Fabricating a Super73 like frame and fork

Tongovida

100 µW
Joined
Jan 25, 2021
Messages
8
Location
Minneapolis, MN
Could anyone give my a bit of advice??? I am looking to build a frame and fork that is similar to the Super73. I have the machine shop and all the equipment but I really need some direction and advice. Should I use steel or aluminum alloy tubing? If I buy 4 10ft tubes 1- 1/8 or .065, which is going to be better in the long run??? Also is that going to complete 2 frames and 2 forks? We are looking to have a similar design shown in the link below.

https://super73.com/collections/s-series/products/super73-s1-black


Any advice or comments would be much appreciated. We are going to have fun doing this so I am not worried about the level of difficulty because I got a mad man helping me who has vision and knows what he is doing with the machines(or actually doing the work).

If anyone has blueprints, videos, or something that resembles instructions I would be happy to send you a nice bottle of scotch or tequila for your information upon completion of the frame and fork.
 
Depends on a lot more factors. How much power, how fast you want to go, how much you weigh, what size components you want to run, will it be rigid or suspension. Until you can more accurately define what it is that you want from it there’s not much we can do to help.
 
Tongovida said:
Should I use steel or aluminum alloy tubing?
...
Also is that going to complete 2 frames and 2 forks?
...
I got a mad man helping me who has vision and knows what he is doing with the machines(or actually doing the work).

I'm going to guess you aren't going to get plans for this, so you'll just have to figure out how to figure it out. Don't forget to think about how you're going to put dropouts on there. In general, my feeling is that you'd be better off with that Super73 design, than the frame in the diagram.

The mad man will have to decide what material he would prefer to work with, to do all that bending and joining (and I suppose heat treating afterwards, if welding aluminum.) I'd go steel, because I think it bends better and the joints are easier (not that I'd really be able to do this, but at least I'd stand a slight chance of being able to braze the joints.) Then you need to zero in on which aluminum or steel alloy.
 
I suppose you could use 1020 mild steel and maybe exceed 1.0 mm thickness.1.5mm is about 1/16", I'm not an expert but that's readily accepted as some strong tube. So if you get 1" or 25mm O.D. (Outer diameter) tube the inner diameter would be 7/8" or 22mm.

Use TUBE, not plumbing pipe.
'
Don't build your own fork, find a NICE shocked fork. A swingarm would be a nice touch but you'd have to figure it out. Are you sure that frame is even the right size for you?

There's all sorts of info online about what size tube to use where, but this is a different frame than they are talking about. Sticking with the same size tube all around is probably a good idea.
 
Great Idea to buy a fork with suspension, however I may put together one of my own just to give it a shot. I have 1" x (.085)14 gauge wall steel tubing. I was told not to buy chromoly or DOM because the basic steel tubing is the best for welding. I didn't think bigger would be better since there are 2 sides to the frame and I sure it will be an adventure to bend. There are 3 of us so we are doing 3 bikes. My friend is well educated in most everything but bending, including proper software to assist.

At first glance it looks to be a lot of info out there but most is on gas mini bikes with 10' tires or smaller. I really would like to replicate the Super73 for the most part and not much info is very helpful. There is a guy on youtube that is great and goes through the whole process but its in whatever his Indian dialect he speaks.

We will do are best to document the whole process so future pioneers can learn from all my mistakes.

I appreciate the advice.

Dauntless said:
I suppose you could use 1020 mild steel and maybe exceed 1.0 mm thickness.1.5mm is about 1/16", I'm not an expert but that's readily accepted as some strong tube. So if you get 1" or 25mm O.D. (Outer diameter) tube the inner diameter would be 7/8" or 22mm.

Use TUBE, not plumbing pipe.
'
Don't build your own fork, find a NICE shocked fork. A swingarm would be a nice touch but you'd have to figure it out. Are you sure that frame is even the right size for you?

There's all sorts of info online about what size tube to use where, but this is a different frame than they are talking about. Sticking with the same size tube all around is probably a good idea.
 
Look at QS for a rear scouter D.D hub no spokes. Like something is tall as is 20in tire tall. Something that has a stronger tire than a regular bicycle tire for flats
https://endless-sphere.com/forums/viewtopic.php?f=31&t=65972
They have a whole set up with a swing arm ECT
 
We'll definitely want to see all that. I learned welding in our California ROP system just as the economy was collapsing. Only a shadow of it remained for awhile after, i don't know if it's there at all now, but more had been lost than had been saved. I had plans of my own before an accident that made the steady movement a challenge. But I'm finally recovering.

https://www.harborfreight.com/12-ton-hydraulic-pipe-bender-32888.html?cid=paid_endless_sphere.com

Yeah, tubing bender is definitely the way to go. Some people cut the pipe at an angle and weld it together again to get out of the one time purchase. It's sort of like using a radius template to draw a round corner just right, the bender will give you that proper curve. They even have cheap stuff at the hardware store that bends that plumbing pipe just fine and maybe you'll be happy with it. https://www.homedepot.com/p/Gardner-Bender-BigBen-Aluminum-Bender-with-Handle-1-2-in-EMT-960H/300348696

Watch the video on the spring insert. But these springs aren't big enough and I don't know where to get bigger. https://www.lowes.com/pd/Kobalt-Spring-Tube-Bender/1002577884

DOM is the preferred frame steel. Not harder to work with, just more expensive than the cheap stuff. Chromemoly is more expensive and harder to work with. But not as hard as aluminum. Drawn Over Mandrell is just another step that makes it stronger. If you get the CREW Cold Rolled Electric Welded you have a seam. I guess not terribly important in your use. (But ewwww, a SEAM.)
 
