A Handy Tool for Considering Tire Size & Differential Ratios

[Gerald Morris]

Greetings C Body Moparians!

Today I applied a little arithmetic for us on a simple spreadsheet to make it easy for folks to estimate speeds at given engine rotation rates (RPMs) in sundry transmission gears with a given differential gear ratio. One can vary the tire size and differential ratios. The arithmetic is done for you. Just stick with varying the tire size and that rear end ratio, and you can get meaningful results. It looks fairly accurate, based on the behavior of the two Newports I've driven this past decade, and I assumed the standard Torqueflight gear rations. Below is a sample meant for our current ride, and the spreadsheet is attached. I hope this helps you when shopping for tires, or selecting rear ends, and maybe the speedo-pinion gears even, though I didn't include them yet....

NEW MEGA LINK SINCE GOOGLE SUCKWARE IDJITEERS CAN'T CODE!

Below is a PIC of the sheet in action:

The MEGA LINK provides the ACTUAL SPREADSHEET! GOOGLE BLOWZ DEAD DOGS BY TEXAS HIGHWAYS!!! DROPCOX LICKS UP THE SPEND AFTERWARDS!!! "The Cloud" has taken on a BROWN TINT and STINKS enough to make a damned buzzard PUKE!

I tested my work against reality last night, and it is good! I hope you all can use this little widget when selecting new rolling rubbers or rear end gears.

ONE Final Post Script: I can't answer for what Micro$uck apps will do with the spreadsheet. It's save in Open Document Spreadsheet (ODS) format. If you're blighted with a Google account, you can upload to that to edit it, or you can get a copy of LibreOffice, OpenOffice, Calligra or another ODF office suite. M$ ****** me out of my data in the Spring of 1999, didn't refund my money, and I don't forgive that kind of high handed idiocy and arrogance.

G.M.

 

[Toolmanmike]

Greetings C Body Moparians!

Today I applied a little arithmetic for us on a simple spreadsheet to make it easy for folks to estimate speeds at given engine rotation rates (RPMs) in sundry transmission gears with a given differential gear ratio. One can vary the tire size and differential ratios. The arithmetic is done for you. Just stick with varying the tire size and that rear end ratio, and you can get meaningful results. It looks fairly accurate, based on the behavior of the two Newports I've driven this past decade, and I assumed the standard Torqueflight gear rations. Below is a sample meant for our current ride, and the spreadsheet is attached. I hope this helps you when shopping for tires, or selecting rear ends, and maybe the speedo-pinion gears even, though I didn't include them yet....

View attachment 730412

You SHOULD be able to click on the image provided and download from my Google Drive a copy of the spreadsheet. Be glad that this corporation hasn't yet declared war on Free Software, and they work with it. The sheet is in Open Document Format (ODF) and will work in Google, LibreOffice or OpenOffice among other apps. I don't know WHAT Certain Other Big $ corps do with ODF these daze....

I tested my work against reality last night, and it is good! I hope you all can use this little widget when selecting new rolling rubbers or rear end gears.

G.M.

That is a read only file and the tire diameter can't be changed. Is that what you are going for?

 

[Gerald Morris]

That is a read only file and the tire diameter can't be changed. Is that what you are going for?

NOT AT ALL!! ******* GOOGLE!!!!! INCOMPETENT, DIMWITTED DAMNED ASIAN "SOFTWARE ENGINEERS" WHO INHERIT THEIR DAMNED DEGREES BY FAMILY CONNECTIONS HAVE RUINED WHAT WAS A GREAT COMPANY UNTIL ERIC SCHMIDT WAS FORCED TO RESIGN IN 2015!!! DAMN THEM ALL!!

Pls let me upload the spreadsheet to a server which permits some damned CONTROL over access!!! COCK-SUCKING DAMNED GOOGLE!!!

I'll edit the link in a few minutes.

 

[traintech55]

Great chart, but 15" tire sizes would help many more of us.

 

[Gerald Morris]

Great chart, but 15" tire sizes would help many more of us.

Then enter 15 in Cell A5. Enter the width of your tire in B5. Enter the Sidewall to Width ratio in Cell C5, then enter your rear end ratio in E5. You should have FULL EDITORIAL FREEDOM IF YOU DOWNLOAD THE SPREADSHEET, OPEN IT, AND EDIT IT AS YOU SEE FIT! I'm in a Killing Fury with Google for ******* up the original permissions on this sheet when I expressly Shared the link to Whoever, so I loaded it onto one of my Aussie accounts, so you all can download the sheet and use it.

 

[Toolmanmike]

Great chart, but 15" tire sizes would help many more of us.

