for that tire size, but over multiple attempts to get the speed dialed in, I believe I ended up at 2670mm which put it dead on with gps at any speeds I drive and plays nice with parksense.

Try measuring the actual height of the tire as it sits on the truck using a level across the tread, then use that to figure up what size to actually calibrate for. This is what I ended up doing and it put me within a few mm of my end result which is within the limits of what allows parksense to work properly."

thanks for the quick reply!

 

[ramchaser]

Yep...Having the same issue changing the tire size and it disables park sense. The only way I can get park sense back is to use my WiTech 2 to rebuild the BCM config. Went to 35's and used 2684mm which put it spot on but did not make park sense happy. I may play with the tire size to see if I can find a happy median. The approved Mopar method is to buy an option code and have it added to the VIN. Then use the WiTech 2 to rebuild BCM config. Costs around $150 to have done.

 

[ramchaser]

Parksense work fine now. I thought I had explained it in this thread, but it was a different one. Here's my reply in that thread about it:

"I used AlfaOBD to do my calibration and found that while calibrating for the 285/55R22 (roughly 34.4") tires I put on, anything over 2710mm circumference caused parksense to freak out. The math works out to about 2740mm circumference for that tire size, but over multiple attempts to get the speed dialed in, I believe I ended up at 2670mm which put it dead on with gps at any speeds I drive and plays nice with parksense.

Try measuring the actual height of the tire as it sits on the truck using a level across the tread, then use that to figure up what size to actually calibrate for. This is what I ended up doing and it put me within a few mm of my end result which is within the limits of what allows parksense to work properly."

Have a 19 Rebel and went with 35's. Programmed in 2684 which works great for the speedo but park sense like others here is now disabled. Played around a bit with it and anything over 2557 causes it to disable park sense. I have done the ABS initialization and walked through that process to no avail.

How did you enter in 2700 and up with it not disabling the park sense?

The official fix from Ram is to purchase a warranty op code and have it uploaded to your VIN, then rebuild the configuration with the WiTECH 2. MSRP is $150. I would like to fix this with Alpha OBD but not looking possible and just want to be done with it.

 

[Njh3409]

I have a 2019 and went with 35" and found my parking sensors disabled with anything over 2557 mm with 68271823AG Parksense module. I tried everything to get them working and I decided to order 68464880AD parksense module from a 2022 with the 12 channel Parallel and Perp Park Assist w/Stop XH5. I swapped it out today and got parking sensors working with the larger tires. I picked it up for under $60. The swap was plug and play. No programming needed. If you have the 10 channel system Parksense Ft/Rr Park Assist w/Stop XH4. 68464879AG would be the correct part number. No issues at all and I have tried over 2700mm without disabled sensors. Just my 2 cents.

 

[WhiteLightning]

Sry to bring an old thread back from the dead...

My '22 TRX has tires that are 36in. This is larger than the stockers that measure under 35in (~34.7). Where are these modules located (one front and one rear?). I want to go look to see if I already have these. I am confused WTH is going on. I tried 2750, then 2700mm. I've used Tazer, and AlfaOBD. I could prob use HP Tuners too... But I can't pass 2700 (ish. I didn' try mm by mm).

Any thoughts? Thank you in advance,
WL

 

[ch53e mech]

I'm limited to 2705. I can't get into the parking module and I truly believe that's where our parksense unavailable is coming from.

 

[jmj12396]

I have a 2019 and went with 35" and found my parking sensors disabled with anything over 2557 mm with 68271823AG Parksense module. I tried everything to get them working and I decided to order 68464880AD parksense module from a 2022 with the 12 channel Parallel and Perp Park Assist w/Stop XH5. I swapped it out today and got parking sensors working with the larger tires. I picked it up for under $60. The swap was plug and play. No programming needed. If you have the 10 channel system Parksense Ft/Rr Park Assist w/Stop XH4. 68464879AG would be the correct part number. No issues at all and I have tried over 2700mm without disabled sensors. Just my 2 cents.

In your post, you say that the parking sensors work after replacing the Parksense module with the newer model year. You didn't say specifically that the Parksense Parallel and Perpendicular Park Assist feature works. Can you verify that everything is working with the new module in place? Thanks.

 

[1BADRAMLIMITED]

after the tire size change does anything need to be done with transmission (shift points) or abs re-cal?

 

[HSKR R/T]

after the tire size change does anything need to be done with transmission (shift points) or abs re-cal?

No, changing the tire size fixes any other issues.