4.10 or 3.73 gears

[Trickman668]

My mustang is a 2002 5spd v8, it has basic bolt ons, headers, bbk x pipe, cai, and a throttle body spacer. I really want to upgrade the gearing but am torn between 4.10s and 3.73s, I dont do much highway driving but when I do go on the highway it is usally for 4-5 hours so the 4.10s concern me, the car is also my daily driver in the summer. Which gearing would be best?

 

[96blak54]

My car has 3:55 rear and driving 75mph puts the rpm close to 2500.

 

[Silver95bird]

My car has 3.73s and I only use 1st gear if I'm at a dead stop, or going slowly up a steeeep hill. Everyone says to go 4.10s with a 5 spd but I don't really see it. All I see is traction problems, lol.

My vote says summer only car, goes on the strip 3-4 times a year, mainly shorter trips close to home, consider 4.10s.
If it's more like a 3 season car, doesn't really see the strip much, 3.73s are better.
If you're not happy with 3.27s, it's hard to justify the cost just for 3.55s. on an older 5 spd that maybe came with 2.73 or 3.08s, 3.55 is a huge improvement and still really nice on the highway. I think all around, general purpose, 3.55 is a great gear.

 

[OLD H2S]

I have 3.73s with tall rear tires so finial drive is 3.50..

 

[3.14159]

I have 3.73s with tall rear tires so finial drive is 3.50..

The gear ratio in the rear end is the final drive. Tire size has nothing to do with that number. If it’s 3.73:1, it’s always 3.73:1. Always.
https://www.roadandtrack.com/car-cu...2293/final-drive-ratio-engineering-explained/

 

[96blak54]

Tire size has alot to do with "theoretical" final drive.

When taking drag racing to a science level factoring in tire size to tranny gears and final gear is common practice.

Although i get what you are saying, the final drive doesnt change unless the mechanics are changed.

 

[evilcw311]

Tire size makes a huge difference if your talking about the difference in a 17” wheel with a low profile sport tire to a drag tire which is generally much taller. Your turning a much larger radius which affects wheel speed.

Now if talking about the same size wheels and just a little bit of a change between low profiles then no, no real difference. A 35 to a 45 isn’t gonna affect much at all.


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[OLD H2S]

Obviously I have done the math and my tires are not stock 24.7" tall

 

[3.14159]

I’m not debating that tire size doesn’t affect speed of the car - what I’m stating is that tire size does not change final drive ratio. You do not have 3.55’s because you put taller tires on your car. That’s not what final drive means. Please learn what these terms mean.

 

[96blak54]

hum......good that you posted that link

 

[OLD H2S]

Theory VS reality..call it total finial ratio
We are both right.

 

[JGcoupe]

Put 3.90’s then if your torn but I think 3.73’s are perfectly fine for a daily with occasional weekend warrior...I think Richmond/Motive are the only ones who make them though.

 

[castine917]

My mustang is a 2002 5spd v8, it has basic bolt ons, headers, bbk x pipe, cai, and a throttle body spacer. I really want to upgrade the gearing but am torn between 4.10s and 3.73s, I dont do much highway driving but when I do go on the highway it is usally for 4-5 hours so the 4.10s concern me, the car is also my daily driver in the summer. Which gearing would be best?

Play here. Start with T5 and adjust for your exact ratios. It takes each transmission gear, rear gear, and tire in to factor.

http://tremec.com/calculadora.php

 

[Randall Garner]

For a street sometimes strip car with a manual. People have a great luck with the 3.73. Most people that still drive on the hi-way complain of the excessive rpm of the 4.10. Find a online calculator. Like wallaceracing.com. Using your current gears and tires. Enter that info see what’s the results. Should be close to your current rpm and speed, then only change The gears. It will give you the the new rpm for the same speed.

 

[weendoggy]

My vote is 3.73. I also have an '02 with about the same as what you have. The 3.27 set is useless for any type of "power feel" and more for fuel economy. Wake that thing up with 3.73 and be happy. I don't use mine as a DD but do drive it and open track it. The gearing woke the pokey pony up a bit. Next step is a Coyote.

 

[BigBore96]

This is kind of a late response but there used to be a debate floating around about the "excessive rpm" from 4.10s and up which turned into a fuel consumption discussion. I'd have to find it but the sweet spot for the 4.6 was within the 4.10 rpm range at highway speeds.

FWIW 5 speed 4.6 cars all motor 2vs I'll always run 4.10s and 4v all motor cars I'd run 4.30s.

Not a 3v fan so cant comment.

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[01yellercobra]

I ran 3.73's in my 98 with a 5 speed and my MPG went up. I went from 3.27's to 3.90's in my 01 with a 6 speed and MPG didn't change. Although the loud BOV got annoying.