I would ride it, looks interesting. I am curious about how stiff that rear 2/3 triangle is. Same type of idea as the Bp Stealth a while back. It was stiff enough, be pretty heavy. Also, did you actually get a wind tunnel data on this bike? Kind of curious how that frontal portion of the bike looks in the tunnel. It looks like those two beams bending over the front wheel would move the airflow around quite a bit. Cool effort!

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Yes, I shave my legs. Yes, I am comfortable with this. I am enlightened.

The frame has been inspired by quite a few bikes! Boardman's lotus bike, Yamaguchi actually built a track bike in a similar Z configuration also. At the moment its stiff enough for my 120lbs to not feel like a wet noodle. My consideration was that in most tri races, you would only stand to get up to speed and for hills - the rest of the time should be spent smoothly spinning the pedals...:-) In any case, it would be like putting energy into a large steel spring - I suspect you might not lose very much.

I'm planning to get it tested in the windtunnel when the weather warms up. I've helped out in a couple of session when it was 32F outside - with a 30mph windchill it was even worse inside! I originally wanted to have just one tube for the fork - but it needed to be stiffer so I added another tube. Even so, there is a theory to why I added it on like that which I will eventually try and prove with results. But if looks are anything to go by, I think it is as clean as you can get without some fancy carbon work.

Are you kidding me? Not a freakin' chance...the colour doesn't match any of my kit.

I love seeing innovation like this...keep us posted

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blood, sweat...and big gears

I hated every minute of training, but I said, ''Don't quit. Suffer now and live the rest of your life as a champion.''
- Muhammad Ali

Ha ha... I'll make sure that I have a range of lurid luminous colors that customers can choose from when I finally get it into production...

What is the virtual rake on that bike? Interesting set-up!

The trail is similar to my road bike - about 5.75cm. The sliding dropouts would allow me to increase (or decrease) the amount of trail depending on the course, how windy it is and also what aero wheel I would want to use. More trail for more stability. Less trail for more twisty courses.

I don't like it. Weird green color. Funky front end.
Nothing much could ever come of a bike like that...



Hey, wait a minute...

Brad

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3SIXTY5cycling.com

Looks like one wouldn't have to worry much about front wheel contact in close quarters. ?????

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Dick

Take everything I say with a grain of salt. I know nothing.

Thanks for the vote of confidence... :-)

Yes, the bumper bar function did come to mind when I initially designed it... makes a great place to mount lights as well... ha ha

I love the idea and design, but i wouldn't ride it without some MAJOR reinforcement at the head tube junction and both of the seattube connections. On another note I bet it rides smooth due to the inherent flex of being highly cantilevered.

The fortunate thing is that the amount of flex was quite balanced between the front and the rear - i.e. the bike bounces up and down rather than rocking back and forth like a seesaw. The lateral stiffness is not too bad given the design. The suspension effect was a deliberate design for comfort in a long distance tri race. I haven't been able to measure it properly but I think I might have about half and inch of give...

For the moment, I'm trying to keep the bike looking as clean as possible and I'm depending on the thickness of the material to hold the loads (its nearly aluminum thickness but in steel!). I definitely would have to do more load testing to make sure the design is strong and safe enough if it ever went into production. Since its just for me, I'm willing to take a little more risks...

wild thinking. looks crazy, but i like it.

before you take it to the tunnel, or have a carbon version made, or make version 2.0 :

if you are trying to keep the fork blades 'horizontal' to minimize drag, i bet aero drag on the front wheel could be far better reduced by having a fairing behind the front wheel rather than in front of the wheel (but this would only work if you could sculpt it, such as with a carbon composite, to hug the back of the wheel and end with a nice trailing edge). so maybe you should try that when you build your next fork. this guy has tried something similar, but he shaped the frame quite differently.





on your other question, tri rules are pretty wide open. if the bike was safe, i think your design would be legal for most tri racing in the usa.

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Where would you want to swim ?

I've met Brent Ruegamer before - he builds great bikes! In fact, this bike was also another thing that got me going to try and build something better...

If you looked at the closeup pictures of his fork, the rear part of his fork acts like a cup and I think would cause more drag. I think that if it was a convex (like the leading edge of some of the aero down tubes) rather than a concave (which seems to partially enclose the tire) it might do better. For my fork, I just moved what seems to work for the rear wheel, i.e. fairings, cut outs etc and move it to the front. I believe that it may work better because the air up front is not turbulent before it reaches the fairing so the fairing can work better. The rear fairings probably also work to an extent - but I think that it is less effective because the air would be very turbulent by the time it reaches the rear of the bike.

