Velo: Thus far, thus bonkers
http://www.mrinitialman.com/StandAlo...e_design.xhtml
So, this page shows the general shape I'm going for, the general length and width (not height yet), and some of the front suspension. I hope this would be useful as a sort of blueprint and/or plan. |
I don't know what you plan on making it from but it looks heavy, if it were me I'd consider a couple of cheap electric motor hubs for two of the wheels to assist on the up hills.
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Steel tubing with 1/8" wall if I have to, aluminum if I can afford it. Since it will be a four-wheeler, motors are a no-go (Alberta regulations)
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Originally Posted by MrInitialMan
(Post 21541024)
Steel tubing with 1/8" wall if I have to, aluminum if I can afford it. Since it will be a four-wheeler, motors are a no-go (Alberta regulations)
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Originally Posted by guy153
(Post 21541053)
I would go with 1/16" wall if it's just mild steel (and even less if it's cromoly, but cromoly is much more expensive).
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Originally Posted by MrInitialMan
(Post 21541217)
Would that be strong enough?
I suspect a lot of us here wonder about the strength of the rider being enough... I forget why you feel the need for suspension. A performance go cart frame can see one wheel lifted an inch+ off the ground and still have the other three wheels stay on the ground. How much weight will you be placing in this thing? Andy |
I admire your DIYness but this is way over built, is will weigh too much to pedal. Check images online to see what is needed in the way of a frame. Have you thought about making a pan type frame/bottom from fiberglass kind of like the VW beetle but fiberglass. Google quadricycle
Forum member cs641 in this thread https://www.bikeforums.net/framebuil...-builders.html. says he builds 4 wheel bikes similar to these https://rhoadescar.com/ Maybe he would advise you. Good luck |
Originally Posted by Andrew R Stewart
(Post 21541680)
I suspect a lot of us here wonder about the strength of the rider being enough...
Originally Posted by Andrew R Stewart
(Post 21541680)
I forget why you feel the need for suspension.
There's a video of a guy riding a velo in winter. The timestamp shows how bumpy the roads can be.
Originally Posted by Andrew R Stewart
(Post 21541680)
A performance go cart frame can see one wheel lifted an inch+ off the ground and still have the other three wheels stay on the ground. How much weight will you be placing in this thing? Andy
Originally Posted by wsteve464
(Post 21541787)
I admire your DIYness but this is way over built, is will weigh too much to pedal. Check images online to see what is needed in the way of a frame. Have you thought about making a pan type frame/bottom from fiberglass kind of like the VW beetle but fiberglass. Google quadricycle
Forum member cs641 in this thread https://www.bikeforums.net/framebuil...-builders.html. says he builds 4 wheel bikes similar to these https://rhoadescar.com/ Maybe he would advise you. Good luck I've checked out some images, including the Rhoades cars--which don't give much protection from anything beyond a light drizzle or a very sunny day. Sadly, I have NO ability to work with fiberglass. I was planning on using plywood for the actual bodywork. So, let's leave the overall size and shape as it is, and add in the fact that I'd like SOME sort of suspension. Where would I save weight? UPDATE: Just did some calculations, and the weight of the floor frame alone (using 16-guage tubing) alone is about 84 lbs. *Sighs* UPDATE #2 The weight is around 55 lbs if I use 6061 Aluminum at 1/8" wall. *Still sighs* |
Originally Posted by MrInitialMan
(Post 21541217)
Would that be strong enough?
1/8" wall (about 1.5" diameter) mild steel DOM is about what they use for roll cages in racing cars. That's strong enough to crash at over 100mph. But your project has no engine and will be going more like 10mph. You want to keep it as light as you can. 1/16" is already overbuilding. |
Originally Posted by Andrew R Stewart
(Post 21541680)
I suspect a lot of us here wonder about the strength of the rider being enough.
Originally Posted by Andrew R Stewart
(Post 21541680)
I forget why you feel the need for suspension. A performance go cart frame can see one wheel lifted an inch+ off the ground and still have the other three wheels stay on the ground. How much weight will you be placing in this thing? Andy
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Originally Posted by guy153
(Post 21541947)
I think an e-bike as has been suggested is a very good idea.
