Mini Chopper.

I've Always admired recumbents for years since I first saw the design in the early 90's.

The cost of them stopped me getting one at the time. Then Kids came along, Cars, Computers, Work, Welding, and so on.

Until now I find myself in a position to make one with my own hands. I have all the gear to make one, and some idea's of what I want to do, and possibly the ability. Ya never know

But.... First... While tinkering with my new tig welder I decided to make a proper trolly for my welding kit. Somewhat safer then dragging the gas bottle around. Heck, and easier. It went from simple to something that would carry 3 welders and 2 gas bottles with stability and style. Well style-ish.

I must admit it's slightly over engineered.. 2 adults can sit on it. I knew all that 25mm square 3mm Wall pipe I scavenged would come in useful one day. I was just a pitty I only had black paint. I had visions of bright yellow for some reason.



Anyway to the current build..

Take 1 Kids Frame (16 Inch Wheel I think) and strip down.



I spent a while (30 Mins) thinking about what to do... The next night after spending some time looking at various websites I pickup the angle grinder and turn the MIG Welder on.



I removed the rear triangle and put on some extensions on the bottom tube. This gives around a 3inch increase on the bottom tube. This increases the lean on the forks (I don't know the differance between Trail, Rake, and so on) Meaning the forks will need a 6 inch lengthening to keep the bottom of the rear triagle level with the ground

I also cut the forks and leant them forward a little to fix the apparent wobble effect some learned builders speak of.. OK I went looking for the maths behind it, but I have the excuse; I want to ridable by my 8 year old tomboy. She's the one that saw a chopper in a shop (piece of trash) and drooled for weeks.

Measuring the changes made give a increase of 10 inches to the current fork length.

My next job is that I need to increase the distance between the pedals and the seat.

I'm thinking I can cut the rear section to the same angle as the top of the rear triangle (must learn the right names) then extend back and a little up (just enough) to clear the rear wheel.

Any thoughts or suggestions will be welcome. I'm trying to make a reasonable but obvious chopper for my bike mad daughter. So while I want chopperness I also want it rideable.

I'm also looking at my wife bike that she's not ridden for 4 years.......... Recumbent parts.

This is more fun then the kit car chassis I built. No measuring, just using my eye.. If it doesnt' ride straight I'll blame my daughter. The car chassis got stupid at then end. 1mm accuracy wasn't good enough.

Lanzecki said:

1mm accuracy wasn't good enough.

Click to expand...

Really? That rules out me making one then.

Your chopper project give me an idea for my 2 year old and some little BMX bikes we've got around the place. I'll keep an eye on your project for more inspiration...

Angusdog said:

Really? That rules out me making one then.

Click to expand...

It was me being anal.

http://www.rawsteelchoppers.co.uk/Picture 011.jpg

kids chopper

Thanks for the link Stuvy, Looks like a change to the headstock angle?

This frame I'm using is the one she had when she was 5. Now she's 8, and much taller, so the frame is just too small. I need to move the seat up and back to take that into account. I'm currently thinking that I'll cut the seat tube out and angle it back so as to shove the seat up and back.

Kinda think it would almost be easier to make a whole new frame to fit the headstock and hangers. But we shall battle on. Small steps and all that.

The current state of play :



A trial fit of the and a check for size. I was surprised that she looked to fit it ok.. Even though i haven't changed the angle of the bars or the seat.



I have 2 options with the seating :

1, cut and reposition the seat pole back and down.
2, cut the seat post out and continue the top frame rail back to the rear wheel. Then bend a seat post to come from the chainstay to the newly extended top rail.

I'm favouring Option 2 for the better look, but I have no way of bending a pipe.... Any ideas?

The boss was wheeling it around while I went to find the Camera. Reports are "It's really cool dad! It's easy to ride as well."

Just wait till I finished. It'll be a pig, but look cool!

OK, I've bitten the bullet and lengthened the rear triangle. The chain stay is another 11 inches long now.

I've also cut out the top rail and replaced it.



This will allow me to lower the seat to just in front of the rear wheel. The bosses eyes lit up once I sat her on it.

And I've placed a strengthening bar just in front of the rear wheel. But this is not shown.

Damn stylish.
It wil be your fault when she marries an 18stone biker.
On the technical side it mught be worth looking at bracing the fork, as bikes longer the load on the forks increases (doesn't it burf).

Keep us posted.

Chunko'.

Thanks chunko.

There are much worse types for her to get involved with later in life. Boy racers for instance.

You mean a horizontal brace joining the forks just above the wheel? Or something springer like?

The tubes I'm using are 2mm wall. Quite solid, but there is certainly no harm in belts and braces.

Bracing forks?
When I can get hold of them I like to use dual crown forks as this spreads the load and looks well 'ard.

First things first, a beefcake photo for your daughter. My Son Cedric also know as Mr Sellotape.

And what great accessorising, when the brolly blew off the back it was hilarious. The basket was great for carrying Dad's rehydration solution.

Forks?

I found on the tallbike and some chops the forks get a bit too bouncy so I shoved a stem up the bottom of the steerer tube and braced onto that.

Keep up the good work. When do we see Mrs Lanzecki on a proper bike.
And of course Mr Lanzecki on his tallbike. Then we need the whole family racing downhill in The Klunker Classic.

STOP PRESS Emergency Edit.
The forks are not butt welded are they? if they are make a new set now.
Butted forks snap with no warning, if the joints are sleeved they bend gracefully. A notorious face remover in the chopper scene. Your daughter is to beautiful to have no face.


Chunko'.

Nicely put Chunko! The forks had me worried too. Facial battle scars like great on well hard boys but not on pretty girls!

It's something I'm aware of. I had a set of forks on a professionally made bike fail on me one. Face 0 - Road 1. Not fun.

The tubes are internally strengthened by tube on the upper cuts, and solid bar on the lower cuts. But I like what you've done in your pictures Chunko. A picture tells a thousand words and all that, it makes a lot of sense. It spreads the load.

I'm no Mathematica but I can see the increased load on the head set. I'm currently considering new one peice fork tubes from the hubs to the top of the head set. Then solid place joining the tubes to the top and bottom of the headset. This seems the norm on many bikes I've looked at, and looks much better on your pictures.

Or, a fake springer like affair.

I'm getting low on the tube I'm using for the frame though. Nice stuff, but I couldn't get enough

I'm going with the one piece tubes as per Chunko's message above, safety being paramount when an 8 year old is involved. But I'm not sure on the join between the forks and the head tube.

Obviously I'll need to make the top connection removable and I can work that out, but the only way I can think of connecting the forks to the top tube is by using flat plate with holes drilled in for the forks. I don't have a drill that will cut the 1.5" I'll need.

Any thoughts on other methods?

PS. I stuck around 170lbs across one of the forks I welded up. It failed at the tube. Not the weld. Something was right with my weld then Maybe the welding courses did some good.

Lanzecki said:

Obviously I'll need to make the top connection removable and I can work that out, but the only way I can think of connecting the forks to the top tube is by using flat plate with holes drilled in for the forks. I don't have a drill that will cut the 1.5" I'll need.

Any thoughts on other methods?

Click to expand...

I did mine like this:













Which screws onto this sort of contraption:








Hope that's of any use.
The whole project can be found here:
https://picasaweb.google.com/the.joxor/ChopperCycleProject

Note that most of the stress is taken up by the lower part of the fork "connectors", the top is merely a stabiliser (mostly under compression).

Of course. How simple. I was getting to complicated. Thanks for the info.

I Just had a quick look at your site. Nice Chopper.

Lanzecki said:

Of course. How simple. I was getting to complicated. Thanks for the info.

I Just had a quick look at your site. Nice Chopper.

Click to expand...

Thanks! Glad it was of some help. There's plenty of bike hackers over on http://forum.atomiczombie.com/

good job, amazing bike, thanks for sharing

OK, Finished and rolling. Thanks to everyone for advice. I re-built the front end from scratch using one peice of tubing per side instead of the extended original.

While I need to clean it up and paint it, I'll leave it for a week as is. If it survives my kids it'll be fine. Then find a slightly smaller front wheel. And a chain guard.

As an idea of the stress testing that goes on in this house one of my kids has a bent chainring on her 4 month old bike. How it happened I'll never know. Another bike has a screwed bearing in the pedal.

Riding report: it's not as bad as I expected. I'm finding it a little cramped, but then it's not for me. All 3 of my kids are flying around on it. Once at speed it's stable.


Anyway, pictures anyone?



Giving it some 'attitude'


Attitude in pink is hard to pull off...

Fabulous.
The angles all look good, and nice lines.
Ho about gears and a cool mock tank with built in ghetto blaster? massive sissy bar? flames? skulls?
Those gurlies look like trouble.
Next up, chopper for Mum and Tallbike for dad.
Are you guys the mad family on the street?
Chunko'.

Brilliant!! That's the way!