20's and mpg?
10-30-2007, 03:40 PM
#21
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ok you explane to me why would i get 23 miles to the gallon on my Silverado with 20's and 3.73 gears and my friend with his 18's gets 21 on the freeway. Same truck only difference is rims.
10-30-2007, 03:53 PM
#22
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Weight doesn't play as much of a roll as tire diameter does. I went from 83 pounds on stock 20's with 275/55/20 to 68 pounds and shorter 275/45/20 and mileage went from 18 to 15 on the interstate. Mileage around town went from 15 to 14. Measured every tank since I got it a little over 2 years ago.
10-30-2007, 03:57 PM
#23
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Weight doesn't play as much of a roll as tire diameter does. I went from 83 pounds on stock 20's with 275/55/20 to 68 pounds and shorter 275/45/20 and mileage went from 18 to 15 on the interstate. Mileage around town went from 15 to 14. Measured every tank since I got it a little over 2 years ago.
10-30-2007, 05:32 PM
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LOL. theres always two sides of the arguments.
People claim tailgates down better MPG, and people claim tailgate up better MPG, and now theres another group no tailgate = better MPG
I may not be good at articulation or explenations, but i am offering from professional experiances i had with gas mileage.
People claim tailgates down better MPG, and people claim tailgate up better MPG, and now theres another group no tailgate = better MPG
I may not be good at articulation or explenations, but i am offering from professional experiances i had with gas mileage.
10-30-2007, 05:38 PM
#26
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I heavier rotating mass does play a part in getting crappy MPG. My stock wheel/tire combo and the 20' are the same diameter. I don't have a scale or I would weigh them. The 20's are definitely heavier than the stock combo. I would guess that one weighs about 90 lbs each and my stockers about 60-70 lbs each so 20-30 lbs times 4 is a big difference. Also as far as a bigger gear goes that only helps you taking off it doesn't help on the hwy.
10-30-2007, 05:56 PM
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I heavier rotating mass does play a part in getting crappy MPG. My stock wheel/tire combo and the 20' are the same diameter. I don't have a scale or I would weigh them. The 20's are definitely heavier than the stock combo. I would guess that one weighs about 90 lbs each and my stockers about 60-70 lbs each so 20-30 lbs times 4 is a big difference. Also as far as a bigger gear goes that only helps you taking off it doesn't help on the hwy.
10-30-2007, 05:58 PM
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I heavier rotating mass does play a part in getting crappy MPG. My stock wheel/tire combo and the 20' are the same diameter. I don't have a scale or I would weigh them. The 20's are definitely heavier than the stock combo. I would guess that one weighs about 90 lbs each and my stockers about 60-70 lbs each so 20-30 lbs times 4 is a big difference. Also as far as a bigger gear goes that only helps you taking off it doesn't help on the hwy.
Now this calculations was from Richmond gears site.
Rear End Ratio: 3.73
Tire Diameter (Height) in Inches: 35
Over Drive Ratio (1 for no OD): .71
RPM: 1653 at 65 MPH
Now if we do the same calculations with a smaller tire height
Rear End Ratio: 3.73
Tire Diameter (Height) in Inches: 30
Over Drive Ratio (1 for no OD): .71
RPM: 1928 at 65 MPH
This is even smaller
Rear End Ratio: 3.73
Tire Diameter (Height) in Inches: 25
Over Drive Ratio (1 for no OD): .71
RPM: 2314 at 65 MPH
As we look at this calculations we see that the rpms drop as the tire gets larger and increase as the tire gets smaller. Increase in RPMS means more gas per minute to turn the engine.
Now heres the tricky part. The tire width of the large tire has to be the same width of the smaller tires to get the increase in MPG. Surface area increases and so does drag, and this is the reason that larger tires are not MPG friendly. if the surface area on the tire ( the part that touches the pavement ) is the same width as a smaller tire then you should see a increase of mpg with the taller tire.
10-30-2007, 07:30 PM
#29
Dude you are throwing out all this technical jargon and it means absolutely NOTHING.
"My friend got 21 mpg and I get 23 with 20's so it must be true"
Do you realize how stupid you sound.
first of all 20" rims(on the average unless using billet) are much heavier than a stock 16/17" rims.
Secondly, like said, the rotating mass is pushed further out.
Third, you have no idea what you're talking about.
Physics doesn't lie. Hell if you want to throw out the "Objects in motion will remain in motion unless acted on by an opposing force" bull **** then I'll remind you that we all drive a 5000 lbs brick that is about as aerodynamic as Rosie O'donell
Here is what is going to play a factor in your gas mileage:
RPMS- Obviously if you spend time at WOT throttle you'll get terrible gas mileage, however, go too low and you'll be constantly downshifting on hills.
Speed-While related to rpms there is also another factor to take into account....the law of diminishing returns. you may get 15 mpg going 50 mpg and 20 mpg going 70 mph but you won't get 25 mpg going 90 due to aerodynamics and the higher rpms the engine will be turning.
What you're driving-we're driving a truck, it isn't a ford gt or a ferrari, there are very little aerodynamic features that silverado's have.
