Tow rig gear ratio

[Provience]

Not seeing anything in search.

Curious what people are running, if you made changes etc

Engine
Trans
Axle
Tire

Pretty much minimum standards for any post

Contemplating going from 4.1 to 4.8 in my class c, not sure if that's too aggressive compared to 4.5. Target weight is about 13k lbs on the chassis and under 20k with a trailer

460 efi
E4od
D70 4.10 currently
225/75r16 highway tread

Mostly looking to address sluggish start uphill with a load, don't cruise above 70 mph due to wind

 

[472man]

2001 Cummins 2500, 3.55 ,295-70-18 nv5600. The truck would love 3.08 gears for empty cruising and would love 4.10 for heavy towing. When I tow my gooseneck it usually puts me at 23-26,000 totally weight. It does fine but I don't use 6th gear much

 

[rockota]

OBS is 7.3/E4OD, D60/D110 w/ 4.88's and metric 35" tires.
Alumaduty is 7.3/10-speed w/ 4.30's and metric 35" tires.

4.88's is a lot for the PSD on the highway... but it's fine around twon.

 

[AKnate]

4.88. 08 5500 6.7L
pulls ok, nothing awesome. Sucks Down fuel like a 70s BBC... like 7-8mpg towing only ~10k. Whatever factree size it. 225 something 19.5 i think.


F-350 i think is 4.10s. 7.3L. Mostly pulls in 3rd gear WOT. ~12mpg. 235/85r16s

 

[TRINDU]

With 4.56 you'd be spinning 2700 rpm at 70.

Which is about where to need to be with that weight and aero.

 

[Gbkeith]

OBS is 7.3/E4OD, D60/D110 w/ 4.88's and metric 35" tires.
Alumaduty is 7.3/10-speed w/ 4.30's and metric 35" tires.

4.88's is a lot for the PSD on the highway... but it's fine around twon.

Tell us more about the OBS. I’d kind of like to do an old F-SuperDuty with super duty F-4 or 550 axles one of these days.

 

[CDA 455 II]

Not seeing anything in search.

Curious what people are running, if you made changes etc

Engine
Trans
Axle
Tire

Pretty much minimum standards for any post

Contemplating going from 4.1 to 4.8 in my class c, not sure if that's too aggressive compared to 4.5. Target weight is about 13k lbs on the chassis and under 20k with a trailer

460 efi
E4od
D70 4.10 currently
225/75r16 highway tread

Mostly looking to address sluggish start uphill with a load, don't cruise above 70 mph due to wind

4.88s FTW

 

[YotaAtieToo]

7.3
Zf5
4.10 to 3.54s
285/75r16s

4.10s obviously sucked for highway use, even towing, it was common to drop to 4th on most hills, then 3rd on steeper or longer hills. The 3.54s made it more likely to drop down, but also gain mph in each gear and almost worked better really. 3.73s would probably be a perfect middle ground.

I could post about my 2016 6.7 F350 or work truck 2019 6.7 F550, but I doubt anyone cares much as the newer stuff will just pull like crazy no matter the gears.

Not seeing anything in search.

Curious what people are running, if you made changes etc

Engine
Trans
Axle
Tire

Pretty much minimum standards for any post

Contemplating going from 4.1 to 4.8 in my class c, not sure if that's too aggressive compared to 4.5. Target weight is about 13k lbs on the chassis and under 20k with a trailer

460 efi
E4od
D70 4.10 currently
225/75r16 highway tread

Mostly looking to address sluggish start uphill with a load, don't cruise above 70 mph due to wind

What's it like to run 70 mph in 3rd?

Mathematically, 3rd gear with 4.10s would be the same as 5.80s in 4th of that makes sense. Sometimes that's a good way to get a rough idea of what you want for gearing.

Regearing is always a bit of a gamble as everyones opinions and situations are different. 4.10 to 4.88s is about 440 RPM different according to this

Gear Ratio Calculator

I've read too many stories of people saying they were disappointed in the difference between 4.10s and 4.88s or similar. But not usually with a motorhome. At least you only have one diff to deal with.

