wut kinda gears?

hey guys wassup? i've got soo used to having my 32's on my ride that they look tiny noW!!! i want to push 33's or bigger but i dont want crappy gas mileage and be really really slow... I mainly wanna be able to go faster.. i have a 2wd with 3.73 gears... I got a intake and exhaust and that helped a little with my speed but i'm still pretty slow... I was wondering, wut would be better 4.10 gears or 4.56 gears? i'm gettin a ARB locker pretty soon and wanna change gears too.. which gears would be best suited for off-roading and acceleration?

 

[Klowns]

I would say obviously if you're looking for low end power go for the 4.56's, then if you go with a bigger tire, then you're fine, i'm running 4.56's on my 35's seem to be doing alright. I got decent high end, nothing to brag about, well not until i'm done rebuilding. Won't be as insane as Troll, but my little V6 will be maxed out. Don't plan to go up to 4.88's as of now anyway, the 4.56's have been fine for wheeling.

 

[Alec]

On a 2wd, you also have the option of 4.30. That's what I have and they're perfect IMO. If you frequently drive more than 80 on long stretches of highway, I think 4.56 is a bit too low for 33s. However, if 35s are in the future for you, that's the ratio to go with.

 

[Robert]

I feel 4.56 are pefect for 33s since that would put my RPM range back to my stock range. My '97 came stock with 30" tires and 4.10 axle. Now that I have 33s on it, I have to put 4.56s in to get the RPM back to stock. Anything lower and my RPMs would be lower at speed than Ford intended. With the better lower RPM torque from your V8 and the fact that you are 2WD, the 4.30 might be a bit better. The RPM differnece at 70 MPH will be about 150 RPM (4.56 will be running about 150 RPM higher). The thing is your tires are a lot heavier than your stock tires so some extra gear will be needed to turn them with the same performance as your stock gear/tire combination.

In other words if your V8 came stock with 3.73s and 29" tires. Putting 33" tires on will result in your RPMs being about 13% lower. To keep your stock RPM you would need a 4.24 ratio. The 4.30 would put your RPMs right at stock level for any given speed. Your performance will still be less than stock though since you have tires that weigh about twice as much. If you spend a lot of time off-roading the 4.56 would be a better choice unless you spend a lot of time driving at 80+ MPH.

 

[clarkkent]

my friend was telling me the higher the number numberically the lower the gear? so 4.56 are lower then 3.73 if he's rite? And he was also telling me that the higher the gear would be best for rock crawling.. I don't do any rock crawling and just alot of highway driving, city driving and alot of sand and mudd.. I'm planning on slappin 33's on, So would the 4.56's be the best for my driving habits? I like acceleration....

 

[Robert]

I'm not sure where the higher/lower came from. I've seen the same gears quoted both ways. Some people say that 4.56 are higher than 3.73s, other's say that the 4.56s are lower than a 3.73. I'm sure I've even said it both ways when talking about the same gears. In any case, a 4.56 gear ratio will give you a higher RPM at the same speed as a 3.73 would. Higher RPMs results in better torque which helps get you moving quicker. If Acceleration is your main concern, 4.56s would give a bit better accleration than 4.30s would. That is why Mustang owners are so quick to swap out their factory 3.08 for a 3.27. I wish I would have done that to my '95 V8 Thunderbird. It came with a 4.6L V8 but 3.08 axle. That thing was a dog off the line, but would cruise along at 80 MPH while only turning about 2200 RPM.

 

[clarkkent]

Originally posted by Robert
In any case, a 4.56 gear ratio will give you a higher RPM at the same speed as a 3.73 would

if i'm spinning at a higher rpm then i was at 3.73, especially on the highway, doesnt that mean im wasting more gas going the same speed as i was with the 3.73?where does the saving gas come in then?

 

[SteveVB]

Originally posted by clarkkent
if i'm spinning at a higher rpm then i was at 3.73, especially on the highway, doesnt that mean im wasting more gas going the same speed as i was with the 3.73?where does the saving gas come in then?

The gas savings comes in when the new lower gears(higher number) allow your engine to run in its most efficient rpm range (usually 70-80% peak torque. If you add larger tires to a otherwise stock truck you move the engine out of its operating range. Gears can bring it back where it belongs.
Likewise if you add a cat back exhaust and a TB, say an open air filter and move the torque peak up a couple hundred RPM if you were geared high to begin with you may move the engine out of it operating range.

You cant do everything well, you need to ID how you drive and what you want to do. If you want mileage- you sacrifice for acceleration, which trades off top speed, which trades off rock creawling, which trades off around town driving, etc

In your case 3.73s would give you great top speed, highway mileage should be ok on the flats , may suffer if you have lots of hills. Around town milage will be down, and away from a light you will be sluggish.

4.56s should get you off the line decently, around town mileage would be back to around stock I would bet, and highway may be down slightly at the extreme top end, but pretty good at moderate speeds. Offroadability (low speed control) will be good.

Also as a general rule a vehicle with a manual trans needs more gear than a similarly equipt vehicle with an Automatic trans. So an Auto with 4.30 may have some of the same low speed properties as a manual vehicle with 4.56's.

just some impressions.

From what you said with a stock (only bolt ons) engine I would think the 4.30s like Alec suggested would be for you- the 4.56s if you paln on lots of off pavement - but 2wd is limited in mud - even locked up. I doubt you would notice much with the 4.10s going from 3.73s

Good Luck

 

[clarkkent]

thanks steve.. u explained alot man.. I'm planning on doing a ARB locker and a shift kit with my new gears so i hope the 4.30 gears or 4.56 will really help.... I dont care for much top speed since i'm in a suv, but acceleration is the funniest part of speed.. being able to smoke someone off the line around town in my explorer is fun.. but also I wanna be able to float on sand with my new gears?

 

[Klowns]

To "float" on the sand, your gears aren't gonna really mean anything, sure, it all goes hand in hand, but its more in the tires, and air pressure, you could float on near bald tires aired down to like 7 psi. Bit of a stretch but still...