Tire Swap?
- Thread starter bereta1
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Danny k
Junior Member
You shouldn’t have any issue that middle number is size of sidewall of tire. Your not going to low which is fine shouldn’t have to recalibrate anything
Answers here:
tiresize.com
Tire Size Comparison
Tire size comparison the easy way. Use our tire size comparison calculator to compare diameter, width, sidewall, circumference and revolutions per mile.
kurek
Senior Member
- Joined
- Aug 7, 2019
- Posts
- 2,661
- Reaction score
- 3,813
- Location
- Northwest
- Ram Year
- 2015
- Engine
- Hemi 5.7
275/55r20 are 3.3% smaller than 275/60R20 so your speedometer will read 3.3% higher . It's not a lot, it means when your speedometer reads 75mph you'll really be going about 72mph... may save you from a ticket some day 
Ideally you probably should recalibrate, the truck uses that calibration for transmission and throttle behavior too. You can use JSCAN or AlfaOBD along with an OBD2 dongle, people have their preferences there and my preference is JSCAN (Android app) . The cheapest-while-still-good OBD2 dongle is the BAFX one, about $25 . The best one I've personally used is OBDLink MX+ , about $100 . A license to use JSCAN on your truck was $22 as of when I did mine. I think an AlfaOBD license is about 2x that. Both apps do about the same stuff just with different user interfaces which is why people have preferences for one or the other just like iphone/android/linux/windows/mac/whatever.
Ideally you probably should recalibrate, the truck uses that calibration for transmission and throttle behavior too. You can use JSCAN or AlfaOBD along with an OBD2 dongle, people have their preferences there and my preference is JSCAN (Android app) . The cheapest-while-still-good OBD2 dongle is the BAFX one, about $25 . The best one I've personally used is OBDLink MX+ , about $100 . A license to use JSCAN on your truck was $22 as of when I did mine. I think an AlfaOBD license is about 2x that. Both apps do about the same stuff just with different user interfaces which is why people have preferences for one or the other just like iphone/android/linux/windows/mac/whatever.
