Zero Tongue Weight Trailer Hitch

[bystander]

http://forums.segwaychat.com/gallery/albums/userpics/13270/Trailer-hitch_s.jpg

Here's a way to add a trailer to your PT without having to worry about the tongue weight of the trail destabilizing the platform angle.

The weight of the trailer is borne at the wheel hubs. The "C" shaped object is the hitch, and the trailer tires are tubeless wheelbarrow tires. All of the tubing and fittings used on the hitch is 1/2" PVC, and nearly all the tubing on the trailer is 1" PVC. The trailer platform is 5/8" plywood. There is a pivot point between the back of the hitch and the front of the trailer. It is important to allow the trailer to track left and right without the pivot moving up or down very much, otherwise the pivot would drag on the ground.

This is more of a "concept" trailer and hitch. For long term durable use, it would probably be better to build one from steel tubing. I don't know the practical weight limit for this PVC one, I suppose it could do 50 lbs easily, maybe 75 lbs. And maybe even more than that, if only going short distances. It handles pretty well forwards. Backwards, of course, you have to avoid jackknifing, but it seems to do just fine, if you know how to steer.

I've only road tested it a short distance so far. Haven't done any hills yet. If things go smoothly, I will be displaying it at the polo practice (http://forums.segwaychat.com/showthread.php?t=13717)this weekend (Oct 22nd, 2006) in Palos Verdes. If you have a gen1, I'll even let you try it out on your machine, if you want. If you have an i2, I can explain how it could be adapted to fit it.

The hitch / trailer is semi-portable. If you don't have a load to haul, it can be rotated up and secured against the CS. A little awkward, but I have to get it up and down a flight of stairs from time to time!

Please don't forget that a trailer is not recommended for use with the PT. It could be a safety issue and may not qualify as a EPMAD in some cases because it now has more than two non-tandem wheels.

[bystander]

"Zero tongue weight" may be a bit of a misnomer, as there is still some tongue weight. But it is applied to the point on the PT where it won't affect platform tilt, as conventional hitches do.

[byped]

But want to use the mount points on the inside of the fender going straight back (on an i2).


I like it!

[bystander]

But want to use the mount points on the inside of the fender going straight back (on an i2).


I like it!See Figures 6 through 11 of patent number 7000933 (http://patimg1.uspto.gov/.piw?docid=US007000933&PageNum=9&IDKey=A3D97473FB29&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526 p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum. htm%2526r=1%2526f=G%2526l=50%2526s1=7000933.PN.%25 26OS=PN/7000933%2526RS=PN/7000933) (might need a .tif file viewer plug in for your browser)

[polo_pro]

I'm looking forward to seeing these new innovations in trailer/hitch design! I'd also like to see some mechanism to dynamically redistribute the weight for when you go up or down steep hills. (And no, I don't have any idea of how to do this...I just make the requirements! 8^) 8^) 8^))

[bystander]

I did a little load testing tonight.

The trailer and hitch together weighs 26 lbs.

For a load, I just happened to have three full soda cases around. These cases hold four 8-packs, or 32 sodas per tray. Each tray weights around 29 lbs. All thee together weigh about 87 lbs.

All I did was to run it around on a very flat surface at low speed (sub black key), just checking things. The plastic flexes a little under that much weight, which is to be expected. The soda cases tend to shift around, so I stabilized them with a couple of bungie cords.

I found it's best for this design to balance the weight slightly behind the trailer's axle. When balanced slightly in front, the plastic flexes more in tight turns. There is a bit of rocking / flexing when starting or stopping abruptly. But none of the extraneous movement is transferred back to the PT. The trailer is the only thing rocking around.

If this negative tongue weight was applied to a typical PT trailer hitch, it would send the PT into a potentially dangerous oscillation or runaway condition because it would tip the platform forwards. With the tongue weight applied at the hubs on this design, it is not a problem.

I may experiment with lowering the center of gravity. As it stands now the platform of the trailer is about 9 1/4" high. By turning the assembly over it would be about 6 1/2" high, but the axle would intrude on the flat area. The wheelbarrow wheels are approx. 14 1/2" in diameter.

I don't think I would load it to 87 lbs. like this on an extended trip right off, but I think it would be good for, say two sets of spare Saphions (around 45 lbs.) and another 10 lbs. of misc. equipment. And that's just this PVC based model. If executed in steel tubing, I would think it would be strong enough to do a couple of hundred pounds with little trouble.

