Pulling a UniGo

[DaveDragon]

Just picked up the UniGo Sunday and drug home to Florida.

I have been pulling a trailer for a year or so that I built and it handles very predictably and stable as a rock loaded or unloaded at any speed.

While zooming through Louisiana on I-12 in traffic the UniGo started dancing around and the tail wagged the dog way too much.

In a slight right hand bend at 70mph I crossed over one of the bazillion asphalt defects in the road that made the UniGo bounce.

It was tracking directly behind the rear tire, bounced and landed just to the right of the rear then bounced again landing just to the left of the rear tire and with each bounce the trailer felt like it was stepping out farther away from the center line.

By this time the LT's rear end was feeling yanked side to side and it was obvious to me it was not going to get any better without something changing.

Cars on the left and right of me and an 18 wheeler about 60 yards ahead of me along with a car about two car lengths behind me defined my space.

I initially let off on the throttle just a tad and the motion got much worse so I kicked it down a gear and nailed the throttle and the UniGo recovered from the PIO ( Pavement induced oscillation ) and started tracking perfectly again.

This all took place in about 6 seconds and scared the crapola out of me.

Anybody here been through this?

I'm thinking about some ways to dampen the motion to prevent this in the future. Maybe an offset steering dampener from the hitch plate to the drawbar.

[jeffklt]

Dave,

I certainly have never experienced anything like what you described but having pulled my 10k+, I find the more weight I have in it the better it tracks. I have never pulled it empty, but when it only had a riding suit, gloves, boots and liner it definitely had a vertical bounce to it. I'd suggest putting some ballast in it and see if that makes any difference and have somebody ride behind you for a few miles to make sure it is tracking properly. It seems that if it were out of alignment that might create instability.

HTH

[RVB1019]

I've never pulled a Uni-go or a trailer with my LT. Could it have been because the trailer was empty? I know the utility trailer I use for chores handles very differently when empty.

[rspyder]

I have a UniGo and experienced exactly what you experienced when the trailer was heavily loaded and unbalanced. I have never had a problem with a near empty or lightly loaded trailer (although Stick cautioned me about pulling an empty trailer because they have been known to get airborne). I pulled my UniGo to CCR5 from Sacramento. I started to feel the trailer sway after I purchased water and just stuck it on top of everything else in the trailer more toward the side than the middle. The trailer bouncing was obvious at 55 mph. I stopped and repositioned the water to the bottom middle front of the trailer and the trailer oscillation went away.

I found my biggest problem was when I was going about 75 and passing trucks on the interstate with a cross wind. The UniGo will really wag if not properly balanced. I found that if I accelerate past the truck and then still accelerate until I am back into the slow lane, at that point I can finally ease off on the throttle and there is no sway problem.

Want to easily test if your trailer is balanced? go about 50mph and stand up on your pegs. If the trailer starts oscillating, it is not properly balanced.

Just as a statistic, I weighed my entire trailer with the load on a bathroom scale when I returned from CCR. Total loaded weight was 175 lbs. The trailer is supposed to weight 70 pounds and carry 110 pounds, so I was near max weight. My trailer u-joint has also be changed to the NAPA roller bearing as the original u-joint was frozen to two caps (one on each axis).

I agree that the first time you experience the oscillation it will scare the crap out of you, but I still like the UniGo and will keep it loaded with lighter stuff in the future. Carrying liquids in the UniGo is probably not a good idea.

I also thought about the damper, and it would probably help.

[jorawro]

Exercised that "special" muscle?? This is part of the reason I built my own with two wheels. At least I could throw in a little extra toe-in to overcome the potential "tail wagging the dog" problem.
Let us know your results. I can't imagine all your future video's being shot at a sedate 50 mph. LOL !!

[DaveDragon]

Exercised that "special" muscle?? This is part of the reason I built my own with two wheels. At least I could throw in a little extra toe-in to overcome the potential "tail wagging the dog" problem.
Let us know your results. I can't imagine all your future video's being shot at a sedate 50 mph. LOL !!

I built a two wheel trailer as well and it puls like a dream.
I wanted a UniGo for those long solo trips to ease the packing and the shorter two up trips Sue & I do.

[DaveDragon]

I found my biggest problem was when I was going about 75 and passing trucks on the interstate with a cross wind. The UniGo will really wag if not properly balanced. I found that if I accelerate past the truck and then still accelerate until I am back into the slow lane, at that point I can finally ease off on the throttle and there is no sway problem.