I agree about the seam but the saleswoman told me it is not very visible on the outside. She told me I can look at them and change to DOM tubing if I feel like it will completely ruin the look. I learned my lesson the hard way trying to build my first motor bicycle with a lot of upgrades not knowing what I was doing. However I would still like to build a clean solid bike.



Dauntless said:
We'll definitely want to see all that. I learned welding in our California ROP system just as the economy was collapsing. Only a shadow of it remained for awhile after, i don't know if it's there at all now, but more had been lost than had been saved. I had plans of my own before an accident that made the steady movement a challenge. But I'm finally recovering.

https://www.harborfreight.com/12-ton-hydraulic-pipe-bender-32888.html?cid=paid_endless_sphere.com

Yeah, tubing bender is definitely the way to go. Some people cut the pipe at an angle and weld it together again to get out of the one time purchase. It's sort of like using a radius template to draw a round corner just right, the bender will give you that proper curve. They even have cheap stuff at the hardware store that bends that plumbing pipe just fine and maybe you'll be happy with it. https://www.homedepot.com/p/Gardner-Bender-BigBen-Aluminum-Bender-with-Handle-1-2-in-EMT-960H/300348696

Watch the video on the spring insert. But these springs aren't big enough and I don't know where to get bigger. https://www.lowes.com/pd/Kobalt-Spring-Tube-Bender/1002577884

DOM is the preferred frame steel. Not harder to work with, just more expensive than the cheap stuff. Chromemoly is more expensive and harder to work with. But not as hard as aluminum. Drawn Over Mandrell is just another step that makes it stronger. If you get the CREW Cold Rolled Electric Welded you have a seam. I guess not terribly important in your use. (But ewwww, a SEAM.)
 
I'm no expert on this, but I think the appearance of a seam is the least of your worries. It's more about having a frame that will handle its stresses well and make for a pleasant ride. Of course also that it's a workable material that can be bent and joined with reliable results, but you can bend and weld DOM tubing.

Now, that's about building a bicycle. Which the Super 73 is, but your diagram apparently isn't. I don't think you'd be surprised to get advice that's relevant to bicycle construction, on the "Electric Bicycles < E-Bike General Discussion" forum, but if you aren't building a bicycle, that's something to bear in mind. If you're building a bicycle after all, then maybe the way to go is just go ahead with the material you have and consider that a mock-up. There's bound to be something of a learning experience here. When you've decided how it worked out and what ought to be different, you can go back and do it right with better materials, and that mock-up will be very useful if you want to make weld-up jigs and stuff.
 
Good advise, I am building a bicycle and I will change my steel to DOM fabrication . The frame work on the posted photo is a mini bike but I have found similarly constructed frames that allow the 20" x 4.25" tires. My problem is, I am finding absolutely nothing for dimensions on the Super73 style. It is starting to get more frustrating but also make me more determined. I am not trying to plagiarize another companies design, I really just like the ride. I think the parallelogram shape is the best way to approach building the frame, I just wish there were a few more specifics on dimensions out there.

I appreciate your insight.


Good advice
donn said:
I'm no expert on this, but I think the appearance of a seam is the least of your worries. It's more about having a frame that will handle its stresses well and make for a pleasant ride. Of course also that it's a workable material that can be bent and joined with reliable results, but you can bend and weld DOM tubing.

Now, that's about building a bicycle. Which the Super 73 is, but your diagram apparently isn't. I don't think you'd be surprised to get advice that's relevant to bicycle construction, on the "Electric Bicycles < E-Bike General Discussion" forum, but if you aren't building a bicycle, that's something to bear in mind. If you're building a bicycle after all, then maybe the way to go is just go ahead with the material you have and consider that a mock-up. There's bound to be something of a learning experience here. When you've decided how it worked out and what ought to be different, you can go back and do it right with better materials, and that mock-up will be very useful if you want to make weld-up jigs and stuff.
 
m2Af0c9.jpg


ERW pipe is fine. on this bike i used 1.8mm wall because i was using fluxcore at that time. i got co2 MIG now i'm building another one w/ 1.4mm wall

steel is the way to go w/ garage builds but if you're equipped then 6061. requires big quenching tank and heat treat to get T6 temper.
 
Tongovida said:
My problem is, I am finding absolutely nothing for dimensions on the Super73 style.

You can get most of the dimensions (close enough, if not perfectly accurate) for anything you have a good clear picture of by measuring the known-size items (tires, rims, handlebars, sprockets, chain links, screws, nuts, axles, etc) in the pictures and then determining how many pixels that a unit of measure then equals. Then count pixels (or measure with a paint program that shows this in the status bar or ruler, etc, like the Paint program built into Windows) for the parts you need sizes for, and then multiply those pixels by the pixels-per-unit you determined.

