"Pedal painlessly and efficiently and master the bike." These goals unite all cyclists from weekend cyclists to Tour de France winners. "Once you've achieved these goals, you have found the right bike that feels natural to you", explains cycling expert Robert Kühnen.
In an interview, Kühnen reveals how to achieve these goals. Robert Kühnen is a mechanical engineer and has been working in the bicycle industry since 1993: As a journalist, he heads the test & technology department of TOUR magazine. He supervises hobby and professional athletes and he is the managing director of BIKE ENGINEERING. He is also a successful cyclist off-road and on the road and. In 2011, he was time trial world champion amongst journalists and finished second in road racing. Kühnen is an independent thinker.
How do I find the right bike frame?
"There is no single bike configuration that fits everyone," says Robert Kühnen, "it varies, for example, depending on the type of bicycle," but there is a clearly defined size that must fit on a Dutch and a racing bicycle: the correct seat height. "It's easy to determine and also the most important aspect", says the expert, who also reveals the formula for this: "The length of the inner leg multiplied by 0.885 equals the seat height, which can also be described as the distance from the bottom bracket to the top of the saddle." By measuring the length of your leg, you can determine the correct height that you saddle should be:
How to determine your seat height
The correct seat height on the bicycle is based on your length of your inseam. You can easily calculate this:
1. Stand barefoot and without trousers on a flat and even surface.
2. Put a level or book between your legs and push it up.
3. Now ask someone to measure the distance between the upper edge of the level or book in your crotch and the floor.
Then simply multiply the measured inseam length by 0.885.
What is the perfect biking position?
“From my own experience, I can say that there is no definitive right or wrong. Of course there are certain standard positions that work for most people, and if you have no experience with sitting positions, they are a good starting point.
But you cannot rely solely on measurements and simply determine that rider ‘A‘ with an arm length of ‘A‘ and a leg length of ’A‘ needs the frame size ‘A ‘. Every person has a different level of mobility. This is due to different back, pelvis and hip shapes as well as leg postures and knee mobility. Even the ankles and soles of your feet play a role in this.
In my opinion, bike fitting is therefore only effective if the athlete has the opportunity to test the one-off bike designed for his body measurements for at least 500 kilometres. And that includes long-distance, uphill, downhill and, with mountain bikes, especially demanding terrain.
It often takes the customer many kilometres to determine whether the bike is comfortable or not. The best seating position is pointless if you have a problem with your knee or shoulder and your fingers and toes fall asleep.”
How do I find the right position on my bike?
There is no one perfect position though. For example, a slightly higher saddle is always going to be more effective while going uphill compared to riding on flat land. And if you are trying to go as fast as possible, adjusting the saddle a little forward is naturally more effective. Strictly speaking, you would actually need a switch on the handlebar that moves the saddle in all directions - that's an idea for the future.”
Which factors are important in finding the right frame size?
“The top tube length, head tube length and the angle of the seat tube are the key parameters. You always have to consider how sporty you want to sit as a rider and what you want to do with your bike: do you want to ride fast, sit comfortably, ride more uphill or do a triathlon? Should the bike be suitable for urban use, flat terrain or mountains?”
Even if I know all of the customers' requirements, I don't feel comfortable calculating the correct frame size on the spot. I like to do this at my leisure and inform the customer once I'm ready. Then we go over my result together and pick the right frame.
At least that's how it works with sports bikes. If you want to buy a trekking bike or a standard mountain bike that is only available in three to four sizes anyway, you can of course calculate the right size relatively quickly".
Can I calculate the frame size by myself?
“A cyclist who's maybe had 10 good fitting bikes before and has more than 100,000 kilometres under their belt can probably decide for themselves.
Are you interested in more articles about cycling? Then read our article on the subject of compensation training in cycling.
We thank Klaus Jockers for the interview and wish you a pleasant ride!
Images: Cover image: © iStock/ RyanJLane; Images: © iStock/ Mypurgatory- years; © iStock/ mel-nik