Fat Tire Chopper Bicycle

It's time.:devilish: Building mini choppers and 2 1/2 years of dabbling with MB's It's time for me to
combine one sport bike with another.

I've spent 3 weeks working on a frame to fit a 6 ft. adult rider. I saw this frame design a
year ago and couldn't stop thinking about it so I gave it a whirl. Not as easy as I thought.

In tradition of keeping a radical bicycle look, the frame is designed with a single down tube.
Of course keeping a peddal drive train. (different than my mini choppers)

Im going with a 45 to 47 deg. rake, with a 24" 72 spoke front wheel. Chrome billet forks.
I'm not building the rear frame until I find the ultimate 11"wide x 23"tall rear tire/rim combo.
The head frame is bowed, to accept any engine style. I may start with a HT to save costs.
If I love the bike I may upgrade.

This will be a slow going project due to a busy life. This is where i'm at so far. I'll keep this
thread updated as things progress. graucho
 

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Started a little bodywork.
Then I went to tractor supply for a #41 chain and I ran across a bearing sprocket idler, then I had a brainstorm for a tensioner for the bike.
I went home and made a bracket, welded it on then checked the idler for fit. Also found a kickstand in my shelved stock and i'm looking for a good spot to mount it. I may have to move it depending on the bikes weight distribution. Or I may need to find a good v-mount. Thats yet to be determined.
 

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man..... this is coming together nicely!!

that jackshaft is a clean looking design. ( :geek: I'll be borrowing all kinds of ideas here...thanks!!)

Impressive build!!
 
This is an incredible project Graucho and so well documented and illustrated. I've been feasting my eyes on it for hours!
I'd like to know what type of tubing you used for the frame - standard steel circular hollow section or Chromoly or what? What wall thickness etc.? Also is it Mig welded and are any joints brazed. How did you bend the tubing? I absolutely love the whole shebang and I think you'll be doing more than 20 mph on this beast.
It's a delight to read this project from the start through and to see how you reached a certain point where everything had to be the best. I'm blown away by the whole thing. Can't wait to see the final paint job. Hope that headlight is good enough cos it looks so lovely.
 
Thanks guys.
Hi Irish John, To answer a few questions, its 1/8" round standard steel tubing. 1", 11/2" and 2".
Its Mig welded, nothings brazed.

I had an expensive $550.00 mig welder and a 400.00 tube bender that I sold thinking I was going to get out of these hobbies. But ive seemed to have built 3 more things since. So I now have a 119.00 tube bender that I bought off e-bay that suites my needs and a 119.00 mig welder (110v 20 amp) from Harbor Freight that keeps on running and running. Ive borrowed it out many times and its probably lasted for at least 20 projects between 4 guys. I'll never spend the big $ again since scaling down to just bicycles.

When I get to the painting stage Im going to post every supplier. Wheel, rim, fork, pillow bearings etc..etc... and show how I paint my bikes. Cheap tips, tricks etc. (even spill gas on tank, safe) 250.00 paint job for 75.00 including the air brush gun/kit.

The only new photos that I have are the new seat, upgraded disk brake disk, and second stage of primer, rebuilt the headlight, and made a 3.25x6.25 license plate that i'll mount with a tail light above it.

Its dropped to -2 deg again so things have slowed a bit. Thanks again, graucho
 

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Thanks Graucho, that answer is like your bike project - detailed, crisp & precise. Much appreciated. You know 2 years ago looking at something like this would have made me want to give up and crawl off in despair but this project of yours has inspired me. My old arc welding was never much good and it's 30 years since I did it but I can now recruit those with the skills I lack to help me. I'll show them your project and they'll be hooked. I'm maybe talking in the future and not next month but tonight I'm off to bed and I'll be dreaming of something like this with my name on it. Your bike is quintisentially American as Pecan Pie which shows its provenance and my bike will be something maybe like a Manx Norton look with a touch of Irish road racing heritage but you've got me going. That undercoat paint job is so edible and I can practically taste the chocolate - a slightly salty sweetness from the purest of Utah's salt flats as that fat tyre gets hot and splatters steaming saline crystals over the chain stays as she rumbles through the sonic barrier - a shimmering speck in the distance disappearing over the flat white horizon. I must go to sleep before my dream ends.
Thanks so much for your fantastic efforts I'm enjoying this project immensely.
It's 2.30AM and 28 celsius here but back in a garage somewhere in Minnesota it's freezing.
I'd like to try brazing a frame.
 
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Wow thanks Irish John. Id better keep the posts coming. LOL

I welded on license plate supports. Then assembled the license plate frame and lights. Then welded up a battery tray. Then "fished" a big wire through the frame to use to pull all of my wiring up through the frame for the main light switch and kill switch. Im going to hide all of the wiring in the frame.

Then i fired up the light to take a peek. All lights in the rear are LED. The blue lights are 1 amp, the red 2 amp. The battery is a rechargable 12v from radioshack used normally use for security system lights. I ran the tail lights for 9 hrs and they still burned bright. I'll have to see what I can come up with for the headlight drain. Im hoping to get 4 hrs before recharging?
 

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As long as you know that you'll need to put that license plate on the other side when you take her to The Isle of Mann for the TT.
 
Is it the right side in NSW? Here its the left side. I need the plate/light on the left side so cars coming up upon me on my left can see me better.
Excuse my ignorance, do you guys drive on the left side of the road? or right.
 

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Is it the right side in NSW? Here its the left side. I need the plate/light on the left side so cars coming up upon me on my left can see me better.
Excuse my ignorance, do you guys drive on the left side of the road? or right.

Pretty well anywhere that was ever a British colony will drive on the left with the exception of the USA which became independent somewhat earlier than intended and before cars etc were invented and thus drives on the right.
Ireland drives on the left too but because we don't like the British we are going over to the right from next year. from Jan 1st 2010 all buses and trucks will drive on the right and if it proves successful then cars and bikes will follow suit the following year!
 
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