Anything I need to know when Going from 265/75/17 to 275/60/20?

[D-Roc]

Just like it says. Looking for any input anyone may have about swapping from 17's to 20's. Is it absolutely necessary to recalibrate the speedo and shift points? Anybody have any experience running the 20's and not recalibrating for them? I want to run the 20's for summer and the 17's in winter and really don't want to keep changing settings in the BCM. Will this cause damage to the truck? Thanks in advance for the replies.

 

[GTyankee]

any tire store can tell you more about Height & Especially Width differences

Most Rams with 20" wheel/tires, come with a 1" Ride Height, right from the factory

 

[GeauxinUp]

Just like it says. Looking for any input anyone may have about swapping from 17's to 20's. Is it absolutely necessary to recalibrate the speedo and shift points? Anybody have any experience running the 20's and not recalibrating for them? I want to run the 20's for summer and the 17's in winter and really don't want to keep changing settings in the BCM. Will this cause damage to the truck? Thanks in advance for the replies.

Wheel size doesn’t matter as far as the speedo goes. Those 2 tire sizes are nearly identical in their circumference, so your speedometer will still be pretty accurate. And btw, even big differences in tire sizes won’t cause any kind of damage.

 

[kurek]

I just went from 285/70R17 (32.7" diameter) to 275/65R20 (34.1" diameter) -



It takes about 90 seconds to recalibrate the speedometer using JSCAN.. worth doing not only for the accuracy of the speedo itself but also for transmission shift behavior and throttle behavior since those are also based on road speed, engine load and commanded throttle position. You'll save the price of a JSCAN license in fuel before summer.


In my case going from 32.7 to 34.1 is about a 4.3% difference which is almost identical to the 4.4% difference you'll see going from 31.6" to 33".