Finding a back-friendly bike
The perception of back-friendly bicycle ergonomics has changed in recent years. Up to now the focus was on design principles such as full suspension or low weight. Today the configuration of bicycles is defined by the individual needs of the customer. The main emphasis is on the following questions: What is the purpose of the bike? Which paths/surfaces will it be used on? Which distances should it cover? Which speed will be used? What are the customer's physical prerequisites? Bicycle ergonomics therefore have to adapt to the individual wishes and needs of the customer.
This change in outlook has shifted the focus from the manufacturer to the retailer when it comes to "ergonomic, back-friendly bikes". It is no longer appropriate to make general statements such as "the products of this bike manufacturer are back-friendly". Instead, the solution is as follows: "this retailer offers ergonomic expertise and is capable of selecting the right product for each individual customer from a wide range of bicycles, and knows how to optimise the ergonomic design with the right additional components and correct adjustment of the bicycle".
This changed approach is also supported by the wide range of available bicycle components. Manufacturers of bicycle accessories have improved the ergonomic quality of grips and saddles in recent years with a differentiated expansion of their selections. A comprehensive range of handlebars, stems and seat posts is available. In principle, this makes it possible to adjust the right saddle and the right grips to every necessary position so that the "ergonomic triangle" comprising saddle, handlebars and pedals can be adapted to every individual cyclist.
A competent retailer should be able to find the ideal solution for the specific combination of ergonomic positioning, cycling behaviour/cycling dynamics and individual needs. The basic bike and its additional components such as handlebars, grips, stems, saddle, seat posts, cranks and pedals should be individually adjusted to warrant a physiological posture and physiological movement sequences.
Three steps to a back-friendly bike
1st step: choosing the right type of bike and frame size
The retailer must offer a sufficiently broad fleet of bikes for test-riding, including city bikes, trekking bikes, mountain bikes, racing bikes, recumbent bikes or even folding bikes. The range on offer should include at least different city and trekking bikes. There are many different types and names of bikes on the market. There are also various mixed forms so that boundaries often become fuzzy.
- The most important types of bicycle are explained below.
- City bikes are relatively heavy and are equipped with or without gears. They permit comfortable cycling in town in an upright position. The upright position tends to prevent the bikes from being used for long journeys. City bikes can carry relatively high loads and only rarely have derailleur gears. Dutch bikes are a special type of city bike and are designed among others with a closed chain case.
- Trekking bikes, also called cross bikes or ATB (all terrain bikes) can be simply described as a combination of racing bike and mountain bike and come fully equipped with all features needed for cycling on the road (luggage rack, lights, mudguards and stand). These bikes are intended for general mobility in town and on tours. The tyres are broader and with a deeper profile than racing bikes, but much narrower than mountain bikes. Trekking bikes are usually equipped with luggage racks – but are not as stable under full load as touring bikes.
- Touring bikes are specially made for cycling tours. In appearance they look like a mixture of racing and trekking bike. They are equipped with sturdy, durable parts and designed to carry heavy loads. They are designed for more moderate cycling behaviour.
- Mountain bikes (MTB) offer a compact and robust design for sporty cycling on unsurfaced paths and open terrain. Many different subcategories of mountain bike have emerged in recent years, with varying wheel sizes, tyre widths and suspension types.
- Racing bikes are used for road racing and for covering long distances at high speed.
- The frame geometry
- Frame and seat height
The frame height (stated in centimetres or inches) is measured between the middle of the pedal crank bearing and the upper edge of the seat tube. The correct seat height indicates the distance from the upper edge of the saddle to the lowest position of the pedal that can still just be reached with the heel. Correct adjustment of the seat height is a basic prerequisite for fatigue-free cycling. Cycling with the seat height too low will sap energy and can cause knee problems.
- Frame and seat length
The effective length of the frame is the horizontal distance between the middle of the seat tube upper edge and the middle of the head tube that takes the steer tube. This length dictates the seat length, i.e. the distance between saddle and handlebars. The correct seat length permits the cyclist to stretch the spinal column in its natural double-S shape when sitting leaning forward slightly (max. 30 degrees). This is the only way for the back muscles to hold the upper part of the body and reduce the pressure on hands and arms. If the frame is too long or too short, the required sitting position won't be possible, not even with stems of different lengths or by adjusting the saddle. In addition to ergonomic aspects, the frame length also influences performance dynamics.
