Towing

[Wild one]

Huh?? ... LOL

Apparently rear end gear ratio doesn't matter but if an exact clone of your truck was made and had 3.21 gearing and your truck has 3.92 gearing... Which one would you want to be behind the wheel of in a race to the next stop light(0.4km away) from a 20 roll??

3.21 it's going to carry 1st gear alot farther then the 3.92 geared truck,the 3.92 truck is going to be shifting out of first way sooner from a 20 mph roll,and will also make one more gear change,and every gear change loses you time. My truck was as fast with 3.21's as it was with 3.55's Phil.It depends on your power band more then anything,i built mine to build torque,and it spun the rollers to 572 lb-ft at 3200 rpm,but only made 500 rwhp ,so the taller gears worked as good or better then shorter gears,but if your truck has a bigger cam,and is built more for top end power,then the 3.92's might be the better choice. I kicked my ass for ever believing Green and going to 3.55's,i knew i should of followed my gut,but at the time i figured he knew more about the trucks then i did,20/20 hindsight afterwards,lol

 

[Wild one]

You are correct, the left front gets pulled up, but I already knew that. However, the torque counteracts the engine weight so the left front wasn't getting ripped apart but rather having the weight of the engine removed from it. As one would expect, that's not the one that kept failing. Right front has the torque adding to the weight, and surprise, surprise, that's the one kept failing! Sorry, the owner's manual made no mention of having to add a chain to keep the motor mounts from failing.

With a diesal i might give you that,especially a lump of a 6.2 cast iron GM diesal that's just a touch lighter then the Titanic,but we're not talking heavy diesals here,we're talking light weight aluminium headed gas pots,and they tear the drivers side mount apart,and don't weigh enough to crush the passenger side mount,lol.Chaining the drivers side down,also lessens the weight transferred to the pass side mount,as the engines torque is now split with some of it applied to the drivers side frame rail,reducing the torque applied to the pass side mount

 

[crash68]

@Wild one ok so don't answer question about the taillights... LOL
you went further into the torque/gear relationship of drag racing than expected

 

[Wild one]

@Wild one ok so don't answer question about the taillights... LOL
you went further into the torque/gear relationship of drag racing than expected

Tail lights we don't need no stinking tail lights. LOL. I'm just having fun with this thread now,it was getting to serious,so i thought a little humour might lighten the mood

 

[ramffml]

Huh?? ... LOL

Apparently rear end gear ratio doesn't matter but if an exact clone of your truck was made and had 3.21 gearing and your truck has 3.92 gearing... Which one would you want to be behind the wheel of in a race to the next stop light(0.4km away) from a 30 roll??

Wait. The guy with the poky little diesel is concerned about 0 to 60 now??

 

[yrraljguthrie]

The transmission or the axle ratio does not change torque. Going up a hill with a 3.21 or a 3.92 rear axle requires the same torque. There are two ratios at work, one in the transmission and one in the axle. Together they allow the engine to rev to the required rpms to get the pickup up the hill. The transmission CANNOT change the torque, period. If it did we could just use a little two-banger engine and let the transmission provide the torque. The engine is pushing the truck up the same hill and the SAME torque is required in both cases. There are no increased forces in the transmission. The job of the transmission is to even out the forces and allow the engine to do its job. If more torque were created either by the engine or by your special transmission then the truck would climb the hill faster or climb a bigger hill. Same hill, the same speed, the same engine speed, and the same torque. When the axle ratio is dropped from 3.92 to 3.21 then the transmission needs to be shifted down to get the same overall ratio. The engine sees the same resistance. How could the engine know if the ratio was changed in the axle or the transmission? The 3.92 axle may be required to operate the transmission in the highest gear if the load is large enough. The transmission doesn't "work" as in making an effort, it facilitates the work of the engine. So far as increased gas consumption. The truck using a 3.21 using 7th gear should get the same fuel consumption as the 3.92 in 8th gear. Or thereabout.