Not to say this PVC model couldn't. I just don't want to destruction test it the first day I built it! Ask me again in a couple of weeks!

But first, I'll be trying a 20-30 lb. load up and down hills, then work up from there.

And Steve, If a load cell, such as one from a digital bathroom scale was placed in the arm between the trailer and the hitch, maybe the amount of stress / flexing in the arm could be used as a control input to run a motorized lead screw to push the main load, or a portion of the trailer's load, forward and back, respective to the trailer's axle, if that part of the load was mounted on a sliding drawer-like mechanism. Once the stress in the trailer's arm is equalized, the adjustment stops. But that will take power.

Even if the mechanized lead screw is impractical, the load cell reading could be used to alert the operator that it's time to pull over and repack the trailer for better balance - before it becomes blatantly obvious.

What would really be clever is a "bump" escarpment. If the load leveling system determines the load needs to go forward, it releases the forward latch and striking bumps in the road ratchets the load forward. When it is far enough up, the forward latch is locked down again. Same deal if the load needs to go backwards. That would use much less power, but be more complicated mechanically.

I'll think about that some more after attempting some hills...

[sholloway]

Nice prototype. I hope to share a prototype with you all in a few more months. It should be fun.

[svalent]

Scott, please give us a hint as to your prototype.

[SEGsby]

Pretty darn cool...

SEGsby

"Zero tongue weight" may be a bit of a misnomer, as there is still some tongue weight. But it is applied to the point on the PT where it won't affect platform tilt, as conventional hitches do.

[sholloway]

It'll be like a trailer but zero radius turns won't be a problem. Not trying to tease too much since we have a couple of months to go.

[SEGsby]

Okay, then it would have to be a rotating ball design for that to happen...

SEGsby

It'll be like a trailer but zero radius turns won't be a problem. Not trying to tease too much since we have a couple of months to go.

[sfrantz]

I can't wait until the production model.
Steve

[sholloway]

there's more to it than that. Otherwise I wouldn't have a couple of months left. There are in fact to universal casters involved but there's also a little more involved as well.

[SEGsby]

Interesting....

SEGsby

there's more to it than that. Otherwise I wouldn't have a couple of months left. There are in fact to universal casters involved but there's also a little more involved as well.

[GadgetmanKen]

Very nice Bystander. I really like the parallel piping look. Sounds similar to an idea I mentioned awhile back in this thread.http://forums.segwaychat.com/showthread.php?p=106060#post106060 here
What happens is when you turn the rider platform rolls/glides to the left or right following the Segway, but still horizontal to the ground and doesn't tilt like the Segway does and wont affect the drivers ability to lean and go or stop. The rollers would have to maybe be a dual set slightly spaced and be on both sides (front and rear of the bar)for lateral stability, don't know, worth a try, tho? You could start with just your basic bicycle fork with wheel attached. Lay it out behind the Seg and see where to go from there. Add Curved square tubing , attach swivels, ball joints to the ends, figure out how to attach it to the wheels or make a new connecting bolt for the wheel. What ever it takes. Use some creativity.

"Wouldn't it be cool, if?...is like Folgers in my cup"

and here

I really hate giving advice for free and would some how like to be compensated for it, but I think that if they put ball joints, swivels, or elbows on the axles of the wheels on the outer edges of both wheels of the Segway, they could have a u or half circle, square tubular bar wrap and hang from both ends, where a roller guide attached to a short horizontal rear facing bar where a platform could be fixed or welded. The platform could be as simple as having one twenty inch or twenty-four inch bicycle wheel centered with foot pegs or patios attached to the bicycle wheels axle, and a low height almost to the wheel, seat. The wheel would need to be fully enclosed as to protect the passenger, as well. Springs could be on the seat to absorb bumps, as well. Even a shortened, lowered handlebar and grip. A flat, circular cover plate would go over and between the Segway base and the round curved u-shaped or half round bar and shaped flat foot base with friction tape from the patios to the curved bar and platform. All entrapment areas are enclosed this way. It seems so simple to me. No tilting of the Segway would be interfere with the rider, or vice versa. The only thing I think could be mandatory now is that the curved u-shape bar would have to be square tubing, possibly steel for the extra strength so that the attached roller and bar attached to the platform doesn't wobble up or down, only the bar, should stay parrallel to the ground. If it were round it would tilt and cant and wobble. Anyone think this would work?

