Back to the subject matter;

Bicycle aerodynamics are very difficult. We all know that most of the aerodynamic drag comes from the rider, and that the frame/wheels do not contribute more than 20-25% to the overall bicycle drag. It is also convenient to think that there isn’t much benefit to improving the bicycle frame and wheels aerodynamics since the assumption is that the current aerodynamics solutions for bicycles are so good that any further improvement is deep into the “diminishing returns” area.

However, improvements are possible, but due to the peculiarities surrounding low speed, low surface area aerodynamics (low Reynolds number), they are very hard to identify and implement. Air behaves very differently in the bicycle racing realm than it does around cars, Formula 1, or air planes. The basic principles are the same, but the “devil is in the detail”. This minor detail is called induced drag. None of the current bicycle designs come close to solving this problem. While just about any medium to high aspect ratio (how long it is versus how thick it is) airfoil, or even truncated airfoil (cf. Kamm) will do very well in zero to shallow angles of attack (yaw), none of them can cope well with higher angles of attack starting at about 5 degrees…or better said, they are all as good as each other with very minor differences. See the image below for visualisation of induced drag at 5 degrees angle of attack. This airfoil is otherwise a very well performing design.

Extensive vorticity is present, causing significant induced aerodynamic drag.

We will change the lay of the land and deliver the first truly aerodynamic bicycle design, and the first ever airfoil designs that work at the bicycle scale. This is not an empty (vacuous) boast, so how will we do that?

See the press release below…

Velocite and NCHC set to revolutionize aerodynamic bicycle design

Velocite Tech Co. Ltd. (Velocite) and the National Centre for High Performance Computing (NCHC), a laboratory under the umbrella of the National Applied Research Laboratories (NARL), Taiwan, have signed a cooperation agreement aimed at solving and developing an aerodynamically optimized bicycle – designed completely by a supercomputer.

Following an exhaustive search for a development partner, Velocite has partnered with the NCHC to develop the next generation of aerodynamic bicycles using specially developed algorithms employing both Computational Fluid Dynamics (CFD) simulation and Genetic Algorithm (GA) optimization engines conceived and written by NCHC researcher Dr. Matthew Smith and a team of researchers from the Applied Computational Engineering (ACE) and Applied Scientific Computing (ASC) divisions.

Among the significant resources that are made available to this joint project is the GPU  supercomputer housed within the NCHC location in the Tainan Science Park. This GPU based supercomputer was constructed and configured by NCHC staff and possesses more than 240 Tesla computing devices and approximately 8.4 TB of total system memory, making it one of the most powerful computer systems in the world.

The major determinant of the level of detail, and therefore the real-life accuracy, is the number of cells in a 3D mesh that defines the object that is being studied. Previous CFD work conducted on bicycles was limited to approximately 20 million cells. Because software for the collaborative project is written by NCHC researchers specifically for the GPU supercomputer, the 3D mesh employed by the CFD solver can potentially have in excess of 2 billion cells. The ultimate goal of the NCHC is to simulate the complete bicycle in motion, including a moving and pedalling rider derived from 3D scans.

Optimization of the design will be conducted by a genetic algorithm where the final solution evolves over successive breeding generations. It is expected that approximately 500 generations will be required, resulting in at least 7500 individual CFD simulations. This means that during the course of optimization at least 7500 individual aerodynamic bicycle designs will be evaluated and tested automatically by the artificial intelligence GA for aerodynamic performance before the optimal design is found. “Without the supercomputers and our fast CFD algorithms, this task would be impossible.” said Dr Smith. Even so, the final simulation run will take in excess of 25 days to compute – the same task, running on a standard desktop PC, would take over 150 years to complete.

“We are absolutely thrilled to have NCHC and Dr Smith engaged with Velocite to perform this much needed research on bicycle aerodynamics.” said Victor Major, Velocite CEO. “After spending considerable time looking for suitable partners and staring in the face of staggering costs for this type of work, we were forced to either reduce the scope of development, or to abandon the aerodynamic optimization project altogether. With NCHC, Dr Smith and his team on board, we now have more engineering and development capability at Velocite than we ever expected to obtain.”  also said Mr Major.