Have you looked into a newer trans swap at all? For really though, a 6 speed auto would be awesome with that engine.

 

[rockota]

Tell us more about the OBS. I’d kind of like to do an old F-SuperDuty with super duty F-4 or 550 axles one of these days.

F250 cc converted to dually. D60/110, 4.88/truetracs. Stazworks, Deavers, bilsteins, hydro assist, shafts, etc.

Bought it with the idea of ditching the cray computer controlled 6.7, but things change. It’s fun for around town, even though it’s huge.


And it’s for sale.

 

[rockota]

7.3
Zf5
4.10 to 3.54s
285/75r16s

4.10s obviously sucked for highway use, even towing, it was common to drop to 4th on most hills, then 3rd on steeper or longer hills. The 3.54s made it more likely to drop down, but also gain mph in each gear and almost worked better really. 3.73s would probably be a perfect middle ground.

I could post about my 2016 6.7 F350 or work truck 2019 6.7 F550, but I doubt anyone cares much as the newer stuff will just pull like crazy no matter the gears.




What's it like to run 70 mph in 3rd?

Mathematically, 3rd gear with 4.10s would be the same as 5.80s in 4th of that makes sense. Sometimes that's a good way to get a rough idea of what you want for gearing.

Regearing is always a bit of a gamble as everyones opinions and situations are different. 4.10 to 4.88s is about 440 RPM different according to this

Gear Ratio Calculator

I've read too many stories of people saying they were disappointed in the difference between 4.10s and 4.88s or similar. But not usually with a motorhome. At least you only have one diff to deal with.

Have you looked into a newer trans swap at all? For really though, a 6 speed auto would be awesome with that engine.

How’s that engine swap coming along?

 

[arse_sidewards]

You got a D70. Go all the way to 7.17 and if that's too slow tow get a spicier cam and bigger trailer.

 

[YotaAtieToo]

How’s that engine swap coming along?

Still trying to get through the butthurt phase

 

[Provience]

What's it like to run 70 mph in 3rd?

Mathematically, 3rd gear with 4.10s would be the same as 5.80s in 4th of that makes sense. Sometimes that's a good way to get a rough idea of what you want for gearing.

Regearing is always a bit of a gamble as everyones opinions and situations are different. 4.10 to 4.88s is about 440 RPM different according to this

Gear Ratio Calculator

I've read too many stories of people saying they were disappointed in the difference between 4.10s and 4.88s or similar. But not usually with a motorhome. At least you only have one diff to deal with.

Have you looked into a newer trans swap at all? For really though, a 6 speed auto would be awesome with that engine.

3rd at 70 with the 4.10 is pretty well the top of any hill. Normal driving, shifts out of 3rd at 60mph.

6spd swap would be tits, but for $400 I can swap gears. Not interested in 6r80 for this and the 6r140 doesn't have nearly as much swap support.

So looking at options to get similar results. I'll have to get in the computer and pull numbers and charts, but deeper gears would probably put me into the same spot on tq curve as a couple thousand of motor work would put me

 

[Provience]

With 4.56 you'd be spinning 2700 rpm at 70.

Which is about where to need to be with that weight and aero.

Yeah that was the initial thought, then I was looking at east coast gear website this morning and there is a ton of options

 

[Thatg9659]

you could try splitting 1st with over drive can do 2nd too but it’s only .10 difference.

 

[KB6Chris]

17 Ram 3500

6.7 Cummins Tunes/Deleted
G56 Dual Disk
3.42 Gears
Stock tires (33's)

I don't tow often or very heavy. Towed this setup from eastern illinois to southern cali and back. Took I70 through the mountains and I was happy with it. Averaged 12mpg. 6th was great on the flats and most hills and 5th(direct) worked great in the mountains. I'm sure if I was heavier I would be down into 4th is some places. If I was doing this kinda towing a lot I would invest in some headstuds and some gauges because the cruise control would push the boost 35+ if I let it. But man it would sure pull lol

As far as OP's situation. I think the only rear cure is more gears in the trans or more hp. A trans with a lower first while keeping O/D would be the best. I wonder if you could stick an Aux Box behind your E40D to have more selection? It prolly boils down to how much are you driving this thing and if you do put deeper gears in the rear are you okay with the motor spinning faster on the flats to pickup power in the climbs?