A four-wheeled vehicle with a motor of any kind is a passenger car and subject to all regulations thereof. This is what I got from the Alberta DOT, and that's a can of worms I do NOT want to open. By the way, do you guys think that in the floor frame I could get away with 1x1" and 1x2" 18-gauge tubing? That drops the weight of the floor frame down to 44 lbs. Even 16-guage brings it down to 58. Or maybe even 1/8th" wall aluminum tubing of the same size? |
Originally Posted by MrInitialMan
(Post 21541959)
There is no such thing as a four-wheeled e-bike in Canada; power-assisted bicycles are described under Canada's Motor Vehicle Safety Regulations (C.R.C., c. 1038) as (amongst other things) " is designed to travel on not more than three wheels in contact with the ground."
A four-wheeled vehicle with a motor of any kind is a passenger car and subject to all regulations thereof. This is what I got from the Alberta DOT, and that's a can of worms I do NOT want to open. By the way, do you guys think that in the floor frame I could get away with 1x1" and 1x2" 18-gauge tubing? That drops the weight of the floor frame down to 44 lbs. Even 16-guage brings it down to 58. Or maybe even 1/8th" wall aluminum tubing of the same size? |
Originally Posted by MrInitialMan
(Post 21541959)
There is no such thing as a four-wheeled e-bike in Canada; power-assisted bicycles are described under Canada's Motor Vehicle Safety Regulations (C.R.C., c. 1038) as (amongst other things) " is designed to travel on not more than three wheels in contact with the ground."
A four-wheeled vehicle with a motor of any kind is a passenger car and subject to all regulations thereof. This is what I got from the Alberta DOT, and that's a can of worms I do NOT want to open. |
Originally Posted by wsteve464
(Post 21542419)
Based on this and the overall weight you have to pedal I'd seriously think about about a 3 wheeler so I could hook up a motor. Use a cheaper suspension fork in the front and a trailing arm suspension in the rear with an electric motor in the front wheel or adapt one of the mid drive motors to the rear wheels and you could probably hit 30+ mph on the flats. Or easier to make as far drive train (and guaranteed fun) reverse the 3 wheeler and put the two wheels in front use a mid drive motor for the single rear wheel. :)
... where's the "digging in heels" smiley? |
Originally Posted by MrInitialMan
(Post 21543220)
It will be a four-wheeler.
... where's the "digging in heels" smiley? Well if it gets done at least you will be in great shape . Ok last idea :) have you thought about a 3/4 inch plywood floor, instead of a metal frame, with a couple of metal cross braces to hold the wheels, that's it. And I am going with bonkers. :) I wish you the best of luck. |
What I actually had an idea of was to replace some of the crossbraces with flatiron, and much of the side tubes and the diagonal tubes with angle iron. Most of my weight will be on the center, anyways.
And the plywood sheet would be even worse for weight. |
I will defend your right to try projects that might seem like poor choices:)
Have you thought about the wheels and tires much? Tensioned spoke wheels have a very high strength to weight ratio IF the forces are kept in plane with the wheel's structure. The cars of yester year got away with thie design by having a very wide rim and more then two "sets" of spoke bracing between the hub and rim. Bicycle wheels lack these elements. Your 4 wheel design will not readily allow for the wheels to lean into the turn like a bike's do. Likewise the tires ability to not deform under turning forces will be challenged. Designing the front suspension and steering geometry well will mitigate this to some degree (pun intended) and canting the rear wheels like some wheel chairs do will help that end of your machine. As to the frame members I know thin wall Cro Moly tubing well so would likely use that. I braze, not weld, so would use that joining method. I likely would use various diameters and wall thicknesses depending on my thoughts about the stress levels each might see. I would hope that .035" and .049" walls would be enough for most parts. But I'm no engineer so... Andy |
Originally Posted by Andrew R Stewart
(Post 21543515)
I will defend your right to try projects that might seem like poor choices:)
Have you thought about the wheels and tires much? Tensioned spoke wheels have a very high strength to weight ratio IF the forces are kept in plane with the wheel's structure. The cars of yester year got away with thie design by having a very wide rim and more then two "sets" of spoke bracing between the hub and rim. Bicycle wheels lack these elements. Your 4 wheel design will not readily allow for the wheels to lean into the turn like a bike's do. Likewise the tires ability to not deform under turning forces will be challenged. Designing the front suspension and steering geometry well will mitigate this to some degree (pun intended) and canting the rear wheels like some wheel chairs do will help that end of your machine. As to the frame members I know thin wall Cro Moly tubing well so would likely use that. I braze, not weld, so would use that joining method. I likely would use various diameters and wall thicknesses depending on my thoughts about the stress levels each might see. I would hope that .035" and .049" walls would be enough for most parts. But I'm no engineer so... Andy As for geometry, I know the steering setup is over-complicated. That's so that the steering can be adjusted. How much more expensive is Chromoly compared to steel or aluminum? |
Originally Posted by MrInitialMan
(Post 21543363)
What I actually had an idea of was to replace some of the crossbraces with flatiron, and much of the side tubes and the diagonal tubes with angle iron. Most of my weight will be on the center, anyways.
