How to Select Proper Truck Axle Ratios
Can someone please enlighten me to the importance
of different axle ratios. I was told that the 3.42
was the best for a Z71 or 2 WD chevy that would
occaisonally be used for towing. What is the axle
ratio and why is a 3.42 better? Thanks for your
help.
of different axle ratios. I was told that the 3.42
was the best for a Z71 or 2 WD chevy that would
occaisonally be used for towing. What is the axle
ratio and why is a 3.42 better? Thanks for your
help.
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The gear ratio is important because it determines the amount of mechanical advantage your truck has when pulling itself and any payload/trailer. The lower (numerically higher) the ratio is, the easier it will be for your truck to pull a given load, provided other things (engine/tranny combination) remain the same.
However, you can't get something for nothing, or else we'd all be driving trucks with 4.11 to 5.00 axle ratios! In getting more mechanical advantage, you give up mileage, since your engine will have to turn more rpms for a given road speed. For example, where a 3.08 axle truck might turn 1400-1500 rpm at 65 mph, a truck with a 3.73 or 4.11 will turn upwards of 2000 rpm.
There's some background, but let's look at your situation. I'd say that the 3.42 should be fine for light towing situations (2-3 tons) on relatively flat terrain, providing good mileage at highway speeds, especially with GM's overdrive transmission. You could go with 3.73, which has even more mechanical advantage, but there's an attendant loss in mileage when not pulling that you probably wouldn't be happy with.
Good luck.
if you get a 2WD, get the 3.42. geared perfect for no-load, runs great, still has good power for pulling. will get low mileage (~11 or 12) when pulling, but good mileage when empty.
if you get a 4x4, get nothing (numerically) less than the 3.73. the 3.42s and 3.08s are too tall for these heavier trucks, and the engine really strains compared to the 3.73. the 3.73 4x4 runs as effortless as the 2x4 with 3.42. i've heard some Z71 owners with 3.42's getting worse mileage than those with 3.73s. that means the engine is working harder.
if you plan to tow regularly, you might get the 3.73 in the 2x4, for much better pulling performance and mileage, but otherwise the 3.42 gets better mileage and runs great.
i wouldn't get any chevy with a 3.08. my experience is it is just too tall a gear, and the only way to ever get good mileage with it is to travel on long trips often, something i don't do.
Don't let anyone talk you into a 3.73 or lower(higher numerically)for any truck that isn't 4x4 or a heavy tower. Heavy as in anything over one ton(2 thousand lbs).
It's what you really need that should matter. Don't listen to any clown telling you need a super low ratio unless you really need it. Otherwise, you will be paying Texaco every 200 miles.
I couldn't do any towing when I test drove a sample of what I recently bought, of course, but I felt the 3.08 was adequate and got it. But I've had shorter axle ratios (bigger number) before and enough experience to believe I know what's good for me. If you have never been through this before and are going to make a decision based entirely on what someone else tells you, I'd say you would be taking a chance getting a 3.08 and your best bet would be the 3.42, which I guess is what you were going to do even if you hadn't started this topic. You won't have to ask anyone the next time you buy a truck. By that time you'll be as pig-headed regarding this topic as the rest of us.
To bring the concept up close and personal, Borrow a multi-speed bicycle and try starting from a stop in the highest gear. Then do the same maneuver in the lowest gear. See how fast you can go in low gear and still keep your feet on the peddles, then see how high gear does. When YOU are the engine, it becomes more clear.
Now review the above entries again. :-)
My hats off to you for an excellant analogy!!
Like cdean mentioned, they have been using them in the big Econoline vans. Until they built the Superduty, they didn't have an engine compartment big enough to hold the V-10. It won't fit in the F-150.
I would go along with the majority here and go with the V10 (if you're sold on gasoline) strictly because the Super Duty trucks weigh more than the old 1980-1997 chassis. If you notice, the GVWRs were raised substantially, but there wasn't much increase in payload compared to the older body. All DRW Fords are now at 11,200 GVWR, up from 10,000, but there's a lot less than a 1200 pound payload increase in the otherwise identical configuration.