 

[Provience]

playing around with the grimmjeeper calculator and taking some notes

E4OD w/4.1 and 225/75r16 does about 3300 rpm at 70 mph in 1:1 (2340 rpm in O/D)
C6 w/3.5 and 9.5r16.5 does about 3300 rpm at 78 mph in 1:1 and i commute at that speed pretty well every day

going to 4.56 does 3664 at 70mph in 1:1 and 2600 in O/D

4.88 does 3921 at 70mph in 1:1 and 2784 in O/D

Dyno comparison/results Holley 4160/4150 and Edelbrock 1405

www.460ford.com

relevant thread link, engine specs in that thread, overall sounds like a mild 460 or approximately a good running EFI 460. point is the shape of the curve and that this shows a lower RPM load than most of the internet. This cam is pretty close to all the "stock" charts I can find that roll off between 3200-3400 rpm.

chart on the left is current 4.10 and chart on right is theoretic 4.88. Currently, 3500 RPM & 50 MPH is where I have to force the transmission to hold 2 for climbing hills at decent load. It will do that for miles without complaint. Using the dyno chart above, even though the TQ is dropping off, the net HP doesn't start dropping off until closer to 4200 rpm (which means i'm still gaining RPM faster than losing power)

all of that is to say, i guess i'm not so afraid of the top end being too wound out.


mostly, more concerned if it would be noticeable from a stop and in 1st gear. "according to the internet" stall should be 1200-1600.


Edit: adding these links so that I can find them in the future

1994 Ford 460 mild performance upgrades

www.460ford.com

EFI 460 power upgrades

www.460ford.com

 

[YotaAtieToo]

3rd at 70 with the 4.10 is pretty well the top of any hill. Normal driving, shifts out of 3rd at 60mph.

My fear would be with 4.88s, you're still dropping to 3rd on the same hills, but that much more RPM. Or is that not a worry to you?

Personally, I don't think 4.10 to 4.56 is worth the effort. Unless you can find a whole rear axle to swap.

6spd swap would be tits, but for $400 I can swap gears. Not interested in 6r80 for this and the 6r140 doesn't have nearly as much swap support.

Ya, I figured, but we can dream right?

So looking at options to get similar results. I'll have to get in the computer and pull numbers and charts, but deeper gears would probably put me into the same spot on tq curve as a couple thousand of motor work would put me

 

[Provience]

My fear would be with 4.88s, you're still dropping to 3rd on the same hills, but that much more RPM. Or is that not a worry to you?

Personally, I don't think 4.10 to 4.56 is worth the effort. Unless you can find a whole rear axle to swap.






Ya, I figured, but we can dream right?

I'm not at all concerned with dropping gears, auto's were meant to be shifted. I guess other than the initial start, i'm trying to really get away from the 2nd gear 45mph hill climbs.

if i drop to 3rd on the same hills without continuing to lose speed and avoid dropping to 2nd, that's a win. Granted, it's not often that I hit 2nd on a hill, but it does happen. it is far more likely that i hit traffic on a hill and need to get going or up to speed.

as for the 6 speed, i went all as far as somebody could possibly go on the swap without actually buying anything.....and then bought an E4OD to swap into my 78 because it was just sooo much cheaper than even a wrecked/need rebuilt 6r80 would've been.

this thread leads into that as well because i'm going to want to go away from the 3.5 after that trans has been swapped, and probably to a 4.1 there

 

[Provience]

