A frank talk with the K9 front man and suspension authority about bike setup, data-logging, suspension, and if there really is one design that trumps all of the others.Luis, you are known for being one of the brighter minds in the industry, as well as running your own K9 brand, but tell us about the early days. How did you end up going from Venezuela to living in Oxford, UK, and running K9?I had a great childhood in Venezuela, back then we used to play on the streets and empty lots. Whether it was baseball, football (soccer), BMX, it didn't matter, it was a lot of fun. Most weekends we went to the beach or the mountains. My family was always very active, so we were always water skiing, snorkeling, pier diving, swinging, etc... not really the type to just lay on the sand and soak up the sun. My father was a jet fighter pilot in the air force so we traveled a bit and lived in a few different cities around the country.That must have been very cool to be a young guy and be able to say that your dad flies fighter planes! When did your family make the move to the U.S.?For my father's last year in the service, he was appointed as a military adviser to the UN in 1990, so we moved to Greenwich, Connecticut, when I was thirteen. What's really funny is that we thought that most towns were like Greenwich! I got an after school job as a paper delivery boy around the neighborhood, so my parents bought me a mountain bike (my first ever MTB) and I hated it, I wanted a BMX because we used to ride BMX back in Venezuela. Now I had to ride this huge and heavy bike with gears and it wasn't much fun at first.
Alright, so it wasn't love at first ride with mountain bikes. What about cars?Well, that's funny story. I must have been around nine or ten years old and I was watching an awesome car movie, the original Cannonball, at a neighbor's house. I was fascinated by cars like the Ferrari's, Lamborghini Countach, DeTomaso Pantera, Porsche's, etc... so I began talking to my father as to how I could design and make cars like that and he told me that I would need to be a mechanical engineer in order to do that.I'm pretty sure that at that age I was catching frogs, building forts, and didn't even know what a mechanical engineer did...By the time I was ten years old I was pretty sure of what I wanted to do with my life. I wanted to be a car engineer/designer and work for Ferrari, but as it happens many times, sometimes you change your mind. Everything started in the U.S.A.. The plan was to go Maryville University in St Louis to do pre-engineering, then transfer to Wash. U in St Louis for the undergrad in mechanical engineering, and then do a masters in automotive engineering at Michigan State. When I was in STL, I began to read a British magazine called "Racecar Engineering" and I was hooked. I went every month to Borders (an American book store) to read it for a few hours before buying it. One day I saw an add for Oxford Brookes University which had a motorsports' engineering degree. I spoke to my family, then ditched a skiing Spring break trip to Vail to go check out the school. I liked what I saw, and after my return trip I began to do the paperwork to transfer and move to the sunny Oxford, LOL!So you started off wanting to work on fast production cars, but made the jump to the racing side of things. Why? My plan from day one was to work in high-end motorsports such as F1, WRC, Paris Dakar rallies, etc... anything with 4 wheels that was technical and interesting. I wanted to work in an area where engineers were as valuable as the drivers themselves.When and how did mountain bikes start coming back into your life?I really was not aware of MTB at this time at all, I was mainly into racing cars, football (soccer), and rollerblading was my thing at the time. When I got to Oxford, I noticed that everyone got around using the bus system and bikes. I bought a used MTB for £50.00 and commuted everywhere. One day a friend of mine invited me to go on an off-road bike ride and I loved it, however my bike did not, as it almost fell apart by the time I got home. But it was too late for me, I got hooked on it and wanted to go mountain biking.I think that a lot of riders get their start that way, going from commuting to mountain biking. But how did the big jump to suspension design come about?As I was approaching my last year of the undergrad and the final year project, I really wanted to do a bit of DH, but my bike was not up to the task. So I began to do a bit of research about the type of full suspension designs available e.g. VPP, FSR, Lawwill, single pivots, etc... because I wanted to know how they all compared to each other before I spent my savings on my first DH bike. After awhile I thought that there was room for improvement and talked to my advisor at the university about doing my project on bicycle suspension. After graduation I had problems getting a job due to my visa and decided to take my design to market, and here we are.Mountain bikes and race cars are very different vehicles. How does what you know translate to the world of bicycles?Yes, they are quite different vehicles with different characteristics, requirements, and constraints. But cars and bikes are both ground vehicles and the same vehicle dynamic principles still apply to both, so they can be analyzed in the same way. You're saying that, despite our bodies putting out a meager 1hp, the same principles and demands are pertinent?The demands are very similar, but there is still quite a difference. When it comes to power, it is not just the amount of power, but how