Factory Tire / Wheel sizing Questions.

[TommyGuns777]

Hello everyone,

I picked up a 2021 Ram Warlock AT Edition a little while ago and love it. It came with the 17” Off-road wheels and Yokohama 265/70r17 tires. I used these stock rims for winter tires, which are currently on the truck.

I picked up a factory set of black 20” MOPAR rims that I plan to run the stock tire size on (275/60r20) but I noticed they are 1.5” taller.

Will I be okay to put the 20” rims and 275/60r20 tires on for the summer without doing any programming to the shift points? Worried about possible damage.

Any input would be appreciated. Thanks!

Tom

 

[Jeepwalker]

The difference will be measureable and possibly slightly noticeable, but I doubt it would be a major issue.

However, if you know someone, neighbor, etc with a decent, up-to-date pro or semi-pro scan tool (Snap on or equivalent), they ..or you, should be able to adjust the tire size in your truck's software in 5 minutes, and the size difference would be a non-issue. I say 'should' bc I haven't personally done it on a '21, and the software is 'locked' on newer Chrysler vehicles. You/they'd need a Secure Gateway (SGW) Bypass to get through the obd (not sure if tire size feature is locked out however). On older trucks where the OBD isn't 'secured' changing wheel/tire size is as easy as pie and takes 5 minutes.

AlfaOBD software, made for Chrysler vehicle owners, would be another way, probably the best for an owner. I'm not an AlfaOBD user so check the 4th Gen DIY forums, or maybe the 5th gen forums, for more specifics on AlfaOBD and your yr of tk. If it'll work for you, you could use your phone/tablet and AlfaOBD to change the tire size seasonally ...and make other tweaks adjustments too.

For reference, this is what the tire size section looks like on a Snap-on scanner (for a 2012). There are 3 or 4 additional screens of tire/wheel sizes (not shown), that include larger wheels, so you'd pick the combo that matches what you have:

 

[MADDOG]

The 275/60R20 set up will be about 2.5" taller and about 0.5" wider.

You will have a small speedo error of 0.9 MPH @ 20 MPH, 1.3 MPH @ 30 MPH, 1.8 MPH at 40 MPH, 2.2 MPH @ 50 MPH, 2.7 MPH @ 60 MPH, 3.1 MPH @ 70 MPH, 3.5 MPH @ 80 MPH and 4 MPH @ 90 MPH so be aware of that.

The transmission should be able to handle the change. It will be interesting to see if the automatic trans shifts to the highest gear at freeway speeds.

 

[kurek]

Takes 90 seconds start to finish recalibrating with jscan..

 

[Nicholas Cove]

I've got an autel maxisys pro do you think it would work to change tire size ? I've never had a customer request and only done things like that to my mustang in the past with an set tuner.

 

[Jeepwalker]

I believe they do have that capability. Obviously dependent on your unit's software year, etc. You might have to get a secure gateway cable/interface for tks 2018+. Search ebay for SGW. There's probably an Autel forum where guys are recommending certain products. I see some of the inexpensive bi-directional chinese scanners on Amazon could do it as well (although I don't own one to personally vouch for it) ...but it was on the feature list for whatever that's worth.


Edit: Within the Snap-on scanner the change wheel/tire size section is within the 'Miscellaneous' section as ya look through the main menu of options. It's easy to not see. In fact, didn't know snap-on could do it either until I read it on some forum. I went and checked and I'm like "holy cow!" Also, I checked and the older Gen4 Rams ..at least with my truck, a guy can enter a truck's OBD software using different years of truck (don't to an auto vin scan). For example: your scanner software goes up to 2015 max you can manually enter a 2016 Ram and 'talk' to the 2016. That's good to know if a guy's scanner software tops out at, say, 2015, and you own a 2016 or 17. I haven't tried it with these years specifically, but the older 4th gen Rams I was able to 'talk' using different yrs in the scanner (manually entered). This is true for many vehicles on my S-O scanner. I'm not sure about Autel, but worth a shot if a guy didn't buy the most up-to-date software pkg. Worth a shot just to see. Just sayin.

Guys who don't already have a scan tool, the AlfaOBD would probably be the best solution. Good luck

 

[TommyGuns777]

The difference will be measureable and possibly slightly noticeable, but I doubt it would be a major issue.

