Bike/Trailer wobble

[GaryRatliff]

I'm a bit embarrassed to post after seeing some of the other trailer builds here but I thought the Tripple P (Poor Preacher Project ) was complete before I took it for a test ride. I built a "camper" on a Harbor Freight trailer (40 1/2 x 48). I extended the camper out over the fenders an additional 3 3/4" on each side and 1' in front and 1 1/2 feet in back so the camper itself is now 4x6 1/2'. It is wood so I believe I have added about 75 lbs to the original 150 lbs. The trial run was fine until I got to about 45mph when it started wobbling the bike something furious throwing me into instant prayer mode . Thankfully I got to the side expecting to find a flat but everything appeared normal. I was close to home and rode slow and haven't pulled it since. I don't want to tell the wife because she was opposed to the project from the beginning, lol. I pulled the trailer with a VTX 1800 before the camper build without a problem and I'm confident the weight should be a breeze for my 2001 Goldwing. From what I have read in the other threads, I need a longer tongue which I'm doing. The HF tires were recalled so I now have their replacement tires but have not done anything other than putting them on the trailer. I really do want to make this work not only because I love to camp and the tent is not always the ideal fix but obviously I want to do it safely.

Am I being unrealistic?

[Aussie81Interstate]

You need to work out your trailer dynamics. A longer tongue would more than likely address a lot of your problems - but it is also relevant when you pack your trailer that it has weight centred over the axle and slightly forward.

IF you have too much weight at the rear it will fishtail all over the place- and be dangerous. you need to read up on the weight distribution and the tongue weight and even the height of the tow ball in relation to your trailer - it all impacts in some way..

I will see if I can provide some links in a minute or two..






https://theusatrailerstore.com/blog/let ... otorcycle/

https://selil.com/archives/33

these are just a few of hundred available...

See how you go - make small changes and test - not multiple changes -

[Alan_Hepburn]

I'm by no means an expert on trailer towing with a bike, but I've got over 40 years experience towing with cars and trucks. If bikes follow the same "rules" then you need to make sure that the tongue weight is between 12% and 17% of the total trailer weight - trying to stay closer to the upper end. Many people will say that 10% is adequate, but my experience, and many others, indicates that 10% can really be marginal.

So, weigh the trailer, loaded for travel, then make sure the tongue weight is around 15%, make sure your tires are inflated for the load, and try again.

[AZgl1800]

I'm by no means an expert on trailer towing with a bike, but I've got over 40 years experience towing with cars and trucks. If bikes follow the same "rules" then you need to make sure that the tongue weight is between 12% and 17% of the total trailer weight - trying to stay closer to the upper end. Many people will say that 10% is adequate, but my experience, and many others, indicates that 10% can really be marginal.

So, weigh the trailer, loaded for travel, then make sure the tongue weight is around 15%, make sure your tires are inflated for the load, and try again.

I too agree, that 10% is marginal and does not control the trailer well at all.

My Toy Hauler did not get truly "under control" and safe to pull, until I shifted the unsprung weight forward until I had an estimated 1100 lbs hitch weight, on a trailer that empty weighs 7700 w/o water in any of the tanks, bedding, crapola, or fuel in the 20 gallon Generator's fuel tank ( which is located just aft of the rear tandem axle ). Plus, I had to add on two heavy AntiSway bars to resist sidewinds. ( bumper pull) ( stock empty hitch weight is 800 lbs, just barely over 10% )

I had to move the spare tire from the garage, to sit on the hitch frame behind the propane tanks.
and had to move all of our internal crap forward to the bathroom which is 4 feet behind the hitch ball.

Loading up the GL1800 proved to be more than even that can handle, so the 1800 does not go with us anymore..... bought a little Piaggio MP3 scooter which is 420 lbs lighter than the 1800, plus the engine weight is 30 inches closer to the axles than the 1800 was. IMO, Warrior set the tandems about 24 inches too far forward, they must have assumed that only beach toys and plastic chairs would be in that garage.

