Need to know what rpm and driveability you will have in your Cobra after a gear swap?

[mrmustangman357]

Look here:

Got bored asking the same questions about gearing in my 99 Cobra. So I put my engineering degree to use and whipped up a spreadsheet that shows some common gear ratios and tire sizes for you guys.

-I also included a section for how much mph you will be at at 3000 rpm in first gear, the judgment I use for 1st gear usability. I'm the only one that cares about this for a DD?

-I also included a couple tire sizes that you can try out to mimic a different set of gears. These are based on my needs but you can change as necessary

BWill Inc gear calculator 99 cobra.xls - DivShare

Take a look and tell me what you think I can add or change. Any questions PM me and I'd be glad to receive any critiques. Hope this helps. Brian

 

[99BlackSVTvenom]

looks pretty good man just a couple things it might need to be changed. the tire diameter at the top is the same with only a width change and is the bottom chart for the final drive ratio? its probably because of my excel not cooperating but a few words and informational text was covered up by graphs. nice job though bud!

 

[black4vcobra]

Looks good, I too am a little confused about the theoretical gear at the bottom. I would understand if you started with stock gears, stock tires and started changing tire size but I don't understand what your starting point (gear ratio, tire size) is to conclude the theoretical gear ratios...

 

[TrueBlueCobra01]

You're thinking too much. Just do it. The drawback in drivability is purely opinion. Some people think the higher reving is too much. Some people think the quicker reving is awesome (for everyday driving as well as racing). Personally, I find 4.10s to be much better in daily driving. Instead of doing spreadsheets you could do much better research by just driving a car that is already geared.

 

[mrmustangman357]

You're thinking too much. Just do it. The drawback in drivability is purely opinion. Some people think the higher reving is too much. Some people think the quicker reving is awesome (for everyday driving as well as racing). Personally, I find 4.10s to be much better in daily driving. Instead of doing spreadsheets you could do much better research by just driving a car that is already geared.

not all of us are lucky enough to have friends with 4v cobras with 4.10s. I don't like having excessive rpm on the highway since my application is almost 75% highway driving.

The tire height applied to my combo which had a 3.55 gear. The theor. gearing is compared to a standard 245-45-17 tire.