axles
Recovery Vehicle
Joined: Feb 2007
Posts: 1,088
Likes: 1
From: Ottawa, Ontario, Canada
RE: axles
Well, I was gonna ask what the stock gear ratio is ???? The axles are Land Rover.
My wife's X-Terra had 4.63 and my friend's 4Runner had 4.56. So, while I think that I read that the Disco 2 have3.55 gearing, I wonder why the others have much lower ratios?!? I know that they have 6 cyl., but their 6 have as much HP and Torque as the Rover 4.0L. Is it that the transmission and t-case are geared low??? or what???
Probably with lower gearing, the 4.0 wouldn't struggle has much to get that 2 tons body goin!!!
My wife's X-Terra had 4.63 and my friend's 4Runner had 4.56. So, while I think that I read that the Disco 2 have3.55 gearing, I wonder why the others have much lower ratios?!? I know that they have 6 cyl., but their 6 have as much HP and Torque as the Rover 4.0L. Is it that the transmission and t-case are geared low??? or what???
Probably with lower gearing, the 4.0 wouldn't struggle has much to get that 2 tons body goin!!!
RE: axles
Can you imagine the mpg if they had lower gearing?
I think that the others have lower gearing because of a smaller engine so they need the lower gears to get more tourqe.
I really like the diff set up though, you can change the whole rearend without removing the axle. The gears come as one unit and can be replaced in the field. Imagine that. Who would of thought that a trk build to spend its entire life in the jungle would have been designed to be repaired in the jungle? You gotta love these things.
I think that the others have lower gearing because of a smaller engine so they need the lower gears to get more tourqe.
I really like the diff set up though, you can change the whole rearend without removing the axle. The gears come as one unit and can be replaced in the field. Imagine that. Who would of thought that a trk build to spend its entire life in the jungle would have been designed to be repaired in the jungle? You gotta love these things.
Winching
Joined: Aug 2006
Posts: 727
Likes: 2
RE: axles
Gearing vs final drive ratio are entirely different. You need to look at a number of factors including the transfer case ratio and the diff ratio as well as the ratio of each of the gears in the transmission. So on a Disco you have 7 gear ratio settings, 1 of which is fairly easy to change but fragile if you do (diffs) 2 are in the transfer case and can be changed fairly reliably (see Ashcroft) and 4 are in the ZF auto-box (if you have a manual there's obviously 5 there)
That being said, you gear based on the amount of torque you have and the strength of your components and most importantly where you want your RPM to sit at a given speed. This is why when you put larger tires on you need to lower your final drive ratio or you appear to lose power. There isn't less of it, you're just not able to get it through the system efficiently. It's also why when you put big tires on you need heavier duty components, if you put more stress on them you break things like axles and CV joints.
The whole thing is a balance to make sure that at a given speed you're within the power band of the engine or the efficiency band (to save fuel) vs breaking components or lugging along.
That being said, you gear based on the amount of torque you have and the strength of your components and most importantly where you want your RPM to sit at a given speed. This is why when you put larger tires on you need to lower your final drive ratio or you appear to lose power. There isn't less of it, you're just not able to get it through the system efficiently. It's also why when you put big tires on you need heavier duty components, if you put more stress on them you break things like axles and CV joints.
The whole thing is a balance to make sure that at a given speed you're within the power band of the engine or the efficiency band (to save fuel) vs breaking components or lugging along.
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