Trailer for Vespa Scooter

Intro: Trailer for Vespa Scooter

I enjoy my Vespa (GTS250ie) a lot, I use it both for professional transportation, as well as for personal use.
Downtown, traffic is often congested, parking is always expensive or problematic, and the Vespa is a very effective solution to both.
On holiday trips, I started to realize it is actually one of the best vehicles to discover the world :
* riding on a motorcycle (or bike) allows to experience the landscape and scenery in a more intense way (compared to car, bus, train,..)
* it's speed is slow enough to be able to experience everything, yet fast enough to make some progress through the day
* it's not too expensive

The only disadvantage or problem is that you can't really take a lot of luggage with you : there is a small rack at the back, but it only accomodates a small bag. In front of the driver is a hook, which will hold a small rucksack.
I really needed more storage, either for equipment on profesisonal jobs, or for camping gear during the holidays.
After seeing some examples of single-wheel trailers for bikes and scooters, I decided to make a multipurpose-trailer for my Vespa

Given the complexity of this project, and the safety (and road-legal) requirements, this was going to be a project which would take several months. Your needs and capabilities are likely to be different, and so you probably won't be able to build one yourself simply following this instructable. Still I hope that this story may help and inspire you to build one, some day.

Good luck & Hope to meet you on one of my trips one day !

STEP 1: Requirements - Parts List - Tools - Costs

Requirements

1. Meet legal requirements. They differ from country to country. Google is your friend, as well as the forums of local scooter or motorcycle clubs
2. Safety : strong construction for worry free rides.
3. Durable : must withstand Europe's roads and weather conditions.
4. Payload : >100 liter of volume, and about 40 kg of weight. Legally, the trailer has a maximum weight of 50% of the vehicle towed by (150kg), so that means a total weight of max 75 kg. This led to the option of building it in Aluminum.
5. Comfortable ride : should not limit maneuverability of the Vespa itself. Ideally it should feel as if there was no trailer being towed/
6. No permanent modifications made to the scooter. (in case I want to sell it some day.)

Parts list

1. 12" wheel : I managed to buy one on ebay for 25 euro
2. Faes Cases Defender Aluminium Case. I used a FA-74 type of 990mm*450mm*380mm (162 liter of volume)
3. Aluminium tubes : 40mm*20mm*3mm
   1. 2 * 1050 mm
   2. 2 * 400 mm
   3. 2 * 360 mm
   4. 2 * 150 mm
   5. 2 * 380 mm
   6. 1 * 220 mm
   7. 2 * 255 mm
4. Plywood : 980 mm * 440 mm * 12mm
5. 2 x 4-function light block (rear light, braking light, turn indicator, license plate light)
6. 3" caster.
7. 2nd license plate

Tools
I can't be 100% exhaustive on the list of tools, but here are the most important ones

• Tape-measure, Caliper
• Steel carpenter's square
• Disc grinder
• Drill press
• AC TIG Welder

Costs : total 500 euro = 650 $

• Case : 300 euro
• Aluminium tubes : 70 euro
• Argon (TIG Welding gas consumed) : 20 euro
• Plywood : 5 euro
• Lights : 40 euro
• Caster : 15 euro
• Wheel (second hand - ebay) : 25 euro
• 2nd license plate : 25 euro

STEP 2: Google Sketchup Model

In order to get the dimensions right, and to solve several design challenges, I made a google sketchup 3D model.

I know Instructables.com is a fan of AutoCad, but hey, Sketchup is free and it does the job.

STEP 3: The Frame

The frame consists of Aluminium tubes, welded together.
I decided to go with Aluminium for a number of reasons :

1. the case itself was also aluminium (and also the wheel had an aluminium rim)
2. it would reduce the weight of the trailer itself, yielding more useful payload
3. no extra protection agains corrosion is needed
4. it is a bit easier to handle than steel for cutting, grinding, drilling holes, etc.