TPSI: on the Toy Hauler, 1st trip out, set the TPSI at 75# and did not like the "drag or feel" of the truck and trailer combo.
Then I read something from the tire manufacturer for TT tires, set the initial TPSI before the trip at 85# so that if you go into a cool area, the tires will stay inflated to the minimum of the Sidewall rating... Sidewall rated 80# on 10 ply.

Could not believe the difference that made in how easy it pulls across the ground now.
the truck also has 10 ply tires, and they are set at 80# rear, 70# front now.

[themainviking]

When you extended that camper body 1 1/2 feet to the rear of the flat deck of the HF trailer, you took all the weight off the tongue, as Aussie81 suggested. This caused your problem tail wagging. Both extending the tongue, and adding tongue weight will fix this, each to some degree. It is all a trial and error till you get it right. I would also be tempted (if it was me) to tow this with a small car rather than a motorcycle until I got it right. If it is still wagging, with a small car, you should still feel it, without putting your life in jeopardy.

[Aussie81Interstate]

Good call "themainviking" - a sensible approach - sometimes you won't feel the wobble with a car at all - or it is less exaggerated.

[GaryRatliff]

I appreciate all the input. When I pulled the trailer, it was empty so all y'all are saying is making a lot of sense. I will start working on the suggestions. Thanks again. Gary

[AZgl1800]

I appreciate all the input. When I pulled the trailer, it was empty so all y'all are saying is making a lot of sense. I will start working on the suggestions. Thanks again. Gary

earlier when I posted, I should have used my bike's tow behind trailer as an example.... same is true for all trailers though.

when I 1st bought it, it would dog wag badly at speeds over 55 mph.

I lengthened the tongue, moved the spare tire from under the rear, to the tongue right under the swivel.
and replaced a bad axle with a new custom made axle.

totally eliminated the wig wag, it has been pulled at speeds of 100 mph ( briefly while passing a big truck ) and I could not even tell it was behind my 1800.

[armsrn]

Morning All
We have pulled our Combi Camp over 50,000 and other than a little 'wobble' starting out travelled like it was on rails
I kept the tongue weight between 20-25 lbs
It has a longer tongue than most trailers wee looked at
Always weighed the hitch every time to ensure we were packed right
Enjoy


every day is a good day....some are just gooder than others

[PastoT]

I feel everyone pretty much hit it on the head, too little tongue weight. I've had as much as 60lbs tongue weight on my 2002 with a loaded trailer, I would not want to go beyond that, 30-40 lbs seems about right. In the wagging always appears between 45-55mph for some reason and I've experienced it with my truck several times, never the bike. I'd also make sure your tires are up to pressure, my utility trailer tires were low one time when hauling it out empty and it became a circus act.

Something additional to consider is your camper design will lighten its tongue weight at speed as the wind striking the front will lever upward against the parked tongue weight. I'd slide my axle back a bit, that would extend the effect tongue length, increase the tongue weight on the hitch and help fight the wind levering action.

[BikerGuy]

I've been told the correct ratio is 40% of the body to the rear of the axle, 60% toward the front of the axle. Heavy weight toward the front, lighter weight toward the back. Should have no problems then, ever!

[GaryRatliff]

Thank you Biker Guy!

[GaryRatliff]

PastoT, thank you for the response. I haven't got to work on the trailer for a few weeks because of time and weather yet but I will be re-distributing the weight. I had plan on only carrying about 50-70 lbs tops inside the trailer but I think I will mount my small generator on the tongue to aid in the forward weight. Thanks again my fellow AF Retiree .

[PastoT]

Never thought of a generator but that's an idea. I use a cooler rack there but if it's empty out would be much help for me. Loading heavier things to the front certainly would help. I actually had to reduce tongue weight at times so it is a learning process depending on the trailer and what is loaded.

[GaryRatliff]

It's only about 30lbs but it might help . I'm curious; is the "Pasto" an abbreviation for "Pastor?"

[BikerGuy]

You're welcome! Maybe if you move the box forward and redrill the holes? Or turn it around?

