Anyone built their own bike frame before?

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awesome bike. how much extra work is that thing compared to a regular xc bike?
 
That looks like a winter hoot! Nice work. Where do you find tires to fit those rims?
 
awesome bike. how much extra work is that thing compared to a regular xc bike?

I'm guessing you mean to ride, not to build? Design was tougher, build was the same. Riding is an "it depends" answer. On smooth pavement it is ridiculously slow compared to an xc bike. Places where you'd need to get off and walk the XC bike, it is a bit easier (no walking required). Through tall, thatchy grass, soft sand, or through smooth mud, it is faster (no idea why, but the type of mud where you'd pick a 1.95 over a 2.25 to get down to the base and displace less width, the 4.3 floats over and is even better than the 1.95). On rough, loose gravel, they are about even. On smooth-ish trails, the xc bike is substantially faster. In babyheads or through serious exposed roots, it is substantially faster.

The funny thing is it favors moment maintenance techniques so much that even in the same terrain, the longer/slower the ride, the more it would favor these tires.
 
I'm guessing you mean to ride, not to build? Design was tougher, build was the same. Riding is an "it depends" answer. On smooth pavement it is ridiculously slow compared to an xc bike. Places where you'd need to get off and walk the XC bike, it is a bit easier (no walking required). Through tall, thatchy grass, soft sand, or through smooth mud, it is faster (no idea why, but the type of mud where you'd pick a 1.95 over a 2.25 to get down to the base and displace less width, the 4.3 floats over and is even better than the 1.95). On rough, loose gravel, they are about even. On smooth-ish trails, the xc bike is substantially faster. In babyheads or through serious exposed roots, it is substantially faster.

The funny thing is it favors moment maintenance techniques so much that even in the same terrain, the longer/slower the ride, the more it would favor these tires.

that was the question. i definitely want to try one.
 
that was the question. i definitely want to try one.

mudbay: Surly Pugsley $1300

P1000702-Copy.jpg
 
I't's a tight squeeze, but i think you can even fit decently wide rims on that so you can run ultra low pressures, too.
 
crazy designs. I have been seriosly thinking of taking my k2 beast parts off the frame, and make a recumbant frame for these parts.

Anyone here have plans for a three wheel recumbent bike? I want to also include a grosherie box or travel box on it.
 
have any of you mig welded chrome moly steel before? I would LOVE to make a three wheel recumbent bike but would like to make the frame out of chrome moly. I could use my 115 volt Lincoln gas welder to weld the pieces together.

So what do you all think?
 
Have you used mig on the wall thickness of tubing you are contemplating before? it is not impossible, but it is a different challenge than most other stuff (tougher than sheet metal in some ways), and inevitably looks ugly to the discriminating eye. Buy some tube and try it out. That will answer your question for you.

In the end you use the skills you have, or you learn new ones. Mig can work fine, but it wouldn't be my first, second, or third choice. It might be your first choice and work fine for you. On 4130, be sure to use a "no post weld heat treat needed" filler. If you use 4130 filler and don't post weld heat treat, your welds may crack on your after just a year or two.

The front end geometry jigs, mitering, chain routing, etc are all more challenging on a trike. Might i humbly suggest starting with an easier project first to get your feet wet?
 
Sure that would be no problem. I can try some sample pieces. BTW, is there a big difference between Chromemoly and mild steel welding?
 
Sure that would be no problem. I can try some sample pieces. BTW, is there a big difference between Chromemoly and mild steel welding?
You should match your welding wire to the metal. Most welders don't do that an it can cause problems later.
 
What wall thickness of mild steel tube can I use for my recumbent? I will be making mine with stearable wheels out front of pedals "good idea??" with one large main rear wheel. I will have a basket between the rear wheel and seat. Or should the basket be in front to be used as a crash cushion?

I once joked to some one, I was going to make a recumbent where the rear wheel was attached to a collapsible mast with a hybred electric motor in it. Once I got to my camping site, the rear wheel/mast would be unlocked, rotated to the sky, and extended up 20 feet where a windmill turbine is attached to it. That would be my power for the stay at the camp site :)
 
Tadpole style trikes with the front wheels about even with to slightly behind the knees is becoming most common. Weight wise they also seam to have the advantage. If the wheels are moved further forward, the main tube needs to be stronger for the same weight load handling.


Catrike: Catrike Expedition Recumbent Trikes
 
I would like to make my own...just to say "I made it". I could use alot of the existing parts from my own bike to keep the cost down.
 
Yep, I understand that, and the Catrike is an example of the tadpole design. Take a look at them to see what they did in their designs. Look at what components they are using. How the frame is designed.

I'd not put the wheels way yup front. That requires a stronger frame, and you need to transfer the steering up to them. Putting them to either side right about the knee/thigh area allows more direct steering geometry. As for the baskets, use a rack and panniers over and to either side of the rear wheel like a regular diamond frame bike does. No since reinventing the wheel.

Also I strongly suggest reading up at the 'BentRiders forum I mentioned earlier in this thread.

I'm not sure I'd worry about reusing parts from your bike. I'd be more worried about finding suitable parts. Gearing for a recumbent trike is different than a diamond frame road bike so that doesn't transfer well. It can be done but you will be missing the super low gears for hill climbing, and the high gears for high speed cruising. Missing the super low gears is the big killer. You'll need three brakes, two of which will likely have to be disk. The hubs for the front wheels may have to have a larger interior diameter than the ones you have due to the axle needing to be larger in diameter because it is only supported on one end. In all likelihood you will have to make your own front steering mechanisms. When you design them, remember to include disk caliper and fender mounts. You'll want front wheel fenders if it is to be anything other than a dry conditions only bike.

Front wheel hubs was an area I wasn't happy with what I could find. As of 5ish years ago this is what I'd found out:

Front hubs
  • Sturmey Archer makes wheelchair stub axle hubs with integral drum brakes. Model is X-FD(H) and is available in both fixed and quick release, and is made in right and left hand use models.
    • 12mm Axle
    • 36 hole
    • 13/14 G Spokes
    • 70mm drum brake
  • Phil Wood Wheelchair Hubs
  • Others with disc brake mounts?
  • Mountain bike hubs for down hill runs are supposed to have 15mm or 20mm axles. Most use sealed bearing units. They could be converted easily.
    • Use grade 5 bolts.
      • No higher as higher ones are brittle and the strength isn't needed.
  • Use hydraulic disc brakes for braking on hills, etc.
    • Link the two fronts together.
    • Rear is a separate circuit.
Steering geometry is also important. Mess it up and stability at high speeds and handling will suck. Again a cut-n-paste of what I had for steering geometry. Rest of the section was on the front suspension design.

  • Slight toe-in of about .1" or so.
  • Ackerman compensation. Steering arms point to the axle of the rear wheel. A slight amount of anti-Ackerman compensation allows for stabler high speed operation. About 2 degrees is fine.
  • Kingpin for steering should point to the center of the tire patch to compensate for braking forces, and bumps in the road.
  • Kingpin to axle should intersect or at most the axle should be less than .5" behind the king pin.
Some of that I got from others making their own trikes, and some comes from reading up on steering geometry for cars, etc..
 
I guess due to the fact that the rider is not using gravity to pedal, he has to equally try to push against the pedals forcing his or her back against the seat to get the same effect. I imagine this is not as efficient then peddling in the upright fashion, that there needs to be lower gearing to make it possible to climb steep hills.
 

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