But there are some drawbacks as well :

1. It is not as strong as steel (although strenght per weight is )
2. It is more difficult to weld than steel.

I didn't have any experience welding aluminium, but I had the right Welder, and I definitely wanted to learn to weld Aluminium.
So I decided this would be my first real Aluminium welding project. (I did practice on some leftover pieces first)
I also designed the trailer in such a way that if I made big mistakes in the frame, I could still make another one, and reuse all the other parts. The frame itself costs under 100 euro

The biggest challenge here was keeping all angles and lines straight : welding joints tend to shrink when cooling, and that often distorts the thing you're building. During preparation, I was extremely accurate about all parts. Still after welding not everything was perfectly straight or square. I need to improve my skills in this area. But the result (let's call it a prototype) was certainly good enough for real use. (the welds were strong, but not always as estetic...)

Lessons learned : Welding ALU needs practice, especially fillet welds are still hard. Thermal distortions are a real problem, so you need to design with that in mind !

STEP 4: Coupling

The trailer coupling was another DIY challenge. As the trailer has only 1 wheel, it needs to rotate on 2 axes, but not on the third : no rotation along the length axis of your motorcycle.

At first I planned on using a Cardan coupling from a car's steering wheel transmission.
But after giving it some more sleep, I found a much simpler, cheaper and stronger solution : a caster wheel

What is important here is that a caster has nuts and bolts along its 2 axis, which are adjustable. This way by adjusting the nuts, the whole coupling can be adjusted to have absolutely no space or clearance along the third axis.

Furthermore, a caster has a nice base-plate allowing it to be easily connected to the rear rack of the scooter with only a few extra welds

I decided to make things a bit more compact, and drill new holes for the up-down axis. Then some unused metal could be cut away, making the piece a bit smaller, but same strength and functionality.

Lessons learned : when welding on the caster, decompose it to its pieces, then do the welding and reassemble.

STEP 5: Light - License Plate

I wanted to have the electrical cables for the lights inside the frame tubes. This is safer and cleaner.
You can't however have them there during the welding, as the heat of the welding proces will melt the insulation of the cable.
So I used a copper wire (leftover piece of 1.5mm2 solid core electrical wire) and pulled the final cable in once the frame welding was ready.

As for the connector, I thought the standard 7 pins connector was a bit bulky for a scooter, so I took a 5pin XLR connector and assigned lights as follows : 

1. Earth (or ground)
2. Rear light and license place light
3. Brake light
4. Turn indicator Left
5. Turn indicator Right

In Belgium, a trailer needs a separate license plate, and furthermore it needs one that is conform to very detailed legal specifications. So I ordered one from a shop that was certified to make replica license plates :http://www.nummerplaat.be/dyn/oude-nummerplaat
It was not that easy, as motorcycles have/had different kind of license plate, but only rarely need a 2nd copy for a trailer.

Lesson learned : weather-proof XLR connectors exist. I had better used one of those.

STEP 6: Test Drive

How does it drive ?

General driving : very smooth. On good road surfaces, you don't notice the trailer at all : No sounds, no bumps, vibrations at all. On bumpy roads, you will feel to some extent the bumps hit by the trailer. The center of gravity of the trailer is quite low, (in fact it is on a line from coupling to 3rd wheel) so the Scooter is not being pulled in any direction in turns.

Maneuverability :  The trailer is the same width as the scooter, so any gap the scooter manages to get through, the trailer will follow. Furthermore the turn radius isn't constrained by the trailer : it will happily follow the scooter when turning minimum radius curves

Load : until now I have loaded it with a maximum of ~ 30 kg. At this load, the handling was still perfect. However it is designed be loaded with 50kg. After having done more test-driving, I will load it with this maximum load and report back.

I will post a video one of the next days.

STEP 7: Oh, and One More Thing

We are trying hard to get a Techshop in Belgium, so if you are from Belgium, please follow and support us on :

website : strooom.be
twitter : @techshopbe

Who knows, one day you'll build your own Vespa Trailer in TechShop Belgium :-)

Thanks for reading and Enjoy the ride !

Thanks to Guy (VespaShop.be), Marc (Aluminum), Dirk (Mentor), Ivek & friends (Mentors), Testas.be for their advice and support !

Comments

[Francescodeco]

Is it legal?

[Francescodeco]

Is it legal?