it is delivered that makes the biggest difference. On a race car, a driver is on the power everywhere except while in the corner entry and the middle of the corner, and the power is delivered fairly constantly until you shift gears, but on a bike it is a lot more sporadic, and not only that, but riders can only produce a sinusoidal power delivery (wave form) rather than the constant delivery of the car.Given what you've said above, can a rider benefit from taking the time to do proper bike setup for a course in the same manner that a race car driver would?Any rider can benefit from a well setup bike. I would like to add that you do not need to be pro lever rider or racer to enjoy the benefit of a good setup; weekend warriors, epic riders, and XC riders (anyone who rides off road) can all benefit from the benefits of a good setup.Do you think that mountain bikers are prone to sell themselves short when it comes to taking advantage of the technology available?This is not as straight forward as it should be. I know that there is all of this technology that will help you ride better, safer, and faster, and it would be foolish not to take advantage of it. But with all the marketing and trends, not all products will be the right one for each and every rider or condition out there. So how do you determine what's truly useful from what isn't, without taking into consideration the placebo effect that if you think it will make you go faster, perhaps it will just because you believe in it and therefore increased your confidence?How large of a part does bike setup play in a World Cup rider's performance? Do any of those guys have questionable setups?I think that at the top level, 90 percent is the rider and the remaining 10 percent is the bike and equipment. A rider who has the skill, ability, and confidence to compete at the top level can ride anything fast, as they can compensate for whatever the bike is doing with their skill and ability. Now if you apply those same skills and abilities with a well setup bike and equipment, their performance will increase. While not all the top pros have a perfect setup, most of them do seem to have their bikes fairly well setup, or with a setup that they like and feel confident on.
From Venezuela, to the U.S., to Oxford to pursue a motorsports engineering degree. Luis then started up K9 Industries after designing the L.A. Link suspension system and offers his data-logging services for those who want to take bike setup to the next level. And no, you don't have to own a K9 to take advantage of his services.
And what about the average rider, there must surely be benefits for them as well to take the time to get some proper settings nailed down?I believe that the biggest differences will be seen by amateur and semi-pro riders, more so than professional riders. To the average rider, the bike and equipment play a bigger percentage in their performance because they do not have the same skill, strength, mental ability as top athletes do, and I am fairly certain that their setup is not as dialed either. So can a regular rider benefit from a well setup bike? Definitely. Where a pro may see between one tenth to five tenths, other riders may see entire seconds of benefit.I could use a few seconds here or there! Moving from setup to actual suspension design; there are many different bike designs out there at this point, with each touting benefits over the others. Do you think that there are one or two that are truly better than the competition?All rear suspension designs have positive and negative characteristics, sometimes it may not be the actual design itself at fault, but the execution of the design. Let's take as an example two single pivot bikes with rocker links: will a Chumba F5 work and feel the same as a Tomac Primer? I do not think so.So you are saying that there is no clear winner, that it is too complicated to simply say that one design is better than another? While the L.A. Link (Luis' own design used on his K9 bikes) is a 4-bar suspension design, I am also a big fan of the single pivot for its simplicity and predictability. However, 4-bars are great because they allow you to manipulate a lot more parameters to achieve what you want. That's why they are used in motorsports, short long arm suspension (SLA is an unequal length, double wishbone design) being the perfect example. But they are more complex and they require a skilled engineer to get the most out of them. Take a look at the FSR, which I think is a very good design. There are so many different bikes using the Specialized design in different configurations, but not all are equal in terms of handling and performance.That is very refreshing and unexpected to hear, coming from an engineer who has designed, patented, and put into production his own suspension system. Alright, one design may not be vastly superior, but there must surely be some overall traits that are mandatory for a bike to be considered great?Well, there are several parameters that will dictate how a bike will perform. These include: sizing, suspension travel, suspension rate, dynamic geometry, axle path, pedal induced torque, pedal kickback, weight, etc... While the overall performance of the bike is determined by the complete package and balance of all these parameters, the two most important factors are sizing and dynamic geometry.
A K9 DH001-S ready to do some testing with a telemetry unit strapped to it. Running telemetry on a mountain bike has been done before, but it's never been available for the un-sponsered rider to take advantage of.
