What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Gear Ratio Calculator

folkenheath

folkenheath

Volcano Manifolds
Vendor
GMOTM Winner
Author
Joined
Nov 12, 2004
Posts
9,053
Reaction score
8,336
Location
Wisconsin
This is a calculator to calculate engine RPM, vehicle speed, gear ratios for transmissions, transfer cases, differentials, tire diameters, etc. It also will calculate the tire diameter in inches of a metric tire size. Make sure to look in the other sheets at the bottom for other calculators and lists.

The first sheet is "GM calculator". It's kind of self instructing. You select the information you know, and leave blank the cell you want to calculate. It wil do the rest. It displays all info in the bottom box of cells so you can also see what ratio it's using when you selected the transmission, and which gear, etc.

The 2nd sheet is the exact same thing, except it will allow you to type in any tire diameter you wish.

The 3rd sheet is another repeat, except this one will allow you to manually fill in every variable if you have a completely unheard of (or a Furd) drivetrain or something.

The 4th sheet is a "Metric Tire Converter" Just fill in your tire size, and it will tell you the "alleged" size in inches. I say alleged, because they aren't always what they are supposed to be.

The 5th sheet is a list of different transmissions and their gear ratios, the first couple sheets pull information from this one. If you happen to have one I forgot, then you can just use the custom(3rd) sheet.

The 6th sheet is a list of different transfer cases and their gear ratios, the first couple sheets pull information from this one. If you happen to have one I forgot, then you can just use the custom(3rd) sheet.

The 7th sheet is a list of some possible differential gear ratios, the first couple sheets pull information from this one as well. If you happen to have one I forgot, then you can just use the custom(3rd) sheet.

The 8th sheet is some various tire sizes, the first sheet pull information from this one as well. If you happen to have one I forgot, then you can just use the custom tire(2nd) sheet.

Click on the link, then click on the download arrow (top right)...

https://drive.google.com/file/d/0B7VthQm31EE6b1o4dDI2S19xbkE/view?usp=sharing

Any questions send me a PM or e-mail.

Thanks,

Heath
 
Last edited:
Sorry, I should of specified. You need to right click the link, then click "Save Target as". You need to save the file to your computer and then open it in Excel or "Open Office."
 
folkenheath said:
Sorry, I should of specified. You need to right click the link, then click "Save Target as". You need to save the file to your computer and then open it in Excel or "Open Office."
Click to expand...

Does not work. Please check your link - for me it links a HTML page, not an Excel file.:confused:

thanks,
 
I am not sure, because depending on what computer I am using, it always shows the correct link, but sometimes it redirects me back to the thread. The file is there, and it is working and public, it appears to be an issue here, I'll double check the hyperlink.
 
No problem, glad you like it kyler.

Keitha, try it from a different computer. I think it may be your browser or your computer, because I have tried it on 3 different computers, and it worked on 2 out of the 3, and I also tried it without logging into CK5. I think the link is working, but some browsers or computers don't link to the correct address for some reason, and I don't know why. The one that it didn't work on is really old running Windows 2000 with a browswer that isn't supported anymore. The other two, it worked fine.
 
I have no any idea about this thread. please update me with complete information.
 
Go to the link in the first post and download the file, the instructions are in a sheet in the file.
 
it works fine for me, but I cant use it to figure ouit what gears I currently have cause I'm too cheap to buy a tach:whistle: guess I'm gonna have to count em when I change the diff lube.
 
That's pretty cool, I have one that lays out a variety of speed and tire sizes on the spreadsheet so you can see more than one speed and size at a time that I like but it doesn't have the built in data, you have to look all that up every time. Or memorize more useless (for most people) info.

Keep in mind that you can't use the sidewall size for tires. Technically you need to measure from the hub center to ground and double it for the calculators to work out right. We usually subract and inch or two from the sidewall size to get the true rolling dia. This will make your results match the world a lot closer.
 
Stephen said:
That's pretty cool, I have one that lays out a variety of speed and tire sizes on the spreadsheet so you can see more than one speed and size at a time that I like but it doesn't have the built in data, you have to look all that up every time. Or memorize more useless (for most people) info.

Keep in mind that you can't use the sidewall size for tires. Technically you need to measure from the hub center to ground and double it for the calculators to work out right. We usually subract and inch or two from the sidewall size to get the true rolling dia. This will make your results match the world a lot closer.
Click to expand...

Thanks Stephen, you may have noticed there are a few sheets in it, you could do exactly that in the 2nd or 3rd sheet in the file. I didn't have it subtract anything because there are so many variables with tire and rims and different pressures I left that up to the user.