Don't stir the pot. He's already pissed that the software won't allow you to change that.

 

[Toolmanmike]

Then enter 15 in Cell A5. Enter the width of your tire in B5. Enter the Sidewall to Width ratio in Cell C5, then enter your rear end ratio in E5. You should have FULL EDITORIAL FREEDOM IF YOU DOWNLOAD THE SPREADSHEET, OPEN IT, AND EDIT IT AS YOU SEE FIT! I'm in a Killing Fury with Google for ******* up the original permissions on this sheet when I expressly Shared the link to Whoever, so I loaded it onto one of my Aussie accounts, so you all can download the sheet and use it.

I went to my Sheets and that option seems to have disappeared.

 

[Gerald Morris]

I went to my Sheets and that option seems to have disappeared.

DAMN GOOGLE!!! Then the scumbags have broken the ODF. You'll have to use an actual spreadsheet editor on your drive. Be SURE and download off my MEGA account, download LibreOffice, install and use it.

GOOGLE IS WORSE THAN WORTHLESS NOW!

Many Thanks Mike!

 

[Gerald Morris]

Folks, I NEVER expected SO MUCH DIFFICULTY with editing a downloadable, free spreadsheet. JUST to show what a 15 inch tire size looks like, I typed in a common tire size, R15 235/70 and screencapped that for you to look at.

You all can thank unregulated crapitalism for ******* people out of the ability to do this in a simple, online spreadsheet editor, forcing YOU to DOWNLOAD AND INSTALL ONE INSTEAD! Google USED TO HAVE ONE, but thanks to "Sundar Pichai" and Co., they've ruined that for ABC Corp's pursuit of as much money as they can squeeze from Moron Advertising, which, alas, is what their actual Business is. The same such ethics destroyed Chrysler of course.....

 

[CBODY67]

That is a read only file and the tire diameter can't be changed. Is that what you are going for?

In my Word version, when the file downloads it will say "Read Only", BUT there is a click in the upper tool bar which will allow editing. Clicking that should allow for changes. Then save the resultant file.

CBODY67

 

[Vaanth]

Following is a link to a shared Google Sheets version of the Speed Estimator spreadsheet if you want to use it within Google Sheets. This should be viewable if you don't have a Google/Gmail account as view only with restricted menu access, but it should be viewable if you do have a Google/Gmail account as view only with menu access.

When opened, the linked spreadsheet is "View Only", so make a local copy by clicking File in the menu, then Make a Copy in the dropdown. This will create your own copy which you own, can change the input fields, and edit rest of the spreadsheet itself as desired within Google Sheets.

Speed Estimator

This might help. I tested this with a different Google account user across different computers and it worked okay. Let me know if it does or does not work for you.

 

[Barry S]

Nice work, Gerald! I was able to download it from your link and I was able to change the different options, including the rim size.

 

[Gerald Morris]

In my Word version, when the file downloads it will say "Read Only", BUT there is a click in the upper tool bar which will allow editing. Clicking that should allow for changes. Then save the resultant file.

CBODY67

Glad to see Wurd will import ODF now. About damned time. The arithmetic should work fine. I'll now look into a table for the speedometer pinion gears and how to work some logic to make it puke out the right gear for the tire and differential combination. I've got 4 or 5 pinion gears here, for various possible combos, but I hope to stick with the little red one now in the tranny....

 

[Gerald Morris]

Nice work, Gerald! I was able to download it from your link and I was able to change the different options, including the rim size.

XLNT News! I'll see about a speedo pinion gear X-ref ASAP.

 

[Gerald Morris]

Following is a link to a shared Google Sheets version of the Speed Estimator spreadsheet if you want to use it within Google Sheets. This should be viewable if you don't have a Google/Gmail account as view only with restricted menu access, but it should be viewable if you do have a Google/Gmail account as view only with menu access.

When opened, the linked spreadsheet is "View Only", so make a local copy by clicking File in the menu, then Make a Copy in the dropdown. This will create your own copy which you own, can change the input fields, and edit rest of the spreadsheet itself as desired within Google Sheets.

Speed Estimator

This might help. I tested this with a different Google account user across different computers and it worked okay. Let me know if it does or does not work for you.

Good Work Vaanth! This really WAS exactly what I'd intended. WHY they buggered the permission to All and Sundry as I'd first set the sheet on my Drive, IDK, but I rejoice you made it work. Sheets runs on a modified Open/LibreOffice system, served back to the Web, so it damned well SHOULD work.

 

[Vaanth]

Good Work Vaanth! This really WAS exactly what I'd intended. WHY they buggered the permission to All and Sundry as I'd first set the sheet on my Drive, IDK, but I rejoice you made it work. Sheets runs on a modified Open/LibreOffice system, served back to the Web, so it damned well SHOULD work.

