I'm looking for responses mainly from people who have gone from one gear ratio to another on a decently built motor.

I have heard that if you go from a 3.50 gear to a 4.30 like I'm going to do, traction can actually increase due to the tires not spinning as fast at any given rpm. Basically the tires may break loose eaiser, than before, but since they wont be spinning as fast, you'll take off faster than before and not spin for as long. I'm wondering this because I have absolutely no traction in first gear at all. I can spin the tires at any speed in first gear. I know I need better tires. I also need different gears. Since the gears are half the price of tires, I think I'm going to start there.

Is there any truth to this?

 

No, with higher gears if you break traction in the first place, the wheels will be spinning faster and harder to gain traction, not better? Unless you meant going from such gears like 3.73 to a 3.42 or something.

 

No I meant from a 3.50 to a 4.30 For instance at 4000 rpm with a 3.50 gear I will be doing roughly 34 mph. With a 4.30 gear I will be doing a little over 27. Same rpm but 9 mph slower.

 

Higher gear means wheels spin faster for same speed. In your example, at same 34mph speed, your rpm's will be higher with the 4.30 gears - thus tires spinning faster. So, from a take off, the tires spin faster, thus greater potential for loss of traction with higher ratio gears.

For pure traction purposes, you'd want the lowest gear you could get (like a 2.73 posi). But this isn't going to get you to the end of the 1/4 mile until next week because you'll never see the power band of the motor.

I can't see any logic in getting more traction with higher ratio gears - it just doesn't make any sense intuitively or otherwise. If that were the case, we wouldn't need hot gummy slicks on drag cars. But I'm not a racer either. I just know that with my stock 2.73 rear end, I got all traction - only way to spin wheels (break traction) was some serious power braking. But with same everything except 3.08 gears, it took way less power braking, and then with the 3.42 gears, no powerbraking required at all (depending on the pavement condition - my car won't just spin tires under pure power on rough streets, but it will easily on smooth sprayed asphalt).

 

This is the comparison I was hoping for. Looks like I'm wrong then.

Basically I knew the tires would break loose with either gear. In my mind (and it works wierd sometimes ) I thought that because at any given rpm the tires would be spinning at a lower mph, that I may actually take off a little faster, rather than having the tires break loose and spin so fast that the car almost sits still.

I'm not saying at all though that this would replace a good set of tires. Nothing can do that, I'm just wondering if the gear change in its self would help a little.

 

Technically I can't explain it - but intuitively I can't see any way higher ratio would mean any better traction.

Thinking about this got me wondering (for a second) why in 4x4 trucks they use higher ratio gears (most factory 4x4's come with like 3.73 gears that I've owned), since in theory you want better traction and thus lower ratio gears. But again, I guess it's so you can get into your motor's powerband and get optimal power to the wheels in order to power over that big rock without stalling.

Your mind sounds like mine - no telling what kinda it'll come up with next. Sometimes the logic seems to point in a direction you know intuitively is wrong, and you begin to wonder if you are just crazy or stupid (in my case I often just admit that I'm both and move on).

 

A higher gear ratio will increase the torque to the rear wheels. If traction was at a premium with a 3.40 gear set, it will be worse with a 4.30.
Greater torque multiplication will increase the rate of acceleration provided the traction is there to go along with it. Hence "hot gummy slicks".
For the record, with only a gear change from 3.27:1 to 3.70:1, my 60' improved by 2/10ths. Traction was not an issue then. As I increased the power of my engine, traction became the limiting factor ( I actually started losing 60' time) until I moved up to a slick compound tire.

 

First off lower numerical numbers mean it's a high gear. For example 2.73 is a high gear.

Higher numerical numbers mean it's a lower gear. For example 4.11 is a low gear.

The wheels spin the same RPMs. Your engine, transmission, drive shaft and pinion spins faster the tires still spin the same.

That's a high gear not a low gear.

Higher gears (lower numbers) will not let the engine rev as fast . That means the torque can't be applied to the tires as fast. This can be used to tune a car for better launch. If you use a lower gear (higher number) the engine torque is applied to the tires faster that is what causes the tires to break traction.

