Reverse Gear ratio

[scknf]

I noticed that the reverse gear ratio is much higher than 1st in forward is. Why is that?

The last couple of times we had a lot of snow the Santa Fe seems to have lots of torque to go forward through it from a stop, but when I reverse into my driveway through the heavy snow the city snow plow has pushed up I really have to give the Santa Fe a lot of throttle before it is able to push through. Like 75% throttle.

Traction is great, but it almost seems underpowered in reverse.

[nemohm]

Theoretically - the higher the gear ratio the less power is needed..

[OldSantaFeMan]

Originally Posted by nemohm

Theoretically - the higher the gear ratio the less power is needed..

I don't think so!! The higher the ratio the more power required to move the vehicle. Try moving off on a push bike if you're in too high a gear! That's why 1st gear is a low ratio.

[nemohm]

The case here is -low gear.
BTW- the torque is needed to move the vehicle - exactly what the gears are for.
Power is for speed...

[nemohm]

First Gear Ratio (:1) 4.21
Second Gear Ratio (:1) 2.64
Third Gear Ratio (:1) 1.80
Fourth Gear Ratio (:1) 1.39
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.77
Reverse Ratio (:1) 3.39
Transfer Case Gear Ratio (:1), High 1.00
------------------------------------------------

As the reverse ratio is lower than first gear - the 75% more power you observed is quite close to the difference of ~80%

[scknf]

Thajks for the replies and thanks for the gear ratios. But I am a little confused. It looks to me like the gear ratio for reverse is between the gear ratios for 1st and 2nd at 3.39, right? So reverse is a higher gear than first? Not lower.

Is there any reason manufactures do that? Is it just to be able to drve at a higher speed in reverse?

Scott

[Ruperts Trooper]

Originally Posted by nemohm

First Gear Ratio (:1) 4.21
Second Gear Ratio (:1) 2.64
Third Gear Ratio (:1) 1.80
Fourth Gear Ratio (:1) 1.39
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.77
Reverse Ratio (:1) 3.39
Transfer Case Gear Ratio (:1), High 1.00
------------------------------------------------

As the reverse ratio is lower than first gear - the 75% more power you observed is quite close to the difference of ~80%

On those figures, reverse is higher geared at 3.39 than first at 4.21 - the gearbox reduces, not increases !!

Power is power, regardless of the gearing - gearing only multiplies the torque.

[OldSantaFeMan]

Originally Posted by scknf

Thajks for the replies and thanks for the gear ratios. But I am a little confused. It looks to me like the gear ratio for reverse is between the gear ratios for 1st and 2nd at 3.39, right? So reverse is a higher gear than first? Not lower.

Is there any reason manufactures do that? Is it just to be able to drve at a higher speed in reverse?

Scott

Absolutely correct, Reverse is higher than first. I'm sorry Nemohn but, politely, you are wrong. And as RT says power is power.

We used to get people putting in a higher ratio diff and then wondering why the vehicle went slower because the engine had insufficient power to pull the higher gear!

[Pawper]

Lower ratio=higher gear, therefore need more engine torque with a lower ratio.
P.

[nemohm]

Hmm, well

Not here to argue about the ground principle of the mechanics.
Some clarification is needed:
The lower the dear --> the higher the gear ratio.
The lower the gear --> the easier to move the car.

Most people with manual transmissions gobble the concept easier.