The fast pace of life requires one to quicken one’s pace. Every cyclist, even those who cycle for exercise, would rather have a lighter and a faster bike, but for commuters it is not just the matter of preference. Actually having a different bike may affect the user’s perception of a “long distance” in terms of time and energy consumption for commuting by bike. A human being can travel on a bicycle at low to medium speeds of around 10-15 mph (16-24 km/h) using only the power required to walk. PRO-STRAIGHT aims to achieve an average speed of 30 Km/h for exactly the same power... for a speed of 30 km/h almost 75% of effort required is order to overcome aerodynamic drag. Just by knowing this we can realise the importance of reducing the frontal area and setting a better air flow... W(aerodynamic drag) = p/2.Cw.A.V² P = air density Cw = drag coefficient A = frontal area V = speed. Less drag results in less effort, higher speed and longer commuting in the same period of time. Here is the question: “how far do you consider a long commute by bike?” would you consider 10 km as long a distance by bike if you could travel it by doing just less than half an hour of easy peddling?
See also : INFLATABLE FAIRING FOR BIKES
Great design. I really like this bike. Your work is amazing. Keep up to great work.
ReplyDeleteThis is a really interesting design. It is a good combination of aerodynamics and a powerful body angle. I would love to try riding it. I wonder how long it would take for my shoulders to be rather tired? It looks like they are holding up a significant amount of the rider's weight.
ReplyDeleteBuild one and tell us what it is like.
Do not build one.
ReplyDeleteReally like the thinking. It looks like it would be great in a straight line but could be hard work on tighter turns as you're having to steer through your elbows, or lift yourself up to steer through the aero bars. A could also imagine neck strain could be an issue over longer periods due to the low body angle. Should be rapid, in theory.
ReplyDeleteWhat about the fit of the seat and sensitive anatomy? This design looks great but calls for a seat without an extension between the legs (these seats are available) and a chest rest to take some weight off the arms.
ReplyDeleteYeah, this looks really interesting. I've often thought about this - more for pedalling efficiency than from the aero angle.
ReplyDeleteThe only thing I'd be concerned about is the amount of pressure on my nether regions. Would be interesting to build one and see though.
Problems:
ReplyDelete1) Most of the weight is on the front wheel. The "optimal" weight distribution for bicycles is somewhere around 45% front, 55% rear. On this design, I guess over 60% of the weight is on the front wheel. This causes lack of traction and danger of fishtailing when cornering with high speed. It also makes steering very quick.
2) TT-style handle bars are notoriously difficult to operate. They are actually forbidden in mass start bicycle races because of the decreased amount of rider control. Combine this to the front-heavy weight distribution and you have a death machine.
3) Despite the split saddle design, this bike places a terrible pressure on the male reproductive organ. No human male will be able to ride this device comfortably.
And as aelazenby said
ReplyDelete4) Shoulders carry all the weight that is on the front wheel. The rider needs to have very powerful pecs and neck muscles to ride this. Training those muscles is counterintuitive when the objective is to move quickly on a vehicle operated by rider's legs.
Sorry to spoil your fun, but please do some research before flooding the net with half baked designs. There already exists a load of recumbent bike designs that are just as "quick" as your design but have none of the flaws you designed into it.
I guess "at rest" position would be to lean on your forearms.
ReplyDeleteYou don't need to build the bike to demonstrate the feasibility of this bike's position. Lie prone on the ground like you're about to do pushups. Fold your elbows so your arms are in the position shown in Mohsen's diagram. See if you can even last 5 minutes in that position (the answer is likely "no").
ReplyDeleteI have actually ridden a custom bike in this geometry, and it was difficult and uncomfortable to ride. The UCI banned the recumbent configuration, and ignored the prostrate design for a reason.
ReplyDeleteThank you guys for the comments.
ReplyDeletefirst of all: I am not a bicycle designer.
by the way this idea occurred to me and I thought it was worth to be presented, so I tried to develop the idea despite of presence of many defects as you guys have just mentioned some of them...