 

[Wild one]

I think he's talking more about the torque applied to the pinion then anything,and he is right. 3.92's do require less pinion torque then 3.21's do,but by the time the applied torque transfers through the ring gear and makes the right angle turn to the axles and tires,the applied torque to the axles and tires equals out as the ring gear equals out the final drive ratios. 3.92's in a higher gear are applying less engine torque to the transmisions output shaft/driveshaft and pinion,then 3.21's in a lower gear are applying to the same output shaft/driveshaft and pinion.In that sense the man is correct. The torque applied to the tires is the same between the 2 ratio's as long as both have the same final drive ratio's,but from the pinion ahead,the 3.92's do require less applied torque
You have to think of how the transmission multiplies the engines torque to wrap your head around what he's talking about.
3.21's in a lower gear are multiplying more of the engines torque to the driveshaft then the 3.92's in a higher gear are.
Even though i was giving him a hard time about his motor mount theory,the man is correct,but the motor mounts are more then robust enough to handle the extra twist applied to them

 

[ramffml]

I think he's talking more about the torque applied to the pinion then anything,and he is right. 3.92's do require less pinion torque then 3.21's do,but by the time the applied torque transfers through the ring gear and makes the right angle turn to the axles and tires,the applied torque to the axles and tires equals out as the ring gear equals out the final drive ratios. 3.92's in a higher gear are applying less engine torque to the transmisions output shaft/driveshaft and pinion,then 3.21's in a lower gear are applying to the same output shaft/driveshaft and pinion.In that sense the man is correct. The torque applied to the tires is the same between the 2 ratio's as long as both have the same final drive ratio's,but from the pinion ahead,the 3.92's do require less applied torque
You have to think of how the transmission multiplies the engines torque to wrap your head around what he's talking about.
3.21's in a lower gear are multiplying more of the engines torque to the driveshaft then the 3.92's in a higher gear are.
Even though i was giving him a hard time about his motor mount theory,the man is correct,but the motor mounts are more then robust enough to handle the extra twist applied to them

And that's why it's so important and why I keep saying: "real world".

If you look on paper only and say "what do I need", you can end up with a different conclusion vs "what actually matters, given the various limits of the truck, and given what happens while we're towing".

The limits of the truck are 8000 pounds regardless of gear ratio. We simply don't have more payload available on like 95% of the the trucks out there.

And what happens when I'm towing: the 3.21 scoots great off the line while towing. Where it peters out is on the freeway passing a semi or getting onto an on ramp. Where I need extra power, the "granny gear" the 3.92 offers won't help one tiny bit.

And finally, I still think towing in direct drive (6th gear) is better long term for the transmission, and funny enough the 3.92 will want to tow that same load in overdrive/7th.

Combine all that with a missundertanding that both trucks must be using the same transmission gear at the same time and therefore the 3.21 puts less torque to the ground - well that's why the 3.21 is bashed so often.

I actually have no issue with the 3.92. I'd buy a truck with it if it checked all the other boxes. I just like to be honest and accurate, the 3.21 will do the job perfectly fine.

 

[Wild one]

And that's why it's so important and why I keep saying: "real world".

If you look on paper only and say "what do I need", you can end up with a different conclusion vs "what actually matters, given the various limits of the truck, and given what happens while we're towing".

The limits of the truck are 8000 pounds regardless of gear ratio. We simply don't have more payload available on like 95% of the the trucks out there.

And what happens when I'm towing: the 3.21 scoots great off the line while towing. Where it peters out is on the freeway passing a semi or getting onto an on ramp. Where I need extra power, the "granny gear" the 3.92 offers won't help one tiny bit.

And finally, I still think towing in direct drive (6th gear) is better long term for the transmission, and funny enough the 3.92 will want to tow that same load in overdrive/7th.

Combine all that with a missundertanding that both trucks must be using the same transmission gear at the same time and therefore the 3.21 puts less torque to the ground - well that's why the 3.21 is bashed so often.

I actually have no issue with the 3.92. I'd buy a truck with it if it checked all the other boxes. I just like to be honest and accurate, the 3.21 will do the job perfectly fine.

