Dec-02-2019 10:55 AM
Dec-05-2019 10:19 AM
valhalla360 wrote:Terryallan wrote:
My contention is that a lower gear will give you a higher tow rating / capacity, and in fact the engineers back me up with their tow capacity numbers.
A 3.73 has a higher tow capacity / rating than does a 3.55. Why. Because the 3.73 can deliver more power to the ground at lower speeds.
According to the engineers. The idea that rear gearing no longer matters in towing is completely wrong. If that were to be true. It would not matter what rear gear was installed in the truck. They could be using 2.15 and tow the same thing. And we all know that isn't going to happen. I can tell you having just went from a 3.55 to a 3.73. there is a world of difference.
The honest truth is GM, and Ford put in high gears in most of their truck to meet the CAFE numbers mandated by the Gov. And in so doing make most of their trucks gutless. But for most customers that doesn't matter either. They are not going to use the truck to work, or tow. They just use them like a car. I have a friend that just bought a F150 with the EcoBoost, and a 3.15 rear. We were talking, and he told me. it has a low tow capacity. But he wasn't planning on towing anything any way. So it works for him.
If you are pushing the truck to it's absolute towing limit...yes, a deeper rear end will increase the tow rating. But if you are within the ratings, it won't improve the towing.
If you compare two trucks identical except: one with a 10k tow limit (& lower numerical rear end) and one with a 12.5k tow limit (& higher numerical rear end) and you are towing 7k...it really doesn't matter with modern 8-10 gear transmissions. Basically, the transmissions will pick different gears to effect the same overall gear ratio (or at least close enough it won't be noticeable when looking at engine RPM and efficiency).
This is different from the good old days of the 3 or 4 speed transmission. Yes, in those days the low numerical rear ends were about getting better MPG. Most miles ran empty and the set up the transmission around that.
Problem as soon as the engine can't hold top gear...with a 4speed, you are going from say 1.00 to 1.36 or a 36% change in gear ratio (some transmissions can be upwards of 60%). That was often WAY MORE of a drop than the engine needed, so the engine would race like mad (36% increase in RPM) to keep the RPM up high enough to maintain highway speeds. By upping the rear end, the truck could hold top gear and stay at a reasonable RPM...when towing... but will run higher RPM than needed when not towing hurting MPG.
But say the modern Ford 10 speed transmission, dropping from 10 to 9 goes from 0.63 to 0.68 or about a 7.5% change in gear ratio. So if the engine can't hold top gear and drops down, the engine sees a 7.5% RPM increase to hold the same speed and that will often be enough...if not, it can drop to 8 or 7 and so on but it can dial it in with small percentage changes. It can do this with either rear end, you will just see different gears being used for the same conditions but for the same speed the engine RPM and load will be within a few percentage points...the rear end simply doesn't matter if you are within the tow limits.
Dec-05-2019 09:55 AM
Lwiddis wrote:
“I have a friend that just bought a F150 with the EcoBoost, and a 3.15 rear. We were talking, and he told me. it has a low tow capacity.”
My new Silverado has a 3.24 rear end and 8000 max tow weight. I don’t consider that low, or huge.
Dec-05-2019 06:36 AM
Dec-05-2019 04:02 AM
valhalla360 wrote:
If you are pushing the truck to it's absolute towing limit...yes, a deeper rear end will increase the tow rating. But if you are within the ratings, it won't improve the towing.
If you compare two trucks identical except: one with a 10k tow limit (& lower numerical rear end) and one with a 12.5k tow limit (& higher numerical rear end) and you are towing 7k...it really doesn't matter with modern 8-10 gear transmissions. Basically, the transmissions will pick different gears to effect the same overall gear ratio (or at least close enough it won't be noticeable when looking at engine RPM and efficiency).
This is different from the good old days of the 3 or 4 speed transmission. Yes, in those days the low numerical rear ends were about getting better MPG. Most miles ran empty and the set up the transmission around that.
Problem as soon as the engine can't hold top gear...with a 4speed, you are going from say 1.00 to 1.36 or a 36% change in gear ratio (some transmissions can be upwards of 60%). That was often WAY MORE of a drop than the engine needed, so the engine would race like mad (36% increase in RPM) to keep the RPM up high enough to maintain highway speeds. By upping the rear end, the truck could hold top gear and stay at a reasonable RPM...when towing... but will run higher RPM than needed when not towing hurting MPG.
But say the modern Ford 10 speed transmission, dropping from 10 to 9 goes from 0.63 to 0.68 or about a 7.5% change in gear ratio. So if the engine can't hold top gear and drops down, the engine sees a 7.5% RPM increase to hold the same speed and that will often be enough...if not, it can drop to 8 or 7 and so on but it can dial it in with small percentage changes. It can do this with either rear end, you will just see different gears being used for the same conditions but for the same speed the engine RPM and load will be within a few percentage points...the rear end simply doesn't matter if you are within the tow limits.
Dec-04-2019 11:03 PM
Terryallan wrote:
My contention is that a lower gear will give you a higher tow rating / capacity, and in fact the engineers back me up with their tow capacity numbers.
A 3.73 has a higher tow capacity / rating than does a 3.55. Why. Because the 3.73 can deliver more power to the ground at lower speeds.