What about overrated qualities? There seems to be a race on to see who can build the lightest production DH bike, but it's not that simple, is it?Weight is an important attribute, but it is not the defining factor. It is not about how much weight there is, but where it is located and what type of weight it is that will have the biggest impact on the performance and feel of the bike. What is the sprung to un-sprung weight ratio? Is it on the swingarm, wheels, main frame, etc...You run your own company, K9 Industries, and not only design your own bike and components, but also offer your data acquisition services for hire. Can you explain the system and how a rider is able to benefit from such a service?The data logging services that we offer is a service which can be tendered to anyone. It is like providing a race car pit service to you on your bike. Basically, we strap a on motorsports-grade data logger (hard-drive) and attach sensors around the bike. Then you get to ride the bike, and after each ride we connect the logger to the computer, analyze the results, and make the required changes according to the data and rider feedback.
I'd say that it's just a touch more complicated than a typical bike computer. Thankfully, it also tells you a whole lot more information that if used wisely, could make you faster and ride with more control. What is going to make a bigger difference to your riding: upgrading from last year's fork to an up to date model, or letting Luis play with the dials on your suspension?
And what sort of results would the rider see from this?The goal of the data logging depends on the costumer and on his requirements. We mainly try to set up the bike so that both front and rear suspension is balanced and works as an uniform system. Racers may prefer to have the bike setup for ultimate speed, while more leisure and recreational riders may prefer a more comfortable ride.So we come back to balance, something that is very important in any form of motorsports. What variables are you measuring?The data is collected through the sensors connected to the data logger unit. We can log a lot different parameters such as: front and rear wheel speed, fork displacement, shock displacement, crank rotation, GPS position, accelerometers, and a few others. From these sensors we can use the software to tell us everything we want to know about the bike.How hard is it to take into account both empirical testing and rider feedback? Is one more important than the other?It is extremely important. You cannot just look at the data and make your decisions based solely on the data, it has to be processed and analyzed alongside rider feedback. Sometimes you have some contradiction between the data and the rider, and you have to determine the cause of it. Remember that the data is the result of what is happening, so sometimes you have to figure out why it is happening. Sounds silly, but it is highly important to ask the right question to the rider to get the right feedback. Sometimes you need to recollect the data as well to verify the previous results.It is common to read about a bike's "balance", or lack thereof, in a review. You touched on it above when talking about telemetry, but why is it so important?As is the case with any type vehicle, it needs to have a suitable balance in order to provide a comfortable and controlled ride. An unbalance bike will always be more difficult to ride as the rider has to react and second guess what the bike is doing. A well balanced bike is easier and safer to ride because it is very predictable. There are a few reasons why a bike would be out of balance, but most of the time it is to do with wrong spring rates and rebound settings.Are you saying that there is clearly a right way and wrong way when it comes to suspension setup for a given course or type of terrain?Yes, suspension setups can vary from rider to rider, even when the same bike and components are used. The difference in setup will be due to the rider's weight distribution, riding style, and preferences, but this can all be accounted for and fine tuned using a standard base setup as a starting point.I see... start with a good base setup and make small adjustments. You've designed and produced your own bike, the DH001-S, that uses your L.A. Link Suspension System. It is a very unique looking bike, can you tell us a bit about it?I am glad you asked that question. Yes, the bike is quite unique as it was originally conceived to be a pure race bike. The DH001-S was born out of the L.A Link suspension design. The L.A Link is a suspension design which provides the following characteristics: minimal pedal induced torque and chain length growth, a rearward axle path, a linear progressive leverage rate, and constant anti-squat. The idea behind the design is to provide a ride that is very efficient, stable, and keeps the pedals level while in rough ground, and is active while pedaling. It is a very stable and comfortable bike.
An Orange Five fully kitted out with data-loggers. You don't need to have a full blown DH rig to get the most out of running a proper setup.
