| Author | Message | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
All sorts of threads come up, "will this or that hitch hold the weight" etc. but the one thing I have never known or figured out exactly how to know, is: "what does my trailer tongue actually weigh?". This is super important, both for hitch safety as well as trailer dynamic... not enough weight on your tongue will get you into a heap of trouble on the highway. Too much tongue weight may well get you into a heap of trouble almost anywhere. So what to do? I recently became aware of this nifty little doodah, and I bought one. It's the best insurance I ever got for peace of mind that my hitch isn't going to fall off and my trailer go and kill someone, not to mention that I like what I tow and don't want to see it destroyed. Check out: Go to McMaster-Carr and type "tongue weight" into their search window. Part number 17645T21,22, or 23...The coolest little tongue weight scale I've ever seen, and only $123 ! If it were me, I'd say everyone who tows a trailer should have one.... | ||
| bathroom scale Rating: N/A |
http://www.rverscorner.com/articles/tongueweight.html | ||
| david anderson (Davidanderson)
Rating: N/A |
Hey bathroom scale, Thanks for reminding me that some of that high school math and science I had to learn 30 years ago would be useful. It's nice to get our memory jogged once in a while. David Anderson | ||
| gusc Rating: N/A |
bathroomscale, The page didn't mention that tongue weight should be measured with the tongue level, very important for accuracy. On the other hand if the tongue is not level when connected to the tow the weight should be taken at this same angle for the true weight. If you can pick up the tongue alone one bathroom scale is probably enough. | ||
| Leslie Robinson (Lesrmc9)
Rating: N/A |
just happens that this months trailer life has an explanation as to how to use the bathroom scale for this purpose Les R MC-9 1981 BC can | ||
| Doug R Rating: N/A |
Gary, Just a question: Are you using a weight distribution kit for your trailer? That can push tongue limits from 500/5000 pounds (tongue weight/trailer weight) to 750/7500 pounds provided the hitch, frame, drivetrain and brakes can handle it. Look on your hitch to see if it states two different sets of numbers, one higher with the words "with WD". If you do use a kit, that scale would come in very handy indeed. Remember, you may have 600 pounds of weight distributed over a broad area pushing down. With an upset, it's 600 pounds of force plus the mass of the trailer at the ball trying to get loose. Makes me think...never take the act of pulling a trailer for granted, no matter the size. (I do from time to time, except for non-braked tow-dollies, which I DESPISE but find myself using anyway.) Thank you for the topic. Guess I'll never stop learning something useful. Good post! Doug Roote | ||
| Marc Bourget Rating: N/A |
Gusc, Tongue level? Maybe, but only significant with short trailers with high center of gravity, not a good combination, BTW. Best stability configuration is to stay around the 15% point with the trailer in towed position. | ||
| c Rating: N/A |
this one works great. http://www.sherline.com/lm.htm | ||
| gusc Rating: N/A |
Length or CG has nothing to do with tongue weight or total weight. The only way to get accurate weight is by having the object and scales level. Since hitches are rated partly by download the need is to know the tongue weight at the towing angle. Pretty simple really, no need for theories or dynamics. | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
Ever wonder what happens wihtout enough tongue weight? I had a fairly heavy load for a car that I was to tow about 50 miles to a storage area for shipment to a mission. When we were moving my son (with a different trailer with brake) we ended up with too much tongue weight on the last load and I had to go get a truck to tow it so I went overboard to avoid doing that again. The load was a 12 foot utility trailer loaded with an 8 foot utility trailer, topped with a diesel lawn tractor for towing the trailers (one or the other) at the mission. These were surrounded with various storage bins of tools and other useful items that I had accumulated that I had not used in 10 to 20 years plus bins of new tools and various items. I had been careful to avoid too much weight on the tongue by putting all the heavy bins to the rear and the light ones to the front. I left home and went about 2 miles, turned onto a busy US highway and sped up. At about 45 mph a violent fish tail commenced but I was able to bring it under some control by carefully slowing down. I pulled off onto a county road found that I could do the same speed and faster with no trouble and thought it was a fluke so I looped around, got back on the busy US highway and IT DID IT AGAIN,immediately on reaching 45 mph, only this time I could not stop it by slowing down. The fishtail became more and more violent and began to wag the car. It threw the car off the road and felt like it was going to turn over. I was lucky to be able to bing it toward the right so it threw me onto the right shoulder instead of across the median. I said threw me on the right shoulder, down in the ditch. It was completely uncontrolable. A passing pick up truck pulled me out of the mud and I limped home 2 miles bereft of all driving confidence. I repositioned some of the bins to increase tongue weight and made the trip without incident. This trailer did not have brakes and will not need them where it is going. It will be towed by a lawn tractor at 5 mph around a project site. The fairly smooth county roads would not induc the occillation. It was the truck grooves on the US highway that started the process, both times. I am now a believer in adequate tongue weight. By the way, I tested the lawn tractor / trailer set-up around my place for several months to be sure it would do the job down there. It could haul 3000 lbs and used about a gallon of diesel fuel a week. It has a foot operated hydrostatic transmission so anyone can drive it safely and it can create the torque with a 3 HP engine to haul a load like that. | ||
| Marc Bourget Rating: N/A |
