18" Wheels with 3.08 Gears?

[BOOMER119]

Considering upgrading my 17" stockers - 255-70R17 tires - to some new 18" takeoffs from Ebay - 265-65R18 tires.

 

I have 3.08 gears, however, and am cocerned about performance and acceleration with the somewhat larger and heavier wheels.

 

Anyone out there have 18's with the 3.08's?

 

Should I stick with the 17's?

 

Thanks in advance ... Any and all thoughts would be appreciated!

[Stevens03]

There isn't going to be much of a difference. I say go for it!

[high country]

You only need to worry if you are changing overall diameter of the tire.

[Norcalace]

Go to Tire Rack and check the specs for OE tires in 17" and 18" sizes. Depending on the manufacturers you will see between 4 and 9 less tire revolutions per mile for the 17s. In other words any difference in acceleration, mpg or performance will be almost zero.

[Test Alpha]

My wife's CC SLT w/3.08's came with 18" wheels and the SRA tires. It runs great, barely any difference from my RCLB with 3.42's Both have the 5.3. Get the 18" wheels, you won't even notice the difference!

[jdg24]

That's the tire size on my truck and I have 3.08. I haven't noticed any problems at all does great.

[mlowe6417]

My CC had the dealer installed 20 inch chevy wheels 275 55 20 tire size, I have the 3.08s and it will still move down the road pretty good.

But pound for pound here ya go

 

255 70 17

Diameter- 31.1

Width- 10.04

Sidewall 7.03

 

265 65 18

Diameter- 31.6

Width-10.43

Sidewall- 6.78

 

275 55 20

Diameter- 31.9

Width-10.83

Sidewall-5.95

[jeffsig]

I'm running 20s with no issue nor would I ever expect one.

[SLESierra]

you will be fine my truck came with 18s with the 3.08 my last truck had 3.73 and 18s and the only major difference I can tell is I get a little more to the tank thank I did with the 3.73s and on long grades I have noticed the 3.08 will downshift sooner with my trailer loaded but does not struggle.

 

some people on here make a big issue of the 3.08 in these trucks - the 3.08 was used by GM back in the late 70s and early 80s as the corporate gear in those days then the 3.73 came into favor again. It was like it was the gear of choice then it died off for the 3.73 but the nice thing about today is you have all these choices and no standard which would be nice with the 3.42 imho.

[BOOMER119]

Thanks for all the input and advice!

 

At this point I'm trying to decide which tire / wheel combo to go with.

 

Also trying to decide if I really want to spend the money at this point :-)