So it's designed to go fast. The DH001-S uses 15CDV6 steel for the front triangle and aluminum for the rear. Can you shed some light on why you went that route?The 15CDV6 was a godsend. I was adamant to manufacture the bikes in the UK, but finding 7005 & 6061 aluminum alloys and people who knew how to use them proved to be almost impossible. We got talking to a few fabrication shops around Oxford about making a some prototypes in T45 and they introduced me to 15CDV6. This is a German steel that is extensively used for race car chassis', roll bars, and suspension arms for its strength, stiffness, fatigue and durability. So after careful studying of the material properties, it was clear that is was more than suitable for bike frames. The rear swing arm is aluminum as we are trying to reduce the un-sprung mass of the suspension, while still having sufficient stiffness in the back end.And what about the idler wheel, what does it accomplish?The suspension was designed to work in conjunction with the idler; you can say that it is the heart of the L.A. Link suspension. The bike has a very rearward axle path, and the instant center is located very close to the idler and that allows me to greatly reduce the amount of chain length growth and pedal induced torque. It basically separates the suspension movement from the pedal inputs and vice versa.So the idler helps the bike get around some drawbacks of a very reward axle path. I've read that you've designed in a lot of dynamic stability into your bike. What is this and why is it beneficial?You can define it as the ability of the chassis/bike to remain stable while under different conditions; such as acceleration, cornering, braking, pedaling, bump absorption, etc.. A bike that has a good dynamic stability will be very predictable. You're obviously a big fan of adjustability, with the DH001-S allowing riders to pick from three chainstay lengths, five head tube angles, and three levels of pedal feedback. The bike features several adjustable parameters, such as head angle, chain stay length and pedal feed back. No two riders are the same and neither are the tracks and conditions that people ride and race, so the adjustments allow the rider to tailor the bike and setup to the specific course, requirement, style, etc... In the neutral position the bike has a 63 degree head angle, 16.75" chain-stay length, and 10 mm drop bottom bracket. Also, the 13T idler sprocket provides about 5 degrees of pedal feedback. This setup will work very well for most downhill tracks, but you can also make the bike slacker and longer for higher stability, or shorter and more manoeuvrable if required. Personally, at K9, we prefer the bigger 13T sprocket as it provides the least pedal feedback and more control, but some riders choose either of the 2 smaller ones in order to feel more connected to the drive train.
The K9 DH001-S. Certainly different looking from the swoopy lines and hydro-formed tubes that you'll find on many of the latest downhill weapons, but is that going to be a factor for you? Should it be?
The DH001-S touts that its "instant center migration is engineered for constant anti-squat". In simple terms, what are you referring to and why is it important?The instant center is the same thing as a virtual pivot point, and its location and movement (migration) is as important as the position of the pivot on a single pivot bike. It determines the axle path and the anti-squat of the bike throughout the travel.There are many designs out there that use a triangulated rear end and two short suspension links to manipulate wheel travel and suspension rate. It seems very easy for ill-informed readers to assume that because one design looks similar to another that it must perform the same (picture all of those "it looks like a..." comments) Thoughts?There are several reasons why there are many suspension designs using this linkage configuration. The two short links and triangulated swing arm configuration provides a very stiff and structurally sound design. This configuration makes it easy to manipulate how the suspension will work. Yeah, small changes in length, orientation, position, and angle of the links can have a great effect on how they will work and ride, so just because they may look similar, does not mean they will work the same. The devil is in the details!It's almost like that paragraph should be included with any bike test! Do you feel that the media should make more of an effort to educate readers as to why one design is different from another?I think that the media has a degree of responsibility to educate the readers and riders, but in the end it is up to the general customer to either discard the new information or not.That sounds fair to me. According to many readers, your bike will never win a beauty contest. Are you the least bit concerned?Yeah, we are aware that a lot people do not really like the look of the bike as it looks very different to most mainstream bikes. It really is very much about form follows function as it rides beautifully. It is a concern to us at K-9 and it will be addressed in the future. I'm looking forward to seeing what you have cooking. Besides the DH001-S frame set, what else is in the works for K9 in 2011?Well, we have got a few things coming very, very soon. The philosophy behind the new component range is that they provide some performance gain, an advantage, or a unique solution. For 2011 the range will include:
Much like you may have seen on some rear shocks, K9's fork bearings allow the spring to turn freely under compression.
• Redesigned ARC head tube cups in both 1.5" and Frustum standards
• Three coil spring options (steel, lightweight steel and titanium) with bearings and adapters
• A 115 gram two piece direct mount stem, which we believe will be lightest and stiffest stem on the market
• Adjustable length handle bars
• High performance and race only brake pads
• A very light set of pedals with a very unique internal mechanism which lets you adjust how much it spins
• Fork bearings for the BoXXer, Bos Idylle, and Fox 40
• K9 IndustriesO.K., you're going to have to explain the fork bearings to me...The fork bearings are some very cool little components. They allow the fork springs to move more freely and react a lot faster to the terrain, which in turns provides more grip.
Luis Arraiz will be writing monthly columns for Pinkbike that will explain the physics of mountain biking in an easy to understand and interactive format. How long will it take a hot brake rotor to cook a steak? Does your suspension really move faster than you driving down the highway? Stay tuned!Did you like what Luis had to say? Excited for his upcoming articles?