- Stack and reach: new parameters for selecting frame size
According to the bicycle experts, frame height is now obsolete as a reference size. Today it is stack and reach that tell you whether a frame has the right size. Stack and reach refer to the distance between the middle of the pedal crank bearing and the upper edge of the seat tube. Stack is the vertical distance, i.e. the height. Reach is the horizontal distance, i.e. the length. Bikes with more stack and less reach are higher and shorter. The cyclist sits in a more upright position, while less stack and more reach results in the cyclist bending forwards in a more stretched position.
2nd step: "bike fitting" – individual adjustment of the selected bicycle type
Selection of bicycle type and frame size is followed by "bike fitting", i.e. individual fine tuning of the components.
The sitting position and handlebar shape need to be adjusted to each other. The handlebar should be ergonomically curbed so that the lower arms and wrists can be held in a straight line. The flatter and more stretched the cyclist's sitting position, the straighter the handlebars may be. Straight handlebars make sense for sporty bikes. They support direct steering but put a higher load on the muscles in the arms and shoulders. Make sure that the wrists are not bent when grasping the handlebars as this could cause incorrect loads. Handlebars with differing grip positions are therefore recommended for long journeys. For sporting cycling, the handlebar is lower than the saddle, but above the saddle when cycling for pleasure. The width of the handlebars should be the same as the width of the shoulders and be adapted to the cycling purpose. Basically, the handlebars are only correctly positioned when there is a certain pretension in the back muscles. This pretension stabilises the spinal column and protects it from excess loads. An extremely upright "Dutch bike" position with the handlebars and grips close to the body tends to put more strain on the back.
- Handlebar stem
The handlebar stem is the element connecting steer tube and handlebars. Adjusting the stem angle changes both the distance between the cyclists body and the handlebars and also the handlebar height.
Anatomically shaped grips with shock-absorbing characteristics help to avoid jolts and pressure on the nerve roots. A large contact area is ideal to minimise pressure and possible numbness in the ring finger and little finger. Specially shaped multi-position handlebars allow for different positions of the hands and grips to avoid early fatigue of arms and wrists.
The retailer should offer saddles and seat posts in a range of varieties. The saddle must be selected individually (shape, size, hardness) and the position adjusted correctly (height, tilt, length position). It is also advisable to measure the sitting bones when selecting the right saddle.
3rd step: individual suspension/shock absorption
The suspension reduces shocks and jolts caused by uneven road surfaces. The German Sport University in Cologne has investigated the impact of suspension systems on the spinal column and came to the conclusion that jolts are reduced by 35% in bicycles with full suspension. This protects the spinal column from critical shock loads. Full suspension also protects the cyclist's entire locomotor system, as well as improving safety aspects.
The retailer should offer solutions that permit individual suspension/shock absorption.
There are various suspension systems:
- Suspension fork adjusted to bodyweight (with minimum spring deflection of 80 mm)
- Suspension in the seat post
- Rear wheel suspension adjusted to bodyweight (with minimum spring deflection of 80 mm)
- Full suspension (suspension fork and rear wheel suspension)
Requirements for the suspension/shock absorption of a bicycle:
- The spring kinematics must warrant low reciprocal effects between drive and suspension.
- Any luggage must also be suspended and therefore fastened to the frame. The load carried on the bike may not impair the suspension functionality and safety aspects (weight distribution).
- Attention should also be paid to selecting special tyres with adjustable tyre pressure to take account of performance dynamics.
Ten reasons for the E-bike
Electric bikes a.k.a. Pedelecs are the boom segment in the cycling branch. They have already acquired a market share of 10 %, which increases to a good 20 % when taking sports equipment and children's bikes into account. But why are people so keen for a bit of powerful assistance? pressedienst-fahrrad ("cycling press service") has summarised the ten key arguments.