Due to the groundbreaking nature of this joint development project significant new technological and design breakthroughs will be achieved. Velocite and NCHC will publish some of the findings in relevant scientific and engineering journals, detailing the experimental method and results for independent review and public reference.

The objective expectation is that the resulting “truly computer generated” design will be the most aerodynamic, non-recumbent bicycle possible given modern computing technology. To ensure that the best design is manufactured Velocite will not consider the UCI limitations and will therefore deliver a bicycle aimed at triathletes and cycling enthusiasts seeking only the highest performance. The bicycle frame and rims will be made using Velocite’s advanced carbon fiber composites manufacturing and material science skills, thus ensuring that the riding performance remains at the best in class level regardless of complexities of the final design.

Velocite 1.5 TiB headset

The new Velocite 1.5 TiB headset is the standard headset supplied with all our frames and will also be available for purchase as a standalone part as an upgrade for any bike that uses an integrated headset with 1 1/8″ -  1.5″ tapered head tube for angular contact bearings. Price TBC.

The latest samples of our Gram SL carbon matrix clincher rims are here. This time with all the decals and with what we think is the final specification. The weight with final design decals and top coat is excellent with a consistent 399g per rim. This low weight is very good for non-weight limited 25mm clincher rims, even for full carbon clinchers.

The obvious benefit of Gram SL rims versus full carbon clinchers is in increased safety margin and superior braking performance in all conditions. Versus comparable weight alloy rims, the benefits are higher strength and stiffness. The Gram SL carbon matrix wheelset, once our new hubs are finished (eta January 2012) is intended to challenge any 25mm wheelset in the market in terms of performance, and win.

The Super Noir wheels

What are the Super Noir carbon tubular wheels? They are a wider picture experiment, focused on our own quest for ultimate performance using transparent and independently verifiable scientific methods. To clarify this up front, before I go into the “super” part of these Velocite Noir wheels.

Any scientific, or purportedly scientific data that cannot be verified by a third party due to lack of a documented experimental method is normally declared invalid. Withholding the detailed experimental method information and claiming proprietary secrets also invalidates the experiment and any data that the experiment provided. This of course does not stop anyone in the bicycle industry from claiming empirical (data driven) superiority of their products because data sells, even though it may be about as scientifically valid as astrology.

With that out of the way, back to the Super Noir wheels. The thing that makes them super are the hubs. The Super Noir wheels are built using Velocite Noir 50T and 90T rims laced to Gokiso Aerospace Hubs. Gokiso are a bicycle focused branch of Kondo Machine Corporation, Japan. To save me from paraphrasing the Gokiso supplied product information, here is a link to their site that provides a detailed description of the hub and their design intent: Gokiso Aerospace Hub

The premise of the Gokiso Aerospace Hub is that it just about eliminates any loads on the bearings, except the radial load. This means that the bearings are rarely, if ever loaded in a way that would even momentarily increase their friction. No other current hub design can achieve this feat. Gokiso claim that due to their advanced chassis design and aerospace grade micro ball bearings the Aerospace Hub achieves “5% efficiency improvement” over high end cup and cone hubs. The claimed improvement seems high since in road wheel tests, bearing drag was not seen as a significant contributor to wheel’s overall performance. However, the bench tests were not done in real life conditions, thus we are willing to take this 5% claim and see for ourselves. If the improvement is real, then we have a true winner in our hands since this improvement is “free” (after purchasing the wheelset of course) and constant, regardless of the wind conditions, your position on the bike, or any other external factor.

We will construct a randomised outdoor, actual riding experiment with a control wheelset, using an SRM power meter and time, speed and GPS readings to establish how much improvement, if any, is gained by the special hubs versus “standard” Velocite Noir 50/90 wheels at the constant power output. Randomisation will take care of the environmental variables and rider position changes. Unfortunately it will not be possible to blind (or deafen) the rider and thus avoid the introduction of bias.

