Tire sizing question

[Mack Mason]

I have a 2019 four wheel drive 1500 Silverado. It came with 22 inch wheels, and 275/50-22 tires. I’m considering switching to 18 inch wheels, (long story).  According to Tire Rack, the 275/50-22 has a diameter of 32.9 inches.  The OEM 18s are 265/65R18, which have a diameter of 31.5 inches.  They show a size of 265/70R18 (non OEM) of being 32.6 inches diameter, (very close to the OEM 22s. If I make the switch, should I use the 265/70R18?  Or, am I over thinking this, and use the OEM sized 18s even though they have a smaller diameter than my 22s? 
 

Thanks in advance for any input.

[Peter Thiessen]

I think it makes sense to go with The 265/70/18. With these tires you will be travelling at 70.4 mph when your speedometer shows 70 mph instead of 68.3 mph that you would get with the 265/65/18.

[CamGTP]

Yes, you want to run 265/70/18's to keep everything good with the speedo.

[Rad64]

It seems kinda simple to this country boy redneck but couldn't you get the tires you want and just have the speedo reprogrammed?

[Mack Mason]

1 hour ago, Rad64 said:

It seems kinda simple to this country boy redneck but couldn't you get the tires you want and just have the speedo reprogrammed?

I am sure that I could do exactly that. The tires I like are available in both sizes though, so the non-OEM size would just simplify things for me. Assuming of course, there wasn’t a reason not to stray from the OEM size.

Edited January 3, 2021 by Mack Mason
Skipped a couple words

[amxguy1970]

On 12/27/2020 at 6:20 PM, Mack Mason said:

I have a 2019 four wheel drive 1500 Silverado. It came with 22 inch wheels, and 275/50-22 tires. I’m considering switching to 18 inch wheels, (long story).  According to Tire Rack, the 275/50-22 has a diameter of 32.9 inches.  The OEM 18s are 265/65R18, which have a diameter of 31.5 inches.  They show a size of 265/70R18 (non OEM) of being 32.6 inches diameter, (very close to the OEM 22s. If I make the switch, should I use the 265/70R18?  Or, am I over thinking this, and use the OEM sized 18s even though they have a smaller diameter than my 22s? 
 

Thanks in advance for any input.

Should be a pretty short story, you realized how silly it is and all the trade offs of having big wheels causes and decided to improve your truck with some proper sized wheels and tires...

 

Thanks for not just asking how big you can go. That is interesting the stock 22's are nearly a 33" tire, wonder why GM didn't put the 265/70/18 on there stock in keeping close to the stock diameter of all tires? Either way shouldn't be any issue considering the stock size is that large but don't quote me on that, I deal with K2 body style. 

 

Tyler

[Gangly]

The factory tires that come on the upper end 18's, 20's, and 22's share an approximate 33" diameter even though the tire for the 18" wheel is closer to 32" than 33".  The reason, I would assume, is to keep simplicity across the board with tire/speedo calibration, but I could be way off.  I would stick more closely to a 275/70-18 which would put you right about 33.16" diameter if speedo calibration/accuracy is a concern of yours.

Edited January 4, 2021 by Gangly