Adjusting Tire Size with AlfaOBD on 2020 Ram 1500

[@epic2003]

This guide helped a ton. Tire size is updated. Speedometer working as it should now, no fault codes. Thanks a ton!!!

[@Gtown_81]

Have to watch this every six months. Thanks bro!

[@precisionmarksmanshiphq773]

Sounds much the same for Ram 2500s too....I am getting new tires in a couple days and I'm nervous about this....I've seen lots of videos, so I should be ok....Hopefully 2022 Ram 2500s are on there for me.

[@kd221]

thanks for the equation!

[@Justin12833]

Why did you go in and do that second change? Isn’t doing what you did first enough? That’s what I have been doing with my 15 just the first part that you did.

[@dieselrebel4]

The first should be enough. The 5th gen rams forums suggested doing both, but should be fine with only first step.

[@shaunferris6063]

hello just tried it to mine and the abs initialization is greyed out , i have tried this mulitple times to a T. still nothing. do you , or anyone in these comments possibly know why ?

[@mikedelgadillo5010]

Did you find a fix for this. My 2016 is stuck at the same spot

[@Salm1500]

The same happened to me following the steps in this video, ABS initialization was greyed out and I waited few mins on the ABS initialization page and it became clickable, just give it 2-5 mins and dont leave the page

[@HenryJp510]

@@Salm1500so after clicking abs initialization, you waited 2-5 minutes befor the start turned red?

[@juanprenteria5077]

Question I have a 2020 ram when the truck came out with 20 inch but later I purchased the 22s original OEM do I need to do this change on the settings?

[@will_estes]

What size are your tires? technically if they were both 32" then you wouldn't have to

[@juanprenteria5077]

@@will_estes the original was 275/55/20 And the one i have right now its 285/45/22

[@will_estes]

@@juanprenteria5077 Those would be 31.9" vs 32.1", so should be negligible difference. So should be good to leave it as is

[@seankenneth680]

So I followed your instructions on my 2020 ram 1500 and I now have a electronic parking brake light stuck on that I can't seem to get rid of. Could really use your help!

[@dieselrebel4]

I believe you need to redo the ABS step of the video

[@seankenneth680]

@@dieselrebel4 i tried and when I do the abs initialization the start button is greyed out. It's very frustrating as I am usually good at this type of reprogramming

[@dieselrebel4]

@@seankenneth680 sounds like it may not be connected if it's grayed out. What year/model is your truck? Could still try the steps under ABS Initialization and see if it clears it. 1. ECU Initialization 2. Clear Rolling Codes Also could just try checking and clearing any faults if you haven't already

[@seankenneth680]

@@dieselrebel4 it's connected because I can do everything else under abs. If i cycle the ignition I can get it to not be greyed out anymore but it doesn't seem to actually do anything when I hit start. I have done all of the steps under ABS initialization mutltiple times and it will clear everything except for the parking brake. I'm going to send a picture of what code comes up. Seems like I need to initialize the electronic parking brake somehow? It's acting like it needs that to be initialized as well but I don't know how to. 2020 1500 5.7 big horn

[@seankenneth680]

Not sure how to attach photos anyway I can dm you?

[@_h0nkyk0ng_]

I ran into 2 issues. I ran the equation and came out with 2793 for my tires. I selected Vehiconfig4, and when I went to input the 2793, the original number was 56xxxmm. Why is the number so high and not the 2793 I input? Do I still continue and change it to 2793, then run ABS initialization? The other issue I have is, my parking sensors and Automatic Emergency Braking were disabled after I did the tire size change. I redid it and got them to work, but now my parking sensor warning in the instrument cluster doesn't beep (even though I have it enabled in the settings). I'd appreciate any help!

[@dieselrebel4]

The 2793 should be right. 56XXX would be way too high, so not sure why it displayed that on yours. Might retry the ABS initialization step to get parking sensors to work. People have reported issues with parking sensors when they go 2700 or above try lowering it to 2690 or so and see if that fixes it. If that doesn't work follow Daverous steps in this thread 5thgenrams.com/community/threads/tire-size-change-alfaobd-now-bunch-of-codes-lights-wont-go-away.28792/#post-812036

[@_h0nkyk0ng_]

@@dieselrebel4 I spoke with Alexey, the alfaobd creator. He suggested skipping Vehiconfig4 and just running ABS initialization. I did, and when I ran the fault check, it came up with a u0402 (not receiving messages from the TCM). I cleared it, ran it again, had no faults, then finished the initialization. Parking sensors and AEB work, and my digital speedometer in the cluster is spot on with GPS. It's still 2-3mph off on the actual speedometer, but I'll live with that. Trans is shifting better and mpg has already gone up. I ended up setting the tires at 2655mm. Thanks for the response and the help!

[@joemastroianni9220]

So if I have a 2019 big horn 1500 in my body computer I would select my 2019 power net correct?

[@dieselrebel4]

Yes that should be correct

[@JGSnave]

Can you show how to connect the bypass cable?

[@dieselrebel4]

Yes, I show it in an earlier video kzbin.info/www/bejne/l3rHg4CNetF3oaM

[@JGSnave]

@@dieselrebel4 I found the earlier video and have already followed your direction with the cable I bought. I appreciate it.

[@TAZTALKS2022]

@@dieselrebel4 will this work on the gas 1500's also 2020 big horn here with 5.7 and went to a 275 60 20 from the 275 55 20.. cut my gas mialage by almost 40% also where do I get the bypass cable from and is it system specific? Like security modual or body com.?

[@TAZTALKS2022]

None of the tire shops or dealership can get tire size to change with their set-ups..

[@dieselrebel4]

@@TAZTALKS2022 yes this should work on all 1500s, I have the link in the video description for the bypass cable. I bought it on Amazon

[@armandtv6091]

Can you still connect with your alfaobd? A lot of people are complaining that I want to know if it’s an isolated thing before I purchase. Thanks.

[@dieselrebel4]

Mine still connects for 2020 year model

[@wendelkurz3335]

Are you using millimeters for tire size?

[@dieselrebel4]

Yes, I have a formula in video description

[@off-roadingexplained8417]

Anyone try this on Cherokee Trailhawk?

[@dieselrebel4]

I did it on 2015 Grand Cherokee and worked the same

[@jordanlight4830]

Any idea if this will work in a 2022?

[@dieselrebel4]

I believe it should, haven't tried it though

[@undagroundrican]

Hi, is there an option to change the wheel size ?, I'm going from a 18" to a 20" . Thanks in advance.

[@dieselrebel4]

It's more about the total diameter of wheel and tire. If that changes when you change wheels then you need to adjust, but if it's the same you can leave it. What are the two tire sizes?

[@undagroundrican]

@@dieselrebel4Thanks for the reply, I'm going from 275/65/R18 currently on my truck to 275/55/R20

[@dieselrebel4]

@@undagroundrican probably won't see a significant difference since they are close in size 18s at 32.1" and 20s at 31.9". Speed difference is almost negligible

[@undagroundrican]

@@dieselrebel4 Thanks again, I appreciate the information.

[@wzupmane]

Can I turn of the auto start/stop? Is the app you used $49?

[@dieselrebel4]

Probably so, could check the forums with a Google search. Yes the app was only $49