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16 or 18in wheels?

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Necred, Jun 9, 2013.

  1. Necred

    Necred Member

    I current have the stock (265/70/16) wheels & tires,,,I have an option to purchase 2013 18in wheels & tires..My question is how much will these effect my mpg and response?
    thanx
    Last edited: Jun 9, 2013
  2. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    I the new wheels are heavier than your old ones the unsprung weight will affect things some, whats the overall size of the tires your using because that'll make a difference too.
  3. jbjones240

    jbjones240 Rockstar 100 Posts

    You will probably see a bigger difference in gas mileage from tire size than wheel diameter. When I upgraded mine from 16s to 17s I really did not see much of a difference, I also went with stock tire dimensions.

    -JJ
  4. RayVoy

    RayVoy Active Member 2 Years 1000 Posts

    17", 18" and 20" wheel and tires were available for my truck (an '09) when I compared each tire I was surprised to find the circumference of each tire was almost the same. So close, that I'm sure there would be no difference in speedo readings, or mpg.

    Check 'em on here: http://www.michelinman.com/
  5. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    a 32" tire that is 10" wide will have the same mpg, response, etc., whether its on a 15" wheel, 16" wheel, 24" wheel" 30" wheel....
    does not matter wheel size. its all about outside tire size and width.
    and as far as weight, if your going up in wheel size, weight will increase obviously, but tire weight will also decrease hand-in-hand.
    the marginal difference in weight, IF its even any heavier, will yield NO effect on your parameters. Since your tires are in contact with the ground, an additional 10 pounds in weight on one tire and wheel (40 pounds for all four), is the exact same as 40 pounds sitting in the bed of your truck. and if 40 pounds affects your mpg, I feel sorry if you ever carry any passengers in your truck LOL
  6. Necred

    Necred Member

    The chart shows 265/70/16 tire (on truck now)is 30.61 dia. the stock tire on 2013 was almost 2 in taller (I don't recall the size) as I put the 2 tires side by side after making sure they would clear fender well. I cant reach owner of truck to ask the tire size but im sure it was 2in taller. So the weight will affect the mpg & response more than the size?
    The stock tire on 00 Z71 is the 265/75/16 (31.65),, I may just put them on it. my mpg now is 18.6 mostly hiway...
  7. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    No.
    the marginal weight difference, is not going to affect anything. however, You MIGHT see a difference if each wheel and tire is about 200 pounds heavier.


    SIZE and only SIZE (I.E. height and width of tire) will effect your mpg and response.
  8. RayVoy

    RayVoy Active Member 2 Years 1000 Posts

    Looking at mpg, this is probably true, but unsprung weight, compared to sprung weight, will wear suspension components faster. Unsprung weight has the effect of lower traction, and drive-ability if you are after performance; but, it can improve comfort in the seat of the pants.

    I agree, if all we are looking at is weight and size. Rubber compound and thread pattern will have the biggest impact on mpg.

    To the OP, if the wheels/tires coming off are OEM, for your truck; and, the wheels/tires you are looking at, are OEM, for your truck, you will notice very little difference in mpg, and/or, performance. GM selects the tires based upon mpg, performance and most of all, road noise.
  9. steved

    steved Former Member

    As I have mentioned in other posts, they changed the bolt pattern from a SAE to metric in 2011 for the 2500s...did they follow suite with the 1500s? Might be worth checking before buying...
  10. stchman

    stchman Active Member 1 Year 1000 Posts

    I doubt you will see much effect in gas mileage from tire size alone, but you will see a big effect in speedometer accuracy. You will need to get some kind of unit to tell the ECU the new tire height.

    Another thing that happens is that when the speedometer is off, it throws off automatic transmission shift points, so your fuel economy will suffer.

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