 

[QUOTE=MotorMouth;4685873]First off lower numerical numbers mean it's a high gear. For example 2.73 is a high gear.
Higher numerical numbers mean it's a lower gear. For example 4.11 is a low gear.QUOTE]

For the record, when the desricption says "high ratio" that states the the number itself is high. 4:1 is a "higher ratio" than 2:1. This not only applies to cars but to math in general.
If you wish to use the terms high gear and low gear, then it's best to include the numerical value so as to avoid confusion.
As always, to each his own.

 

Motormouth beat me to it. 34mph is 34mph. Speed is a result of tire diameter x rotation speed. Gearing changes drive line speed at a given mph. This link may useful in understand the effects of changing your rear gear, and help with your decision.
http://www.angelfire.com/fl/procrastination/rear.html

 

I can't speak to the higher HP motors but I'm a Jeeper and just went form 3:73 to 4:88. I run 37 inch tires and needed to have better throttle control when off road. I used to have to be very careful when coming up to obstacle's as a little throttle moved the jeep forward quickly, now I can give it throttle and it doesn't move forward so fast. I have tons of torque and more control but do turn MUCH higher RPMS on the motor when on the street. This probably doesn't answer many of your questions but I wanted to give my observations.

 

For the record the correct term is what I put. High ratio is lower numbers and low numbers are higher gears. It helps when you don't spread misinformation. Teach the correct terms then people will know the correct terms when teaching someone else. This is not "an each to their own" term. In a transmission 1st gear is not low because of the 1. It's low because it's the lowest gear ratio of all the forward gears.

 

The numerically higher gears will help you accelerate, but there are trade offs depending on transmissions.

I've had 4 gear sets in my car with 2 different transmissions.
3.23 and 3.73 with an Auto. 3.73 made a huge difference in acceleration and made it easier to break traction. dropped half a second on my 1/4mile time and gained 4mph.

With my T5 I had 3.73, 4.10, and now 3.42 gears.
4.10's were fun but 1st gear was super short, like 15-20mph and only had a top speed of maybe 125. Gas mileage sucked as well.
Auto-x was a pain with the 4.10's since I would run out of 2nd gear quite often.

I ended up breaking the 4.10 rear end and bought a stock 3.42 rear and have been running that for a few years now. It took a few days to get used to the gear change since with the 4.10's I would just let off of the clutch and the car would start to move and with the 3.42 I had to give it gas, so I was stalling out a lot the first couple of days.

 

I understand all of that.
Pay attention to what I wrote.
High ratio means 5:1 as opposed to 3:1.
Simple as that.
High ratio IS NOT lower numbers. Learn the terms. Ratio is the difference between input and output. Not the position on the shifter.
When you want a low gear on the shifter, you shift to a higher ratio. When you want a high gear, you shift to a low ratio.
Understand?
Please don't say I spread misinformation. I was trying to be polite when I said "to each his own".
These are facts.

 

In other terms that is the case but not when you are talking about gears! That is what we are talking about here. I read what you wrote and it's wrong.

 

Fair enough.
So when I want to accelerate and pass someone on the highway, I downshift shift to .......
a)high gear
b)low gear

 

I would think you would shift to low gear. As in downshift.
That means higher numerical ratio.
If there's a difference in interpretation, I'm ok with that.

 

1. <----These are not what makes them lower or higher gear ratios
2.
3
4.
5. <----These are for the selection on the panel that's it.

2.68 <---- This is
1.80
1.31
1.00
0.75 <---- These are the gear ratios in a transmission....

Gears ratios are the 2.73, 3.37. 4.11 it's high to low. See the example above. The higher number in the transmission is the lower gear!

 

Now you've lost me.
What I'm saying, in any given application you start off in low gear. Correct?
If you agree, then that low gear has a HIGHER NUMERICAL VALUE than the next gear you choose.
I.E. First gear is 5:1. Second gear is 4:1.
I understand completely where the confusion comes from.
If that's the case we can agree to disagree on interpretation.
If we're at the track, we can talk ratios all day long.
I'll take my high geared 4.56:1 and race your 2.30:1 low geared car.
Wait.
Come to think of it...
I see your point of view.