And the plywood sheet would be even worse for weight. Cromoly is about 3x the price of mild steel here but it might be different where you are. Bear in mind though that very thin-wall tubeis much harder to weld. Also, although it's stronger than mild steel it isn't any stiffer, so you will want large diameters and might need a bit more triangulation spaceframe type stuff going on. Aluminium might be an idea but you need to be sure your design will be OK for fatigue and things-- steel is much more forgiving. |
Originally Posted by guy153
(Post 21543738)
Tubing is usually better for a lightweight structure than flat bar or angle iron because it's so much better in torsion. The thinnest flat bar or angle you (normally) get here in the UK is 3mm ("hot-rolled"). A piece of 3mm angle iron is going to weigh about the same as 1/16" wall square tube of the same length, but the tube will be stiffer in bending and much better in torsion. The best bang for your buck is usually to use quite thin-wall but large diameter tubes (1.25" and above). The large diameter gives you a lot more stiffness. Steel is much stronger than you think so you're normally designing for stiffness not strength. Square or rectangular tube is very easy to cut and weld because it doesn't need to be mitred and you're welding in straight lines, but round is a more optimal shape.
Originally Posted by guy153
(Post 21543738)
Cromoly is about 3x the price of mild steel here but it might be different where you are.
Originally Posted by guy153
(Post 21543738)
Aluminium might be an idea but you need to be sure your design will be OK for fatigue and things-- steel is much more forgiving.
Originally Posted by guy153
(Post 21542220)
How thick are your 16-gauge and 18-gauge? I think American gauges may be different than UK ones (in the UK 16 gauge is about 1/16")
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Originally Posted by MrInitialMan
(Post 21543748)
Aside from comfort, the other reason I wanted to have a suspension system is to cut down on torsion to the frame. I've seen some velo vehicles where the frame actually broke and had to be rewelded.
Again, suspension system. Would that be enough? :). |
Originally Posted by guy153
(Post 21544415)
Yes suspension is good. But it will increase the budget quite a bit because the springs and shocks and things are all a bit pricey. I would go with 1/16" wall mild steel tubing which will be strong enough with or without suspension and cheap enough to make a few mistakes with and make the design up as you go along. If it all works well can consider rebuilding with more exotic chromoly later.
I was also thinking using 1X2" rectangular tubing for much of the floor frame, with the tubing "on edge" so to speak. Also, a bit off the topic of weight (sort of), would you all agree that I should have brakes on all four wheels? |
Originally Posted by MrInitialMan
(Post 21544772)
Well, I know the suspension will be a bit pricy, but a wise person once said "If you do not engineer a point of flexibility into something, it will engineer one for you."
I was also thinking using 1X2" rectangular tubing for much of the floor frame, with the tubing "on edge" so to speak. Also, a bit off the topic of weight (sort of), would you all agree that I should have brakes on all four wheels? The only alternative to bicycle brakes I can think off is to use one car or motorbike disk brake on the rear axle like a go-kart. This would give you all the heat dissipation you could ever need on long descents. Bicycle front brakes could assist with emergency stops and day to day braking. |
I am going to enjoy this build, please keep us updated?
Since it is just for one person + load could you make the chassis much narrower to save weight and resist torsion. This would give you more room for suspension which could then be something as simple as transverse leaf springs. I am no expert by the way :-) |
Okay, taking some of the advice--particularly that I'm underestimating the strength of steel, do you think I could get away with a floor frame like this:
CarCycle Design #3 I haven't put in the measurements for the floor frame, but I have for the overall body. For the floor frame, I managed to save around 24 lbs, so it's about 60 lbs instead of 84.
Originally Posted by mikeread
(Post 21545203)
I am going to enjoy this build, please keep us updated?
Since it is just for one person + load could you make the chassis much narrower to save weight and resist torsion. This would give you more room for suspension which could then be something as simple as transverse leaf springs. I am no expert by the way :-) |
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