In the end it's basically a wash with both having the same final drive ratio's,but on the one hand the 3.92's in 7th are easier on u-joints /driveshaft etc., but on the other hand the 3.21's operating in 6th is easier on the transmission.The strongest gear in a transmission is always the straight through direct drive gear,whether it's an automatic or a manual transmission.I guess you could pick your poison,do you want to abuse the u-joints more,or do you want to abuse the transmission more,the u-joints are definitely cheaper and easier to replace then the transmission,lol
I'd also say we can rule out the motor mounts as being a weak link in a Ram,they've been proven to handle in excess of 1100 rwhp

 

[18CrewDually]

In the end it's basically a wash with both having the same final drive ratio's,but on the one hand the 3.92's in 7th are easier on u-joints /driveshaft etc., but on the other hand the 3.21's operating in 6th is easier on the transmission.The strongest gear in a transmission is always the straight through direct drive gear,whether it's an automatic or a manual transmission.I guess you could pick your poison,do you want to abuse the u-joints more,or do you want to abuse the transmission more,the u-joints are definitely cheaper and easier to replace then the transmission,lol
I'd also say we can rule out the motor mounts as being a weak link in a Ram,they've been proven to handle in excess of 1100 rwhp

I'll hug on that.
My main point was on identical fully loaded trucks it is not the same, a 3.92 in 7th and 3.21 in 6th. The end result of "work being done" may be the same, but it is less of a strain on the 3.92 truck. And like I said from the beginning it may be negligible.
Do we all agree on that?

 

[jh90731]

There is a lot of discussion and opinion about the max towing capacity of a Ram 1500. This is just my thoughts and I welcome any disagreement.
I note that the max towing for any Ram 1500 is 12300 lbs and that's with the 5.7 etorque engine and no doubt some other requirements. So far as I can see the only difference between a Ram that will tow the max and all the others are the rear axle ratio, a tow package, and the weight of the vehicle. The tow package can be dispensed with if towing a 5th wheel or gooseneck. That leaves only the axle ratio. And it seems to me that if one is willing to use lower gears than the 8th. and slow down from 75-80 that axle ratio makes no difference. Others have stated that the 3.92 towing in 8th gear is virtually the same as towing with the 3.21 in 7th gear. Requiring the same power output from the engine.
There might be some insurance issues if one tried to tow more than the max stated for the vehicle, but realistically I can't see a problem as I've stated it. It just seems like "how fast do you want to tow". No issue with safety.

Sure, you may be able to tow it ok, but will you be able to stop it ok. It's more than an insurance issue.

Pickup driver's 'overweight' load and brake failure believed to have caused double fatality crash in Carson City

A pickup truck driver is facing multiple charges in connection with a crash that killed two and injured several others in Carson City, Nevada, on Tuesday. The crash happened on Tuesday afternoon as Roney Rolando Gonzalez-Otazo drove a Ford F-350 towing a large boat on a trailer on eastbound...

cdllife.com

 

[Tulecreeper]

Sure, you may be able to tow it ok, but will you be able to stop it ok. It's more than an insurance issue.

That is a true statement. And this is why I always maintain a 20% safety margin when towing, and if I can't I grit my teeth if I have less than 10%. My truck may be rated to tow 15,500#, but 12,000# is as far as I'll push it.

 

[Wild one]

I'll hug on that.
My main point was on identical fully loaded trucks it is not the same, a 3.92 in 7th and 3.21 in 6th. The end result of "work being done" may be the same, but it is less of a strain on the 3.92 truck. And like I said from the beginning it may be negligible.
Do we all agree on that?

I sort of agree,and sort of not,lol. The strain from the transmissions output shaft to the pinion is less with the 3.92's,but the strain on the transmission is less with the 3.21's if 1's operating in 7th and the other is operating in 6th.After buying and replacing one 8 speed in my truck,i'd rather have the 3.21's if they're operating in 6th. It's way easier and cheaper to replace u-joints and rear ends then it is transmissions,lol

 

[ramffml]

I'll hug on that.
My main point was on identical fully loaded trucks it is not the same, a 3.92 in 7th and 3.21 in 6th. The end result of "work being done" may be the same, but it is less of a strain on the 3.92 truck. And like I said from the beginning it may be negligible.
Do we all agree on that?

The issue is never the "fact" of there being strain or not.

The issue is "does it matter". That's what you haven't picked up in my posts on this.

As an example: we all agree that the more you add to your truck, the less payload you have. Fact. But now some guy comes out and says "well my truck has an empty glove compartment so I can put more in my truck".