[alvaro.caceres.valenzuela]

hello, amazing job !!! congratulations, a doubt, how did you join the box to the frame?
thanks!
greetings from Chile!

[mohamed mamad]

bonjour tre belle construction mais je ne trouve pas les mensuration

[AlistairG5]

I know this is an old post but I have reservations anout the castor.
As far as I can see the only thing supporting the coupling is the centre bolt or pivot on the castor?
The trailer is "hanging" from the castor so the ball bearings are taking no load at all. If the castor was up the other way then the mounting plate would be resting on the bearings as it was designed to do?? Otherwise very nice build although I would prefer some suspension?

[strooom]

You are right, but keep in mind that the biggest load is not the simple vertical force of the weight (max load is 75 kg, so this force is ~ 37.5 Kg or 375N), but rather the horizontal forces when hitting the brakes.. This castor bolt is quite large, I think M12 or so..
Furthermore, I wanted to have the hinge below the carrier rack, so that in case anything goes wrong, it would not hit the driver's back... (eg. when a car crashes into your trailer..)

[ZammilD]

Awesome ideas, you should consider commercial it to Vespa lovers or SIP, Germany.

[ShawnL81]

I'm thinking of doing this what wheel did you get it off front back and make please and the aluminium plate on floor of box is that on that list what size is the flat aluminium plate please have you a link for that caster many thanks

[marzio]

I enjoyed your project very much. In fact I have read it and viewed the photos many times! I have a Vespa LX 150 ie and I thought a trailer like the one you made would be great. I have a 2007 Vespa 150 front wheel. I'm not sure how to mount it on an axle as the Vespa axle is not a single dimension/width. I think I have to install a couple of different sized bearings. You didn't go into much detail about the wheel you used, but it looks similar to the Vespa wheel. Thoughts?

[strooom]

Hi, the wheel I used was bought for 25 euro on eBay... It's a front wheel from a scooter, but not a Vespa.
Mounting it was very easy because it has one large bolt which serves as the axis. I only had to drill two holes in the rear fork

[marzio]

I understand. I have the front wheel of a 2007 Vespa, and as you probably know it uses an offset side axle. The axle itself is tapered. So I guess I have made myself a bit of work! Oh well, winter in Canada is long so I will have plenty of time to work on it! Many thanks.

[_-_I_-_]

Thanks alot for the idea. When my trailer is welded, I will post pictures.

I make all metal profiles (and small mod on your plans) and I found somebody who can do the tig-welding.

Groeten uit Antwerpen 2060 ;-) Hoe zit het met de plannen voor de Techshop ?

[strooom]

Er is helaas geen verdere interesse van Techshop voor Antwerpen, maar er is ondertussen wel Faber Makerspace : http://fabermakerspace.be/

[_-_I_-_]

I will keep you up to date with pictures when the construction is finished.

I am gonna make a mono spring suspension trailer with 125cc dax \ monkey parts for the rear suspension.
I'm going to buy everything new, so the price goes up a bit.
Trailer is for my replica dax 125cc for camping, fly with RC planes and other tests to be able to go outside the city where there is still space.

It is good to thank the people that help you and to inspire others!

Thanks voor de extra info kan handig zijn voor toekomstige projecten.

Ik
heb weinig tijd maar wel bezig en heb genoeg kennis ivm metaal en kunstof
bewerking,goede basis CAD->CNC, goede basis C++,draaibank en frezen,mechanica,elektromechnica, elektronica en telecom\informatica.

[audihenry]

loved the way you repurposed the caster for two axis movement, very ingenious!

[astropapi1]

That's beautiful!

Looks really professional but simple at the same time. Less is more, as they say. :)

[martinkentish]

Brilliant! Sketchup model was really helpful in being able to cut the tubing to the correct size, and also as a base to modify the trailer. One question relating to wiring, where did you connect the wiring to on the Vespa (I suspect to keep it simple you may have taken feeds from the existing indicators etc..)

[JON-A-TRON]

Well done! You've got skills man.

[randall.tinney]

Have you considered making this trailer for order? I would buy one tomorrow if I could!

[zman1204]

IT IS A GEEK MOTORCYCLE TRAILER. A BARNEY DAVIDSON. I LOVE IT!