17 Ram 3500

6.7 Cummins Tunes/Deleted
G56 Dual Disk
3.42 Gears
Stock tires (33's)

I don't tow often or very heavy. Towed this setup from eastern illinois to southern cali and back. Took I70 through the mountains and I was happy with it. Averaged 12mpg. 6th was great on the flats and most hills and 5th(direct) worked great in the mountains. I'm sure if I was heavier I would be down into 4th is some places. If I was doing this kinda towing a lot I would invest in some headstuds and some gauges because the cruise control would push the boost 35+ if I let it. But man it would sure pull lol

As far as OP's situation. I think the only rear cure is more gears in the trans or more hp. A trans with a lower first while keeping O/D would be the best. I wonder if you could stick an Aux Box behind your E40D to have more selection? It prolly boils down to how much are you driving this thing and if you do put deeper gears in the rear are you okay with the motor spinning faster on the flats to pickup power in the climbs?

an under-drive/low range box would pick up a bunch of slack, biggest problem would be if it can be shifted at speed of, say 25 mph would be neat. I've seen many references to slight under drive from US Gear, but it looks like they aren't made and ebay unit is ~$1700. Doing a stacked transmission or anything else really does send the cost/time pretty high.

i've put ~20k miles on this thing in 4 years, so i'm not driving a ton and it is usually long runs a handful of times a year.

I appreciate everybodies feedback in the thread so far, it's interesting seeing the different combinations that are out there. y'all diesel cats put good use to those highway gears and it looks appealing, until i break out the calculator and end up with a few decent gasser rebuilds for the cost to acquire just 1 of those oil burners

 

[KB6Chris]

i've put ~20k miles on this thing in 4 years, so i'm not driving a ton and it is usually long runs a handful of times a year.

I appreciate everybodies feedback in the thread so far, it's interesting seeing the different combinations that are out there. y'all diesel cats put good use to those highway gears and it looks appealing, until i break out the calculator and end up with a few decent gasser rebuilds for the cost to acquire just 1 of those oil burners

I see your dilemma, it's hard to justify spending money on something that gets so few miles. I would say a axle re-gear is prolly your cheapest/easiest option or some engine upgrades with a trans cooler. I'm not to familiar with the e40d and how well it handles more power.

 

[YotaAtieToo]

I'm not at all concerned with dropping gears, auto's were meant to be shifted. I guess other than the initial start, i'm trying to really get away from the 2nd gear 45mph hill climbs.

if i drop to 3rd on the same hills without continuing to lose speed and avoid dropping to 2nd, that's a win. Granted, it's not often that I hit 2nd on a hill, but it does happen. it is far more likely that i hit traffic on a hill and need to get going or up to speed.

4.10x1.54 (2nd) is 6.31, so 3rd gear 4.88s is still a ways from that.

Math wise, 5.13s split your current gears it half. Just up to you if you'd want to give up that much on the top end.

as for the 6 speed, i went all as far as somebody could possibly go on the swap without actually buying anything.....and then bought an E4OD to swap into my 78 because it was just sooo much cheaper than even a wrecked/need rebuilt 6r80 would've been.

I'm a little excited for when the 6 speed autos are everywhere for dirt cheap and the stand alone stuff is fully sorted out.

this thread leads into that as well because i'm going to want to go away from the 3.5 after that trans has been swapped, and probably to a 4.1 there

Even c6 to e4od drops your 1st gear about the same difference between 3.54s and 4.10s, so maybe it will work out?

 

[Provience]

I see your dilemma, it's hard to justify spending money on something that gets so few miles. I would say a axle re-gear is prolly your cheapest/easiest option or some engine upgrades with a trans cooler. I'm not to familiar with the e40d and how well it handles more power.

I will say, being the cut-away chassis for the motorhome, this thing has ample cooling. Significant steering, transmission and engine coolers.

camshaft/lifters ~$350
headers/exhaust would all need to be custom fabbed, probably another $500 for cheap stuff
cheapest possible heads are ~$350 ea to stay iron

anything beyond that just counts by the thousand

 

[Provience]

4.10x1.54 (2nd) is 6.31, so 3rd gear 4.88s is still a ways from that.

Math wise, 5.13s split your current gears it half. Just up to you if you'd want to give up that much on the top end.