Theoretically true and practically true are two different things.

That's all beside the additional facts that there are other strains going on (like we've mentioned with the towing in 6th gear is better for the transmission), and the fact that when the truck isn't towing which is probably the vast majority for most 1500's, the 3.92 is adding more RPMs and shortening the life of the engine by running in 8th vs 8th of the 3.21.

 

[Bricknhank]

The 3:21 ring & pinion ratio increases load and stress on drivetrain from the rear axle U-joint all the way forward to the crankshaft, in comparison to 3:92s.
There's no way around that whether its 4, 5, 6, 7, 8, or 10 spd.
It's a gamble that may not be negligible.

I agree with this having been a gearhead in the 60’s and 70’s and playing with gearing for the dragstrip.

 

[Dusty]

You run out of payload long before you run out of towing capacity. Most of the time, anyways. There are a few truck configs that get you a lot of payload, like a RCLB.

Also worth mentioning that max tow comes with increased oil and trans cooling capacity.

Realistically, if you're towing over 8000 lbs, depending on what you are towing, a 1/2 ton truck is nearing it's limits.

Perhaps because I remember when a half-ton pickup meant 1000 pounds, some of the manufacturers specifications arbitrarily comes from the marketing departments. To some extent, beyond what an engineer may consider to be the "max," there has been a war between the manufacturers on advertising better numbers. Ford in particular has kept upping their towing specifications over time in swift reaction to Ram or GM publishing a better spec., and sometimes without changing any mechanical components. In reality its difficult to determine what the actual mechanical limit might be.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build Date: 3 June 2018. Now at 94694 miles.

 

[Dusty]

Let's imagine two identical vehicles with the same 8-speed ratio transmissions, one with a 3.21 axle and the other with a 3.92 axle, but are manual transmissions. The vehicles must accelerate up the same 6-7 degree incline and stay in gear. The vehicle with 3.21s is in 7th gear, the one with 3.92s is in 8th gear, but with both having approximately the same gear ratios.

The rolling speed for both vehicles is 55 MPH.

Which vehicle will accelerate faster?

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build Date: 3 June 2018. Now at 94694 miles.

 

[star_deceiver]

At 55mph, the G56 Cummins w/3.42 I had couldn’t pull this trailer up grades in 6th gear. 5th or lower had to be used. With a 3.92, 5th gear would have the engine bouncing off the rev limiter at around 65mph.



I’ll give the recommendation of: Buy the gear ratio that will satisfy your ego and gives you peace at night. Reading the forums and arguing to yourself won’t give you that restful sleep your ego needs.

 

[Jane S]

Let's imagine two identical vehicles with the same 8-speed ratio transmissions, one with a 3.21 axle and the other with a 3.92 axle, but are manual transmissions. The vehicles must accelerate up the same 6-7 degree incline and stay in gear. The vehicle with 3.21s is in 7th gear, the one with 3.92s is in 8th gear, but with both having approximately the same gear ratios.

The rolling speed for both vehicles is 55 MPH.

Which vehicle will accelerate faster?

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build Date: 3 June 2018. Now at 94694 miles.

The red one.

 

[Riccochet]

Perhaps because I remember when a half-ton pickup meant 1000 pounds, some of the manufacturers specifications arbitrarily comes from the marketing departments. To some extent, beyond what an engineer may consider to be the "max," there has been a war between the manufacturers on advertising better numbers. Ford in particular has kept upping their towing specifications over time in swift reaction to Ram or GM publishing a better spec., and sometimes without changing any mechanical components. In reality its difficult to determine what the actual mechanical limit might be.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build Date: 3 June 2018. Now at 94694 miles.

That's the problem. The specifications have exceeded real world results. Pulling a 10,000 lb trailer with a 1/2 ton is miserable. People think "oh, my truck is rated for 12,000 lbs and 1500 lbs of payload". Well, sure, but if you try to tow something 12,000 lbs you've exceeded your payload, and if you come close to your payload the truck is miserable or dangerous to drive. Then we get in to length and height, which aren't factored in to their numbers. A 30'+ travel trailer is going to push that 1/2 ton around like it's *****.

Hate when people say "can't even tell it's back there".....b.s. Stay in your lane with 30+ mph cross winds.