"Wouldn't it be cool, if?...is like Folgers in my cup"

When you make a sturdier version why not make it out of Electrical conduit pipe. Its strong, and bends somewhat easily, and can be welded. Did I mention, not really expensive either.

I have a couple suggestions for ya on additional improvements.
One I think your trailer needs a horizontal elbow joint in the tailshaft prior to the base to compensate for differences in inclines between the Seg and trailer. Another axis, if you will. Such as going up a earth bank on one side or the other, and a curb cut like at a crosswalk and once up you need to turn while the trailor hasn't made it up the incline yet, being the difference in the angle. On your pvc model it would most likely snap. On a metal assembly it could bend or tip the trailer.

Another suggestion would be to follow the parallel tubing design around the trailer. Not only would it look as cool, but it would give you something to latch bungie cords to.

[GadgetmanKen]

Course I was referring to a trailer for another rider to sit-n-ride on tho. You could easily have it convertable for a cargo type trailer and convert it to a passenger trailer with a few steps, right?

[KSagal]

Did I miss it? How exactly do you connect it to the hubs? I see what looks like something that might go over the wheel nuts, but if they spin as they do, and they are sextaginal as I believe they are, how do you do it?

[KSagal]

And, by the way, in many past threads I have posted large payloads on trailers, with a truer "zero tongue weight" system, in that I use a 4 wheel trailer.

With this system, regardless of the payload, all the weight is on the trailer wheels, and the tongue weight is a few ounces.

I also use a tiny ball hitch, very similar to a car hitch. The difference it that the ball is only 5/8th of an inch, and I use a gas strut, similar to that which holds up the rear hatch on an SUV.

That gas strut as a tongue not only pivots on several axies, it spins on itself adding another, and the 4 wheel trailer has it's own steering point on the front axle, so there is yet another pivot point...

Lastly, that strut will compress on a hard brake manuever, so I do not get the instability that a heavy trailer may have on an emergency stop...

[polo_pro]

If this negative tongue weight was applied to a typical PT trailer hitch, it would send the PT into a potentially dangerous oscillation or runaway condition because it would tip the platform forwards. With the tongue weight applied at the hubs on this design, it is not a problem.

I may experiment with lowering the center of gravity. As it stands now the platform of the trailer is about 9 1/4" high. By turning the assembly over it would be about 6 1/2" high, but the axle would intrude on the flat area. The wheelbarrow wheels are approx. 14 1/2" in diameter.

I don't think I would load it to 87 lbs. like this on an extended trip right off, but I think it would be good for, say two sets of spare Saphions (around 45 lbs.) and another 10 lbs. of misc. equipment. And that's just this PVC based model. If executed in steel tubing, I would think it would be strong enough to do a couple of hundred pounds with little trouble.

Not to say this PVC model couldn't. I just don't want to destruction test it the first day I built it! Ask me again in a couple of weeks!

But first, I'll be trying a 20-30 lb. load up and down hills, then work up from there.

And Steve, If a load cell, such as one from a digital bathroom scale was placed in the arm between the trailer and the hitch, maybe the amount of stress / flexing in the arm could be used as a control input to run a motorized lead screw to push the main load, or a portion of the trailer's load, forward and back, respective to the trailer's axle, if that part of the load was mounted on a sliding drawer-like mechanism. Once the stress in the trailer's arm is equalized, the adjustment stops. But that will take power.

Even if the mechanized lead screw is impractical, the load cell reading could be used to alert the operator that it's time to pull over and repack the trailer for better balance - before it becomes blatantly obvious.

What would really be clever is a "bump" escarpment. If the load leveling system determines the load needs to go forward, it releases the forward latch and striking bumps in the road ratchets the load forward. When it is far enough up, the forward latch is locked down again. Same deal if the load needs to go backwards. That would use much less power, but be more complicated mechanically.

I'll think about that some more after attempting some hills...
There were times on my trip where either a steep uphill or lousy loading caused me to have negative tongue weight on the hitch. I wouldn't say that things ever got out of control since the segway's speed limitter never was overwhelmed. I will add that in a situation like this, I could readily tell that I was approaching the edge of the "controlled riding" envelope. So I never did do extensive testing (and instead chose to pull over and reload to quickly rectify the problem).

While our trailer platforms are about the same height (10"), my hitch's connecting point is lower. I think this helps stability. My advice is to lower the tongue by putting a bend in it near the segway hub. The PVS should jut downward at a 45 angle for a few inches and then go back horizontally (and possibly allowing a lower axle on the trailer) to give you both a lower connection point and lower center of gravity.