I'm a little excited for when the 6 speed autos are everywhere for dirt cheap and the stand alone stuff is fully sorted out.



Even c6 to e4od drops your 1st gear about the same difference between 3.54s and 4.10s, so maybe it will work out?

i'm at the point that i don't think they will ever be dirt cheap.

my E4OD was $200 and sold as a core, shop was parting the truck and it was older than the range they deal with so they wanted it cleared out absolutely could not find a $50 one anywhere

5.13, sounds deep just saying the words

that's the other part of seeing what other people are running. bunch of 3.7-4.1 stuff out there, little bit of 4.3 and 4.5, more rare is 4.8 but there just aren't many (any?) running 5+ with a ~30" tire

 

[brocolocoli]

7.3
Zf5
4.10 to 3.54s
285/75r16s

4.10s obviously sucked for highway use, even towing, it was common to drop to 4th on most hills, then 3rd on steeper or longer hills. The 3.54s made it more likely to drop down, but also gain mph in each gear and almost worked better really. 3.73s would probably be a perfect middle ground.

like yotaatietoo said i think 3.73s are perfect. i ran my obs 7.3 e4od with 4.10s and 265/75r16s grossing 12-13k with a sail of a bed camper and while 4.10s were nice to get going once i was cruising above 60-65 i always wished it had 3.73's, especially in the states with 70+ speed limits.

It was pretty rare that i would hit 2nd gear but some of the larger passes would get me there because id need to lift to keep egt's in check even with stock injectors and a intercooler.

 

[arse_sidewards]

like yotaatietoo said i think 3.73s are perfect. i ran my obs 7.3 e4od with 4.10s and 265/75r16s grossing 12-13k with a sail of a bed camper and while 4.10s were nice to get going once i was cruising above 60-65 i always wished it had 3.73's, especially in the states with 70+ speed limits.

It was pretty rare that i would hit 2nd gear but some of the larger passes would get me there because id need to lift to keep egt's in check even with stock injectors and a intercooler.

He has a 460. It likes the revs more than your 7.3 does.

 

[Provience]

He has a 460. It likes the revs more than your 7.3 does.

While I'm going to highjack the thread, I do appreciate the wider range discussion as long as people are good to put their combo in there as well.

Gear ratios are bits and pieces in a bunch of other threads, I was surprised there wasn't a dedicated thread for the various combos when I went looking the other day

 

[YotaAtieToo]

i'm at the point that i don't think they will ever be dirt cheap.

my E4OD was $200 and sold as a core, shop was parting the truck and it was older than the range they deal with so they wanted it cleared out absolutely could not find a $50 one anywhere

5.13, sounds deep just saying the words

that's the other part of seeing what other people are running. bunch of 3.7-4.1 stuff out there, little bit of 4.3 and 4.5, more rare is 4.8 but there just aren't many (any?) running 5+ with a ~30" tire

There was some one who went to 4.56s on a newer superduty and wished they'd gone 5.13s and another guy who went 5.13s on a V10 Ford and like it.

Like I said, it's still not as low as locking out OD

 

[YotaAtieToo]

like yotaatietoo said i think 3.73s are perfect. i ran my obs 7.3 e4od with 4.10s and 265/75r16s grossing 12-13k with a sail of a bed camper and while 4.10s were nice to get going once i was cruising above 60-65 i always wished it had 3.73's, especially in the states with 70+ speed limits.

It was pretty rare that i would hit 2nd gear but some of the larger passes would get me there because id need to lift to keep egt's in check even with stock injectors and a intercooler.

You also have a 0.71 of VS an 0.77, which makes a hug diffence at highway speeds.

I think bumping to 285s would be perfect with the auto.

 

[rockota]

While I'm going to highjack the thread, I do appreciate the wider range discussion as long as people are good to put their combo in there as well.

Gear ratios are bits and pieces in a bunch of other threads, I was surprised there wasn't a dedicated thread for the various combos when I went looking the other day

it's this thread now....