I am hoping to start this experiment within a month. It should be interesting. If the results are positive, and replicated by a willing third party following our experimental design, we will have an excellent product for time trials, iron man competitions, and even ultra long distance and marathon events. Otherwise, the 10 year manufacturer’s warranty on the hubs and otherwise expected excellent performance should still win a lot of business for Gokiso and their Aerospace Hub.

Setup: Velocite Selene 2.0 bike with second generation Velocite MONC 50/90 full carbon clinchers, Vittoria Diamate 700x23mm clincher tires at 120 PSI front and rear.
Rider: Victor the CEO, currently at 100kg (220lb).

Sometimes you read about wheelset and rim testing and besides rigorous machine testing you often come across “rode them around the car park, and they felt good.” Well, we have something a bit better than a car park, depending on your perspective. Next to our office we have the largest park in Kaohsiung that features many kilometers of paved and unpaved pathways.

Broken up garden path - rock slabs actually, pretty dicey

None of these pathways are what you could call smooth which makes them perfect for what I had in mind. I decided to follow up on our previous model’s off-road testing with much more intense off road loop on the new MONC 50 and MONC 90 carbon clincher wheels. Unfortunately as any MTB rider knows, photos rarely capture the actual nature of the trail, but taking a video would have been pointless and potentially nauseating to the viewers due to incessant vibrations and jolts.

Also, just like other road bike riders know, actually riding a road bike off road is not hard, it is downright fun, and if you are confident in your equipment and your skills I suggest that you try it. Just keep your speed sane since 23mm tires can only provide limited amount of grip, especially when cornering.

Unbelievably rough chiseled paving stones. Riding over them was positively unpleasant, especially at lower speeds.

Nice paved path through the park, not recommended for riding over it.

The off road testing circuit included this lovely paved path. Lovely if you are a pedestrian. Riding over this surface is very similar to sitting on a jackhammer, or operating a high powered masonry hammer. It looks a lot smoother than it is.

I now realized that I actually did not say anything about the wheels. Well, nothing happened, and nothing continued to happen, thus breaking with the good story writing principles, I will tell you what happened in the end. Nothing. Nothing at all. I never felt a slightest bit of care, uncertainty or anxiety (not wheel related, only “OMG, am I truly going to ride down, over, through that on my road bike?”).

There was no pinging, no clicking, no rubbing and after all the abuse and disregard, they are still true, with only the front wheel with a slightly perceptible wobble in one spot. I consider that rather good for a 20 spoke road wheel that was ridden by a 100kg dude, off road for over 5km. I will not get it trued since it is truly minor and I only mention it since it is there.

Right then, moving along.The park also features some nice trails with the usual collection of roots, rocks, mud and bumps.

Hard pack, gravel and grass. Holes and rocks too. It is a lot rougher than it seems. Some sections are water damaged and have severe dips and corrugations.

Forest trail, roots, rocks, undulations, and Velocite Selene with MONC50/90 wheels. In art this would be called juxtaposition, I thought it was a really nice ride.

Blasting through the singletrack was a lot of fun. I have to admit that I first took my newly reconfigured for touring titanium Velocite Millennium bike with Vittoria Randonneur 700x28mm tires and prototype alloy 24/28 spoke wheels. The Selene with MONC carbon wheels was no less fun, and if anything, it was even more stable – it felt like it was on rails even on loose soil.

Hard pack singletrack. Very nice and fast.

In conclusion, yet again, the Velocite MONC50/90 full carbon clincher wheels were for all intents and purposes unaffected by their off road trial when ridden by a 100kg  (220lb) rider, mounted on a Velocite Selene alloy road bike. During the intense off-road testing the Velocite MONC wheels proved to be very strong, reliable and confidence inspiring. I look forward to having enough time to take them for a nice long road ride next.

More information about Velocite MONC wheels: Velocite MONC

The presentation ceremony will be held in Taipei on the 20th of June 2011.

To speed up the deliveries of the current outstanding orders, wherever possible the frames will be airfreighted directly from the factory to you.

On behalf of all of us at Velocite I sincerely apologize for the delays and I thank you for your truly outstanding patience during this time.