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Discussion Starter · #1 · (Edited)
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
 

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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.
 

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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
 

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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/
 

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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
 

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Discussion Starter · #6 ·
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...
 

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So the weight will affect the mpg & response more than the size?
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.
 

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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.
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.

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

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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...
 

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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
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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Discussion Starter · #11 ·
Yea, I fitted one tire on front to see if I had clearance, as I said, there was 2in diff in height.
Stchman, this was my concern is the 2in in height diff gonna confuse tranny & reduce my mpg...On my camry I put 195/75/14 over 195/70/14 and I notice a diff in both response & mpg,,mostly in response ....
 

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Yea, I fitted one tire on front to see if I had clearance, as I said, there was 2in diff in height.
Stchman, this was my concern is the 2in in height diff gonna confuse tranny & reduce my mpg...On my camry I put 195/75/14 over 195/70/14 and I notice a diff in both response & mpg,,mostly in response ....
There are a lot of aftermarket ECU programmers that will re-program the ECU. Hypertech makes power programmer (#32500), but the unit will run you ~$325. There might be less expensive ones out there.
 

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Discussion Starter · #13 ·
I think I will stay with 16in & replace with 265/75 tires.. that way I wont have set tires/wheels to get rid of...
 

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I think I will stay with 16in & replace with 265/75 tires.. that way I wont have set tires/wheels to get rid of...
You said you are currently running 265/70/16s. Do they rub any? If they do, you probably don't want to go 265/75/16s as they'll be taller and will rub more. If your current tires do not rub, have the tire shop test fit a 265/75/16 before you buy all four.

Only reason I ask is, I had a set of 265/65/16s that rubbed.
 

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You might be getting confused with all the different answers. Like another poster wrote, what matters is the outside diameter of the tire, width of tread (not "thread"), type of tread, and weight of tire. If you go to a 265/75, you are increasing the outside diameter 1.1"...not enough to worry much about. The 265/75 is also .7" narrower. The weight will be about the same.

So, if you go to 265/75, your speedo will run about 2mph slower than your current tires indicate (IDK if your speedo is currently right or wrong, but that will be the diff), and your odometer will record about 2% fewer miles than with current tires.

If the tread pattern is similar, you will not see a diff in MPG due to that.

good luck....
 

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Discussion Starter · #16 ·
now that you mention it,, as per my garmin my speedo is couple miles off...truck came with 75s....I can get 18s with xlent tread for $900, it will cost me that to put 16s new on it.
 

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Hmmm
265/70 means .7x265x2=371mm of sidewall= 371/25.4=14.6 14.6"+16"=30.6" tall

265/75 means .75x265x2=397.5mm of sidewall 397.5/25.4=15.6" +16"=31.6"

31.6/30.6=1.033=3.3% taller.
so you will be going 3.3% faster than indicated and 3.3% farther
at 60 indicated roughly 62mph
 

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Discussion Starter · #18 ·
No sir they don't rub, even the 18in one I tried on front didn't scrub turning, I never got on raod with it since I had took one wheel home to try. Nor do the 265/70 rub....265/75 are stock as per door.
 

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Not exactly. I did the math quite well by myself, thank you, and got the same result as you (a bit surprised you took that route, though. Much easier to look at the height diff, see it is 1", and just realize that is 3.3%...to each his own). However, real world...it isn't quite accurate. Possibly due to height diff's from calculations when weight is added, compressing the rubber, or possibly due to expansion of air pressure once the tire heats up, or other issues I can't think of off the top of my head. I used those final result numbers because they are what I came up with over several years of travel through a single, metered 5 mile run, with many different tire combinations. Did it maybe 500 times, because I am a bit anal about getting actual results. I gave the OP a very good approximation of real world results. BUT, I am glad someone is checking the math....
 

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buckmeister
No offense meant.
Just thinking out loud.
Yes calculated and height measured numbers never seem to match up with good numbers based on actual distances-road markers etc.
I'm also compulsive about measuring things-but mainly in respect to mpg ,and weight.
With bicycles motorcycles and various trucks I have done various things to drop weight.
On the 98 Suburban I pulled the 3rd row-78 lbs- and the single seat from 2nd row- almost 60 lbs-
Of course we didn't need them-and use the flat space to sleep when traveling -dog likes the big flat space too..
I can't actually measure any improvement in city FE-150 lbs on 5200 lb Suburban-almost 3% less-might get 1/2 of that in improved city FE- but that is barely .1mpg-no way I could measure that in any way that mattered since just letting my wife drive the Suburban ruins my FE

In any case-no offense meant-just compulsive
Charlie
PS-There are lower rolling resistance tires available-but most are more passenger car than truck.
Since I'm a mpg nut-I would stick with stock height width tires.Besides taller sidewalls usually give a more comfortable ride.
 
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