For some reason I'm getting visions of maybe dividing this tongue into two parts. A part that goes down from each hub (either straight down or at a 45 degree angle) to a cylinder on each side that contains a spring. Then horizontal part of the hitch mounts inside the cylinder and with the spring acts like a shock absorber. This might go along way in containing any oscillation.

We'll talk more at polo where I can gesture and wave my arms wildly as I become more excited about the topic of trailers and hitches. How is this different than when I talk/play about polo? It isn't...I gesture emphatically and wave my arms wildly too. But in the latter case, I often have a mallet in my hand so I can't let my arm get above my hips, eh? 8^) 8^) 8^)

For dynamic load redistribution, a mechanical approach would be preferable. I'd think it'd be controlled by two things. A sharp jolt back so the platform is tilted back 25 degrees like in a hard stop should cause the load to come forward over some bumps (or stops). A foot pedal would be tapped lifting the load over the bumps/stops and a spring would shoot the load backward over all the bumps/stops. The goal is to be able to do both of these actions on the fly.

ps - Please be careful as you do more testing with weights and steeper hills. Remember, you're dealing with PVC. When something fails it's going shatter and you're going to control a large jolt. I'd wear knee pads and elbow pads at the very least.

[bystander]

Did I miss it? How exactly do you connect it to the hubs? I see what looks like something that might go over the wheel nuts, but if they spin as they do, and they are sextaginal as I believe they are, how do you do it?The white spots on the black discs in the pictures are plugs that friction fit into the tapered hub hole. The plugs are made from a stack of circular white plastic disks. The black disks are covered with insdustrial strength Velcro hook. There is a corresponding disk of industrial strength Velco pile placed on the area surounding the hub hole. The plug in the hole supports the weight, and the Velcro is an insurance policy to keep the plug from falling out of the hub hole. The black disks could be fastened to the wheel with screws, but that would require holes drilled in the wheels and it would require tools to connect / disconnect. I may eventually do that if I obtain a set of spare wheels.

The carraige bolt that holds the stack of white plastic disks, plus the large black disk, also holds an in-line skate wheel. The wheel has two good quality bearings in it. The outside part of the wheel is zip tie-wrapped to the PVC frame in four directions.

The white plugs that friction fit into the hub holes are pretty much the same as these I made for the hub mounted spinners:

http://forums.segwaychat.com/showpost.php?p=95516&postcount=13

( pics from old album: )

http://forums.segwaychat.com/gallery/albums/segchat/bystander/bits.jpg Unassembled parts

http://forums.segwaychat.com/gallery/albums/segchat/bystander/partial.jpg Partial assembly

http://forums.segwaychat.com/gallery/albums/segchat/bystander/back_close.jpg Assembly complete

[Timezkware Tim]

Bystander,

You really outdid yourself on this one. Great job.

You could even hitch an additional trailer(s) in tandem (with lighter wheels and alloy tubing to keep the weight down). :)

Tim

[polo_pro]

At the polo match, bystander carried my spare sets of batteries on his new trailer. I noticed the shimmy at higher speeds that he spoke of in earlier posts. We also did some "stress" testing where the trailer was dragged down small curbs and shoved forward. The PVC frame of the hitch flexed to absorb the force, and the segway was not jolted significantly.

bystander is going to adjust the toe-in of the trailer wheels to take care of that shimmy. I'm looking forward to seeing the next version of this hitch. If anyone in the SoCal area has access (and skills) to a metal workshop that would be quite helpful at this point in his project.

I was surprised to find out that the axle was not solid all the way through. It's amazing the the PVC holders for the axle can take all this weight!

ps - What impressed me the most was how the connection at the segway's wheel hub was completely break away...yet in all the "stress" testing and under load it never broke away. I'm looking forward to hearing how it handles heavier loads.

Oh one more thing, I saw bystander accidentally do a 120 degree turn in place with the trailer. Again the PVC flexed but nothing broke or disconnected. The trailer was unloaded at that time, so it just skittered to the side as maximum deflection was reached.

[Stan671]

Awesome prototype trailer, Bystander. Very impressive. I have a few questions:

It seems that the trailer and hitch is rigid from the trailer's axle to the pegs that go into the Segway's wheel hub holes, except for one degree of freedom which is side to side at the pin in the middle for steering. Is that right?

This effectively makes the Segway wheel hub pegs bare any net weight (positive or negative) the trailer has in front of it's axles?

