HELP HELP HELP !

[bobhenry]

Bike hitch was installed St patties day test ride yesterday with eggbert.
straight on good road he tows great. Hit a pot hole and it's like a giant hand reached out and tries to drag the rear of the bike in the direction of the offending tire. While this occures the dreaded handlebar shimmy starts, it was controlable but somewhat unnerving and this was at 15 to 20 mph.
The first low speed turn I made I had myself convinced the rear tire on the bike was flat. It shook right and left like a dog shaking off bath water.
If you check my album you will see eggbert has a standard 40 x 48 hf frame but the tear if shoved forward. The tongue is short enough that the pannier box on the bike could make contact with the front of the tear in a tight turn. I know a longer tongue is a must. It tows nose down 3" +/- so the replacement must curve down to raise the tow height. There was a 75# fully equipted kamp kitchen loaded in the very front making tongue weight 35 - 40 lbs. On a second test run I moved it to the rear as far as I could but it was still in front of the axle and while all problems still existed the were very slightly less pronounced. My biggest question is will lengthing the tongue add more leverage and aggrivate the pot hole problem or deminish it. It is not road worthy with the present setup with the bike but it tows fine on the truck and van.

[Micro469]

I don't know what a pannier box is , but I was wondering about your Trailr hitch....The one on your trailer... not your bike.... My brother in law used to tow a small homemade tent trailer with his Goldwing, and it had a hitch that rotated from side to side.If you have a solid hitch on your trailer , could this be the problem??

[Miriam C.]

The off road guys use something that might help. Leon made his own so he will probably chime in too.
http://tnttt.com/viewtopic.php?t=13747

[bobhenry]

I don't know what a pannier box is , but I was wondering about your Trailr hitch....The one on your trailer... not your bike.... My brother in law used to tow a small homemade tent trailer with his Goldwing, and it had a hitch that rotated from side to side.If you have a solid hitch on your trailer , could this be the problem??

click on electrical secrets scroll to 1200 wat gen for $199 and look for dhazards goldwing this is identical to mine. The luggage box directly behind the teddy bear is a pannier box.
I don't feel the articulation of the ball is a factor in the handling. While in my younger days I was known to sand off engine side covers in corners this is a touring bike and I am no longer into extreme riding. I am however going to see what the max lean is. I do know that the straight ahead pot hole problem is more geometry than articulation. I keep you posted in my experiments .

[SteveH]

BobHenry,

Just looking at the picture of "eggbert", it looks to me the trailer tongue is too short. Wouldn't a longer tongue reduce the pot hole effect you are experiencing?

[elmo]

BobHenry,

Just looking at the picture of "eggbert", it looks to me the trailer tongue is too short. Wouldn't a longer tongue reduce the pot hole effect you are experiencing?

+1...Here is a picture of what I pull around...



and it pulls like a dream. I will run it at 75mph without know its there. Even when it does hit a severe pothole it is nothing violent.

I had a home made Jack Daniels Barrel trailer awhile back. (1993ish) It pulled great and had a longer tongue. Just way to heavy for a motorcycle...if you had to stop quick you had to pry the seat out of your...well you know what I mean. I ended up giving it to a guy with a VW trike.

Torsion axles maybe help...or pull a leaf. And I would double check the squareness.

[toypusher]

You might want to experiment with tire pressure also.

[bobhenry]

BobHenry,

Just looking at the picture of "eggbert", it looks to me the trailer tongue is too short. Wouldn't a longer tongue reduce the pot hole effect you are experiencing?

It's the stock tongue. I was asking if a longer tongue would help or create even more leverage against me when a dip or hole was encountered.

[elmo]

BobHenry,

Just looking at the picture of "eggbert", it looks to me the trailer tongue is too short. Wouldn't a longer tongue reduce the pot hole effect you are experiencing?

It's the stock tongue. I was asking if a longer tongue would help or create even more leverage against me when a dip or hole was encountered.

Motorcycle trailers that I have all encountered had a longer toungue.

[elmo]

Here are a couple of quick measements for you of my trailer in the picture.

44" from tongue to where the bottom or the trailer meet.
32" to the nose of the trailer...the nose is just for cutting the wind and not much use for storage. I can usually get my sleeping pad there and nothing else.
39" width outside tire to outside tire.

Don't know if that will help you much. I would have to go past the jack knife point to hit the saddle bags.

If you look that is a bike mount on the spare tire in the front for the times you need another 2 wheel fix on your motorcycle trips.

[SteveH]

BobHenry,

Just looking at the picture of "eggbert", it looks to me the trailer tongue is too short. Wouldn't a longer tongue reduce the pot hole effect you are experiencing?

It's the stock tongue. I was asking if a longer tongue would help or create even more leverage against me when a dip or hole was encountered.

For what it's worth, IMHO it's really not about how long the tongue is, but the angle from the hitch on the tongue to the wheel, and since the location of the wheels is dependant on the width of the trailer, the only thing you can change to change the angle is the length of the tongue.

Take a look at all of the trailers commercially built to pull behind a scooter and you will see they are all very narrow. This is mostly to hide the trailer in the 'shadow" of the scooter, but it also makes the angle very sharp from the hitch to the wheel, which reduces the side to side jerk you are experiencing when you hit bumps with one wheel.

[angib]

I doubt lengthening the tongue will make the problem go away, though it might make it less of a problem.

I would carry out a complete check of the bike and trailer, trying to find a weakness. All the stuff that 'just can't' be wrong!

Things that pop into my head are:
- is the bike hitch is secure (can it wobble sideways relative to the bike)?
- bike tyre pressures (front as well as back);
- hitch ball size (matches trailer coupler?).

The handlebar shimmy makes me think the problem lies in the bike and the trailer is just making it show up - hence wondering about the bike hitch. What you describe sounds like the result of overloaded and insecurely-mounted bike panniers and a loose hitch mount might duplicate that.

Andrew

[bobhenry]

I never closed out this thread with my findings. Warped front rotor sticking caliper and a bad hydraulic hose was the handlebar shimmy.
The side to side jerk remains when hitting a pot hole but it is greatly deminished by the addition of a 9' section of 2 1/2 x 2 1/2 x 1/8 square tube as an extended tongue. I ran the tube clear to the rear of the 40 x48 hf trailer so I now have almost 2' more tongue length than the stock tongue which has been removed. The stock tongue ended at the center of the trailed bed. The tear is 5'6" so from the ball to the front of the tear is 3'6" now instead of slightly less than 2' as originally built.

[madjack]

bobhenry, my bidnez partner rides a softtail Harley NightTrain...he built a camper for it and had some of the same problems, which were cured when he both lowered and lengthened the tongue....if you click my WWW button, you can see some pics in the "bedroll" and "hidden hitch" albums...these were before the mods were made...
madjack

[bobhenry]

MJ forgot to mention I swaped the 8" tires off of the 4x8 frame for Chubby to the bike tear and put the 12 s on Chubby so essentially I lowered the bike trailer also