Dual Suspension Recumbent???
Discussion
Oh-kay so I have been bored at work today and have been thinking about the crankset of the bike.
The Dawes one is adjustable so I need to incorperate this into my design to make fabrication a lot easier and also make the bike easier to live with. I'll use my 34 inside leg as a median so taller and shorter people can use the bike just as well.
If the crankset is clamped into place I don't need to be as exacting with the fabrication. I was worried that the crank would be at a slight angle due to the welding process or issues with jigging during fabrication. The tollerances involved with a front wheel drive bike are a lot less than a rear wheel drive one due to the chain lengh. Every time I pedaled the uneven weight would be transmitted through the drive wheel and steering making the bike unstable and possibly unsafe. With a rear wheel drive bike this would be transmitted through the frame and less obvious.
The Dawes one is adjustable so I need to incorperate this into my design to make fabrication a lot easier and also make the bike easier to live with. I'll use my 34 inside leg as a median so taller and shorter people can use the bike just as well.
If the crankset is clamped into place I don't need to be as exacting with the fabrication. I was worried that the crank would be at a slight angle due to the welding process or issues with jigging during fabrication. The tollerances involved with a front wheel drive bike are a lot less than a rear wheel drive one due to the chain lengh. Every time I pedaled the uneven weight would be transmitted through the drive wheel and steering making the bike unstable and possibly unsafe. With a rear wheel drive bike this would be transmitted through the frame and less obvious.
Former suspension geometrist and designer for Lotus (A.K.A Dad) had a look at my designs and suggested this instead. 
Welding on to the original frame and running a chain to the smallest cog on the existing crankset to gear it up. Could be done by cutting the down tube from the spare frame and welding it in place. Thing is I don't have a T.I.G for Aluminium work and it would require buying a second crank set and chuffing long chain. So the original design brief to build a kit that can be fitted to a bike without buying any new parts isn't forefilled by this design. Would be quick though.
Welding on to the original frame and running a chain to the smallest cog on the existing crankset to gear it up. Could be done by cutting the down tube from the spare frame and welding it in place. Thing is I don't have a T.I.G for Aluminium work and it would require buying a second crank set and chuffing long chain. So the original design brief to build a kit that can be fitted to a bike without buying any new parts isn't forefilled by this design. Would be quick though.
Some mad French man built a bike a few years ago that you needed to lay flat to ride. Hmmmm, I think he missed a trick here. If you are pedaling over the rear wheel why not have a hand crank over the front wheel as well?
Two wheel drive and as aerodynamic as a Crester runner.
Sunday morning at work guys. Sorry.
Two wheel drive and as aerodynamic as a Crester runner.
Sunday morning at work guys. Sorry.
Today I planned to make the fork braces but.....
...I got a bit further than expected. Not my usual (border line OCD) standard of welding, because my poor little M.I.G is knackered.
Had a problem with the mock up frame. The space between the fork support and tube is different.
I could have made a spacer to make up the difference but the down tubes were different diamiters as well.
So I decided to fit the clamps to the forks and quicly tack the frame in place.
This is how far I got before I ran out of gas. Grrrr!
...I got a bit further than expected. Not my usual (border line OCD) standard of welding, because my poor little M.I.G is knackered.
Had a problem with the mock up frame. The space between the fork support and tube is different.
I could have made a spacer to make up the difference but the down tubes were different diamiters as well.
So I decided to fit the clamps to the forks and quicly tack the frame in place.
This is how far I got before I ran out of gas. Grrrr!
I am assuming this is going to be front wheel drive as if it isn't what is going to happen to the chain alignment once you turn a corner?
Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
Roman said:
I am assuming this is going to be front wheel drive as if it isn't what is going to happen to the chain alignment once you turn a corner?
Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
I've seen them and I'd rather do something different. Besides front wheel drive would make better use of the parts I already have. Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
Liquid Knight said:
Roman said:
I am assuming this is going to be front wheel drive as if it isn't what is going to happen to the chain alignment once you turn a corner?
Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
I've seen them and I'd rather do something different. Besides front wheel drive would make better use of the parts I already have. Would it not (for example) be much simpler to run your extended bb section forward from the headtube (as per one of your earlier drawings) & run a linking chain down to the inner ring of your triple chainset?
Several examples of a similar set up on youtube.
The donor frame put up a valient fight but with a little help from my grinder (to heat the frame a little) gave up the sealed crank.
Hats off to the guys from Wisbech engineering again the crankset fits a treat.
Have noticed a slight miscalculation though.
I'll take a hammer and grinder to that in the morning.
So my slight oversight....
...oops. Lucky I spotted it before I tried fitting a chain. The rear mount is welded at 90 degrees to allow an elevated angle because my original plan was an underseat steering mechanism. Due to this possition making the weight too far forward and the bike unstable I changed my mind (I do this a lot). It could be worth making it slightly less than original so I can fit a bigger crankset.
Measure twice (or at all) etc etc.
...oops. Lucky I spotted it before I tried fitting a chain. The rear mount is welded at 90 degrees to allow an elevated angle because my original plan was an underseat steering mechanism. Due to this possition making the weight too far forward and the bike unstable I changed my mind (I do this a lot). It could be worth making it slightly less than original so I can fit a bigger crankset.
Measure twice (or at all) etc etc.
BliarOut said:
Measure twice? I think you'll find that's 600mm and 400mm
Metric System! I measured it with cold hand and cut it with warm ones. It's all been my tried and tested "that looks about right-ish" level of accuracy so far. The bike doesn't have to work to win the bet (prove the consept) I just have to build it.
Edited by Liquid Knight to add corrected picture
Edited by Liquid Knight on Thursday 23 December 09:32
You do know that the moment you steer you'll lose the ability to pedal?
When you "set a bike up" the basic rule of thumb is to put your heel on the pedal with it in it's lowest position for maximum efficiency. Your stroke length will continually vary with the position of the steering.
Did I miss why you didn't affix that extension to the headstock instead of the forks?
You're mad, it'll never work and I want to see the inevitable crash on YouTube
When you "set a bike up" the basic rule of thumb is to put your heel on the pedal with it in it's lowest position for maximum efficiency. Your stroke length will continually vary with the position of the steering.
Did I miss why you didn't affix that extension to the headstock instead of the forks?
You're mad, it'll never work and I want to see the inevitable crash on YouTube
BliarOut said:
You do know that the moment you steer you'll lose the ability to pedal?
When you "set a bike up" the basic rule of thumb is to put your heel on the pedal with it in it's lowest position for maximum efficiency. Your stroke length will continually vary with the position of the steering.
Did I miss why you didn't affix that extension to the headstock instead of the forks?
You're mad, it'll never work and I want to see the inevitable crash on YouTube
About two seconds after I thought of the idea I knew it wouldn't work or would be very limited but a friend of mine said... When you "set a bike up" the basic rule of thumb is to put your heel on the pedal with it in it's lowest position for maximum efficiency. Your stroke length will continually vary with the position of the steering.
Did I miss why you didn't affix that extension to the headstock instead of the forks?
You're mad, it'll never work and I want to see the inevitable crash on YouTube
"if you build that I'll eat a cats arse"
...so it has to be built. There's a McDonalds on it.
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