My PUSH TRAILER

[springsguy]

Hello all.....My name is Dave I live in Colorado Springs and I'm a retired product development engineer.

I wanted to share my Electric Push Trailer with you.
This is the first prototype for plans and kits that I hope to market in the future.

I have just begun road testing and so far....so good.
Flat dry pavement in a light breeze: 24+mph at 8.5 amps roughly. I hit 31 on a slight downhill....fast enough with cargo chasing you!
I'm using a Nine Continents system with 10 amp SLA batteries. I need weight for traction, so SLA work fine.
It handles great with the exception of a loss of traction on steep hills with no cargo on board. Careful throttle application solves that.
This is the first iteration.......changes will come.

I'd enjoy hearing your comments........Thanks

pictures no longer availible

 

[nomad85]

Nice job, looks really clean. How does it compare to your other bike with the hub motor in one of the bike's wheels?

 

[dontsendbubbamail]

I like your solution for the hitch and nice clean design. Tire wear can be an issue for any trailer design. My one wheel trailer wore out a 16" tire in less then 200 miles. Let us know how it goes for you. I found handling marginal when you add enough SLAs to go 25 miles. A two wheel design may handle better with heaver loads. One of these days I will bet back to finishing my two wheel trailer.

Bubba

 

[paultrafalgar]

Well done! Can you explain the hitch, please. I see a "quick release" lever below the square box, but don't understand how it detaches; do you have to remove the saddle post? 'scuse stupidity

 

[etard]

That's awesome! Very clean, just put a saddle and some stirrups and you could have your kids "drive" you around if you have had one too many. :lol: How much does it weigh?

 

[Rassy]

Great looking pusher trailer. I envy you guys with welding ability. Do you get any side to side wobble at higher speeds?

 

[springsguy]

Let me try to answer all your questions....

<nomad85> The other bike is a 36 volt system and isn't as fast (about 18 mph on the flats without pedal)....but it has great range with pedal assist. I haven't gone on a long run with the trailer yet.

<dontsendbubbamail> Tire wear may be an issue. It's right on the verge of spinning going up hill.

<paultrafalgar> The quick release is for the seat post....and, YES, I remove the post to detach the trailer. Originally I used a ball-pin and kept the aluminum jacket with it's bearings on the post. But it turned out to be easier just to pull the post to release the trailer.

<etard> I like your idea!.....Not sure what it weighgs....Hub and wheel maybe 20....four batteries at near 7 each...frame near 12 maybe...NOT SURE. But without cargo it's just enough to hold traction.

<Rassy> NO wobble....but it is top heavy when loaded.....my next frame will be lower slung I think.
AS FAR AS WELDING GOES.............Lowes and Home Depot sell a small MIG welder for under $400.......it works great! I've been welding for many years, but it's not that hard to learn. Pactice, Practice, Practice.

 

[perbear]

Hi Dave,

It is a very nice trailer you have made, impressive!

I was interested in the weight, do you know the weight with and without batteries?
You also wrote that you would like to bring the center of gravity down, but that the wheel almost start spinning when going uphill. What about moving batteries both below the wheel axle and behind the wheel to add extra contact force?

Good luck with you work!

Kind regards,

Per

 

[dogman dan]

Very nice, all it needs for traction is footpegs. Mabye carry batteries pannier style and have more area for cargo on top? But as is, it's better to sit on. Cool the way it could go on any bike in a few minuites, or seconds if the bike has a throttle already.

 

[springsguy]

Well....after several rides of over 10 miles each, both with and without cargo I have come to two conclusions:
1. The center of gravity is too high when loaded for my needs.
2. I don't have enough cargo capacity.

So........I 'm half way through the build of a new frame. It will take care of both of the issues.
However, it also does something I really didn't want to do, and that's to push the trailer wheel back.
Originally I decided that I wanted the trailer to follow close behind the bike and that's what dictated the high cargo platform.
Side folding baskets were going to be added but after a lot of thought, I think I'll move on to a new frame and suffer the extra length.
My intention is to produce kits for this thing when the development is done. The new design is way more user friendly than the old.
For one thing, the old design is a real pain when you disconnect from the bike.....you must lean it against a wall or something stable and you must lower the tow hitch way down to do that.
The new design will have the cargo between the trailer wheel and the bike rear wheel with a 16" wide bed only 7" from the ground. That means that you can 'park' it with the wheel and the two front corners of the cargo bed making contact with the ground for a three point stable resting.
Also the hitch yoke folds back for storage with the simple pull of a pin...........I like it!

Ya Ya....I know there is a design out there that looks like what I have just described. But I think mine is (will be) more elegant and easier to build.