Thank you Biker Guy!

[PastoT]

It's only about 30lbs but it might help . I'm curious; is the "Pasto" an abbreviation for "Pastor?"

Nope Pasto is my last name, T is my first initial (Tom). When I created my account I thought o was entering my email address and it stuck as my username.
I haven't packed my new small generator yet, but it's a small one and might come missing handy on longer adventures. I use a battery pack, with a compressor, inverter, USB supplies and an LED light, but works great for so many things for 2-3 days. Now o do have a small HF 2-cycle generator.

[GaryRatliff]

Yes, mine is a HF too. It has served my purpose well so far. I had planned on taking it in the trailer with me some of the places but I'm thinking the weight on the tongue will serve a dual purpose.

[PastoT]

I've pulled my tag-a-long for nearly 20k. Only replaced the tires last summer and bearings the summer before. It's been great for me. I also have a time out camper but have been stuck local with work so only a few thousand miles added to it. Hopefully next season I'll get a lot more free time to travel and camp. Good luck with your trailer, you'll work it out. Just take your time with it until everything is behaving.

[WingAdmin]

The formula that I have always used is to measure the weight on the tongue right at the ball, and to load the trailer to ensure this weight is 10% of the overall trailer gross weight. I carry a small luggage scale that I use to lift up the tongue at the ball, to ensure proper loading before I hook up. This has worked perfectly for me for years.

[GaryRatliff]

Thank you Wing Admin.

[FM-USA]

Seen your dilemma on trailer wobble.
Forgive me if you already know these, I don't know what you know.

Out of possible 6 things that creates wobbles, 3 can be your problem, 2(?) covered in the thread.
Since others covered the USUAL'S, I'll mention some other probables. As you read here the adding weight, fixes many but still it's good to know the WHYS they happen.
As we pull with smaller vehicles and smaller lighter than normal trailers, weight becomes a big factor. Think of it like throwing a Nerf ball and a baseball. Baseball's mass makes it fly straight and far. A Nerf wobbles, slows fast and winds tosses it around.

1/3 - Empty trailers like yours is like a balloon. Ride behind Semi's with trailers you get wind vortices, same for your trailer. At certain speeds these vortices will pull at alternating corners creating a rhythm that magnifies. That wobble translates to the tongue. Proper placed extra weight fixes it.
2/3 - Your trailer has a WING shaped roof. Faster you go it lifts. Again weight fixes it.
3/3 - It looks like you have a flat front on that trailer. The wind is pushing (or tilting) it up and being empty unloads the tongue weight to negative. That's part of the reason for tongue weight, to pre-load what will be lost. Weight fixes this.

I'll place this here since it's unrelated to the mechanical's above. Side wind gusts will also throw trailers into wobbles. My experience to slow or stop these is use your arms as shock absorbers. Let the bike do what it's doing, it's a natural phenomena and you're not going to stop it immediately. The more rigid you are the more return force your adding to the handlebars. Hence my use of 'shock absorbers'.

Trailer tires that are not the same dia. will turn different speeds. This includes different tire pressures and out of balance wheels. At a certain speed the slower tire tries to catch-up to the faster one and starts bouncing. I bought a HF with one 12" tire on one side and 8" on the other, I couldn't travel faster than 45-ish mph before WILD bouncing started.
I've been astute at loading my trailers equally but once, I loaded it way too quick and forgot. When there's more weight on one wheel, it acts like the previous paragraph. THAT took me 3 stops to figure out.

I grew up in a trailer pulling family, picked up good pre-experiences.
I've pulled my homemade trailers behind my bikes for many decades now and ran across nearly every problem, some mine but mostly others.

Sorry if this seems long winded or too much info, but I had a feeling you might like to know.
I'm just offering help and other unusual kinds of info.

HOPE THIS HELPS
Floyd
.

[GaryRatliff]

Floyd; excellent input; thank you so much!

[offcenter]

just from looking at your picture, I'd move the axle back a bit, or move the
body forward on the frame.