I'll see about putting two side by side for comparison, I did that with the compression calculator but never thought about it with the gear ratio chart. Thanks for the feedback.
 
I have changed the original link because I don't have the comcast account any more it was saved on previously.
 
I just fixed the link, it may not have been working for a couple weeks, sorry about that.
 
I realize this is an old post, but I just ran across it. I did this calculation in high school geometry for grins and giggles. I use to have speeds in increments of 10 in 4th gear by engine RPM written on the windshield of my 84 K10 with the SM465 and used my tach as my speedo.

Engine RPM = ((inches per mile -divided by- tire diameter -times- 3.14)) -times- (axle ratio -times- transfer case ratio -times- transmission gear ratio) -times- (vehicle speed -divided by- 60)

RPM = (63360/TireSize*3.14)(Axle*TransferCaseGear*TransGear)(Speed/60)

This formula gives you engine speed given tire size (how many inches per mile divided by tire diameter gives you the number of rotations per mile) multiplied by everything beyond the tires (axle ratio, transfer case gear, and transmission gear). To know RPM given a speed, you must divide that speed by 60 (since 60 miles per hour (60 minutes) is a 1 to 1 ratio). 15 miles per hour would be 15 -divided by- 60.

The table below are the results of this given formula. If you want the most accurate numbers, measure your tires and run a manual transmission. Automatic trannys slip the torque converter, so it's difficult to fully-calculate.

This is my current setup on my K10 and I can confirm, you'll grenade the engine in 4xLow before you hit 10 mph.

Transmission:1st Gear2nd Gear 3rd Gear 4th Gear5th Gear
SM4656.553.581.701.000.00
Transfer CaseHi GearLow GearTire SizeAxle Ratio
NP2081.002.68334.11
2/4 Hi4 Low
Speed1st Gear2nd Gear 3rd Gear 4th Gear5th GearSpeed1st Gear2nd Gear 3rd Gear 4th Gear5th Gear
5 1,372 750 356 209 - 5 3,676 2,009 954 561 -
10 2,743 1,499 712 419 - 10 7,353 4,019 1,908 1,123 -
15 4,115 2,249 1,068 628 - 15 11,029 6,028 2,862 1,684 -
20 5,487 2,999 1,424 838 - 20 14,705 8,037 3,817 2,245 -
25 6,859 3,749 1,780 1,047 - 25 18,381 10,047 4,771 2,806 -
30 8,230 4,498 2,136 1,257 - 30 22,058 12,056 5,725 3,368 -
35 9,602 5,248 2,492 1,466 - 35 25,734 14,065 6,679 3,929 -
40 10,974 5,998 2,848 1,675 - 40 29,410 16,075 7,633 4,490 -
45 12,346 6,748 3,204 1,885 - 45 33,086 18,084 8,587 5,051 -
50 13,717 7,497 3,560 2,094 - 50 36,763 20,093 9,541 5,613 -
55 15,089 8,247 3,916 2,304 - 55 40,439 22,103 10,496 6,174 -
60 16,461 8,997 4,272 2,513 - 60 44,115 24,112 11,450 6,735 -
65 17,833 9,747 4,628 2,723 - 65 47,792 26,121 12,404 7,296 -
70 19,204 10,496 4,984 2,932 - 70 51,468 28,131 13,358 7,858 -
75 20,576 11,246 5,340 3,141 - 75 55,144 30,140 14,312 8,419 -
80 21,948 11,996 5,696 3,351 - 80 58,820 32,149 15,266 8,980 -
85 23,320 12,746 6,052 3,560 - 85 62,497 34,159 16,221 9,541 -
90 24,691 13,495 6,408 3,770 - 90 66,173 36,168 17,175 10,103 -
95 26,063 14,245 6,764 3,979 - 95 69,849 38,177 18,129 10,664 -
100 27,435 14,995 7,121 4,189 - 100 73,526 40,186 19,083 11,225 -
 
I use my app now, I don't use the spreadsheet much anymore because the app is always with me pretty much.

Gearhead Apps, Innovate Engineering

Apps for Gearheads by Gearheads If you are a Gearhead, this is the app for you! Gearhead Apps are built to help us calculate various...
www.innovateengineering.pro www.innovateengineering.pro

Would you use an app for us gearheads? (available)

All versions are now available on the Google Play Store and the iOS Appstore including the Free one. www.innovateengineering.pro/gearhead I did check into it and at this time it appears there is not a way to use the decimal keypad with apple iOS while using an HTML based app in Xcode. If...
ck5.com ck5.com
 
You must log in or register to reply here.

Latest Posts

Top Bottom