‘The Motor Increases the Saddle Pressure by 20 to 40 Per Cent.’

Riding an ebike feels great. The batteries last for hours. The motor does anyway. Only we humans, we weaken much faster. Because our backsides hurt, our shoulders are tense or one finger after the other goes numb. For years, professional cyclists have been using expert knowledge and imaging technology to prevent such complaints from arising in the first place. Bike fitting is the magic word. Gebiomized is one of the most internationally renowned providers of this professional adjustment of the contact points on the bike. Now the company from Münster is training people interested in bike fitting for ebikes. We talked to Nis Sienknecht from gebiomized about this technology. How does this latest offshoot differ from previous bike fitting? How can ebike riders benefit from it?

Mr Sienknecht, how does gebiomized define bike fitting?

Many of you are probably familiar with the situation: I go to the dealer. He adjusts my bike for me. We call this bike sizing. In other words, finding the right frame size. We define bike fitting as the adjustment of all contact points between the person and the bike. The visible contact points are the saddle, feet and hands. To create a functioning unity from these, we have to take a close look at all these contact points. For this we use pressure measurement technology that gebioMized has developed and manufactures itself. It makes the invisible points visible. After all, we don’t see what happens under the bottom because we sit on the saddle with our bottom. We don’t see what happens in the shoes because the feet are in them and kind of cover this point of contact. The same applies to the hands.

Nis Sienknecht of bike fitting experts gebiomized

How would you describe a bike fitting?

Usually you come to a laboratory or a bike shop. Your own bike is mounted on a trainer. The participants discuss the problems they are experiencing. These are usually seating problems. Or there is pinching in the neck. Or hands or feet go numb. Then the experts check the mobility of the customers. Are there muscular imbalances, postural deformities or other restrictions? Of course, a close look at the bike is also part of the process. Next up is a warm-up. This helps you to become familiar with riding on the trainer and takes away the feeling of suddenly having to do everything right because the cameras are about to turn on. Two of them film the fitting. One is directed at the bike from the front, the other from the side. Then the pressure-measuring film is placed on the saddle. This is the most important one. It shows most of the settings. Foot and handlebar pressure are usually only added for competitive athletes. While riding, people can follow the image of the saddle directly on the screen. They recognise different areas. Where it flashes red, there is a lot of pressure. Orange, yellow, green and blue mean less pressure. In addition, the leg axis position is looked at on the video. How stretched or compressed is someone sitting on the bike? What knee angles do you see? To show this, markers are stuck on the knee beforehand. This way you can see what happens when I raise the saddle. Does the angle get higher or do the riders simply react by lifting their heels and the knee angle remains the same? Next step. Measure again. Next step. Measure again. Until you get closer and closer to the optimal riding position.

What are the best possible outcomes of professional bike fitting?

In the best case, there are two things. The most important thing, in my opinion, is enjoying riding a bike. If you can ride without pain, you’re more likely to choose a bike. Most people go to a fitting because they have some kind of problem. By finding the right position on the bike, problems can be avoided from the start. That means it’s a good way to prevent injuries, especially by avoiding excess strain.

What specific measures result from a bike fitting?

That varies enormously. I am always amazed at the huge influence that even tiny changes can have. Recently, as a test subject in our first ebike-specific bike fitting course, I sat on an ebike with wing grips. Everything felt super comfortable. However, these wing grips put me in a position where my hands tilted inwards. As a result, my arms were suddenly very stretched, even though my sitting position on the bike was actually too short. All of this led to a tense neck, which I felt after only a short time. Then we replaced the wing grips with round grips. That was a world of difference. I wouldn’t have thought that changing the grips would be the solution. I mean, these are the kinds of lightbulb moments we’re talking about.

When adjusting the saddle, a few millimetres can make a huge difference.

Why do we need special bike fitting for ebikes?

This is mainly due to the way people ride and sit on an ebike. Batteries and motors usually make an ebike significantly heavier than a regular bike. That’s why only a few cyclists regularly ride out of the saddle on an ebike. You vary your sitting position much less on a heavy bike than on a light one. But aside from the weight, the motor makes the biggest difference.

In what way exactly?

Let’s assume an absolutely identical sitting position. I ride without motor assistance and I ride in turbo mode. Our studies have shown that the saddle pressure increases significantly. In fact by 20 to 30 percent, often even up to 40 percent. Why? Because the legs have to apply less force to the pedal and you don’t push yourself out of the bike as far while pedalling. In addition, the lateral pelvic movement changes. Without motor assistance, we move three times as much as with electric assistance. When riding an ebike, you simply sit very low in the saddle. In addition, the seating position on many ebikes tends to be more upright anyway. This reduced variability when sitting can significantly increase problems in the long term. However, we need a certain amount of variety when sitting. Mountain bikers, for example, are much less likely to complain about sitting problems than road cyclists. Of course, they get out of the saddle much more often when cornering or climbing. That makes a difference. That’s why the focus of bike fitting for ebikes is much more on the saddle.

The measurement image shows a mapping without motor assistance on the left and with electric drive in turbo mode on the right. The red, orange and yellow areas illustrate the increased pressure. The horizontal red line in the middle describes the movement of the pelvis. On the right, it is considerably shorter. Due to the smaller movement, there are hardly any relief periods, which can lead to problems and pain in the long run.

Is bike fitting for ebikes therefore completely different from the previous bike fitting for bicycles without electric drive?

