parker.rowe
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I'm not sure why people think the rear gear ratio only changes rpm/mph.
It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual
If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.
Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.
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valhalla360
No paticular place.
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parker.rowe wrote:I'm not sure why people think the rear gear ratio only changes rpm/mph.
It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual
If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.
Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.
With all else equal, you are correct...but else isn't equal.
Who cares if you are towing one gear higher than usual if the engine is running at the same RPM/MPH? (assuming you don't exceed the ratings) The engine doesn't know if the torque multiplication is happening in the transmission or in the rear end.
Back in the old day's of 3 speed transmissions, there was so much difference between gear ratios, it was common when dropping down a gear to overshoot the ideal RPM/MPH for the engine and load. This left the engine racing while lightly loaded (not ideal for efficiency or power generation). A different rear end ratio could sometimes help align the RPM/MPH desired with the engine's ideal RPM.
With modern transmissions that have lots of gears to pick from, if you need torque multiplication, it can just drop down a gear (assuming you aren't already in 1st gear and struggling) and since the gear ratios are relatively close, it should be able to find a gear that keeps the engine in it's happy RPM range.
Ford offers the 4.30 for when you are pushing the truck so hard, it does struggle to get beyond 1st gear (or for old timers who automatically think you need a 4.X rear end if you tow?). That doesn't seem to be the OP's concerns.
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MFL
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Cummins12V98 wrote:Jerry Said: "I use non ethanol premium fuel"
UH Jerry the OP is in KOMMIFORNIA and Non Ethanol is a non spoken word.
Oops...maybe not in Ka? Even in my area, pure premium is usually only available at top tier stations. I might add, that pure regular (non-ethanol) is even harder to find.
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time2roll
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Yes KLEANAIRIFORNIA pretty much all has ethanol. Much better than MTBE that was being used.
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mkirsch
Rochester, NY
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parker.rowe wrote:I'm not sure why people think the rear gear ratio only changes rpm/mph.
It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual
If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.
Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.
You know WHY it "tow more easily in all gears?"
Because the engine is running at a higher RPM at all speeds!
The engine produces more HP at higher RPMs, up to the peak of the power curve.
People think "gear ratio only changes rpm/mph" because that is precisely what it does.
If you were doing 60MPH at 2000RPM with stock 3.73 gears, you will need to rev the engine to 2305RPM to maintain 60MPH with 4.30 gears, or you will only be doing 52MPH at 2000RPM.
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lenr
Indianapolis, IN
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The only transmission offered in an F-350 from 2011 to 2019 was the 6R140 6 speed transmission. Shifts down from the top 3 gears down into the next lower gear are all close to 30%. The change from 3.73 to 4.30 is a 15% change. So, about on average the 4.30 axle would save an additional downshift when one is already below 6th about 50% of the time. The 4.30 would definitely reduce downshifts from 6th at highway speeds. Only the OP may decide what is worth what to them. However, if the truck only tows a small percentage of the time, it wouldn't be worth an axle change to most folks.
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time2roll
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lenr wrote:The only transmission offered in an F-350 from 2011 to 2019 was the 6R140 6 speed transmission. Shifts down from the top 3 gears down into the next lower gear are all close to 30%. The change from 3.73 to 4.30 is a 15% change. So, about on average the 4.30 axle would save an additional downshift when one is already below 6th about 50% of the time. The 4.30 would definitely reduce downshifts from 6th at highway speeds. Only the OP may decide what is worth what to them. However, if the truck only tows a small percentage of the time, it wouldn't be worth an axle change to most folks. 30% vs 15% would be an easy choice if the truck seemed to be hunting for that middle gear.
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parker.rowe
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mkirsch wrote:parker.rowe wrote:I'm not sure why people think the rear gear ratio only changes rpm/mph.
It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual
If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.
Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.
You know WHY it "tow more easily in all gears?"
Because the engine is running at a higher RPM at all speeds!
The engine produces more HP at higher RPMs, up to the peak of the power curve.
People think "gear ratio only changes rpm/mph" because that is precisely what it does.
If you were doing 60MPH at 2000RPM with stock 3.73 gears, you will need to rev the engine to 2305RPM to maintain 60MPH with 4.30 gears, or you will only be doing 52MPH at 2000RPM.
You still have torque multiplication happening.
For easy math, lets say you have an engine with a nice flat torque curve.
100ft lbs at both 2000 and 2300rpm.
Running in direct (1:1), also to make the math easier.
100ft lbs x 1 x 3.73 = 373 ft lbs
100 ft lbs x 1 x 4.30 = 430 ft lbs
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.
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Turtle n Peeps
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OP you have very limited options if you don't (can't) run a tuner. You will only gain a few HP out of a tuner anyway.
Unlike the popular belief on RV.net, gears don't make power. If you don't like to rev your engine to peak HP it does not make any difference how many gears you have. If you want peak power, you have to rev your engine to peak RPM. It's that simple.
If you want power at a lower RPM you only have a few choices. Buy a diesel (which you say you don't want to do) or buy some sort of a supercharger. Whether that be a turbo or belt drive.
Another option you can also use is if you want more power is E85. I think your Ford can use it? If so, you should be able to gain on the order of 25 to 30HP buy switching to E85. Be aware if you switch to E85 you will go through fuel at an alarming rate but you will make some more horse power.
My suggestion is just let the engine rev and do what it needs to do.
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dodge guy
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mkirsch wrote:valhalla360 wrote:A deeper rear end won't do anything to help this.
At least not enough to justify the cost and inconvenience of roaring around like an old Army Jeep the rest of the time.
It most certainly will! It will let the truck pull in a different gear. On a gasser as little as 300rpm makes a difference to n towing at the top of one gear or the bottom of the next. It does indeed make a difference. That’s why different axle ratios are offered by the manuf.
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