The kits will come with water-jet and machine cut specialty parts and a very complete instruction/fabrication guide....lots of CAD drawings and photos.
The builder will supply the metal tubing and the welding....but it's pretty straight forward......a couple weekends at most.

So far I have $15 in steel tubing and about $50 in outside welding.

BTW......Now that I have told you what I don't like about the old design......is anyone interested in buying the old frame cheap....contact me.
It really does work well....it's just not what I need it to be for my use and for a kit design.
I'll sell it with a wheel and tire if you just want an unpowered trailer........put a box on top for your dog!!

 

[springsguy]

Here's a CAD image of the new frame.
The battery boxes hang on both sides of the wheel under the deck.
Three point parking with folding yoke for storage.
Bungee hooks will be added to the sides of the frame.
Deck surfaced in Sheet PVC.

 

[dnmun]

why not push through the rear dropouts with a BOB trailer type connection? steep driveway!

 

[dontsendbubbamail]

why not push through the rear dropouts with a BOB trailer type connection? steep driveway!

I can't speak to the Bob trailer, but my Bike Nashbar trailer pushes through the rear dropouts. The rear quick release is replaced by what you see in the picture. That rod just doesn't seem strong enough to carry a large load. I was overloading the trailer with my experiments. If I continue to use the trailer, I plan to go to a solid axle with hitch nuts drilled and tapped to work as axle nuts.

Now some may say that a seat post hitch gives the load a lot of leverage to affect bike handling. I personally don't think that is a problem based on my experience pulling my kid on a trailer bike.

Bubba

 

[TylerDurden]

My suggestions:
Perhaps extend the rails reward (past the axle), to use that capacity to hold batteries in panniers/boxes... articulate the tongue higher up, to allow folding even when cargo is loaded.

 

[springsguy]

Yes......actually I have a 60 yard long, super steep driveway.....but that's not the reason I went the way I did with the hitch design.
First off ....IT'S EASY! No fancy hitch system required. Just a pivit on the seatpost.
I have found the seatpost mount to work great, actually. The leverage for the load is better distributed against the bike.....twist is held to a minimum, and I can quickly change to a different bike without modicication.
I did draw up a version using the Bob-Trailer type mount, but I just like the ease of the seatpost mount, and so far.....no adverse handling issues.

The batteries are mounted on each side of the drive wheel below the frame. The trailer hieght was determined by road clearance needs while turning tight and by 'speed bump' clearance requirements.
I'll post some pictures and maybe a short movie soon.

Thanks for all the suggestions.

 

[JennyB]

I've been looking for something similar, specifically for load-lugging to and from town (six hilly miles away) and carrying my elderly mother. After six months with an xtracycle, I've come to the conclusion that I need something that leans like a bike then I ride it, but naturally stays upright when I stop for easy loading and unloading.

I'm thinking of something like your Mark Two trailer, but in a detachable sidecar hitch ala Chariot Carriers SideCarrier

Just wondering has anyone tried the like?

 

[nomad85]

You could get the fancy kickstand for the xtracycle, mine does fine with the standard kickstand, but there are time I wish I had a flat surface, I don't wish 140$ worth though,

http://store.xtracycle.com/product.aspx?pf_id=KS-KB

 

[springsguy]

I just took a test run....I like it....a lot!

A little paint and the deck and it's done!

 

[Toshi]

very slick execution!

 

[BrandonB]

Extremely professional and a great idea. I like it!

 

[dontsendbubbamail]

A double kickstand on the front of the trailer would be useful. When I get time I am going to circle back to my single wheel trailer and add one. I think that this will be better then a single kickstand on the bike.

Bubba

 

[snowcrow]

Very nice work springsguy 8)

I like the way you've hidden the batteries and controller under the deck!

I'd be interested in knowing how much the trailer weighs after you get the deck on it. It looks heavy!

Hope you have regen braking to help you stop when you load that beast up with stuff

Blessings, Snow Crow

 

[AussieJester]

Extremely professional and a great idea. I like it!

+1 brilliant fab work mate, have to be the nicest push trailer i have seen without doubt and its not even
painted/finished LoL

KiM

 

[springsguy]

Well, I just got back from a short run with the finished unit....about 5 miles.
Sweet.....it handles ten times better than the first version.
But, now I move onto an even simplier version built with off-the-shelf items form Home Depot or a good hardware store.....far less welding, and no fancy metal cutting.
As I say, my intention is to publish a plan set.

This one is heavier than I'd like....BUT, empty, traction is an issue if it were much lighter. It weighs as much as the bike frame I think.

 

[nomad85]

I really like it, does the seat post mount swivel?