However, if you know someone, neighbor, etc with a decent, up-to-date pro or semi-pro scan tool (Snap on or equivalent), they ..or you, should be able to adjust the tire size in your truck's software in 5 minutes, and the size difference would be a non-issue. I say 'should' bc I haven't personally done it on a '21, and the software is 'locked' on newer Chrysler vehicles. You/they'd need a Secure Gateway (SGW) Bypass to get through the obd (not sure if tire size feature is locked out however). On older trucks where the OBD isn't 'secured' changing wheel/tire size is as easy as pie and takes 5 minutes.

AlfaOBD software, made for Chrysler vehicle owners, would be another way, probably the best for an owner. I'm not an AlfaOBD user so check the 4th Gen DIY forums, or maybe the 5th gen forums, for more specifics on AlfaOBD and your yr of tk. If it'll work for you, you could use your phone/tablet and AlfaOBD to change the tire size seasonally ...and make other tweaks adjustments too.

For reference, this is what the tire size section looks like on a Snap-on scanner (for a 2012). There are 3 or 4 additional screens of tire/wheel sizes (not shown), that include larger wheels, so you'd pick the combo that matches what you have:
View attachment 482402

Really appreciate the detailed reply. Thank you!

 

[TommyGuns777]

Takes 90 seconds start to finish recalibrating with jscan..

Looking into Jscan now. Seems like the simplest route. Thanks for info, brutha!

 

[Jeepwalker]

JScan probably is a good route. Esp for Jeep guys. I personally haven't used it though...

 

[TommyGuns777]

JScan probably is a good route. Esp for Jeep guys. I personally haven't used it though...

Looks like the simplest method based on what I’m reading. Also seems like it would be okay without any programming but just good piece of mind.

With the 3.92 gearing I think it “should” be okay in theory…. Not like I’m running 35’s or anything.

I’d just like to stay away from the dealership if I can… they quoted almost 600$ for this service and I’d have to do it 2x a year.

And you’re right about the Jeeps guys liking it.. all the pictures within the software are Jeeps. Lol

 

[Jeepwalker]

Plus it's inexpensive.

It's amazing all the 'affordable' diagnostic software's coming out for owners. And some of the low-cost Chinese scan tools which do about what the Snap-on scanners do for a fraction of the price. It's a real win-win for owners. Gotta be tougher and tougher for Snap on to continue their pricing model. Ford software pricing model seems to be really out of step compared to others. Won't be long and a company will probably undercut them.

 

[British Bulldog]

Hey. OP.
I ran 17” wheels on my old 2017 for three winters instead of 20”. There was a size difference in diameter, but
I NEVER bothered doing the speedo thing as it seemed a pain for three months only. I had 3.92 axle, caused no issues. I knew my Speedo would and did read out about 3 MPH and I just used to deal with it!
Hope this clears up any wondering of mismatched gears etc. Never happened.

 

[TommyGuns777]

That is great information and what I was hoping to hear! Appreciate that, thank you.

 

[Nicholas Cove]

I believe they do have that capability. Obviously dependent on your unit's software year, etc. You might have to get a secure gateway cable/interface for tks 2018+. Search ebay for SGW. There's probably an Autel forum where guys are recommending certain products. I see some of the inexpensive bi-directional chinese scanners on Amazon could do it as well (although I don't own one to personally vouch for it) ...but it was on the feature list for whatever that's worth.


Edit: Within the Snap-on scanner the change wheel/tire size section is within the 'Miscellaneous' section as ya look through the main menu of options. It's easy to not see. In fact, didn't know snap-on could do it either until I read it on some forum. I went and checked and I'm like "holy cow!" Also, I checked and the older Gen4 Rams ..at least with my truck, a guy can enter a truck's OBD software using different years of truck (don't to an auto vin scan). For example: your scanner software goes up to 2015 max you can manually enter a 2016 Ram and 'talk' to the 2016. That's good to know if a guy's scanner software tops out at, say, 2015, and you own a 2016 or 17. I haven't tried it with these years specifically, but the older 4th gen Rams I was able to 'talk' using different yrs in the scanner (manually entered). This is true for many vehicles on my S-O scanner. I'm not sure about Autel, but worth a shot if a guy didn't buy the most up-to-date software pkg. Worth a shot just to see. Just sayin.

Guys who don't already have a scan tool, the AlfaOBD would probably be the best solution. Good luck

Thanks man I'm going to play with it on my truck and see what happens. It's strange what features are locked and unlocked for modification across the different manufacturers.

 

[Quick_Shifter]

Plus it's inexpensive.