I appreciate your comments and would consider all of them for designing Beta version(in case of Re-design if it happens to make a prototype).
There is no point in even thinking about redesigning this. Prone position never works. To make it "somewhat usable" one would have to use a support under the torso, but then all the weight of the rider would lie on the organs we use for breathing: lungs and diaphragm. Good bye aerobic performance.
ReplyDeleteDon't design bicycles if you are not a bicycle designer. Do something you are qualified to do instead. That is what smart people do.
@ aelazenby, I am also wondering how long it would take for me to be rather tired but i think in this position, instead of shoulder, it's chest muscles that would bear the most tension, i am hopeful that a cyclist body would be able to bear this weight more than what Yokota assumes(yet it requires a test)
ReplyDelete@ Asb:
Thank you for your detailed discussion, it is more helpful than just rejecting it or even giving compliments.
in reply:
1- as you already mentioned, vehicles with more weight on front wheel tend to steer quickly , it could be corrected by applying a trail of maybe 60 mm and on the other hand this trail could compensate the difficulty of steering and replacing it by just leaning in high speed.
2- you are right about "decreased amount of rider control" but you should also consider that in this bike the center of gravitation of biker is at least 20 Cm lower than a normal bike, and you know that in high speed the torque of this inertial force is the cause of fishtailing and lifting rear wheel in case of braking. so there is some benefits in lowering the center of mass which may compensate this decreased amount of control.
3 about the saddle and repruduction organ, if you rotate the picture 15 degree C CW till the saddle looks even. you would see that placement of the body on the saddle looks quite the same as normal bikes. in contrary of what you think i guess the thing that would disturb rider would be sliding on the saddle downward which is something really tiring.
HaHa :)
ReplyDeleteThank you Asb for recommendation... I am already doing the same, take a look at the rest of my projects, I would be glad if just one of them satisfies you ;)
Wow, what a bunch of angry internet haters you all are!
ReplyDeleteI agree that this design has some problems... but prone bikes aren't a terrible idea - I think they are actually incredibly fun, if quite dangerous.
For starters, you should look at the H-zontal bike
http://www.youtube.com/watch?v=d-akkbNyiXE
Which is a similar design but has solved a lot of the seat and neck strain problems your design would encounter.
If you want an easy way to test out riding a prone bike without finding one or building one, borrow a tandem from someone or a bike shop! All you have to do is take out the driver seat, put your feet on the stoker pedals, and your hands on the driver handlebars, and you have a very simple prone position bicycle.
Ultimately, the usefulness of a (forward facing) prone bicycle is limited, I think, because they will never be allowed in UCI bicycle races, they inherently put your most vulnerable parts (head and neck) at the very front of the bike, and their aerodynamic advantages are nothing compared to just putting a fully enclosed fairing on a safer and easier form of recumbent (like a low-racer style)
But that doesn't mean they aren't fun to ride! And design, I suppose.
This looks awesome! Have you made a prototype yet? Let me know if it's ready for sale. I would really like to buy one of these bikes. I actually had the same idea myself. But thought that someone must've invented it already. Which it was :) I think u should really develop this great idea if u have time and money to do it. Best wishes and good luck!
ReplyDeleteEngineering is all about the excitement of overcoming seemingly insurmountable problems. Human history proves that again and again. Here is a small suggestion to the weight distribution/traction problem: move the rear wheel closer to under the pelvis until it carries the ideal 55% of the body and move the front wheel forward with a simple articulated steering system. The pedals and crankset can be mounted up and behind the rear wheel. The bike will be longer with the pedal arrangement set on back but the purpose of this bike would be speed and efficiency not drop-dead-gourgeous-ness.
ReplyDeleteThanks Phil. In fact last year Graeme obree already designed the prone bike with configuration that you suggest in an effort to to break the record of HPV.
ReplyDeleteWomen can choose between a women's specific road bike, or a unisex road bike. Many bike brands report data that shows women have a sorter wingspan (arm length) on average when compared to men of the same height. Therefore, best electric bike for women are generally shorter in the top tube, to cater for this.
ReplyDelete