Gusc, I'm sorry I was not more clear but you make an issue of length of my posts(hah!). You have the "general rule" right but you're focused on the useless condition of "accurate" while level. What needs to be "accurate" is the tongue weight at the angle it will be towed. The angle of the trailer, level or not, will affect the tongue weight significantly if the trailer is short and the CG high. Given both those conditions, (worst case conditions) mounting a short trailer with a high center of gravity to a high hitch point (tilting CG back) MIGHT put the CG behind the center of (to keep it simple, I'll call it . . )"drag". When the CG is farther aft than the center of "drag" you get a positive divergence condition that (again, keeping it simple) will act like Steve Fessenden described. For an extreme example, try shooting an arrow backward. The 15% tongue weight criteria is a simple rule for "head in the sand" people that ensures the CG stays sufficiently ahead of the center of "drag" so the trailer does not act like a backwards arrow. There's people out there that will read your words about "accurate" but ignore the significance of your "at the towing angle" and figure that a trailer weighed level (accurate by your criteria) and mounted to a high hitch will be safe. Not necessarily so! The 15% rule gives sufficient margin to make up for mounting angle and other variables. The need for CG forward of the center of drag to ensure stability is what dictates hitches "needing" a download rating. You don't put a download on a hitch simply because it has a weight rating. A blind adherence to a certain "download" can lead to an aft CG condition, especially with dual or triple axle trailers, that could get quite dangerous the heavier you load the trailer. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Marc, I completely understand the 15% thing. Well, maybe not.... perhaps you can explain one that is a mystery to me and has been for a lonnnnng time... intuition says it's "all wrong"... Years ago I bought a little single axle gypsy-wagon trailer that was used for selling stuff at Ren. Faires. I towed it home 200 miles with my Chevy Blazer. It's tongue weight was very light and it was also a very short trailer with a very short tongue. It got into "almost" uncontrollable oscillations just as Steven described, when going down anything steeper than about 1%, anywhere over 45mph. It wasn't a disaster because it was recoverable, but yes it was a nasty nasty drive. Not knowing what I was doing, and taking a lead from those giant gravel trailers you see everywhere on freeyways that have VERY long tongues, all I did was extend the tongue by 5 feet in length, and the trailer became a perfect tow. That means that in doing so I actually lessened the tongue weight a lot... so according to the 15% rule I should have made things worse...why did it get better? (perfect in fact) | ||
| Marc Bourget Rating: N/A |
Gary, With out asking lots of other questions all related to the following points, my first guess would be harmonic couple. By lengthening the tongue you increased the period and took the trailer part of the trailer/car combination out of the range where they contributed to eachother. It's possible by switching to a different tire, stiffer springs (if the trailer had springs) adding a panhard type bar rather than relying on the springs to locate the axle for side forces, or a host of other things, you could have avoided the problem without lengthening the tongue. It's possible that moving the axle back a couple of inches may have reached the same result you encountered. These last points are relative to converters towing trailers because they might run into overall length issues and lengthening the tounge may not be an option. This response was "off the cuff" Hope these thoughts helped. If you have more info to add, I'd be glad to give you more of my $.02 worth! Onward and Upward | ||
| Mrc Bourget Rating: N/A |
Gary, PS. recalling your high school geometry, lengthening the tongue by 5' (assuming the original was about 4') probably doubled the hitch/axle distance. In such situations 7-1/2% tongue weight might very well be enough. The % is just to ensure CG in front of center of drag. At twice the distance 1/2 the percentage would be just about the same. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Thanks Marc, that makes sense. And that's what happened... the tongue-to-axle distance almost doubled..  Gary | ||
| gusc Rating: N/A |
Marc, After wading through your post I'm not sure what you said? I get lost is those long winded paragraphs. The original question was "what does my trailer tongue actually weigh?" The actual weight is only possible when level. There was no question about length, height, drag, harmonics or CG and I tried to stick to the question. The need is to answer the question. Brevity promotes clarity. I thought I covered tongue tow weight in my brief second paragraph. | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
Gusc, every thread diverges. Some of us enjoy the finer points. Others would prefer to skip them. I don't expect to understand everything that is posted by everybody, but I appreciate the information. | ||
| Marc Bourget Rating: N/A |
Gusc, At this point I think it's better if you just stay lost. Sorry if this pops your "bubble" but the post really wasn't intended for you. Yes, you did show an understanding but then you went South and said something further that tends to confuse those that don't think the way that you do. Contrary to popular belief, I ain't going to try and change your mind. I will try to stop the less experienced from getting confused. Don't take this personal cuz it ain't meant so. Like the prophets, many may hear but few may listen. The post was intended for those who listen. Onward and Upward | ||
| Marc Bourget Rating: N/A |
Gusc, I re-read my post and decided that it sounds less "simpatico" than was meant. If you're talking absolutes, and only absolutes, yes, you should measure the trailer while it's perfectly level. But trailers in real life are seldom perfectly level. In such case, your absolute perfect tongue weight is all but meaningless. What is meaningful is whether or not the trailer will "behave" or act like Gary and Steve experienced. In Gary, Steve's or anybody elses "real life" what counts is whether the trailer "tags along" or puts you into the ditch, like Steve. As a practical matter, 15% of gross with a 4-5 ft. tongue length, REGARDLESS OF TRAILER ANGLE OR CG is what really matters. It's pretty much a safe reliable "yardstick" for towing trailers. While your "absolutely" perfect tongue weight measuring process is correct, it's only valid or relevant for the "absolte" weight on the tongue while level, not whether the trailer will tag along in a docile fashion. It's pretty easy with a two or three axle trailer to get what you would feel is an acceptable tongue weight, within the design limits of the hitch, BUT A MULTI-AXLE TRAILER COULD STILL HAVE ITS CG BEHIND THE CENTER OF DRAG. Gary and Steve time, again! Onward and Upward |