It's amazing all the 'affordable' diagnostic software's coming out for owners. And some of the low-cost Chinese scan tools which do about what the Snap-on scanners do for a fraction of the price. It's a real win-win for owners. Gotta be tougher and tougher for Snap on to continue their pricing model. Ford software pricing model seems to be really out of step compared to others. Won't be long and a company will probably undercut them.

My Snap on Scanner has been flawless changing settings on rams and Jeeps. I’m so happy that’s a feature

 

[CanRebel]

I changed my 2021 Rebel from 18 to 20.
Didn't really have to do the Tire size, as someone mentioned above the speedo will be off a tiny bit.

If you are going to do it yourself. You need more than just software.

You need OBD device. There are some cheap ones and some better ones. I have OBDLink MX+, works great.
Then you also need you Gateway Bypass module as someone mentioned above.
I'm using ZAutomotive Module, the one I have cost more, but it's easy. Plug it in, done. There are cheaper
ones, and some that have cables you have plug in certain spots.

I have that too, but on my 2021 Rebel it's pain in the ass trying put those little cables in. The module is easy.

Then you need either AlfaOBD or JScan. I have Jscan for my jeep, but use AlfaOBD for my truck.

 

[CheechDogg.0n37s]

I love my AlfaOBD , have changed so many things and added so many things ... Pulled the pin to activate a FOB for my friend, changed tire sizes and the gear ratio from 3.21s to 4.88s when I regeared my truck ... added the cargo camera a couple days ago ... Just so many things with this little app ..

 

[TommyGuns777]

I changed my 2021 Rebel from 18 to 20.
Didn't really have to do the Tire size, as someone mentioned above the speedo will be off a tiny bit.

If you are going to do it yourself. You need more than just software.

You need OBD device. There are some cheap ones and some better ones. I have OBDLink MX+, works great.
Then you also need you Gateway Bypass module as someone mentioned above.
I'm using ZAutomotive Module, the one I have cost more, but it's easy. Plug it in, done. There are cheaper
ones, and some that have cables you have plug in certain spots.

I have that too, but on my 2021 Rebel it's pain in the ass trying put those little cables in. The module is easy.

Then you need either AlfaOBD or JScan. I have Jscan for my jeep, but use AlfaOBD for my truck.

OBDLink MX+ And the Jscan is what I was thinking if I go this route. I downloaded the Jscan app and was playing around in the demo software. - Lots of cool features!

Was really hoping to avoid the gateway bypass module for simplicity reasons and $ so that’s a bit of a bummer but no big deal. Searching thru YouTube and other forums some say they have to use the bypass some say they don’t, weird. - I’m thinking that’s because they locked them out after a certain year?

 

[CanRebel]

OBDLink MX+ And the Jscan is what I was thinking if I go this route. I downloaded the Jscan app and was playing around in the demo software. - Lots of cool features!

Was really hoping to avoid the gateway bypass module for simplicity reasons and $ so that’s a bit of a bummer but no big deal. Searching thru YouTube and other forums some say they have to use the bypass some say they don’t, weird. - I’m thinking that’s because they locked them out after a certain year?

Correct. It's 2018 and above that need the SGW.
This is one I purchased, it is more than other options. But it works and easy to plug in.

Security Gateway Bypass Module – Z Automotive

www.zautomotive.com

If you haven't purchased JScan, I would say look at AlfaOBD. While the intereface is old, it has many more options for Ram Trucks, than JScan.
(That is my view with limited experience, as mentioned. I've only used it for my Jeep. )

As @CheechDogg.0n37s mentioned above, there many things you can do with it. If you plan on doing any mods on your truck in future.
So it is good tool, even just check for error codes.

 

[boblonben]

Hello everyone,

I picked up a 2021 Ram Warlock AT Edition a little while ago and love it. It came with the 17” Off-road wheels and Yokohama 265/70r17 tires. I used these stock rims for winter tires, which are currently on the truck.

I picked up a factory set of black 20” MOPAR rims that I plan to run the stock tire size on (275/60r20) but I noticed they are 1.5” taller.

Will I be okay to put the 20” rims and 275/60r20 tires on for the summer without doing any programming to the shift points? Worried about possible damage.

Any input would be appreciated. Thanks!

Tom

Looked right after I read this, at the Warlock net door tgo me and see his fctory label says the stock tire for the 20" rims is a 275/55r20 - that is what is on it. Curious as to why the difference. who knows ? cheers