A GVWR Question

[kc5grw]

Jedna věc, kterou lidé mají tendenci přehlížet, na přívěsech nárazník tah, který může být stejně důležité jako hmotnost přívěsu je přívěs délka vs tažného vozidla rozvor.

Tento vzorec [(WB - 110) / 4 + 20], kde WB je rozvoru tažného vozidla v palcích vám pravidlo pro délku max. trailer v nohou pro vaše tažného vozidla.

 

[Disney Bunny]

Also because I would rather hear direct from someone with experience rather than those who provide Monday morning quarterback advice, did you encounter this sway when getting up to around 40 mph or more for the first time on the highway that day?

My reason for asking is based on other similar stories where people ultimately found the trailer load was too far behind the axle. A co-worker of mine found this out when picking up a trailer used for environmental testing. It was a replacement trailer with new equipment similar in shape to a travel trailer but designed for on-site environmental testing. They hit nearly uncontrollable trailer sway at around 45 mph on the highway after picking it up. Found that the percent of the weight on the trailer ball was less than 9% of the overall weight. This seems to be the same argument used by the folks that developed the Sherline portable scale to determine the trailer tongue weight.

I have one and found that when we packed to leave the Fort in August 2008 I had less than 600 pounds on my trailer hitch. Just had to move a few items to the front storage compartment and it corrected to where I need to be at around 700 to 750 pounds.

No, actually. We had been on the road for almost 2 hours when this happened.

 

[Disney Bunny]

I was also wondering if you had weight distribution and sway control on your hitch when towing?

When we were kids, my father had replaced a travel trailer with a new bunkhouse style travel trailer. There was a chance to go to Atlanta for an unexpected trip and he did not take the time to install the weight distribution part of the hitch to the new trailer before leaving, was not overly concerned because he was driving a 3/4 ton with extra suspension that I think was called a camper special package or something (designed for more payload in the bed with extra leaf spring capacity). The truck drove terrible due to the amount of "squat" on the rear axle, and one of the front shocks had come loose by the time we reached Atlanta due to the uneven weight distribution. Braking and handling were terrible despite being well within the vehicle weight limits.

I know we had sway control. To be honest, don't know about weight distribution.

 

[Disney Bunny]

One thing that folks tend to overlook, on bumper pull trailers, that can be as important as trailer weight is trailer length vs. tow vehicle wheelbase.

This formula [(WB - 110)/4 + 20] where WB is wheelbase of the tow vehicle in inches will give you a rule of thumb for max trailer length in feet for your tow vehicle.

Mike, that is great information to know. So I looked up the specs of the tow vehicle we were using at the time......2000 F150 Super cab with regular lenght bed. WB of 138.5 inches, subtract 110 equals 28.5/4 equals 7.125 plus 20 equals 27.125. So according to that formula, with a 28 foot TT (which I went back and looked and verified that it was instead of 27 feet) we were slightly over the length of what we maybe should have been towing.

That truck was also rated for 8300 lbs of towing. The dry weight of the camper itself was about 6350. We also had not totally dumped our tanks that morning before we left either. I am now very paranoid about that. I won't start out with more in the tanks than just an overnight stop.

 

[ftwildernessguy]

There's a lot more to actual weight than just the holding tanks. A dry weight is the basic trailer with nothing added. Add in options, luggage, utensils, all the extra stuff we stick in trailers to make them liveable - that's what adds the weight to the trailer. When I look at what my TV can handle, I look at the fully loaded weight, not the dry weight. 200 or 300 lbs of water alone wouldn't push that trailer over your weight rating.

 

[kc5grw]

Tam je také několik zádrhel systémů na trhu, které mnohem lepší práci houpat kontroly a rozložení hmotnosti, než je typické hmotnosti šíření závěsy.

Hensley a ProPride jsou stejné typy systémů. Jsou kompaktní 4-bodový závěs, že 'projekty' otočného bodu směrem k zadní nápravy tažného vozidla. Pullrite, podle toho, jak se váže, fyzicky najde otočného bodu na zadní nápravě.

Zde je velký lego demonstrace, která ilustruje, proč je pojem Hensley tak dobře funguje:

 

[caveat lector]

This is a great conversation and provides a lot of food for thought. Making notes to myself.

 

[Hyper35]

Trailer sway is caused by not enough tongue weight on the tow vehicle or the TT was not level and was higher in the front. Not because the trailer is heavy.

 

[bigdisneydaddy]

Trailer sway is caused by not enough tongue weight on the tow vehicle or the TT was not level and was higher in the front. Not because the trailer is heavy.

If the trailer were "heavy" in relation to the tow vehicle the length of the trailer and the weight has the ability to put too much side to side force on the tow vehicle. No matter what type of weight dist hitch you use there are some forces from the trailer that will attempt ot yaw the truck. A big trailer vs a small truck can be a factor.

 

[disney4dan]

Another factor that I have noticed, probably only applicable to those of us with 1/2 ton tow vehicles, is the passenger rated tires that come with the vehicle. Upgrading to load range C will give stronger sidewalls to the tire and there is a noticeable difference in the way the combination works to reduce (not eliminate) the minor side to side rolling motion.

When I bought my replacement truck, it had the longer wheelbase (165 inches) and higher tow rating, but came with Michelin passenger tires on it which I think the prior owner may have had installed. It handled great as a daily commuter and got great gas mileage, but I replaced those tires with load range C tires before we took off to Florida. It made a huge difference.