Could you give us some details of the steering pin at the front end of the trailer's tongue? How does that vertical pin pivot point work?

Are there any provisions for a dregree of freedom where the Segway can tilt one way and the trailer another, such as when one wheel goes over a bump?

What is the diameter of the trailer's tires? What is the effective ground clearance under the axle and tongue? Is it more or less than the Segway itself?

[bystander]

Awesome prototype trailer, Bystander. Very impressive. I have a few questions:

It seems that the trailer and hitch is rigid from the trailer's axle to the pegs that go into the Segway's wheel hub holes, except for one degree of freedom which is side to side at the pin in the middle for steering. Is that right?It is "rigid" insofar as plastic PVC can be, that is, there is a bit of flex and shock absorbsion "built-in" to the PVC material. As for counting the degrees of freedom, most trailer hitches have all three degrees of freedom at the ball hitch. The design presented here separates each DOF physically. The first degree of freedom is at the PT's hub, allowing for pitch, as in going up and down inclines. The second degree of freedom is the pivot point at joint between the center of "C" shaped section and the trailer arm. This allows the "yaw" of turning. The "roll" axis (one wheel bumps) is the flex of the PVC material itself. The "C" shaped section gives a little and the trailer arm also gives a little.

This effectively makes the Segway wheel hub pegs bare any net weight (positive or negative) the trailer has in front of it's axles?Yes, that is the idea. The plugs do bear some weight, but the black disks could be bolted to the wheels to bear all the weight. The way this one is done currently allows for quick connect / disconnect.

Could you give us some details of the steering pin at the front end of the trailer's tongue? How does that vertical pin pivot point work?It is two in-line roller skate wheels on a long 1/4" carriage bolt. The outside of the wheels are fastened to the forward section, and the long bolt is fastened to the "arm" going back to the trailer proper. It is important that the structure does not "sag" here as it would drag on the ground. That's why two points of contact (the two skate wheels) are used. If only one bearing was present, it would have been more difficult to avoid sagging.

Are there any provisions for a degree of freedom where the Segway can tilt one way and the trailer another, such as when one wheel goes over a bump?Yes and no. The slight flexing of the PVC provides for this third axis of motion. If the structure were to be built from more rigid materials, a means would have to be added to allow for the "roll" axis. Something like a short section of garage door spring in series with the long "arm" between the pivot point an the axle. Care would have to be taken to not let the structure "sag" where the spring would be placed.

What is the diameter of the trailer's tires? What is the effective ground clearance under the axle and tongue? Is it more or less than the Segway itself?Wheels are 14 1/2" diameter. Overall clearance is generally an inch or two more than a PT with Saphions, or around one inch more than a PT with NiMH. I'll do more field testing before deciding whether to lower the center of gravity or ground clearance any.

The sides of the "C" shaped section add about 1 1/2" to both sides of the PT's clearance requirements. The current trailer is narrower than the PT to avoid having to turn around and look every time a clearance situation occurs. The trailer could be built wider, if desired.

Just how many bananas will it carry?If each banana weighs about half a pound, I figure I could carry quite a few, maybe upwards of a hundred or so. The ones at the bottom may get a bit bruised though. Maybe I can rig up a shelving system to avoid that.

Uh, Stan didn't really ask that last question. But I have a feeling he wanted to ask it!

[polo_pro]

If each banana weighs about half a pound, I figure I could carry quite a few, maybe upwards of a hundred or so. The ones at the bottom may get a bit bruised though. Maybe I can rig up a shelving system to avoid that.

Uh, Stan didn't really ask that last question. But I have a feeling he wanted to ask it!
Bystander and I already talked about this, but I'll toss this out so the topic is in this thread. I'm most interested in carrying batteries, and someone (cmonkey? Stan? I forget who) suggested a shelf suspended below the trailer platform. (Yes Stan, banana's are nice but for my purposes I'd also have to have one of those "Back to the Future" Mr Fusion battery packs to make them useful.) If the shelf is sturdy enough, I think it would be acceptable to give up 4 or 5 inches of clearance to be able to lower the center of gravity below the axel.

When you look at it, the form factor for batteries are almost made for this type of stowage underneath. In a sense, you're almost making a "sub floor" of batteries as you put them side by side on this "under shelf". Changing batteries would become simpler to if you had a quick release system built into the shelf system.

ps - I stacked the batteries at the back of my trailer for my trip from SF to LA, but that was a necessity due to where the axel was relative to the overall trailer. Since the axel was 3/4 the way back along the frame, my batteries had to be stacked at the back to balance the overall trailer load and produce almost zero tongue weight.

