Tow vehicle weight transfer from trailer

[mudman2]

My question is that when you attach your trailer and use a properly fitted weight distribution hitch is the max weight you are transferring to your tow vehicle the max cargo rate your truck is rated for.

[clarkbre]

Let me take a stab at this....

If the tongue weight is 1000 pounds sitting on the ball and no WD bars are in place, the 1000 pounds of tongue weight is on the ball. As the rear axle acts as a fulcrum point, the front axle is lifted slightly.

Once the bars are applied and working, the upward tension relieves some of the 1000 pound pressure off the ball and pushes it to the tow vehicle's front axle and the trailer axles. So, the ball might only see a weight of 600 pounds, the front axle will see an additional 200 pounds and the trailer axles will see an additional 200 pounds.

And, you are not really transferring weight. The bars are applying tension to help bridge the weight and support the tongue weight more evenly.

[Boomerweps]

Short answer: No.

Some weight yes but not normally your TV max payload. You have to leave room in that for you, passengers and stuff.

The WDH transfers some weight OFF the TV's rear/drive axle to the TV's front/steer axle AND some to the TT axle(s).
In my case, the WDH levers about 180# to the front axle and near the same to my single TT axle. My rig sets almost exactly level ith the WDH connected.
So your tongue weight AND any weight pushed onto the TV front axle count as part of your TV payload capacity.

[mudman2]

Originally Posted by Boomerweps

Short answer: No.

Some weight yes but not normally your TV max payload. You have to leave room in that for you, passengers and stuff.

The WDH transfers some weight OFF the TV's rear/drive axle to the TV's front/steer axle AND some to the TT axle(s).
In my case, the WDH levers about 180# to the front axle and near the same to my single TT axle. My rig sets almost exactly level ith the WDH connected.
So your tongue weight AND any weight pushed onto the TV front axle count as part of your TV payload capacity.

So the next question is would you maintain your tow vehicles tire pressure as recommended by vehicle manufacturer or air up when towing and why.

[Lins]

Originally Posted by mudman2

So the next question is would you maintain your tow vehicles tire pressure as recommended by vehicle manufacturer or air up when towing and why.

Generally with a WDH you are wanting to RESTORE the weight you lose from the front axle when you hook the trailer up without the WDH.

As for what PSI to use, the door listed PSI is really all you need. However, the best way to determine what PSI to use is to load up like you're going camping, and go hit the scales to see what your axle weights are. Then go look up the load and inflation table for your tires and see what the recommended PSI is (hint: they are virtually identical between all manufacturers - after all, does your door label state which tire manufacturer, or just the tire size and load range?). My label says 65 front, 80 rear. HOWEVER, according to scale weights, I ONLY need 55 front and 45 rear when we're fully loaded up and the truck is just under the 3/4 ton limit of 10k. That way, I get good load carrying ability, traction, tire wear and it doesn't needlessly ride like a tank.

[Dustyhd]

“My label says 65 front, 80 rear. HOWEVER, according to scale weights, I ONLY need 55 front and 45 rear when we're fully loaded up and the truck is just under the 3/4 ton limit of 10k. That way, I get good load carrying ability, traction, tire wear and it doesn't needlessly ride like a tank.”

Please don’t tell noobs to this, it’s wrong. Even if the weight on the tires doesn’t need full rated pressure it increases tire cornering stiffness which increases grip as well maintains proper TV oversteer.

[wabakami]

Originally Posted by Lins

Generally with a WDH you are wanting to RESTORE the weight you lose from the front axle when you hook the trailer up without the WDH.

As for what PSI to use, the door listed PSI is really all you need. However, the best way to determine what PSI to use is to load up like you're going camping, and go hit the scales to see what your axle weights are. Then go look up the load and inflation table for your tires and see what the recommended PSI is (hint: they are virtually identical between all manufacturers - after all, does your door label state which tire manufacturer, or just the tire size and load range?). My label says 65 front, 80 rear. HOWEVER, according to scale weights, I ONLY need 55 front and 45 rear when we're fully loaded up and the truck is just under the 3/4 ton limit of 10k. That way, I get good load carrying ability, traction, tire wear and it doesn't needlessly ride like a tank.

Don't just use the door sticker, check to see if the tyres have been upgraded by yourself or a previous owner.
I have LTs on my TV, they call for 60# whereas the door sticker is for the original "P" series tyres rated at 35#. I ride with my LTs set to 50# to soften the ride but bump them to 60 when towing so as to get my full payload capability.
If you have upgraded tyres, watch out for the oil change people, they look at the door sticker (maybe) or more likely not and deflate the pressure to 35#, last four oil changes I've had to have them re-inflate back to 50.

