Gear question?

[NC98GT]

A buddy of mine just bought a 98GT and the guy who sold it to him says it has gears in it. How would he be able to tell which gear ratio he put in it? The guy says he doesn't remember if it was 3:73 or 4:10. I've ridden in the car and it is not a stock gear, I can tell that much, but I can't really tell which one it has.

 

[StangLou]

I think you can tie a piece of rope or something to one of the rear axles, spin it and count how many times the knot passes the same spot in a wheel rotation. I could be way off on this, but I think Ive heard of something like that being done. If it stops short of 4 then hes got 3.73's, possibly 3.90's. If its a bit past 4 turns, you have 4.10's
Again if Im wrong, somebody help the man out

 

[tjm73]

Measure the tire height.
Go out and drive the car at 60 mph in 4th gear. Write down the RPM.

Multiply 3.73 x 60 mph, then divide that by the tire height (25.7 w/stock tires). Finally multiply that by 336. It should be very close to the RPM you wrote down. (about 2900 w/stock tires). If not substitue 4.10 for 3.73 and see if that roughly matches. (4.10 should be about 3200 w/stock tires).

Hope this helps.

 

[Joel's98GT]

you guys are working to hard.

with a manual GT 3rd gear at 55-56 mph will tell you your gear ratio.
3270 = 3.27 4100 = 4.10

 

[tjm73]

you guys are working to hard.

with a manual GT 3rd gear at 55-56 mph will tell you your gear ratio.
3270 = 3.27 4100 = 4.10

My calculations say otherwise. Using the same numbers for each gear (3.73 & 4.10) I get 3626 & 3986 respectively. That's with 25.7" tall tire at 55.5mph.

Besides I already did the math. If the car is running stock size tires it'll turn about 2900 with 3.73's and about 3200 with 4.10's in 4th at 60 mph.

 

[Red mustang Gt 46]

Jack the car up, put in neutral, mark a spot on your driveshaft (6 o'clock position) and a spot on one tire (12 o'clock position), turn tire until the driveshaft completes one full revolution, the amount of revolutions (tire) it took to make the driveshaft turn one full revolution ='s your gear ratio....

 

[Joel's98GT]

My calculations say otherwise. Using the same numbers for each gear (3.73 & 4.10) I get 3626 & 3986 respectively. That's with 25.7" tall tire at 55.5mph.

Besides I already did the math. If the car is running stock size tires it'll turn about 2900 with 3.73's and about 3200 with 4.10's in 4th at 60 mph.

works for me and most the other people i tell to use that method.

 

[ChrisXoxide2]

Turn rear tires, watch driveshaft. For deeper accuracy, turn more (3-4 driveshaft revolutions)

No rope required. Just use chalk on DS and chalk on the edge of the tire. Or look at your valvestem.