According to the engineers. The idea that rear gearing no longer matters in towing is completely wrong. If that were to be true. It would not matter what rear gear was installed in the truck. They could be using 2.15 and tow the same thing. And we all know that isn't going to happen. I can tell you having just went from a 3.55 to a 3.73. there is a world of difference.
The honest truth is GM, and Ford put in high gears in most of their truck to meet the CAFE numbers mandated by the Gov. And in so doing make most of their trucks gutless. But for most customers that doesn't matter either. They are not going to use the truck to work, or tow. They just use them like a car. I have a friend that just bought a F150 with the EcoBoost, and a 3.15 rear. We were talking, and he told me. it has a low tow capacity. But he wasn't planning on towing anything any way. So it works for him.
Dec-04-2019 01:37 PM
Dec-04-2019 01:09 PM
Dec-04-2019 12:30 PM
valhalla360 wrote:Terryallan wrote:mkirsch wrote:I'm skeptical what the "tow package" includes if your truck has 3.23 gears, by the way. A hitch receiver is not a "tow package."
Get your head out of the 1970's. The days of 3-speed transmissions and needing 4.10 gears to tow an empty wheelbarrow are long gone. This truck has an 8-speed transmission with a super deep first gear, and well spaced gears between there and the double overdrive.
Where you get the gear reduction is irrelevant, as long as you have it available. 3.23 is a perfectly fine towing gear.
Wonder why the engineers give the lower gears a higher tow package??? Just saying.
His last sentence covers the answer. If he's within the tow ratings of the truck it doesn't matter where the overall gear ratio comes from.
But if he is exceeding the truck ratings, that suggests the necessary gearing is not "available" and the only way to get that without upgrading the engine or chassis is a lower rear end gear.
Now of course, those ratings are assuming fairly tough conditions (climbing a steep grade in hot conditions), so if you are running on flat land, you may be able to cheat and get away with it but this is a different issue.
Dec-04-2019 03:32 AM
patperry2766 wrote:
It's not only corporate, it the fed govt. It's called CAFE (Corporate Ave Fuel Economy) and the govt sets a fleet wide average for all cars, SUV's and 1/2T trucks. 3/4 and above are exempt for now.
Basically for 2021, the CAFE for manufacturers is 40.3-41 MPG, and if you can't meet it, then you have hefty fines to pay to Uncle Sam. F,C,D are gonna have a hard time making that since they've basically abandoned the car business and concentrating manufacturing efforts on SUV's and trucks.
https://www.transportation.gov/mission/sustainability/corporate-average-fuel-economy-cafe-standards
Dec-03-2019 11:28 PM
BenK wrote:
Towing is lower on their mandate from managment...higher requirement is Corporate MPG...even fractions of a MPG is more important to them
Plus, towing metrics is very low on the bean counter management requirements
Dec-03-2019 08:32 PM
Terryallan wrote:mkirsch wrote:I'm skeptical what the "tow package" includes if your truck has 3.23 gears, by the way. A hitch receiver is not a "tow package."
Get your head out of the 1970's. The days of 3-speed transmissions and needing 4.10 gears to tow an empty wheelbarrow are long gone. This truck has an 8-speed transmission with a super deep first gear, and well spaced gears between there and the double overdrive.
Where you get the gear reduction is irrelevant, as long as you have it available. 3.23 is a perfectly fine towing gear.
Wonder why the engineers give the lower gears a higher tow package??? Just saying.
Dec-03-2019 05:51 PM
DutchmenSport wrote:
If you had to ask the question in he first place, well??? probably not!
Dec-03-2019 03:46 PM
Dec-03-2019 03:45 PM
twodownzero wrote:
Uh, no I didn't. It's simple arithmetic. GCWR - GVWR = 8k pounds. It's in the specs for the vehicle.
And .2 lower gear ratio magically gives it 2000lbs more gcwr, but whos counting. Also payload considers 2 - 150lb passengers PRIOR to deducting anything from payload number and the heaviest publihsed curb weight is just over 5klbs, 5008 lbs, for the highest zooted RST 6.2L 10 speed. Granted the 5.3 crew cab is probably still 4700lbs easy.
Oooh, good one. What percentage of full size pickups come with gears that high? Does Ford even offer a 3.23 on an F-150? Even within GM sales numbers or on a dealer's lot, what percentage of trucks do you think come with 3.23 gears? I bet it's not many.
Ooooh, you're speculating again... This aint about F150s, but you're absolutely right, they don't offer a 3.23 gear truck. But they do have 3.15s, 3.31s, 3.55s and 3.73s.
And the GM twins only have 2. The little motors and the 5.3s with the old 6 speeds get 3.42s, as do the max trailer package 5.3 8 speeds and max trailer 6.2 10 speeds. The bulk of the trucks are the 5.3 8 speed trucks with 3.23s and the 6.2 non max tow also get 3.23s.
I've been looking at them. Hard to get a 3.42 with the bigger engines = high $ trim packages that come with the high $ engines and trans.
But whatever.
Where you get the gear reduction is a big deal for the transmission if you want it to last. I'm sure rebuilding that 8 speed transmission isn't cheap.
Dec-03-2019 02:11 PM
Terryallan wrote:
Wonder why the engineers give the lower gears a higher tow package??? Just saying.