Custom Bicycle

[richl]

i've built a couple beach cruisers, roach cruisers, customs, board track racers. Its how i got into machining, I am certainly not the person to talk to if you are looking for a traditional bike, but if you want something outside the box, i've hacked together a couple frames. Cro Moly is a good choice, easy to work with, strong, light, and forgiving. .065 ga is common, some go lighter, some heavier. .065 works nice in a manual tubing bender, I've used mine to make bends for the front forks, and the rear. The above mentioned harbor freight tubing roller makes nice sloping tubing that woks well for the main frame. With the use of a lathe of moderate size you can make your own custom head tubes to accommidate any head bearings...
making rear rims from cars into bike tires is slick, motorcycle tires are rounder on the sides so they are easier to lean than the squarer profile of a car tire. something to consider when making a rim selection

hth
rich

 

[NortonDommi]

Hello,
I had a friend who used to make custom racing bicycles & he used 22ga. 4140, he reckoned lighter & stronger than Aluminium plus a breeze to braze/Bronze weld with Eutectic 16F. He used a vapourflux unit which sped things up & no mess. I use the Eutectic rods too with powder flux and it is great as you can get penetration through mating surfaces,(braze), let cool slightly then go back and build a fillet for maximum strength,( like Bronze weld). Purpose designed for light weight tube,(e.g. furniture, wheelchairs ect), and is redily available.
A great site for insiration and help is Atomic Zombie.
Cheers,
Barry.

 

[NortonDommi]

Just had a thought, most tubing can be had in different shapes for instance I use oval or a shape that is like a flattened round tube. Anything but square.
Barry.

 

[rwm]

I just bought an awesome Harley rear wheel. Polished aluminum 5 spoke. It's 8" wide so I plan to mount a 240/40/18 tire.

Next question: Richl- should I plan on lengthening the frame so the crank is in front of the rear wheel or can I make a wide crank set that clears the wheel on each side? I could widen the bottom bracket. I would prefer the look of the later if it is workable. Remember this is not a performance bike!
Robert

 

[richl]

what you are doing with getting the rims and tires first is not a bad idea, this way you can flesh out the proportions of the bike before you start bending metal, As far as the bottom bracket, getting one of the older roller bearing and axle type allows you to lengthen it easily . The newer sealed bearing type limit you to a smaller size bottom bracket. Bottom brackets are best scavenged from recycled bicycles, though there is no reason you could not turn your own, remember one side is right thread, the other is left thread.

I have never built one that did not weight in excess to 50 pounds, as soon as you start puttin motorcycle rims/tires on it the weight climbs fast. These are cruiser/cool machines not racers.

rich

 

[richl]

These are just a couple random photos from my Dropbox. The beauty of these kind of bikes, there is no one right way to do them. Keep and eye on the head tube and the bottom bracket. If you have a lathe and mill you can make your own head tube, and but bearing to fit. Same with the bottom bracket.

I haven't built one in a couple years, would like to do another this summer.

Rich

 

[richl]

As far as location of the bottom bracket, just keep in mind the path of the chain. There are ways around it by using a transition point and another sprocket dedicated to the rear axle. Again 2 good forums for ideas are atomic zombie and ratrod bikes. Than searching the web for custom bicycles. Surprisingly you will see some amazing engineering .

Hth rich

 

[rwm]

Rich-- that's some nice work you have there. Ladder for a setup table is brilliant!
What are your thoughts on a crank with the pedals set about 12" apart? Would that be workable. That would avoid the secondary shaft.
Robert

 

[richl]

Robert, it's doable.... might be a tad bit uncomfortable to ride, I also wonder about the force applied to the shaft... I've done it with shorter bb, they were about 6" and had on 4" tires, the fat tire bike all had intermediate shafts.
The ladder is a nice poor man's frame jig

Rich

 

[rwm]

Who knew there were more than 7 common standards for bottom brackets?! Crazy. I think I have that one planned out though. I will make bearing carriers that screw in to the bracket and these will hold outboard press fit bearings. Then I can also lengthen the spindle to clear the rear tire.
But how do you attach a freewheel cassette to a Harley wheel? That whole axle-bearing-cassette thing will take some engineering. Any ideas welcome.
Robert