jgemienhardt
Member
Does anyone on here have first hand experience changing the stock 373 gears to, lets say 410 or 456 gears? I am aware that it will drink fuel more, but by roughly how much more? Any thoughts and ideas are welcome. Thanks
Changing Gear Ratio
- Thread starter jgemienhardt
- Start date
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FordandPolaris
Full Access Members
Well I have never done the swap, but it pretty much just comes down to math. Increasing the gear ratio means that you are increasing the RPM's needed to move the vehicle along at the same speed. Basically you gain low end acceleration at the cost of high end speed.
Assuming all conditions remain the same, you can assume that old gear ratio divided by new gear ratio= B
Take B times the RPM's your truck runs at any given speed and that will give you the RPM's running with the new gears.
OK so I just wanted to put that on the table in case you were wondering that part of it. As far as how the fuel economy will suffer, that really depends on how you drive now. If you drive at 80 mph (about 2500 RPM's in my truck with 3.73's and 33 in tires) you will probably see a large loss of MPG since you will be running about 3000 RPM's with the new gears and the same conditions as my truck (which yours might not be). 1800-2000 RPM's is the sweet spot for these motors and fuel economy, at least from what I have found with my truck.
Assuming all conditions remain the same, you can assume that old gear ratio divided by new gear ratio= B
Take B times the RPM's your truck runs at any given speed and that will give you the RPM's running with the new gears.
OK so I just wanted to put that on the table in case you were wondering that part of it. As far as how the fuel economy will suffer, that really depends on how you drive now. If you drive at 80 mph (about 2500 RPM's in my truck with 3.73's and 33 in tires) you will probably see a large loss of MPG since you will be running about 3000 RPM's with the new gears and the same conditions as my truck (which yours might not be). 1800-2000 RPM's is the sweet spot for these motors and fuel economy, at least from what I have found with my truck.
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tonydiv
technical advisor
There are a lot of gear ratio calculators online that will allow you to compare the new gearing to your current setup.
Part of the problem that happens when you do a ring and pinion swap is the 'may as well's' that come up. "may as well put in a limited slip / locker / air locker"
Part of the problem that happens when you do a ring and pinion swap is the 'may as well's' that come up. "may as well put in a limited slip / locker / air locker"
hwy73
Full Access Members
Plus the cost, because on a 4 x 4 truck the "front" has to be changed to match the "rear" ........yes?
tonydiv
technical advisor
It sure does.
