2011 M6 Gearing Spreadsheet
#1
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2011 M6 Gearing Spreadsheet
I have compiled a spreadsheet that details RPMS in each gear at a given speed for 3.31, 3.55, and 3.73 rear gears. There have been many posts recently asking which gears should I choose. This spreadsheet answers all of those questions.
#2
3.73 - 111.5 mph (18" All-Seasons 765 rpm) - 111.1 mph (19" All-Seasons 768 rpm) - 111.8 mph (19" Summer Rubber 763 rpm)
3.55 - 117.2 mph (18" All-Seasons 765 rpm) - 116.7 mph (19" All-Seasons 768 rpm) - 117.5 mph (19" Summer Rubber 763 rpm)
3.31 - 125.7 mph (18" All-Seasons 765 rpm) - 125.2 mph (19" All-Seasons 768 rpm) - 126.0 mph (19" Summer Rubber 763 rpm)
As you can see you appear to be off by 4 mph on average.
#3
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It all depends upon what you believe is the correct tire diameter / revolutions per mile. I calculated everything from the stock 18" tire size, which is 235/50R18 (27.25196 inch diameter). We all know tire sizes can vary, but I didn't have any solid info on the actual diameter so I went by the size.
765 rev per mile yields a diameter of 26.36355. That's nearly an inch difference, and the reason for the differences in our calculated speeds. Where did you get your information?
765 rev per mile yields a diameter of 26.36355. That's nearly an inch difference, and the reason for the differences in our calculated speeds. Where did you get your information?
#4
GTR Member
I don't, and am sure others don't, have the software to open the spreadsheet on my computer.
I just use this calculator: http://www.f-body.org/gears/
Easy to use and you can make all the changes you like to it.
I just use this calculator: http://www.f-body.org/gears/
Easy to use and you can make all the changes you like to it.
#5
Mach 1 Member
I don't, and am sure others don't, have the software to open the spreadsheet on my computer.
I just use this calculator: http://www.f-body.org/gears/
Easy to use and you can make all the changes you like to it.
I just use this calculator: http://www.f-body.org/gears/
Easy to use and you can make all the changes you like to it.
#6
GTR Member
It's called OpenOffice. And, the 21st century. It's not OP's fault that people can't figure out how to use a computer for basic tasks.
#7
Mach 1 Member
I'm sorry, but this is like *****ing at a guy who brings you a gallon of milk because you don't have a fridge in your house. It's 2010, you should have some method of viewing spreadsheets on your computer, especially if you're a car guy (because you might need to, oh, look at gear/speed charts).
#8
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I'm sorry, but this is like *****ing at a guy who brings you a gallon of milk because you don't have a fridge in your house. It's 2010, you should have some method of viewing spreadsheets on your computer, especially if you're a car guy (because you might need to, oh, look at gear/speed charts).
#9
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It all depends upon what you believe is the correct tire diameter / revolutions per mile. I calculated everything from the stock 18" tire size, which is 235/50R18 (27.25196 inch diameter). We all know tire sizes can vary, but I didn't have any solid info on the actual diameter so I went by the size.
765 rev per mile yields a diameter of 26.36355. That's nearly an inch difference, and the reason for the differences in our calculated speeds. Where did you get your information?
765 rev per mile yields a diameter of 26.36355. That's nearly an inch difference, and the reason for the differences in our calculated speeds. Where did you get your information?
Pirelli's site has 761.9 revs/mile.
I've been through this discussion with Gene....believe he's got it down pretty good!
#10
So you used unloaded diameter as opposed to loaded radius or revolutions per mile? That likely would explain the difference.
The listed rpm varies for several tires. I believe the OEM Ford 235/50R18 is 765 rpm (I believe the generic is 762 rpm). However the 763 rpm Summer Tire is for the 255/40R19 XL OEM MB Tire. Ive seen the Ford OEM listed as being 763 rpm / 769 rpm / 769.5 rpm in various places. Im not sure which is acccurate. I simply used the one that gave the closest to your numbers.
The listed rpm varies for several tires. I believe the OEM Ford 235/50R18 is 765 rpm (I believe the generic is 762 rpm). However the 763 rpm Summer Tire is for the 255/40R19 XL OEM MB Tire. Ive seen the Ford OEM listed as being 763 rpm / 769 rpm / 769.5 rpm in various places. Im not sure which is acccurate. I simply used the one that gave the closest to your numbers.
Last edited by Gene K; 5/29/10 at 01:33 PM.
#11
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I hear others saying that 1st gear is much less usable with 3.73 but this confirms that it shouldn't be an issue. I ordered it for but-o-meter in 2nd, 3rd, and 4th.
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So you used unloaded diameter as opposed to loaded radius or revolutions per mile? That likely would explain the difference.
The listed rpm varies for several tires. I believe the OEM Ford 235/50R18 is 765 rpm (I believe the generic is 762 rpm). However the 763 rpm Summer Tire is for the 255/40R19 XL OEM MB Tire. Ive seen the Ford OEM listed as being 763 rpm / 769 rpm / 769.5 rpm in various places. Im not sure which is acccurate. I simply used the one that gave the closest to your numbers.
The listed rpm varies for several tires. I believe the OEM Ford 235/50R18 is 765 rpm (I believe the generic is 762 rpm). However the 763 rpm Summer Tire is for the 255/40R19 XL OEM MB Tire. Ive seen the Ford OEM listed as being 763 rpm / 769 rpm / 769.5 rpm in various places. Im not sure which is acccurate. I simply used the one that gave the closest to your numbers.
My '11 theoretically should be turning 1823 RPM @ 75 MPH, but in reality it is closer to 2k.
Doug
#14
A Man Just Needs Some....
Is it possible to use 5th gear on these and gain any time, or is it a loss between shifts? Just curious. I'm thinking 4.11 and using 5th.
Last edited by AlsCobra; 12/19/11 at 06:42 AM.
#15
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What size tires are you currently running?
#16
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Ignore the whiners who want to measure with a micrometer when the part is going to be cut with a chainsaw...
#20
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The answer!
Bill