gearing question. not 4.88's

[Trainman]

It matters a bunch actually. Same 31-32" diameter street tires with all else the same except 4.10 vs 4.56 the 4.10 will pull through gears longer. It'll also help tire spin in lower gears. I also believe with all else the same the 4.10 should trap higher speeds.

I have a slight disagreement. Tire slippage does change the equations, but back in the old days it was actually a little easier to maintain traction with lower gears.....I know this sounds odd but hear me out. Once you break traction with a higher gear (say 4.10 vs 4.56) there will be a faster spinning tire with the higher gear (4.10) thus making it more difficult to gain traction. But more back to your point (the 4.10 pulling longer in each gear) why not just start in 4th and you can really pull a long time before shifting (I know thats a little extreme, but I'm making a point). Now I think we all agree that our trucks accelerate faster in 1st gear than they do in say 3rd gear....right? That's because 1st gear is lower and multiplies the torque better and has the effect of a lighter car vs heavier car. So with this reasoning, given the same transmission ratios, equal weight , equal horsepower vehicles WILL accelerate faster with 4.56 gears versus 4.10 gears...in every gear. I have been doing this (1/4 mile acceleration) for almost 50 years and it works for me. My job is to figure out how to get the power to the ground, that makes it fun and requires a little skill.:rock:

 

[ARRESTmeRed04]

Ohhhh, makes sense. I can tell you don't much about street racing though. Nothing beats 4.88's on the "streets". Do you even race, bro?

I've never actually raced, but I've read tons about it on the internet.

 

[ARRESTmeRed04]

Oh, and if traction is the problem gears are not the solution....

 

[caveman]

Jerry, I am not quiet sure I follow your logic? First you state that a taller gear (4.10) is more difficult to maintain traction because of an increase in wheel speed for a given RPM. (See quote.)

Tire slippage does change the equations, but back in the old days it was actually a little easier to maintain traction with lower gears.....I know this sounds odd but hear me out. Once you break traction with a higher gear (say 4.10 vs 4.56) there will be a faster spinning tire with the higher gear (4.10) thus making it more difficult to gain traction.

But, then you say that equal vehicles will accelerate faster with a shorter gear (4.56).(Again, see quote.)

So with this reasoning, given the same transmission ratios, equal weight , equal horsepower vehicles WILL accelerate faster with 4.56 gears versus 4.10 gears...in every gear.

So which is it? Will the shorter gear allow for quicker acceleration or will the taller gear out-accelerate the taller gear making it more difficult to regain traction? Only one of these statements can be accurate.


I am a fan of short gears. Most old school hotrodders will tell you that short gears are like free horsepower. However, a shorter gear will not always out accelerate a taller gear. A good example of this are the guys that are running great ET’s in diesel powered pickups. They don’t use short gears. Doing so would be an ineffective use of their narrow RPM range and broad torque curves. Essentially, they want to gain as much MPH as possible with each of their very limited RPM. Gearing should be dictated by a couple things: RPM through the traps (you understand this very well), traction (this is what Justin is talking about and why 4.88 SRT10’s always disappoint at the track), and torque curve. Enough gearing should be used so that the vehicle can rev as quickly as possible. Once that is accomplished, steeper gears do not help a vehicle accelerate quicker, they actually slow it down because the engine isn’t revving any quicker and MPH is reduced for each RPM.

 

[Trainman]

Jerry, I am not quiet sure I follow your logic? First you state that a taller gear (4.10) is more difficult to maintain traction because of an increase in wheel speed for a given RPM. (See quote.)

I made it clear, that once you "break" traction the 4.10 will spin the tire faster than the 4.56. Kinda why I do a burn out in 2nd gear as opposed to 1st gear (with the Line Lock, it heats the tires better because they are spinning faster). If you don't break traction you don't have that problem.

 

[Trainman]

But, then you say that equal vehicles will accelerate faster with a shorter gear (4.56).(Again, see quote.)

So which is it? Will the shorter gear allow for quicker acceleration or will the taller gear out-accelerate the taller gear making it more difficult to regain traction? Only one of these statements can be accurate.

True, the shorter gear (4.56) will out accelerate the 4.10 as long as you maintain traction. I'm just saying when you break the tires loose violently (like in 1st gear with 4.10's) they will be spinning faster at any given RPM than the truck with 4.56's, once traction is grabbed then you will bog more with the taller gear. Traction must be maintained for things to go right. I'm not saying two different things....I don't think?:dontknow: I guarantee you that my truck went quicker with 4.56's than with 4.10's.

 

[ARRESTmeRed04]

True, the shorter gear (4.56) will out accelerate the 4.10 as long as you maintain traction. I'm just saying when you break the tires loose violently (like in 1st gear with 4.10's) they will be spinning faster at any given RPM than the truck with 4.56's, once traction is grabbed then you will bog more with the taller gear. Traction must be maintained for things to go right. I'm not saying two different things....I don't think?:dontknow: I guarantee you that my truck went quicker with 4.56's than with 4.10's.

With the tires you used, yes. But you could've just used a 28" tire with the 4.10's and skipped the gear change

 

[shorty]

While you guys been debating tires, short and tall gears I smacked down 2 Hemi's one BMW and an old woman in at Volvo. :chain:

 

[VPRPWRD]

Great conversation! I love gear talk especially when 4.88s are involved.

 

[stealth78]

Theoretically wouldn't it be more beneficial to go with 4:10's over 4:56's and just use a shorter tire? If you took both gear ratios and paired them up with two different tire sizes so that they both came out to the same ratio, the 4:10 would help you put more horsepower down for the simple fact that you would be spinning a SMALLER, LIGHTER tire!

 

[VPRPWRD]

Theoretically wouldn't it be more beneficial to go with 4:10's over 4:56's and just use a shorter tire? If you took both gear ratios and paired them up with two different tire sizes so that they both came out to the same ratio, the 4:10 would help you put more horsepower down for the simple fact that you would be spinning a SMALLER, LIGHTER tire!

We had this same discussion earlier and I'm putting my gear swap money towards something else while adjusting my gear ratio with a shorter slick.

 

[caveman]

Theoretically wouldn't it be more beneficial to go with 4:10's over 4:56's and just use a shorter tire? If you took both gear ratios and paired them up with two different tire sizes so that they both came out to the same ratio, the 4:10 would help you put more horsepower down for the simple fact that you would be spinning a SMALLER, LIGHTER tire!

Yep. I didn't do the math, but was told by someone smart that 4.88's with the factory wheel/tire combo, equals a 30" slick with 4.56's or a 28" slick with 4.10's. This combo gets you through the traps at redline in 4th. That's why some people here said that a gear swap was a waste of coin. Just use the correct wheel/tire combo and spend mod money elsewhere.

 

[Trainman]

Theoretically wouldn't it be more beneficial to go with 4:10's over 4:56's and just use a shorter tire? If you took both gear ratios and paired them up with two different tire sizes so that they both came out to the same ratio, the 4:10 would help you put more horsepower down for the simple fact that you would be spinning a SMALLER, LIGHTER tire!

I'm convinced, I called A&C Performance and told them to pull my 4.56 gears and install some 2.73's....then I call Bogart and ordered some 13" drag wheels with some 18" tall M&H"s :drool:

 

[stealth78]

I'm convinced, I called A&C Performance and told them to pull my 4.56 gears and install some 2.73's....then I call Bogart and ordered some 13" drag wheels with some 18" tall M&H"s :drool:

Great, look what we've done... Now take the jack out from underneath the riding mower and leave the tires on the Craftsman. :burnout::burnout: