Chopper (Split from George's bike thread)

Hi all

What does the panel think of the welding and engineering in this ?

http://www.atomiczombie.com/ct-granny.html#granny

Something that I may build ?

Sorry to hijack your thread George.

regards Paul

As a chopper builder I like a lot of it, BUT, the man is an idiot making the bottom of the forks like that. if they were gussteed onto the main fork tube they might be a bit safer but that is pure stupid, so there.
Why? they are forks designed to work in compression with load along the tube, he has butt welded them onto a piece of tubing at 90 degrees.
I used to like Atomic Zombies stuff but has spoiled the whole chopper thing.
A chop/freakbike is a home built statement of nothing in particular, not something you buy.

Chunko'

chunkolini said:

As a chopper builder I like a lot of it, BUT, the man is an idiot making the bottom of the forks like that. if they were gussteed onto the main fork tube they might be a bit safer but that is pure stupid, so there.
Why? they are forks designed to work in compression with load along the tube, he has butt welded them onto a piece of tubing at 90 degrees.
I used to like Atomic Zombies stuff but has spoiled the whole chopper thing.
A chop/freakbike is a home built statement of nothing in particular, not something you buy.

Chunko'

Click to expand...

I actually want to build his trike's but was draw to the chopper as I have a couple of lugged frames like the one used.

I understand what you are saying about the individuality of a chopper but not wanting to build a dangerous bike due to my current lack of understanding of what is safe or suspect when designing/building these bikes I would have followed what I thought were safe plans for my first build ?

What do these bikes ride like ? there seems to be no regard for fork angle/rake/trail etc ? also where I live I would need some gears [ they don't look cool when being pushed up a hill ! ] but that spoils the uncluttered looks.

regards Paul

Hi Paul

What do they ride llike?
Some handle like a pig, some handle ok, very raked forks lead to fork flop, a high front end and a long fork looks good and handles better.
Taking a first ride on a bike with no idea of the handling is a great buzz, just make sure that there is at least one functioning brake first (ahem, I learned that one the hard way).

I would say start off messing about with a simple chop to get the hang of the game before building the nice bike.
I built my first chop about 8 years ago, and was going to build the nice recumbent next, still have not got round to it, but have built literally a skip full of bikes over the years.

Angles of forks? draw it on the floor with chalk or use a broom stick in the headtube as a false fork until it looks right.

Gears? essential unless you live somewhere flat. If you leave the rear triangle unmodified the gears will work after a fashion as everything is straight and as originally supplied.
Rubbish full suspension frames are a good place to start as they have small rear triangles.

Lugged frames? a bad place to start, once you start taking lumps out of them there can be huge holes hidden inside the lugs which make life complicated. Best things are cheap and nasty mountain bike frames, they are made of lovely thick pipes and are easy to weld. Dead and dying bikes are so easy to get hold of.

Dont butt weld the forks, unless you like eating through a drinking straw, sleeving them is best, they work in compression and the load is going into the join not in shear.

My first attempt, the front of one frame and the back of another with a piece of pipe linking them.


Dr Hannibal, not bad for a first attempt, note how I avoided any wedling around the headstock, the most stressed part of the frame. Three joints and all the nraze ons for cable were already there. The forks are ERW tubing, they collapsed two years later while downhill racing, two foot drop offs, boulder fields and three foot ruts, on the second race. Dr H s still the best handling chop I have ever ridden.

After that I started bracing them externally to the stem of if possible like on this.


Godzuki son of Godzilla, these forks are indestructible, relatively. I have done flights of steps and massive endo's on them.

Three no four no five points to remember, whatever some guidelines.
Start simple, think triangular, dont butt weld your forks, always have a brake. Dont spend any money on it, you can even recycle frame tubes as fork extensions. When extending your forks dont go too mad, a foot is a long way.
Oh, and dont ever go for fancy pants paint jobs.

A great website
http://www.chicagofreakbike.org/
hosted by my friend Johnny Payphone
also have a look at
www.rat-patrol.org this is the site that set me off.



Dont blame me when you family disown you and you end up being the mad guy down the street with 30 dead bikes in his front room and eating dead rats.

A have been meaning to post on this nonsense for some time.

If anybody asks whey are you doing this just grin maniacally and zoom away looking far cooler than they will ever manage.

Good luck

Chunko'.

You're all gonna get me into more trouble now, cos i am definately gonna be building one of these The trouble and strife aint gonna be to happy though Oh well at least i'll look way cooler than the 10yr old scroat down the road on his shop bought chopper.

"granny's nightmare" certainly would be! Besides the dubious forks eventually depriving you of your front teeth, If you rode it for any length of time, you would risk serious damage to your knees. If you can't lock your leg straight at the bottom of the sroke, the seat is too low. The lower the seat is, the more force is applied to the knee joint whilst pressing down on the pedal, resulting in permanent damage to the cartlidge in the joint.

However, if you're just building it as an art piece, not an issue.

Good (and unsurprising) to see Chunko's bikes have good geometry Metal is definately his friend!

Chunko

Still got a way to go with my welding before I try any of this , when you say sleeve the joints I assume and inside sleeve ?

What do you then weld ? just treat it as a butt joint in thick plate and so leave a little gap so the sleeve becomes the bottom of the joint ? and weld all three at once ?

What about drilling say 3 holes in the outer and plug welding the sleeve in first then tackle the joint ?

just trying to find the best technique then I can practice that ?

' The forks are ERW tubing, they collapsed two years later while downhill racing ' is that electric conduit ? I understand you can buy in 3/4" and 1" ? did the tubing collapse or was it something else ?

regards Paul

Paul-n said:

' The forks are ERW tubing, they collapsed two years later while downhill racing ' is that electric conduit ? I understand you can buy in 3/4" and 1" ? did the tubing collapse or was it something else ?

regards Paul

Click to expand...

Electrical resistance welded. It's made by rolling a flat strip into a tube, and welding the seam. Much cheaper than drawn tubing (CDS), and very nearly as strong. I would steer clear of conduit of any type for structural work, It's a really low grade product!

Welding fork extensions?
Get a set of welded forks, off a mountain bike dont use lugged ones off road bikes, as they are a bit iffy, usually too ovalised and skinny. Try and get round section fork or as round as possible, measure the outside diameter and find the point at which it will fit inside the extension tubing, and cut it there, have about an inch or so slipped inside the new tubing, drill two small holes either side of the newtube half way up the overlap. Gently slap it ith a hammer to get a tightish fit, check the legs are the same length at the dropouts, and facing the right way ahem) once everything is straight put two small plug welds in the holes then make a lap weld around the join. I prefer to braze these joints but have done it both ways and never had a joint fail, the ones that collapsed bent at the top by the fork crown.

Dr Hannibal was all brazed as I did not have a mig welder at that point, as the bikes developed (regressed?) I used more and more welding as I got more confident.

A good starting bike is to get a rubbish full sus bike, take the rear shock out, drop the pivot as far as it will go and weld in a piece of box section, this has the effect of raking the fork, then lengthen the fork, easy and crap. Or if you want to be perverse, fit a motorbike shock, and lengthen the fork instant tall bike.

I think the tube I was using is 25mm OD and 1.5mm wall thickness.

Chunko'.

Think i have put these on here before , think Chunko has seen em. These are a few bikes my lad and i made over the years. All from donor bikes , bits and bobs and spare bits of tube. I found that the stuff that kids climbing frames are made from are spot on for tubing , some is better than others though.
Still got these bikes , my lad gets em out in the summer and cruises around.
The first one we built , sold about 5 years ago , turned up on a forum somewhere i cant remember







Inverted springer



One in progress , this may turn out to be my favourite , i have always been a sucker for the boardtracker style

may get it finished some day

Another

Hi all

Thanks all for your contributions , I have been to Chunk's web sites and others and have been blown away with the number of styles and levels of finish on the bikes featured.

I suppose I am drawn to a pedal version of a traditional m/c chopper but with a dirty drab finish maybe rust/matt black/red wheels/white trim does that make it a ratbike ? [ unsure of the terms used ?]

badersbus - great bikes thanks for taking the trouble to post them , I have seen the bike with the rifle on it on the custom bike site very cool.

chunkolini said:

A good starting bike is to get a rubbish full sus bike, take the rear shock out, drop the pivot as far as it will go and weld in a piece of box section, this has the effect of raking the fork, then lengthen the fork, easy and crap. Or if you want to be perverse, fit a motorbike shock, and lengthen the fork instant tall bike.
Chunko'.

Click to expand...

I though I had one of those in the pile , turns out it was 24" and not 26" so frame is small and when tilted back it would put the seat very close to the pedals , like badersbus blue trike but with the pedals nearer the boys heal than the position shown , needs more thinking.

regards Paul

Ha Ha Paul,

the infestation spreads, your lives are ruined.
You are removed from the gene pool, Why?because any self respecting woman will have nowt to to do with you after you start this nonsense. But then again you may be strengthening the gene pool, a true Woman will see that you carry The Futuregene. The one that will create transport from the cluster**** that will follow the oil crisis.

Badersbus, what is that weird coating on your pimp ass MOFO 'bikes' I use inverted commas because they sure aint bikes.
What are they covered in? is it 'PAINT' bizarre stuff.
Putrid Assembly Incoherent Normalising Treatment
Or some other concealement treatment. these vehicles are meant to be ****e! the covering material probably cost more than the build.
Mine are covered in a much more elite coating,
Random Utility Surface Treatment
Stuff you cant even buy.
Go away children cut cut kill destroy, chop that bike bring some joy.
Think, I can make twenty people smile on my way to the shops in the morning.
that has to be worth something in these medicrioty obsessed times.

Chunko'.

chunkolini said:

Ha Ha Paul,

the infestation spreads, your lives are ruined.
You are removed from the gene pool, Why?because any self respecting woman will have nowt to to do with you after you start this nonsense. But then again you may be strengthening the gene pool, a true Woman will see that you carry The Futuregene. The one that will create transport from the cluster**** that will follow the oil crisis.

Badersbus, what is that weird coating on your pimp ass MOFO 'bikes' I use inverted commas because they sure aint bikes.
What are they covered in? is it 'PAINT' bizarre stuff.
Putrid Assembly Incoherent Normalising Treatment
Or some other concealement treatment. these vehicles are meant to be ****e! the covering material probably cost more than the build.
Mine are covered in a much more elite coating,
Random Utility Surface Treatment
Stuff you cant even buy.
Go away children cut cut kill destroy, chop that bike bring some joy.
Think, I can make twenty people smile on my way to the shops in the morning.
that has to be worth something in these medicrioty obsessed times.

Chunko'.

Click to expand...

well chunko what can you say to that
with that sort of rant you must be on your way to being a genius

he probably shouts at clouds as well!

Aye and wind mills.

Chunko'.

chunkolini said:

Ha Ha Paul,

Think, I can make twenty people smile on my way to the shops in the morning.
that has to be worth something in these medicrioty obsessed times.

Chunko'.

Click to expand...

I do that anyway , only person around here I regularly see on a recumbent is my reflection in shop windows , once had two young guys in a Ferrari nearly break their necks staring at me as I went by , a 50+ year old on a £300 bike

regards Paul

Chunkolini

This looks the best match to what I want to build and the available frames I have plus your advice on not welding near the head tube for a first try.

I can use a lugged frame I have as the only thing it will need changing are the rear seat stays and chain stays removing and a longer rear end adding maybe built up with forks ? or extending the existing one ?

The front needs the forks extending to achieve about 2" of trail.

regards Paul

Badersbus, what is that weird coating on your pimp ass MOFO 'bikes' I use inverted commas because they sure aint bikes.
What are they covered in? is it 'PAINT' bizarre stuff.
Putrid Assembly Incoherent Normalising Treatment
Or some other concealement treatment. these vehicles are meant to be ****e! the covering material probably cost more than the build.
Mine are covered in a much more elite coating,
Random Utility Surface Treatment
Stuff you cant even buy.

Chunko....... You really are a man from another time.
Paint is all the rage now on the street , it comes in lots of lovely colours an stuff. I reckon it is the new Birmingham bags ..... can you remember them. No good for riding a bike though , catch in the chain and that. You can tuck em inyour socks i suppose
Now go and find some helicopters to shake a stick at LOL

Some pretty cool bikes on here too
http://www.ratrodbikes.com/