The other theory that I wanted to test is this balance and optimization of both frontal and side profiles. I think that in a real world situation that a rider will mostly be facing a crosswind. If you buy that, then you also want to minimize the side area to reduce the component of rearward drag on the bike. I think that in the end, you have to make the trade-off for what application you want to use the bike for. One thing that I think makes the point is the appearance of shorter aero helmets at races like ToC. A longer tail will be more aerodynamic but only if you maintain your position very well. If you can't, then maybe a shorter tail will on balance contribute to less drag over the course of a race - less aero but also less drag when you stick the tail in the air.

Of course, this is theoretical argument on my part and only a windtunnel test will prove which is the better design and why.

I've just made some short videos of my test ride this afternoon - I hope to show that it is at least rideable! Enjoy!

http://www.youtube.com/...t?p=828929614B1F5D1B

Why is this an improvement? Is it a TT/tri bike? Why the around the wheel fork? Is it aerodynamics, novelty...

If it is aerodynamics, there are many things I would take issue with. Even if the handling geometry mimics a road bike the flex may screw with the handling characteristics.

Your idea that a flexible frame returns energy like a spring is wrong. When the frame recoils, it isn't in a direction that would return any energy to hte drive train.

So, basically, my question is why is this better than a double diamond frame?

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tech editor, Triathlete Magazine

Thanks for your questions!

The bike is a prototype to test out some aerodynamic ideas I had - it does trade-off some other things like weight but the design exercise was to focus on the aerodynamics. The fork is design to act like a fairing for the front wheel similar to how many frames claim to shield the rear wheel. The removal of some of the tubes is to remove sources of interference with the airflow - either directly head on or sideways. Another reason is just because I could get away with a more unconventional design and aesthetics. Perhaps you could highlight what other things you have issue with - they will provide me with valuable feedback if I decide to build version 3 :-) In any case, I do intend to test out my theories - it would be great if they work but I'll learn something even if they didn't.

The steering is actually not at all funny - it steers like a normal bike even with the roughly half-inch of flex that it has. Admittedly, I've not yet tried cornering at high speed over a bumpy road - but since I can't let you try the bike to convince you, you'll just have to take my word for it that it steers ok at least for my weight. Have a look at the videos.

You may be right about the spring, I haven't really tested it. But the suspension effect does make for a comfortable ride similar to a softride or titanflex and it is not at all uncontrollable.

thanks.

If you want to test the aerodynamic characteristics of a different few ideas, constructing an entire bike that incorporates these ideas makes it difficult to tease out the benefit of individual aspects of the design. Maybe incorporating each of your ideas one at a time into a bike would give you some useful results. The idea is to compare the effectiveness of each design aspect to the standard/best options, not to put them all together and see what happens. If the fork reduces the drag by 3ArBitraryUnits and the missing down tube increases drag by 2ABU's, you will only see a change of -1ABU, which doesn't really tell you anything without knowing where the changes came from.

• Fairings improve aerodynamics by guiding air around objects that may cause drag. Putting an object in front of another object doesn't reduce the drag, unless that shield is powered by something else. Which is not the case here. Maybe if you put a shell around the front wheel that could guide hte air onto the bike/rider... but that is getting close to an upright HPV.
  
• Eliminating tubes to improve aerodynamics seems counter-intuitive to me. Since eliminating these tubes doesn't greatly reduce frontal area at wind angles experienced on a bike, it may be a penalty rather than a bonus. Discs, deep section tubes, long helmets etc. improve aerodynamics because they guide air around the rider in a smoother manner than their conventional counterparts. Getting rid of tubes, rather than using aerodynamic tubes, may increase drag by allowing more low pressure zones to form.
  

As you said, the validity of the designs is really the point, setting up the experiment in a repeatable way that gives you useful information is.

Good luck and have fun with your project

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tech editor, Triathlete Magazine

Thanks. I agree with the step by step approach - but I've only got so much time and resources while I'm here in the US to do it. So it was a decision to fit in as many ideas as I could into one bike. I would be happy if I get a good overall numbers. Its a hobby and not a full-time job (unfortunately :-) ) Maybe if it showed real promise, I could still break down the various features to isolate the effects, i.e. by swapping out a normal fork, sticking the aero fork into a normal frame etc.

That is a nice looking bike!!!!