Lastly, you get the maximum capacity of the tyres when they are inflated to their max pressure as rated on the sidewall of said tyres, as you decrease the pressure you also decrease the weight carrying capability of the tyres.


Geoff
.

[wabakami]

Originally Posted by Dustyhd

“My label says 65 front, 80 rear. HOWEVER, according to scale weights, I ONLY need 55 front and 45 rear when we're fully loaded up and the truck is just under the 3/4 ton limit of 10k. That way, I get good load carrying ability, traction, tire wear and it doesn't needlessly ride like a tank.”

Please don’t tell noobs to this, it’s wrong. Even if the weight on the tires doesn’t need full rated pressure it increases tire cornering stiffness which increases grip as well maintains proper TV oversteer.

X2

Running rear tyres almost at half pressure (56%) while truck is at gross is scary, tyre roll and edge tread ware, damn, Lins should talk to a tyre specialist.

That being said I do run about 15% under max on all four corners when running lightly loaded. But that is the minimum I would run at for the reasons you stated Dustyhd.



Geoff
.

[Lins]

Originally Posted by wabakami

X2

Running rear tyres almost at half pressure (56%) while truck is at gross is scary, tyre roll and edge tread ware, damn, Lins should talk to a tyre specialist.

That being said I do run about 15% under max on all four corners when running lightly loaded. But that is the minimum I would run at for the reasons you stated Dustyhd.



Geoff
.

I've researched the numbers and am getting perfect tire wear after an alignment and adjusting the pressures per scale weights and load and inflation tables - which Ram used to provide and I have from a 2016 model. They also used to provide a 'light load' switch for when you were running empty. You guys need to do research yourself and stop telling everyone they need to max out their tire pressure.

[Lins]

Originally Posted by Dustyhd

“My label says 65 front, 80 rear. HOWEVER, according to scale weights, I ONLY need 55 front and 45 rear when we're fully loaded up and the truck is just under the 3/4 ton limit of 10k. That way, I get good load carrying ability, traction, tire wear and it doesn't needlessly ride like a tank.”

Please don’t tell noobs to this, it’s wrong. Even if the weight on the tires doesn’t need full rated pressure it increases tire cornering stiffness which increases grip as well maintains proper TV oversteer.

How about you post the sentences I typed before that.

[Lins]

Originally Posted by wabakami

X2

Running rear tyres almost at half pressure (56%) while truck is at gross is scary, tyre roll and edge tread ware, damn, Lins should talk to a tyre specialist.

That being said I do run about 15% under max on all four corners when running lightly loaded. But that is the minimum I would run at for the reasons you stated Dustyhd.



Geoff
.

Geoff, with axle weights of 5192 lbs (2596 per tire) front and 4554 lbs (2277 per tire) rear with my stock 285/60R20 load range E tires please tell me how that is scary with the PSI's I've listed. The chart is direct from the Rambuilder website. I didn't say the OP needs to lower his PSI, I said he can use the door label or do what I've done and use the scale and load and inflation tables. If you have too much sidewall flex then you're running the wrong load range or PSI.

[Dustyhd]

They don’t make it right.

[Boomerweps]

Originally Posted by mudman2

So the next question is would you maintain your tow vehicles tire pressure as recommended by vehicle manufacturer or air up when towing and why.

I ignore any tire pressure to weight rating tables. Flat out.
Why? Because I am running my TV, a 2008 Ford Explorer with factory tow package axles (with WDH) AND TT axles at near maximum axle weight ratings. Well under the listed towing capacity (around 3.9K, rated 5225#) but maxing out the axles.
TV door sticker says 35#, tire max 44#. I keep a minimum of 40# in them for mileage and significant temperature changes. For towing I run 44#.
IME, vehicle makers usually trade away some wear on tires for comfort when recommending tire pressures. I.e., with the Explorer's 35# rated tires, Ford recommended 24# in the early 1990's. Unfortunately, people that don't check their tire pressures often ran at 20# or less. 1992 Explorer Owner's manual hidden gem, "Increase the listed tire pressure 4# for every 10mph over the national speed limit" IIRC. National speed limit was then 55mph. THAT was when Ford threw Firestone under the bus! Those Firestones were some of the best tires I ever owned and was on my second set whe they were recalled.

