Why does axle ratio effect trailer GVWR?
08-15-2018, 03:13 PM
#11
Other things than heat management can be effected as well. An example from Class 8 Trucks. A few years ago going from Overdrive Trans to Direct Drive Trans for improved mpg (A very small 0.5% Improvement but if you are a very large fleet buying 250 million gallons a year!). They went from 3.55 x 0.74 to 2.64 x 1.00. 35% More Torque out of the trans into 27% more resistance. That's a 71% average increase in loading to the driveshaft. As a result driveshafts and ujoints had to be upgraded because of premature failure.
08-16-2018, 10:58 PM
#13
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08-17-2018, 10:47 AM
#15
Why do you think the basic towing package has increased cooling? So that in can tow more without overheating.
Two identical trucks. One with 3.31 gears, the other with 3.73. They're both pulling a trailer that is the max weight of the 3.73 truck. Do you really think the 3.31 won't be running hotter and probably overheat? It has to work harder to pull the same weight as the truck with the 3.73 gears...
08-17-2018, 03:16 PM
#16
The J2807 requirements are that they have to maintain 45mph up Davis Dam in a minimum of 100F heat at max GCWR. Ecoboost clearly dont have a power issue, so what else is it?
Last edited by mass-hole; 08-17-2018 at 03:19 PM.
08-17-2018, 05:02 PM
#17
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TerryD64
It's all about leverage.
Taller gears mean longer lever and more PULL.
It's all about leverage.
Taller gears mean longer lever and more PULL.
Forgive me, Terry, but the expression would usually read, "Shorter gears..."
A "tall" axle gearing is lower numerically. A "shorter" axle gearing is higher numerically.
That being said, as has been discussed many times the real limiter on our F-150s is payload, followed by either by axle ratings OR tongue/hitch weight.
Unless you weigh 150 pounds and put nothing in the truck (except fuel) from when you bought the truck. You'll most likely run out of payload long before you ever hit the published max tow values.
Unless you weigh 150 pounds and put nothing in the truck (except fuel) from when you bought the truck. You'll most likely run out of payload long before you ever hit the published max tow values.
Exactly.
08-17-2018, 11:32 PM
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08-19-2018, 01:08 PM
#19
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maybe not not now but in my years of towing a lot of times 3rd was too tall second was too low and a lower rear
ratio would allow 3rd to perform better but as I stated with a 10 speed it really does not matter , if fact I don’t
‘now why they offer more than one gear set anyway.
08-19-2018, 01:21 PM
#20
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I own a 2016 XLT 5.0 equipped with the 6-speed and the 3.31 axle.
There is no 1:1 gear ratio in the 6R80 trans... 4th is 1.14:1 and 5th is overdriven. When I tow in 4th, my effective axle gearing is 3.77:1.
Your effective final drive gearing depends on your tire size if your tire size is anything other than what your truck was shipped with.
There is no 1:1 gear ratio in the 6R80 trans... 4th is 1.14:1 and 5th is overdriven. When I tow in 4th, my effective axle gearing is 3.77:1.
Your effective final drive gearing depends on your tire size if your tire size is anything other than what your truck was shipped with.