- E-bikes get you moving – in everyday life
An E-bike boosts your life. The Pedelec principle ensures that the motor produces power as soon as you push the pedals. Your physical effort feels like a gentle ride while the motor adds a more athletic effect. According to Gunnar Fehlau, head of pressedienstfahrrad and co-author of a book about E-bikes, this phenomenon is the main reason why modern E-bikes are so successful. After all, there are already a good 1.3 million E-bikes on German roads. "More than half of all car journeys are less than five kilometres. Instead of getting frustrated by traffic jams and the struggle to find a parking space, Pedelec users enjoy these short rides as part of everyday life", he adds. Fun is the main aspect, rather than traffic-related fundamental ecology and ideology.
- A need becomes a want – a change in image
Just a few years ago, E-bikes were for senior citizens in need of assistance. But their image has changed. They have become an accepted feature of daily life, just like vacuum cleaners, escalators, percolators or smart phones: they are popular devices that help us through every single day. The range of Pedelecs is almost as varied as percolators: there's an E-version for every kind of bike, even racing bikes, mountain bikes, recumbent bikes, folding bikes or tandems. But most E-bikes are city bikes and trekking bikes. And in terms of design, Pedelecs have become status symbols.
- Pedelecs: the affordable second car
A good Pedelec cannot really be had for less than € 1,500. The average sales price in Germany is about € 2,300. "This is the entry price for robust, universal E-bikes", explains Fehlau, who adds that the price for a good everyday or touring bike will only be just € 1,000 less. Comparing the price of a Pedelec with a car makes the Pedelec an even better proposition.
- Sufficient range
The fear of running out of fuel always accompanies the car driver, but not the Pedelec user. On the one hand, modern batteries produce enough power to cycle between 30 and 100 kilometres. On the other hand - and this is where the Pedelec really scores over an E-car - every (!) Pedelec will get you home even without motor assistance.
- Setting off safely
The first few metres after setting off on a bike are the wobbliest, particularly uphill. Modern Pedelecs are designed to eliminate this problem, with the control offering strong harmonious support as soon as the first pedal is pushed. In brief, it's much easier and safer to set off on a Pedelec than on a normal bike, even uphill.
- Getting there without sweating
While sweating is all part of the fun for racing cyclists, for most other cyclists it is an undesirable side-effect. But Pedelec cyclists don't have this problem: the peak loads, to quote sports scientists, are provided by the motor. The cyclist enjoys a relaxed but swift ride, and arrives at the office or theatre without breaking a sweat.
- Integrated tailwind
If we're honest, cycling is most fun with a tailwind downhill. However, everyday cycling reality also includes the headwind and the uphill climb. But not with the Pedelec: "Most models offer different support modes", explains Fehlau. "When there's a headwind or a gradient ahead, the cyclist simply selects the strongest support mode to send him sailing against the wind or uphill."
- Practical, pleasant cruising speed
The key thing about getting somewhere quickly is not the absolute maximum speed but travelling at a constant rate. The Pedelec helps when starting off, when there's a headwind and when coping with big and little hills. And so the cyclist rides along swiftly without the cruising speed deviating greatly from his powers of perception. This is a totally enriching experience: new impressions on familiar routes are the rewards that Pedelec pilots enjoy!
- Sustainability: individual pleasure with a clear conscience
In contrast to spontaneous city trips half-way round the world, thirsty roadsters or guzzling take-away meals with all the waste these leave behind, the Pedelec is definitely a sustainable pastime. A Pedelec recharged with eco-electricity may even have a better carbon footprint than when riding some classic bicycles, as illustrated by the cycling culture magazine "fahrstil" (www.fahrstilmagazin.de) in its issue 06. In any case, the Pedelec has an excellent ecological balance sheet and symbolises individual joie de vivre without remorse. The green aspects of the Pedelec are further underlined by the fact that the batteries withstand more than 1,000 recharging cycles (i.e. on average 40,000 kilometres), while general component wear is comparable to that of a conventional bike.
- Almost no loss in value
A good Pedelec is a good investment, Fehlau knows this - a fact illustrated by the high prices on the limited market for second-hand Pedelecs. "Someone who buys the right Pedelec for his needs in robust quality will often keep it for many years. Someone who has made the wrong choice of bike will be able to sell it again for a good price."
For Fehlau and more than 400,000 Pedelec purchasers each year, it's quite clear: a Pedelec takes the pain out of the passion of cycling, soon pays off in many respects and puts a smile back on many faces.