Definitely not completely different. Much more individual because the target group is much broader. It ranges from professional athletes to someone who is getting back into cycling after a long time with the help of an ebike. Suddenly, details about cycling take on a completely different significance. For example, when the bike is used as a piece of sports equipment, the pedals and feet usually have a firmer connection. Sometimes with click pedals, sometimes with flat pedals that feature added pins. In addition, you usually use the same shoes. With the ebike as an everyday item, the case is different. In summer you ride with sneakers and in winter with more robust shoes. The sole quickly builds up to three centimetres or so higher. These are massive differences for the knee angle. When fitting, it matters which shoes people ride with most often or whether they use cycling shorts with seat padding. The differences are clearly measurable. If you ride with a different shoe all the time, then adjust the saddle height. Otherwise, the knee angle will no longer match. At first, this is annoying because the carefully determined setup has changed and the actually good feeling is suddenly missing. However, this also offers the opportunity for more variability in the seating position. If you wear shoes with higher heels, you tend to place your foot on the pedal with your heel. With the others, you tend to place it on the ball of your foot instead. This results in similar angles. But you need to be aware of this – and the best way to learn and understand it is through dynamic bike fitting.

In your opinion, who would benefit from bike fitting for ebikes and who might not?

If you don’t have any problems and everything works, then of course you don’t need it. For everyone else, it’s definitely a good idea. The longer the distances you ride, the more important it becomes in my opinion. Especially when it comes to commuting and you cover ten, 15, 20, 25 or even more kilometres each way because you sit in one position for a very long time. If, on the other hand, it’s two kilometres to the train station, then one and a half kilometres to the shops and then 800 metres to take your child to daycare, it’s a different story. You may not be sitting well on the bike and not be enjoying it – which would be reason enough to address the issue. But you probably won’t have to deal with massive sitting problems or neck pain. After all, you’ll be able to recover by getting off and on repeatedly. That doesn’t make the sitting position better, but the problems are less prevalent.

What about people who switch from a regular bike to an ebike?

That’s right, it could be interesting for them too. It’s entirely possible that they used to sit on a bike for 30 minutes and then take a break because of the effort. Thanks to the motor assistance, they can suddenly spend four hours on a bike in one day. The difference between 30 minutes in a bad position and four hours in a bad position is huge. This means that the more they ride a particular ebike, the more beneficial a fitting becomes. Of course, this applies even more in the event that problems are already present. If I know I have shoulder problems, two herniated discs, my knee always hurts or whatever.

A total of 64 sensors in the film developed in-house measure the saddle pressure.

You have already emphasised several times how important the saddle and saddle pressure are in bike fitting. In your opinion, is the bicycle industry making a mistake when it comes to equipping bikes?

Yes and no. The ebike has passed the technical acceptance test at a testing institute with a specific saddle and has been approved for sale. Therefore, it must now either be sold with this saddle or without a saddle. However, in the latter case, an exact list of approved alternative saddles is required. This is stated in the relevant guidelines and regulations of the European Union. Therefore, as a dealer, you cannot simply order 40 bikes from manufacturer XY without a saddle because you would like to give your customers a different one from the outset. So manufacturers opt for a model that fits a lot of people to some extent. At the same time, it should cost little so that the profit from bicycle sales increases. Many bicycles are given an unsuitable saddle in this way. Usually it is too soft. At first it feels good. That’s enough when a bike sells after a five-minute test ride. Later on longer rides, the following tends to happen: The pelvis sinks deeper into the saddle with both the bony structures and the soft tissues. There are a lot of large nerve channels in the softer structures. I then continuously press against them. With little pressure, but over a longer period of time. This can cause pain, numbness, cold, warmth and other things.

In your opinion, how present is the topic of bike fitting for ebikes in the bike industry?

Can I mention negative values? It is definitely not a big topic yet. We are just starting to focus on it. It is possible that retailers will turn to the topic relatively quickly. After all, it would allow them to kill several birds with one stone. One thing is great customer service. You never get as close to your customers as you do with bike fitting. In a relaxed atmosphere, you talk about personal problems and can really help. Anyone who has experienced the difference between a bike sizing and a real bike fitting develops a completely different relationship of trust with the dealer. From our point of view, this also offers retailers the opportunity to differentiate themselves to some extent from the current discount battles on the Internet and to offer a completely different added value. This goes far beyond new bike sales. After all, it affects people with existing bikes just as much. If I can help them, word will certainly get around pretty quickly.

Where can someone who is interested in bike fitting for ebikes turn today?

I would probably start by consulting the internet. But please look at the results carefully. Some of them may say bike fitting when they actually mean bike sizing. Bike fitting will always be more expensive. After all, someone is dedicating two to three hours to you and your ebike and using modern measurement technology. You won’t find that for 79 euros. We recently had our first course. So in the future it will be easier to find the right place, because the first very well-trained people will soon be on the market.

What does professional bike fitting cost?

In the sports sector, a detailed bike fitting costs between 250 and 500 euros. In the ebike sector, I expect cheaper fittings in the future. There is less to adjust on the bike and the contact point saddle takes on an even higher priority. In many cases, a very elaborate foot pressure measurement can probably be avoided because the position and posture of the foot on the pedal change much more frequently. At the moment, both fittings are perhaps available at the same price. In the future, it will probably be less than 250 euros.

Do you have a final bike fitting tip for at home?

Start with the basics and observe how you actually feel and behave. Sit on the saddle without your hips tipping sideways and place your heel on the pedal in the lowest pedal position. Now your knee should be almost fully extended. This is a good starting point when finding the right seat height. No more, but also no less. While you are on the bike, a second person can take pictures from the side. In general, we always recommend listening to yourself. Do I feel stable in my current position? Do I like sitting like this? Do I feel cramped overall? Am I rather restless and keep looking for a new position? The latter would be a very strong indication that the settings are not right.

Mr Sienkneckt, thank you very much for the interview!

Pictures: SnM gebioMized GmbH