[mudman2]

Originally Posted by Boomerweps

I ignore any tire pressure to weight rating tables. Flat out.
Why? Because I am running my TV, a 2008 Ford Explorer with factory tow package axles (with WDH) AND TT axles at near maximum axle weight ratings. Well under the listed towing capacity (around 3.9K, rated 5225#) but maxing out the axles.
TV door sticker says 35#, tire max 44#. I keep a minimum of 40# in them for mileage and significant temperature changes. For towing I run 44#.
IME, vehicle makers usually trade away some wear on tires for comfort when recommending tire pressures. I.e., with the Explorer's 35# rated tires, Ford recommended 24# in the early 1990's. Unfortunately, people that don't check their tire pressures often ran at 20# or less. 1992 Explorer Owner's manual hidden gem, "Increase the listed tire pressure 4# for every 10mph over the national speed limit" IIRC. National speed limit was then 55mph. THAT was when Ford threw Firestone under the bus! Those Firestones were some of the best tires I ever owned and was on my second set whe they were recalled.

I have Michelin 275/55 r20 xlt. The cargo max on vehicle is 1390. Door sticker on rig list 30 front 33 rear. Max tire pressure is 44. On the last trip I had pressure at 40 42. It seemed the tow vehicle wandered a bit. All interstate travel. On return I dropped pressure to 36 38 and wandering was gone. Also I have to say at pressure above door sticker even 2pds made for a much rougher ride.

[MR.M]

So if you have 1000 tw and that's 12% of tt weight and you redistribute 400 lbs then your light on the TW and putting yourself in sway Territory ?

[mudman2]

Originally Posted by MR.M

So if you have 1000 tw and that's 12% of tt weight and you redistribute 400 lbs then your light on the TW and putting yourself in sway Territory ?

Tt is 5400 dry and maybe 6200 loaded 12% would be around 720

[wabakami]

Originally Posted by Lins

I've researched the numbers and am getting perfect tire wear after an alignment and adjusting the pressures per scale weights and load and inflation tables - which Ram used to provide and I have from a 2016 model. They also used to provide a 'light load' switch for when you were running empty. You guys need to do research yourself and stop telling everyone they need to max out their tire pressure.

Hmmm, I emailed your quote above to my local tyre shop and Canadian Tyre store and they both couldn't stop laughing.
Anyways as they both said in similar words "send us links for the proof" of what you say.

Also if you read my post I didn't say you have to run maximum pressure as I run 15% under myself when not towing.

Secondly, as I am not a Ram driver, what is a "light load" switch, does it automatically deflate your tyre pressure?


Geoff
.

[awellis3]

Originally Posted by clarkbre

Let me take a stab at this....

Well done stab. Unless the OP is going to a weigh station and collect data, the ol' get the front wheel well back within a �½ of where you started is as good a method as any.

[Lins]

Originally Posted by wabakami

Hmmm, I emailed your quote above to my local tyre shop and Canadian Tyre store and they both couldn't stop laughing.
Anyways as they both said in similar words "send us links for the proof" of what you say.

Also if you read my post I didn't say you have to run maximum pressure as I run 15% under myself when not towing.

Secondly, as I am not a Ram driver, what is a "light load" switch, does it automatically deflate your tyre pressure?


Geoff
.

http://www.rambodybuilder.com/2016/d...tirecharts.pdf

My tires are LT285/60R20E. Feel free to explain why I need to run 65 front/80 rear when the axle weights truck loaded, trailer attached, is 5192 front, 4554 rear.

[wabakami]

Originally Posted by Lins

Geoff, with axle weights of 5192 lbs (2596 per tire) front and 4554 lbs (2277 per tire) rear with my stock 285/60R20 load range E tires please tell me how that is scary with the PSI's I've listed. The chart is direct from the Rambuilder website. I didn't say the OP needs to lower his PSI, I said he can use the door label or do what I've done and use the scale and load and inflation tables. If you have too much sidewall flex then you're running the wrong load range or PSI.

My tyre store owner never drives less than 20% under pressure on his trucks.
The warranty on any of the seven tyre lines he carries would be void on Road Hazzard and he says any good tech will tell if it is under-inflated.

OK, I sent this chart to my pet tyre man, he said;

#1 Where is the manufacturers info on this chart, someone who you can pin the blame on when you flip your truck when the tyre fails due to underinflation???

#2 This looks like a training aid to teach tyre techs how overloading happens with the same payload but decreases with air loss through leakage or intentional under-inflation.


You did send me out to look at my tyres as your chart says 65# for my Goodyear LT285/70R17 (D). Hmm my sidewall says 60# max, my tyre shop tells me this same tyre in the US is 65# but Transport Canada rates it at 60 as the sidewall says. He has sold both 60 and 65# tyres through his shop, but the payload stays the same, he currently has 8 on the shelf with 60# on the sidewall.



Geoff
.