Jump to content
TEAM SHELBY FORUM

Gear ratio help


Recommended Posts

I have some questions, also need to admit I know nothing about gear ratios as they apply to rearends.

 

With that said, please try to put your responses in idiot proof laymen terms so I can better understand how gearing works.

 

I have seen where a lot of you guys have switched out your gears for the 3.73's As I am not sure what the stock GT 500 started with, what is the stock gear ratio in the 500? Then try to help me understand what the difference is in performance, why the change???.

 

I have noticed first gear in my GT is virtually usless. I am curious if the gearing I had in my 03 Cobra would make a difference in the GT. Here is the ratio that my 03 had.

 

SVT Cobra

1st 2.66

2nd 1.78

3rd 1.30

4th 1.00

5th 0.80

6th 0.63

Reverse 2.90

Final drive 3.55

 

What setup is going to be a better way to go? the setup I pasted above, or the 3.73 gearing. And help me to as mentioned above get a grasp on gearing and how it all works.

your input and insight are appreciated.

 

thanks

Link to comment
Share on other sites

One thing that was key for me when choosing new gears on past cars, is where the RPM's would be at highway speeds. I can't stand exhaust drone - so be careful of that before you make that change.

 

In my 04 Cobra I think 4.10's were the best - in these I'm not certain as I don't have one yet. :hysterical2:

 

Perhaps some others can chime in with their personal experiences to help more than me however.

 

-DC

 

P.S. Did you see the pics in the pig thread? I posted up my Terminator - was pretty much like yours.

Link to comment
Share on other sites

I have some questions, also need to admit I know nothing about gear ratios as they apply to rearends.

 

With that said, please try to put your responses in idiot proof laymen terms so I can better understand how gearing works.

 

I have seen where a lot of you guys have switched out your gears for the 3.73's As I am not sure what the stock GT 500 started with, what is the stock gear ratio in the 500? Then try to help me understand what the difference is in performance, why the change???.

 

I have noticed first gear in my GT is virtually usless. I am curious if the gearing I had in my 03 Cobra would make a difference in the GT. Here is the ratio that my 03 had.

 

SVT Cobra

1st 2.66

2nd 1.78

3rd 1.30

4th 1.00

5th 0.80

6th 0.63

Reverse 2.90

Final drive 3.55

 

What setup is going to be a better way to go? the setup I pasted above, or the 3.73 gearing. And help me to as mentioned above get a grasp on gearing and how it all works.

your input and insight are appreciated.

 

thanks

Cactus, let me see if I can shed some light.

 

As one other person mentioned...the GT500 comes stock with a 3.31 gear. This means that for each 3.31 revolutions of the driveshaft, the rear wheels will rotate one time. Going to a numerically higher ration, such as 3.73, effectively increases acceleration at the expense of fuel economy on the highway...but likely won't hurt fuel economy by very much.

 

You mention your other car...it's difficult to compare because they have different engines. Some cars are "rev happy", meaning they create their power higher in the RPM band.

 

I don't know the transmission gears of the GT500 so as to compare with your other car....but if a 3.55 was "virtually useless" in your other car...you may want to think hard about going with even a 3.73...maybe you can drive someone else's GT500 who has a 3.73 at a car show to see how different it is.

 

Another thing you should know is that tire diameter also affects gearing. A taller rear tire will act the same way as going to a numerically lower rear gear. Therefore, if you change wheels/tires such that the total height is different, don't be surprised if your car seems to accelerate a bit differently.

 

I think the GT500 needs a shorter (numerically higher) gear. It doesn't have the "grunt" off the line that I'm used to. I think Ford did this to increase fuel economy and avoid an even higher GG tax. If you do a lot of highway driving, you might want to stick with the current setup for now. I drive mostly in town, so I'm less concerned with fuel economy on the highway.

 

Good luck. HOpe this helps.

 

Dave

Link to comment
Share on other sites

Cactus, let me see if I can shed some light.

 

As one other person mentioned...the GT500 comes stock with a 3.31 gear. This means that for each 3.31 revolutions of the driveshaft, the rear wheels will rotate one time. Going to a numerically higher ration, such as 3.73, effectively increases acceleration at the expense of fuel economy on the highway...but likely won't hurt fuel economy by very much.

 

You mention your other car...it's difficult to compare because they have different engines. Some cars are "rev happy", meaning they create their power higher in the RPM band.

 

I don't know the transmission gears of the GT500 so as to compare with your other car....but if a 3.55 was "virtually useless" in your other car...you may want to think hard about going with even a 3.73...maybe you can drive someone else's GT500 who has a 3.73 at a car show to see how different it is.

 

Another thing you should know is that tire diameter also affects gearing. A taller rear tire will act the same way as going to a numerically lower rear gear. Therefore, if you change wheels/tires such that the total height is different, don't be surprised if your car seems to accelerate a bit differently.

 

I think the GT500 needs a taller (numerically higher) gear. It doesn't have the "grunt" off the line that I'm used to. I think Ford did this to increase fuel economy and avoid an even higher GG tax. If you do a lot of highway driving, you might want to stick with the current setup for now. I drive mostly in town, so I'm less concerned with fuel economy on the highway.

 

Good luck. HOpe this helps.

 

Dave

 

Just one correction........for more snap, you want to go 'shorter' or 'lower', which is (numerically higher)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...
...