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Dealer recalibration for 275/60/20

Vilas15

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I'm considering going up to 275/60/20 tires (33s). I have a 2020 big horn. Has anyone had the dealer recalibrate their speedo with this specific size? I remember reading a post that said the measured rolling diameter was too small for the dealer to enter (around 32.5") so they couldn't do it, but I can't find that post. If I upsize I will recalibrate so don't suggest just going without it. I'm also hesitant to use a 3rd party (RC) device and I don't want my parking sensors bricked.

All this has me reconsidering and I may just keep the stock tire size. It's a lot of hassle for an extra inch diameter that only I will notice. I don't offroad and don't need additional clearance. I can get Falken Wildpeaks in 275/55/60 that are actually XL rated instead of SL in the larger size.
 

Ericw

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Hey I don’t know if they can do it or not, all the dealers around me say the can’t do it
 

Vilas15

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I called 2 dealers in my area and the confirmed they could do it. One dealer was $150.00 and the other was $400.00.
Reference this when you talk to them. https://static.nhtsa.gov/odi/tsbs/2020/MC-10178664-9999.pdf
So they measure your tires then select the size (between 33 and 35). A 275/60/20 is 33" and will not measure that size on the truck with load on it. That is exactly the issue that I mentioned in my original post. I had read a post about a dealer that wouldn't complete the process since the tires measured 32.5" which is not an option to pick. Maybe depending on the dealer theyd just pick 33" but Id need to discuss that before even purchasing the tires.
 

EJ84

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I don’t want to hijack the OP, but he may be interested in this info.

what’s it cost to recalibrate with alpha? Any warranty issues.
 

HSKR R/T

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I don’t want to hijack the OP, but he may be interested in this info.

what’s it cost to recalibrate with alpha? Any warranty issues.
Cheaper than paying dealer, and zero warranty worries
 

Condor757

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Do you feel like it’s accurate has fair as MPH?
Pretty accurate according to both my dash cam and GPS MPH readouts.
AlfaOBD would’ve been great but I don’t have/use any Android products.
 

RSZ

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The dynamic rolling diameter of a tire is about 3% less than the stated diameter. A 33" tire is actually about 32" with the weight of the vehicle sitting on it.


The parking sensors getting "bricked" is usually because the tire size in ABS computer needs to match the tire size in the body computer. The park sensors are interdependent on the correct and matching tire size in the ABS computer. The park sensors will work correctly once everything is setup correctly.
 

Choate

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iPhone and jscan here. Worked perfectly. It doesn’t have all the functionally of alpha but unless you’re adding new parts to your truck and need capability but you can do quite a bit. I adjusted for the taller tires and made the fogs stay on w high beams. Tested MPH via Waze. Dead accurate. Fogs stay on w high beams as well.
 

Audixs4x01

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iPhone and jscan here. Worked perfectly. It doesn’t have all the functionally of alpha but unless you’re adding new parts to your truck and need capability but you can do quite a bit. I adjusted for the taller tires and made the fogs stay on w high beams. Tested MPH via Waze. Dead accurate. Fogs stay on w high beams as well.
Which adapters did you use for this? Thanks
 

VectorZ

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iPhone and jscan here. Worked perfectly. It doesn’t have all the functionally of alpha but unless you’re adding new parts to your truck and need capability but you can do quite a bit. I adjusted for the taller tires and made the fogs stay on w high beams. Tested MPH via Waze. Dead accurate. Fogs stay on w high beams as well.
Looking at their website and it does not show the Ram Truck supported, but you had no issues? How much was it?
 

Choate

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I saw that on the website too. It is supported. And yes you need a security bypass cable. That’s like $15 and the app I think was $25 for one VIN license which is all I needed 31EF5CF4-7A11-4020-9EDE-D600D7CBB4A4.png
 

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