[KSagal]

Am I the only one that uses a 4 wheel trailer? I really can get a large payload, use the tried and true ball hitch, have an added gas strut tongue that adds both shock absorbing and an additional level of roll control (One wheel high on the seg, other wheel high on trailer)...?

http://forums.segwaychat.com/gallery/albums/userpics/11814/normal_Seg_SUV.JPG

You might even notice that there is so little tongue weight that my E stand is unaffected.

[Stan671]

Just how many bananas will it carry? Eric, I fell out of my chair when I read that. Funny stuff!

Thanks for all of the info in answer to my questions. Interesting. It's got me to thinking.

[Stan671]

Karl, your rig looks like a modern, high tech version of this:

http://www.ogram.org/sperry/illustrator/runaway/dw.jpeg

[KSagal]

I guess the secret is now out as to where I keep all my black clothes!

[bystander]

Eric, I fell out of my chair when I read that. Funny stuff!

Thanks for all of the info in answer to my questions. Interesting. It's got me to thinking.Stan, I'm glad you enjoyed that. I thought you might find it "appealing".



OK, OK, I better stop now. Before I "slip" up!

[Five-Flags]

Stan, I'm glad you enjoyed that. I thought you might find it "appealing".



OK, OK, I better stop now. Before I "slip" up!

Keep THAT up and you're gonna wind up in the 'punitentiary'.[:O]

You know what happens there.... they 'pun-ish' you!!:rolleyes:

[bystander]

For those interested in the hitch & trailer, I will be displaying an "embellishment" at the SegPolo game on Saturday (Nov 11, 2006).

SoCal Polo S A T U R D A Y Nov 11 at 11AM (http://forums.segwaychat.com/showthread.php?t=13902)

[polo_pro]

For those interested in the hitch & trailer, I will be displaying an "embellishment" at the SegPolo game on Saturday (Nov 11, 2006).

I really liked the seat on the trailer. I wanted to try it out, and for some reason, I wondered how it'd work if the whole trailer was adapted to hook up to an i2. Your feet looked like they'd be in the perfect place to push the leansteer, eh? Maybe one of our i2 polo players would work with you on this!

ps - Also, please give us some data on the failure when you get a chance. It might be less pleasant to talk about this topic, but it'll help others in designing their hitch. "Learning lessons from other's experience" and all that stuff...

[clr22182]

http://forums.segwaychat.com/gallery/albums/userpics/13270/Trailer-hitch_s.jpg

Here's a way to add a trailer to your PT without having to worry about the tongue weight of the trail destabilizing the platform angle.

The weight of the trailer is borne at the wheel hubs. The "C" shaped object is the hitch, and the trailer tires are tubeless wheelbarrow tires. All of the tubing and fittings used on the hitch is 1/2" PVC, and nearly all the tubing on the trailer is 1" PVC. The trailer platform is 5/8" plywood. There is a pivot point between the back of the hitch and the front of the trailer. It is important to allow the trailer to track left and right without the pivot moving up or down very much, otherwise the pivot would drag on the ground.

This is more of a "concept" trailer and hitch. For long term durable use, it would probably be better to build one from steel tubing. I don't know the practical weight limit for this PVC one, I suppose it could do 50 lbs easily, maybe 75 lbs. And maybe even more than that, if only going short distances. It handles pretty well forwards. Backwards, of course, you have to avoid jackknifing, but it seems to do just fine, if you know how to steer.

I've only road tested it a short distance so far. Haven't done any hills yet. If things go smoothly, I will be displaying it at the polo practice (http://forums.segwaychat.com/showthread.php?t=13717)this weekend (Oct 22nd, 2006) in Palos Verdes. If you have a gen1, I'll even let you try it out on your machine, if you want. If you have an i2, I can explain how it could be adapted to fit it.

The hitch / trailer is semi-portable. If you don't have a load to haul, it can be rotated up and secured against the CS. A little awkward, but I have to get it up and down a flight of stairs from time to time!

Please don't forget that a trailer is not recommended for use with the PT. It could be a safety issue and may not qualify as a EPMAD in some cases because it now has more than two non-tandem wheels.
Good morning,
This is an elegant solution to the hitch issue! Congratulations.
What are you using for the hub attachments and where are they obtained?
Thank you,
Charles L. Rogers