Rotating mass of the wheels-I have experience on this both from personal experience and from a scientific approach. Having the rotating mass be pushed out further allows outside forces to play a factor in how easy the wheels turn. The further out the rotating mass is taken the more momentum,leverage,etc play a factor.
Anybody can throw out useless terms and then follow it up with "well my buddy got 25 mpg once with his 22's." When you say something like that you lose all your creditability.
"My friend got 21 mpg and I get 23 with 20's so it must be true"
Do you realize how stupid you sound.
first of all 20" rims(on the average unless using billet) are much heavier than a stock 16/17" rims.
Secondly, like said, the rotating mass is pushed further out.
Third, you have no idea what you're talking about.
Physics doesn't lie. Hell if you want to throw out the "Objects in motion will remain in motion unless acted on by an opposing force" bull **** then I'll remind you that we all drive a 5000 lbs brick that is about as aerodynamic as Rosie O'donell
Here is what is going to play a factor in your gas mileage:
RPMS- Obviously if you spend time at WOT throttle you'll get terrible gas mileage, however, go too low and you'll be constantly downshifting on hills.
Speed-While related to rpms there is also another factor to take into account....the law of diminishing returns. you may get 15 mpg going 50 mpg and 20 mpg going 70 mph but you won't get 25 mpg going 90 due to aerodynamics and the higher rpms the engine will be turning.
What you're driving-we're driving a truck, it isn't a ford gt or a ferrari, there are very little aerodynamic features that silverado's have.
Rotating mass of the wheels-I have experience on this both from personal experience and from a scientific approach. Having the rotating mass be pushed out further allows outside forces to play a factor in how easy the wheels turn. The further out the rotating mass is taken the more momentum,leverage,etc play a factor.
Anybody can throw out useless terms and then follow it up with "well my buddy got 25 mpg once with his 22's." When you say something like that you lose all your creditability.
10-30-2007, 07:46 PM
#30
Dude you are throwing out all this technical jargon and it means absolutely NOTHING.
"My friend got 21 mpg and I get 23 with 20's so it must be true"
Do you realize how stupid you sound.
first of all 20" rims(on the average unless using billet) are much heavier than a stock 16/17" rims.
Secondly, like said, the rotating mass is pushed further out.
Third, you have no idea what you're talking about.
Physics doesn't lie. Hell if you want to throw out the "Objects in motion will remain in motion unless acted on by an opposing force" bull **** then I'll remind you that we all drive a 5000 lbs brick that is about as aerodynamic as Rosie O'donell
Here is what is going to play a factor in your gas mileage:
RPMS- Obviously if you spend time at WOT throttle you'll get terrible gas mileage, however, go too low and you'll be constantly downshifting on hills.
Speed-While related to rpms there is also another factor to take into account....the law of diminishing returns. you may get 15 mpg going 50 mpg and 20 mpg going 70 mph but you won't get 25 mpg going 90 due to aerodynamics and the higher rpms the engine will be turning.
What you're driving-we're driving a truck, it isn't a ford gt or a ferrari, there are very little aerodynamic features that silverado's have.
Rotating mass of the wheels-I have experience on this both from personal experience and from a scientific approach. Having the rotating mass be pushed out further allows outside forces to play a factor in how easy the wheels turn. The further out the rotating mass is taken the more momentum,leverage,etc play a factor.
Anybody can throw out useless terms and then follow it up with "well my buddy got 25 mpg once with his 22's." When you say something like that you lose all your creditability.
"My friend got 21 mpg and I get 23 with 20's so it must be true"
Do you realize how stupid you sound.
first of all 20" rims(on the average unless using billet) are much heavier than a stock 16/17" rims.
Secondly, like said, the rotating mass is pushed further out.
Third, you have no idea what you're talking about.
Physics doesn't lie. Hell if you want to throw out the "Objects in motion will remain in motion unless acted on by an opposing force" bull **** then I'll remind you that we all drive a 5000 lbs brick that is about as aerodynamic as Rosie O'donell
Here is what is going to play a factor in your gas mileage:
RPMS- Obviously if you spend time at WOT throttle you'll get terrible gas mileage, however, go too low and you'll be constantly downshifting on hills.
Speed-While related to rpms there is also another factor to take into account....the law of diminishing returns. you may get 15 mpg going 50 mpg and 20 mpg going 70 mph but you won't get 25 mpg going 90 due to aerodynamics and the higher rpms the engine will be turning.
What you're driving-we're driving a truck, it isn't a ford gt or a ferrari, there are very little aerodynamic features that silverado's have.
Rotating mass of the wheels-I have experience on this both from personal experience and from a scientific approach. Having the rotating mass be pushed out further allows outside forces to play a factor in how easy the wheels turn. The further out the rotating mass is taken the more momentum,leverage,etc play a factor.
Anybody can throw out useless terms and then follow it up with "well my buddy got 25 mpg once with his 22's." When you say something like that you lose all your creditability.
Thank's for typing all that so I didnt have too... haha. Case in point, my 20's with tires are the same diameter as my factory 17" wheel and tires setup. However my 20's are a decent amount heavier, Chrome 20's vs. Alum. 17's. With the 20's on I get about 1.5mpg less give or take, I also notice a slight diff. in accel and decel but only when WO or under hard braking. So why do I run the 20's then you may ask... I think they look purdy.