Changing from to 18 to 20 inch factory wheels

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warrenroadie

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I found some factory 20 inch factory aluminum wheels and tires for sale and I want to replace the 18 inch wheels and tires on my 2018 3500 SRW. What do I need to do so truck systems recognize change in wheel diameter? I realize there are sensors on wheels, but do not know what needs to be done for truck to correctly recognize and continue operating as normal. My truck came from factory with the 18 inch chrome style wheels with the street tread Firestones. My truck is a 2018 Ram 3500 SRW 4 wheel drive with Cummins, Aisin transmission and 8000 miles on the speedo. Thanks for your help in advance.
 

Hugh Johnson

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Take to Ram dealer and have them program new tire size so odometer,speedo, and tranny shift points work.
 

muddy12

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As far as the speedometer/ odometer are concerned, if the overall tire diameter is the same, you don’t have to do anything other than bolt on the new ones. Rim diameter makes no difference. It is the overall tire diameter, more specifically, the revolutions per mile, that make a difference.
For example: a 33x12.5R17, a 33x12.5R18, a 33x12.5R20, or even a 33x12.5R22, are all 33” tall and have have the same circumference. The revolutions per mile will be the same between all of them, regardless of rim diameter.

If the tire diameter is significantly different, then as mentioned, you can have the dealer reprogram for the new tire size, or purchase a tuner/programmer, and change it yourself.

The sensors in the wheels are for monitoring the tire pressure. As long as the new ones transmit on the correct frequency range, and have good battery’s, the truck should automatically recognize them after driving for a few miles.


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Gotjeepomaha

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They 20 is actually a tad taller, but i didn't bother resetting, i found take offs black 20's off a similar 2018, paid $1000. The one thing you will notice with the 20's, they are a rougher ride.

I just lowered my TPMS threasholds down to 45, and will be running my tires at 52 psi empty. Tracy at the below link can send you his hardware, you can change anything you want.

https://tehamann.wixsite.com/tracystruck

Ram_2018_black_wheels.jpg
 
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warrenroadie

warrenroadie

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Thanks for your input and information. I'll proceed with the purchase keeping these suggestions in mind.
 
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