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Joined
Jan 21, 2009
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Location
Zambales, Philippines
I'm going to build a swing bike. I'd like to just use scrap stuff I have, but I may need a few things.

I've researched the frame geometry and will make it with headtube angles like a standard swing bike.
01 May 23 sbike.jpg
I'm not using a triangle from an old frame, I'm making it just like one of the original swing bikes. I'm using a fork as part of the rear with the BMX seat post (22mm) sliding right into the fork. I saved the scrap from a couple frames I have cut up and the chain stays and crank housing are all one piece.

This will be a 26" bike, not the usual 20", but will have high bars. No banana seat, I can't ride those anymore.

I laid it all out to get an idea of the frame length and how it will size up. 40-42" long for the two bars going from head tube to head tube. Most of those I've seen are curved together as they transverse between the head tubes, but I think they might look better if the lower one curved downward, the opposite way. That would leave room for an insert or tank of some kind.
IMGP2547.jpg


The crank housing part will get trimmed and I'll hunt for some tubing for the cross bars. Maybe two on either side would work, 4 total.
01 May 23 layout.jpg


I don't have any frames to use for head tubes, but the down tube on this scrap frame might be the right diameter. 2 headtubes could be made from it and I'd be set. The head tube on that frame is a strange small size.
01 May 23 headtubes.jpg


As for wheels, I've used up all my rims and spokes, so I was going to order up some parts when a whole wheelset is cheaper. Actually I ordered two front wheels, as I will lace in the cheap Chinese coaster hub to one of them.
01 May 23 parts.jpg

It's the one that had a lip on the inside of the drum! I used my dremel to smooth it out, but if it still isn't good, I'll order up another one. The other one I had worked well on the Wright Special. I can't find any but the cheap ones over here. I should have stocked up on red bands before I left. I think a swing bike needs a coaster brake as front brakes might make the thing jack knife and cables for handbrakes might get fouled up when swinging. But a rear brake might work with a freewheel as in the blue bike above.


That's where I'm at, tomorrow I'll be doing some cutting on the crank housing
 
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It cools off after 6pm, so I get some work done before dinner.

I'm using a wheelset off another bike for mock up purposes. I'm hoping the new rims will be good quality, but they are cheap at 15 bucks each. 👍 That's to reserve some bike budget for steel and welding.
01May23 rear.jpg


The chain stays are short, that frame was meant for 20" tires. I'll make up a set of dropouts to bolt the rear fork and lower part together.
The caps (races) for my cranks don't fit snugly in the frame, there's a tiny bit of play. The metal is heavy and thick, so a tap or two with the hammer may fix that.
The scrap I wanted to use for head tubes was the same size as the caps, so I'll be hunting for some tubing I can fit the caps in.
01 May 23 headset.jpg
 
I'm going to build a swing bike. I'd like to just use scrap stuff I have, but I may need a few things.

I've researched the frame geometry and will make it with headtube angles like a standard swing bike.
View attachment 229802
I'm not using a triangle from an old frame, I'm making it just like one of the original swing bikes. I'm using a fork as part of the rear with the BMX seat post (22mm) sliding right into the fork. I saved the scrap from a couple frames I have cut up and the chain stays and crank housing are all one piece.

This will be a 26" bike, not the usual 20", but will have high bars. No banana seat, I can't ride those anymore.

I laid it all out to get an idea of the frame length and how it will size up. 40-42" long for the two bars going from head tube to head tube. Most of those I've seen are curved together as they transverse between the head tubes, but I think they might look better if the lower one curved downward, the opposite way. That would leave room for an insert or tank of some kind.
View attachment 229806

The crank housing part will get trimmed and I'll hunt for some tubing for the cross bars. Maybe two on either side would work, 4 total.
View attachment 229807

I don't have any frames to use for head tubes, but the down tube on this scrap frame might be the right diameter. 2 headtubes could be made from it and I'd be set. The head tube on that frame is a strange small size.
View attachment 229804

As for wheels, I've used up all my rims and spokes, so I was going to order up some parts when a whole wheelset is cheaper. Actually I ordered two front wheels, as I will lace in the cheap Chinese coaster hub to one of them.
View attachment 229805
It's the one that had a lip on the inside of the drum! I used my dremel to smooth it out, but if it still isn't good, I'll order up another one. The other one I had worked well on the Wright Special. I can't find any but the cheap ones over here. I should have stocked up on red bands before I left. I think a swing bike needs a coaster brake as front brakes might make the thing jack knife and cables for handbrakes might get fouled up when swinging. But a rear brake might work with a freewheel as in the blue bike above.


That's where I'm at, tomorrow I'll be doing some cutting on the crank housing
Great start! Three swingbikes already in the mix!
 
Now I can't get that song out of my head! :envy:

I measured a dozen headset races and I have 2 sizes but they use the same size bearings. 29 mm and 31mm. I'll take them with me to the steel place and see if I can find a match, then buy a couple feet.
02 May 23 caps.jpg


There are a couple bikes that could be donors, but I'll leave the play bikes alone for now.
02 May 23 bikes.jpg
 
I have found it is hard to get headtube sized tube or pipe these days, I usually end up cutting from other frames.
Yep, everything I've looked at online goes from 32 mm to 38 mm. 1.5 mm thickness. I need 34-36 mm to work. I just might go frame hunting.
 
I found some places in the states that have frame parts. The head tube is 36.5 mm for what I need. But I'll just take the caps and be sure I get something that works. I measured and will need the head tubes to be 4 1/2 inches long, so a foot of tubing is needed.
I can have my seat low enough and still have plenty of space to attach the bars, 4 of them.
02 May 23 rear setup.jpg
I also measured the dropouts. They only need a couple inches of extension for a 26" tire to fit easily. I can make 2 plates matching the existing square drops and have them welded or bolted on. The rear fork doesn't have to attach to the axle, it can be bolted or welded to the dropout. That would make it easy to change out the rear wheel and have plenty of adjustment for the chain. Then the braces from the crown to the bottom bracket need to be worked out. Everything may be bolted up until I know it is where it should be, then get welded.

I'm going to make a seat post that attaches like the old AMF seat posts, with a wedge. The one shown here is too short, the bolt doesn't have threads enough, but the BMX seat post is the same size so it will get used. Just a slanted cut and trimmed to the bolt and I should be in business. I won't need to do anything to the rear fork like a slot for a collar.
 
Very cool build. It's a pretty straight forward design, looking forward to seeing how it goes. I may have to try one someday. I'll just make sure to wear full pads the first time I ride a swing bike! :rofl:
A helmet is probably a good choice for the first ride and setting the seat rather low so you can get both feet on the ground in case of emergency (speaking from experience here 😉). And go slow but not too slow...
 
They look at you funny in the ER when you tell them you were riding a home made bike and crashed. Especially when you are over 50. I did that once when a build flipped over during a wheelie. This bike was too heavy.
1917905_214634536736_2158834_n.jpg
 
First vid of the build!



I also trimmed the dropouts and laid it out for a look. I'll go with a curved support from the crown to the BB, instead of bracing at the rear. That should be stronger.
That small length of leftover tubing is the size I'll use, and also for the 4 crossbars about 42" long each.
03 May 23 rear section.jpg
 

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