This works for just about anything you only have pictures of, as long as there is at least one known-size item in the picture with it. The more known-size items there are, and the higher the resolution of hte pictures, and the more angles you have in different pictures, the more accurate you can get with this method. it's also nice when the pictures are perfect straight-on views, but even if they're angled to some degree you can still use it.
 
I doubt that you can save much by making this kind of frame yourself, unless it is for a large series.
 
I'll tell you what: You want to build a bike more than you actually want a Super 73, right?

Allow me to offer some alternative possibilities that might have fewer obstacles.

https://www.instructables.com/How-I-built-a-suspension-mountain-bike/

You don't have to use Atomic Zombie's steering wheel, but you might like it.

https://www.instructables.com/Atomic-Zombie-s-Carnage-chopper-bicycle/

I'm thinking of resusitating what I was planning when I had an accident. I picked up several of the Pocket Mod scooters (Maybe $50 with a seat and other parts you can use.) and had ideas for the little 16" and 20" full suspension bikes I could use on the interesting frame. A thought being to put the swingarm into the slot for the rear wheel. . . .

Pocket_Mod_WW_1.gif


If you're going to make your own fork, why not still go with suspension? A new thread on the subject.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=110200
 
Sweet as, thanks for the diagram and the recommendations.

Dauntless said:
I'll tell you what: You want to build a bike more than you actually want a Super 73, right?

Allow me to offer some alternative possibilities that might have fewer obstacles.

https://www.instructables.com/How-I-built-a-suspension-mountain-bike/

You don't have to use Atomic Zombie's steering wheel, but you might like it.

https://www.instructables.com/Atomic-Zombie-s-Carnage-chopper-bicycle/

I'm thinking of resusitating what I was planning when I had an accident. I picked up several of the Pocket Mod scooters (Maybe $50 with a seat and other parts you can use.) and had ideas for the little 16" and 20" full suspension bikes I could use on the interesting frame. A thought being to put the swingarm into the slot for the rear wheel. . . .

Pocket_Mod_WW_1.gif


If you're going to make your own fork, why not still go with suspension? A new thread on the subject.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=110200


MadRhino said:
I doubt that you can save much by making this kind of frame yourself, unless it is for a large series.
 
I really appreciate the advice. I am not sure this is proper but I measured a friends 73 and I am going to use those general specs to formulate a plan. I will use the paint program to construct a more accurate and clear picture of where to start. If I am using steel would there be any reason to use chromoly for the axle mounts, anchors, and motor plate between the 2 frames? If it sounds ridiculous it is because I am not really sure what I am doing. I have a friend who knows but I am trying to do as much research as possible so I can be useful.

Thanks


amberwolf said:
Tongovida said:
My problem is, I am finding absolutely nothing for dimensions on the Super73 style.

You can get most of the dimensions (close enough, if not perfectly accurate) for anything you have a good clear picture of by measuring the known-size items (tires, rims, handlebars, sprockets, chain links, screws, nuts, axles, etc) in the pictures and then determining how many pixels that a unit of measure then equals. Then count pixels (or measure with a paint program that shows this in the status bar or ruler, etc, like the Paint program built into Windows) for the parts you need sizes for, and then multiply those pixels by the pixels-per-unit you determined.

This works for just about anything you only have pictures of, as long as there is at least one known-size item in the picture with it. The more known-size items there are, and the higher the resolution of hte pictures, and the more angles you have in different pictures, the more accurate you can get with this method. it's also nice when the pictures are perfect straight-on views, but even if they're angled to some degree you can still use it.
 
What exactly, do you want to do different than a super73 ?

I mean, the super73 is not expansive, and the frame is not designed for high power/speed. Building your own won’t save you enough money to make your time worth, and it is not likely to make a better bike at the end.

When it first came out on Alibaba it was sub 500$, now closer to 1000$. You should be able to buy that frame from China for 89$. If you buy the American version, various options can make it 2500$. It is not the kind of money to make it worth to DIY.
 
I am not looking to alter the concept and design. I have seen some new frames and they are way too complex, we are looking for to work with an "entry level" design if that is possible. The power and speed of the 1500w or 1000w mid drive motor is perfectly adequate. We are trying to embark on a project that we have never done. It is completely for the challenge and hopefully satisfaction of making them our own. With that said I would be very open to any upgrades or enhancement ideas. I would never say no to more speed or power as long as I am not compromising durability and/or added pressure to other parts of the bike.


Thanks




MadRhino said:
What exactly, do you want to do different than a super73 ?

I mean, the super73 is not expansive, and the frame is not designed for high power/speed. Building your own won’t save you enough money to make your time worth, and it is not likely to make a better bike at the end.

When it first came out on Alibaba it was sub 500$, now closer to 1000$. You should be able to buy that frame from China for 89$. If you buy the American version, various options can make it 2500$. It is not the kind of money to make it worth to DIY.
 
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