I figured out the passing the 18 wheelers trick after a few tries.

[bushj1]

Hey Dave,
How old is your trailer? Some earlier ones were not jigged very well and the rear frame that holds the axle was not square with the frame the body or pod bolted to. The only way to truly see this is to take the pod off and use a level to check. Most of them I saw were visible to the naked eye if you really looked. This gave the trailer a slight cant to one side or the other, usually to the left looking from the rear. The trailer had a tendency to hop when empty and when loaded to sway a bit when cornering briskly or following in a truck trough of wind as you pass. A trailer design like this is understandably sensitive to square and alignment with only a single contact patch.

Additionally, when empty they have tendency to want to hop a little. Loading with a 60 / 40 front bias and heavy object low and forward in the pod is essential. They are sensitive to this and will sway if off too much.

[gdroege]

I agree with much that has already been said. Hitch alignment is important. Cross winds or passing trucks can be interesting. Loading is important, but I've never had a problem, other than pulling one empty can result it the tire losing traction on slick spots. The only other thing you need to watch for is tire pressure, make sure it's inflated properly. We love our Unigo but will have to get a new tire next year as this one started losing pressure so assume it needs replacement or a tube.

[rspyder]

I don't know how much UniGo age has to do with what was delivered. My UniGo was delivered in August 2004. Perhaps UniGo was consuming older material toward the end of the New Zealand build, but the latter built u-joints were supposed to have nylon bearings in the caps, but mine was still metal on metal and was assembled with no lubricant. I wound up replacing with the NAPA replacement roller bearings.

I have never checked the correctness of the rear wheel alignment, but I will now.

[DaveDragon]

I don't know how much UniGo age has to do with what was delivered. My UniGo was delivered in August 2004. Perhaps UniGo was consuming older material toward the end of the New Zealand build, but the latter built u-joints were supposed to have nylon bearings in the caps, but mine was still metal on metal and was assembled with no lubricant. I wound up replacing with the NAPA replacement roller bearings.

I have never checked the correctness of the rear wheel alignment, but I will now.

Do you have the NAPA part number for the U-Joint?

I guess I have some weekend work now :)

[rspyder]

Here is a link (http://www.bmwlt.net/ubbthreads/showthreaded.php?Cat=&Board=K1200LT&Number=272792&Search=true&Forum=All_Forums&Words=napa%20u-joint&Match=And&Searchpage=0&Limit=25&Old=allposts&Main=272792)to the old board. The part number is NAPA 210-0153. Mine was not the easiest to take out. Required use of a large C clamp to press out the joint.

[DaveDragon]

Here is a link (http://www.bmwlt.net/ubbthreads/showthreaded.php?Cat=&Board=K1200LT&Number=272792&Search=true&Forum=All_Forums&Words=napa%20u-joint&Match=And&Searchpage=0&Limit=25&Old=allposts&Main=272792)to the old board. The part number is NAPA 210-0153. Mine was not the easiest to take out. Required use of a large C clamp to press out the joint.

Thanks Man, I have the Big C.
Not even sure if it needs a new one but it's a Dave thing :)
I suspect I'll have it in pieces this weekend to go over all the workings.

[beemerlt]

Also, there's another source/part number in the HoW (http://www.bmwlt.com/forums/faq.php?faq=how_index_1#faq_how_faq_acctrailer) (r.6).

[dcg1963]

Set-up and handling related tips for Uni-Go:

I've noted a number of people relate stories of their Uni-Go trailer "wagging the dog". TIP: If you have an early model Uni-Go which does not have a tensioner bolt fitted to it, definitely drill and tap an 8mm (approximately) hole and fit a round head bolt and matching locknut. For anyone using the finger adjustable tensioning screw with the spring tensioner, the best advice I can give you is to throw it in the bin, and replace it with the right sized (allen keyed) bolt and a locknut. There is NO WAY you can achieve the solidly locked up connection you need, doing it using the screw originally provided. The spring...is useless. Numerous riders have related to me that the bolt works loose over the course of a ride. Tighten up the locking bolt tensioner firmly, to ensure absolutely no movement in the coupling, then lock it in place with the locknut. Doing that will solve the "wagging the dog" problem some of you have outlined.

