Does moving from 22" to 20" wheels impact speedometer?

[DennisT]

I really don't like the ride of my Yukon Denali with 22" wheels. I am considering buying a set of 20" take-offs from eBay. If I do, will affect my speedometer significantly and would I need to have the ECM reprogrammed?

thanks,
Dennis

 

[adventurenali92]

It depends on what size tire you’ll have. If the circumference of the tire on the 20 inch wheel is close enough to the tire on the 22 then your speedometer will be pretty close to accurate. If there’s a big difference in size then your speedometer will be off.

 

[Blueinterceptor]

What don’t you like and what tire?
Alenza’s. I was thinking about going to a 22” but have no real experiences?

 

[fiatdale]

It’ll most likely be close enough that it will be within 1mph to your advantage.

 

[DennisT]

It depends on what size tire you’ll have. If the circumference of the tire on the 20 inch wheel is close enough to the tire on the 22 then your speedometer will be pretty close to accurate. If there’s a big difference in size then your speedometer will be off.

I was hoping that the taller profile of the 20” tires would offset the wheel change. I would be going to 275-55/20 from 285-45/22.

 

[DennisT]

What don’t you like and what tire?
Alenza’s. I was thinking about going to a 22” but have no real experiences?

I find the ride of the lower profile 45 series to be too harsh. Before this I had a Tahoe with 20”wheels and the ride was much better.

 

[CMoore711]

It's all about overall wheel diameter; Assuming you're on factory 22's with 285/45R22 tires, the overall tire diameter is 32.1". If going down to 20" wheels you will want to stay as close to that 32.1" overall tire diameter that you can. If you can find a 20" size tire that has n exact 32.1" overall diameter your speedometer will not be affected at all.

This is a good site to use for comparing tire sizes: https://www.rimsntires.com/specspro.jsp

 

[4OFFSHR]

You will be fine. I went from the factory 20" set up to a 22" with 305/45-22 and my speedo has remained just fine. Going from the factory 285 set up to a 20" factory set up will not present any issues.

 

[Its_Shaun12]

I will say that going from my original 18 inch wheels to 20's I had the same concern but can say that the speedometer has been fine and if it is different I can barely tell and this is also after running it against a gps for accuracy.

 

[04_Yukon_503]

I will say that going from my original 18 inch wheels to 20's I had the same concern but can say that the speedometer has been fine and if it is different I can barely tell and this is also after running it against a gps for accuracy.

I did the same on my rig and its roughly 6 MPH slow when going 65 and 9 difference when doing 70