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No ordinary wheel.
A wheel that pushes the boundaries of what is possible.
A bike for those for whom the best is just good enough.
The aim of the development of the tauwerk delight was to create the lightest wheelchair wheel in the world - paired with unique aesthetics and the best possible comfort. And without compromising on durability.
We have taken each individual component and "rethought" it with the most suitable materials and technologies.
After some searching for rim manufacturers that meet our requirements in terms of know-how and manufacturing quality, we found the perfect partner for the development of outstanding carbon rims in the Austrian company Xentis®. The result of the development are rims that are probably unparalleled in the wheelchair sector when it comes to design, reliability and low weight.
The 28 mm high rim has an outer width of 25.4 mm. This harmonises perfectly, both visually and technically, with the widely used 1" (25.4 mm) wide tyres - for example the Schwalbe® One; Marathon or Rightrun.
The 17 mm inner width of the rim also allows for all other common tyre widths between 20 mm and 37 mm. Two minimal humps in the rim bed ensure the precise fit and concentricity of the tyres, even at low air pressures.
The rims are manufactured in Austria in a predominantly manual process to 100 %. The areas of the spoke seats are extra reinforced and thus ensure a permanently stable connection to the spokes.
Despite the very low rim weight of only 340 g with a diameter of 540 mm (24"), the rim has optimum rigidity and strength for everyday use. Each rim has a serial number and an RFID chip, which ensures complete traceability of origin and manufacture.
The valve bore has a diameter of 9 mm due to the production process and is reduced to 6.5 mm via an insert for the use of hoses with Sclaverand valves. It is possible to use tubes with Schrader valves (car valves), but for technical and optical reasons we recommend the more pressure-stable Sclaverand valves. For a 1" wide tyre, the rims are approved up to a pressure of 10 bar.
Our spokes are absolutely unique in the wheelchair wheel market. They are made of a high-strength synthetic fibre, which is five times stronger than steel. This enables us to produce extremely light spokes with a weight of only 2.4g.
The fibre we use has good abrasion resistance and absorbs practically no moisture. The sensitivity to UV light is counteracted by means of a special coating and thus no longer plays a role. The coating also significantly reduces the sensitivity to dirt. The fibre has a high stiffness with practically negligible creep behaviour. It is therefore ideally suited for the spokes in a spoked wheel, which are exclusively subjected to tensile forces.
The fibre yarn is braided into ropes in our house, which opens up the possibility for us to produce patterns from differently coloured yarns and thus create a unique look. The feel of braided and tensioned ropes is also impressive and certainly unique. The ropes are then further "heat-set" under high load and temperature, which further improves their properties in terms of elongation and surface quality.
In further work steps, the ropes are hand-fitted with end connections made of high-strength aluminium and completed to form the finished spoke. The fine threads of the end connections allow for the lacing and precise centring of the rim. The static tensile strength of our spokes is over 2000 Newton, which corresponds to a weight force of more than 200 kg. The tensile strength of the rope itself is even over 7000 Newton. Since ropes per se cannot absorb bending moments, they yield under lateral loads and return to their original shape after the load. The briefly occurring increased tensile loads in the spoke do not pose a problem. Damage or permanent deformation of the spokes by dull objects, as can occur with steel spokes - for example when loading the wheels in the vehicle - is thus ruled out.
The biggest technical advantage compared to steel spokes, apart from the 65 % lower weight, is the self-damping of the fibre material or the finished spoke. This damping noticeably increases the riding comfort without requiring an increased driving force. Especially on uneven roads, this guarantees low-fatigue riding even over longer distances.
For our hubs, we use high-strength aluminium, with which we can realise minimalist hubs weighing well under 100 g due to its 66 % lower density compared to steel and sufficiently high strength.
The design of the hubs is designed to optimally absorb and dissipate the acting external loads. The goal was to evenly load the entire material to a high level, but at the same time avoid areas with excessively high stresses. Modern design and simulation tools provided valuable support here.
The revolutionary surface blasting technology of our paver enables us to produce defined, absolutely uniform and 100% reproducible surfaces.
Any machining marks are thus completely removed, giving the hubs a superior look and feel. In addition, blasting further increases the strength of the areas near the surface.
We only use high-quality ceramic bearings in our tauwerk wheels. Ceramic bearings with their very hard and extraordinarily wear-resistant rolling elements made of silicon nitride are convincing compared to standard ball bearings with steel balls due to significantly low friction and an unsurpassed service life.
Ceramic bearings, for example the ceramicspeed® bearings handmade in Denmark, have been proven to run smoother and are also lighter. They offer five to ten times the service life of standard bearings - even under heavy loads. We think there is no reason to install other bearings in tauwerk delight.
Our wheels are available for axle diameters 12 mm and 12.7 mm (1/2 inch). The bearing distance is 56 mm (outside/outside).
The handrims are bolted axially to the rim at six points. With this type of fastening, we achieve a much more attractive, organic overall design than with the usual protruding and bent handrim lugs. But also in terms of strength, assembly effort, handrim positioning and risk of injury, this variant offers advantages over the mounting type with lugs.
The distance between the handrim and the rim is neatly adjusted using spacer sleeves and can be easily adapted to individual requirements at any time - even with the tyre mounted. All wheels come with corresponding spacers made of anodised aluminium. The bolt-on points on the rim consist of positive-locking, captive inserts made of the same aluminium and permanently guarantee a stable flow of force between the handrim and the wheel. We only use titanium screws for the best possible compromise between strength and low weight.
We only use high-quality and lightweight hand rims from Carbolife®. These are also "made in Germany" and their innovative ergonomic profile shape ensures a force-gentle, controlled and fatigue-free grip. The hand rims are available in different versions.
Every tauwerk wheel is carefully spoked by hand in our factory, centred and pressed several times during the process. For each wheel, the spoke tensions of all spokes as well as the radial and axial run-out of the rim are electronically recorded and documented. The defined repeated bead breaking permanently prevents the tauwerk wheels from having to be (re)centred when used properly.
Tauwerk wheels are radially spoked, i.e. the spokes do not cross and run along the shortest possible path from the rim to the hub. This achieves maximum wheel stiffness in the transverse direction while keeping the total weight to a minimum. Crossed lacing, as usually found on bicycle wheels, is not necessary on wheelchair wheels, as no torque needs to be transmitted in the direction of travel between the hub and the rim. In contrast to the bicycle sector, the drive and braking forces on the wheelchair are introduced directly into the rim via the hand rim and do not first act on the hub. Contrary to widespread opinion, crossed lacing does not result in increased stiffness or stability in the case of loads acting in the wheelchair area.
The oval spokes are aligned in the direction of travel, resulting in a uniform and dynamic look, similar to the so-called "knife spokes" in the bicycle sector.
We centre all wheels with a lateral and radial run-out tolerance of +/- 0.2 mm and a spoke tension that is as even and high as possible on each side. This ensures that the wheel can permanently bear the loads acting during operation without individual spokes being able to briefly lose their tensile stress - and thus become loose - or overloaded.
The wheels are pressed by hand several times during this process. This eliminates further settling of the spokes during operation and the associated out-of-round running.
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