Beyond that, I've heard people speak of "pavement induced oscillation". My experience leads me to believe that the most likely cause of this, is a defect that has recently come to light, with a batch of Uni-Go trailers out of the New Zealand factory. The defect that I speak of is the misalignment of the swingarm mount siderails. It appears that the jig in the NZ factory was knocked out of alignment, and a bad batch resulted. The number of such trailers, I'm sure, is quite limited. Here in Australia I have assisted a number of riders who could not get their trailers to handle right. The few trailers in question had been acquired 2nd hand, and on following it up, prior owners had never been completely happy with theirs either. After eliminating all other possibilities, we ran a stringline through under the Uni-Go's wheel axis, to its drawbar centre. That is when it became quite obvious that the Uni-Go's wheel was not tracking true. We then had the swingarm rails removed from the lower chassis rails, and rewelded on square. The handling issues immediately disappeared, and it performed as it was designed to do. For those of you who have suffered "pavement induced oscillation", I strongly suggest that you perform the same inspection, to ensure your Uni-Go's rear wheel is tracking true. If misaligned, with the swingarm rails out of square, no doubt the normal movement of the suspension will further contribute to the oscillation phenomenon. Those of you who have experienced this, may also be experiencing excessive bearing wear / bearing failure issues.

Please do not hesitate to contact me, if you have any such issues, and I will do what I can to assist you in solving them.

Yours Sincerely,
David G
(Australia)

[dcg1963]

For those of you wondering who I am, my name is David Gordon. I am a Brisbane-based Australian who worked closely with the inventor and former owner of Uni-Go NZ Ltd, Mr Chris Van Eekelen. I've interacted with Mr Mark Huffman of Schoolhouse Motorcycle Accessories a little, since he bought out Uni-Go NZ Ltd in June of 2005.

For those of you who are curious:

http://www.picturetrail.com/scorpion63

Although I'm not in a position to supply you with Uni-Go trailers or products, I'm as well-equipped as anyone to answer most technical questions you may have. Feel free to contact me, should you require such assistance.

- David Gordon

(Brisbane, Australia)

[orchardrt]

Hi Dave
It's good to have a guy so knowledgeable about the Unigo hanging around.
How did you jig up a string line to check alignment.? You really have to take the pod off to do that correct? Or, leave it on ?
Thanx
Ben

[dcg1963]

Hi Dave
It's good to have a guy so knowledgeable about the Unigo hanging around.
How did you jig up a string line to check alignment.? You really have to take the pod off to do that correct? Or, leave it on ?
Thanx
Ben


Hi Ben,

I'd suggest that (with the trailer attached to the bike and visually in line with it) you undo the 6 bolts holding the pod onto the chassis, 2 on the vertical section and 4 in the floor recess (under the carpet), and slide the trailer pod off the chassis. Having it off will give you the clearest view of the wheel, chassis and the drawbar.

Fix a stringline on the ground from back about a foot behind the wheel. Pick up the trailer and move it to one side, while attached to the bike. Attach a fixing point directly under the center of the Uni-Go coupling. Fix the string in place between the two points, then pick up the trailer, and sit the center of the wheel on the stringline. From above, you should note whether the axis of the wheel runs along the line....or if it is out of square.

With the body shell off the chassis, you will also have the opportunity to see if your chassis is correctly aligned with the bike's vertical axis, or tilted to one side. Make any adjustment necessary via the drawbar bolts, to ensure the trailer's vertical axis and the bike's, are aligned.

Regards,
David

[gefmar]

Hi David

Have owned a Uni-go for a few years which I pull behind our R1100RS, bought it second hand and it had the wheel alignment problem which I fixed by cutting and shutting the chassis rail

My question, is the replacement "tow hitch uni joint" the Americans talk about available here in Australia i.e. off the shelf at Supercheap, Repco etc.

Cheers Geoff

For those of you wondering who I am, my name is David Gordon. I am a Brisbane-based Australian who worked closely with the inventor and former

owner of Uni-Go NZ Ltd, Mr Chris Van Eekelen. I've interacted with Mr Mark Huffman of Schoolhouse Motorcycle Accessories a little, since he bought out Uni-Go NZ Ltd in June of 2005.

For those of you who are curious:

http://www.picturetrail.com/scorpion63

Although I'm not in a position to supply you with Uni-Go trailers or products, I'm as well-equipped as anyone to answer most technical questions you may have. Feel free to contact me, should you require such assistance.

- David Gordon

(Brisbane, Australia)