Google Sheets and Google Docs actually grew out of two different entities. In 2006, Google acquired Upstartle to get their Writely product. Writely was actually rather nice. Initially, Google used it only internally by their employees, as alpha testers. Google messed it up some, but it slowly improved and was ultimately released for public use in 2007 as Google Docs and merged within Google Drive. Even earlier, in 2005, Google acquired the company building Excel2Web, which evolved into Google Spreadsheets, then Google Sheets. It was also merged within Google Drive and with Google Docs. More things came later like Google Presentations to Google Slides, Google Draw to Google Drawings, etc. all under the umbrella of Google Drive, and on the commercial side, Google One. The way things are done in the products can seem obtuse at times.

I'm somewhat aware of what transpired, and even suffered and benefited under the growth of these products, and much more. I worked at Google from 2005 through 2019. I was not on the software side, although I was involved with it and what housed it. I worked in the data centers as a Hardware Test Engineer, and did a stint as Technical Writer too. I saw a lot of stuff, and participated in explosive growth and a lot of fun with hardware deployments and installations, test, repair, data center builds, and more, especially in the early years. Things shifted in the later years, and the company soured some, but the growth and success of the company continued. My time there was good, and I made some significant contributions. I retired six years ago when I left Google.

 

[Gerald Morris]

Google Sheets and Google Docs actually grew out of two different entities. In 2006, Google acquired Upstartle to get their Writely product. Writely was actually rather nice. Initially, Google used it only internally by their employees, as alpha testers. Google messed it up some, but it slowly improved and was ultimately released for public use in 2007 as Google Docs and merged within Google Drive. Even earlier, in 2005, Google acquired the company building Excel2Web, which evolved into Google Spreadsheets, then Google Sheets. It was also merged within Google Drive and with Google Docs. More things came later like Google Presentations to Google Slides, Google Draw to Google Drawings, etc. all under the umbrella of Google Drive, and on the commercial side, Google One. The way things are done in the products can seem obtuse at times.

I'm somewhat aware of what transpired, and even suffered and benefited under the growth of these products, and much more. I worked at Google from 2005 through 2019. I was not on the software side, although I was involved with it and what housed it. I worked in the data centers as a Hardware Test Engineer, and did a stint as Technical Writer too. I saw a lot of stuff, and participated in explosive growth and a lot of fun with hardware deployments and installations, test, repair, data center builds, and more, especially in the early years. Things shifted in the later years, and the company soured some, but the growth and success of the company continued. My time there was good, and I made some significant contributions. I retired six years ago when I left Google.

Bravo! Yes, I recall that Drive didn't get all the current suite of apps at once, and that a LOT of code had to be pounded to get it ready for Prime Time. I wanted to get into Hardware while at Uncle Ray, but the issue of Security Clearance reared its ugly head, eventually coming down as a permanent blackball, right about the time the warranty ran out on my health. That's when I lost my first Mopar, the '66 NYer, along with the house, my teeth, family heirlooms et al. But HEY!, I got a neat pet from it all, a monkey I tamed and still carry on my back to this day.

AAAaaaaanywaaay, I worked in the speedo pinion gear numbers with this little sheet, and will post a link to that on MEGA later today. Once Mopar's method of sizing the gears became clear, it was really quite easy. I think I actually run a 34 tooth gear, while my calc shows a 33, but HEY! My old speedo is very accurate for all that.

OK, had to stop and replace a swamp cooler pump which burned up an hr ago or less, done! NOW for the link!

 

[Gerald Morris]

Here Moparians! I just posted my upgraded sheet, with the pinion gear sizes now included. and the Mopar part #s. I think you can use this.

 

[Darby]

Try this, if you don’t have overdrive, just look at the drive at 1 to 1. Someone mentioned they need this info for a 15 inch wheel. That doesn’t mean much without the tire size. Just plugin the info and it’ll give you rpm at any speed. You can change any of the info to see what you might like better.

Gear Ratio Calculator | TREMEC

 

[Gerald Morris]

Try this, if you don’t have overdrive, just look at the drive at 1 to 1. Someone mentioned they need this info for a 15 inch wheel. That doesn’t mean much without the tire size. Just plugin the info and it’ll give you rpm at any speed. You can change any of the info to see what you might like better.

Gear Ratio Calculator | TREMEC

Little of use for C body Mopars there. I note that the only Mopar transmission on their drop-down transmission menu is the 833. Neither the 727 or 904 are present. This page is best suited to more modern machines, though I saw the venerable Toploader and Muncie included along w the 833.