Turning the wheel

We rush across the country on our motorcycles, over highways, crossing mountains and deserts. All on two wheels. The likelihood that these two wheels are spoked is particularly high if you're riding an enduro or a cruiser. However, the wheels are often out of sight and, therefore, out of mind. Even when checking the air pressure, we're more focused on the pressure gauge than on the wheel itself. It’s time for INSIDE Wunderlich to crouch down and take a closer look at the wheels that represent our freedom.

The story begins 4,000 years ago. The spoked wheel was invented then, replacing the heavy, wooden disc wheel. After that, not much happened for a long time. Much later, with the advent of pneumatic tires (Thomson in 1845 / Dunlop in 1888) – initially for bicycles – the so-called artillery wheels appeared. These allowed for the first time to change only the tire-mounted rim instead of the entire wheel. The benefits of fast tire changes were first used by participants in the legendary Gordon Bennett Cup, the precursor of Grand Prix racing.

While Daimler's "riding car" in 1885 still had uncomfortable wooden spoked wheels, the first mass-produced and officially called motorcycle, the Hildebrand & Wolfmüller in 1894, already had (just one!) spoked wheel, the front one. The stress from the connecting rod drive – the engine was a two-cylinder engine with two connecting rods, one on the right and one on the left – directly onto the rear wheel would likely have been too much for a spoked wheel to handle.

Wire-spoked wheels had already existed for a long time, even as large as mill wheels. They proved themselves, and much smaller versions were then used for motorcycles, allowing for the production of light and stable rims.

The spoked wheel endured for a long time but was constantly improved in detail, especially in terms of the materials used for the three main elements: the hub, the spokes, and the rim. In the 1980s, cast wheels appeared, which Bugatti had already used in automobile racing in the 1920s. Cast wheels looked modern and gave designers significantly more creative freedom than spoked wheels did. For a while, Honda used riveted rims called Comstar, which you either loved or didn’t. Yet, the spoked wheel never went out of style. With the simultaneous rise of enduro and chopper bikes, spoked wheels returned for good reasons and still grace these two genres today, as well as some retro bikes. Their advantages are simply too compelling. One sign of this: BMW developed the cross-spoked wheel to use tubeless tires on a spoked rim for the first time. And today? Many bikes still roll on classic spoked wheels alongside ultramodern, ultra-light carbon wheels, just like the Hildebrand & Wolfmüller did 128 years ago.

The renaissance of spoked wheels was no coincidence. In the case of the emerging choppers of the 1980s and today's cruisers, it was certainly for stylistic reasons. For the enduros that appeared almost simultaneously, there were practical technical reasons that still apply today. This is why no serious adventure bike that regularly goes off-road uses cast wheels. The advantage of the spoked wheel is its elasticity and flexibility, which are particularly useful off-road.

IW
When it comes to spoked wheels, the question always arises as to whether it is permissible to insert an inner tube into a tubeless tyre.

Conti
It's not just the tyre that plays a crucial role here, but also the type of rim!
An inner tube can be inserted into our tubeless tyres without any issues (up to a maximum speed of 210 km/h), BUT only when mounted on tube-type rims (generally spoked rims, without a safety hump).
On tubeless rims (MT-H2 type, typically cast rims with a safety hump, and also on many BMW spoked rims with external spoke nipples), we strongly advise against it! The construction and surface of the tubeless rim can damage the tube or limit its function, which could lead to a sudden loss of air and, potentially, loss of control of the vehicle.
There are special types of rims that can be used both with and without tubes, but these are specifically marked (“Tube-Ready”, “Tube/Tubeless” or similar).

IW
In this context, it is certainly important to clarify whether there are any legal regulations prohibiting this.

Conti
We are not aware of any regulations that explicitly prohibit the use of inner tubes in tubeless RIMS.
However, since tubeless rims are not designed or manufactured according to standards to protect the tube from damage or ensure its proper function, we automatically rule out this application.
Furthermore, our inner tubes are only approved for a maximum speed of 210 km/h (due to the risk of overheating), which would not be allowed on many bikes, as they are often capable of higher speeds.
Regarding the use of inner tubes in tubeless TYRES, the ETRTO (the European Tyre and Rim Technical Organisation) only mentions that the tyre manufacturer must be consulted beforehand. For our tyres, we generally allow this as they are developed and produced accordingly.

We would like to thank Continental Deutschland Reifen GmbH, especially Volker Plett (Application Technology) and Frank Rudolph, for their support.

• Spoked wheels consist of a hub, the necessary number of spokes depending on the application, and a rim. The spokes connect the hub to the rim and provide stability to the wheel.
• One advantage of spoked wheels is their flexibility. In the event of bumps or impacts, they can flex – unlike cast wheels – and thus contribute to shock absorption, a valued advantage in off-road conditions.
• Spoked wheels are generally lighter than cast or forged wheels, which can lead to improved acceleration and agility of the motorcycle, as inertia, gyroscopic forces, and unsprung weight are reduced.
• A disadvantage of spoked wheels is their more demanding maintenance. The spokes must be regularly checked and, if necessary, tightened to ensure the correct tension.
• Spokes should only be subjected to tensile stresses; therefore, they are pre-tensioned in such a way that they never encounter compressive stresses under operating conditions, as a compressive load would cause the spoke to buckle.

Typology: With or without tubes

• Spoked wheels can be used both with tubes and tubeless (e.g., BMW cross-spoked wheels). Tubeless wheels have the advantage of being less prone to punctures due to tube ruptures or valve damage (they are lighter – offering more agility). However, they require special tubeless tyres and an airtight seal on the rim.

Advantages and Disadvantages Compared to Cast or Forged Wheels

• Spoked wheels offer better shock absorption and flexibility, which is particularly advantageous for off-road motorcycles and enduros.
• Cast or forged wheels are generally stiffer, providing more precise steering and stability on the road. However, they often require more complex manufacturing and are heavier than spoked wheels.

Cleaning, Care, Maintenance, Spoke Inspection, Preservation

• When cleaning spoked wheels, it is important to thoroughly remove dirt and debris, as these can cause the spokes to corrode.
• Regularly checking the spoke tension is crucial to detect any loosening or over-stretching. Special spoke wrenches are used to tighten the spokes.
• To prevent corrosion, the spokes can be treated with protective agents.
• It is important to identify any damage to the spokes or the rim early on and, if necessary, make adjustments or repairs.

What Not to Do When Handling Spoked Wheels

• When fitting tyres, make sure that no tools or levers rest against the spokes, as this could damage them.
• Avoid using aggressive chemicals when cleaning the spokes, as these can damage the surface of the spokes.

What to Do If There Is a "Wobble" in the Wheel

• If a "wobble" develops in the wheel, meaning the rim is no longer running true, the cause should be identified. This could be due to a loose or overstretched spoke.
• It is advisable to take the motorcycle to a workshop to have the wheel professionally straightened, and the spokes checked and tightened as necessary.

Self-Help on the Road

• While on the road, you can attempt a rough alignment of the wheel using a spoke wrench, at least to ensure a safe continuation of your journey. However, a precise correction should be made at the nearest workshop.

In Case of a Flat: Better to Use Tyre Sealant or a Repair Kit?

• In the event of a flat tyre, it is advisable to use a repair kit to temporarily patch the tyre and allow for continued travel to the nearest workshop. Tyre sealant can also provide a temporary solution in some cases, but it should not be considered a permanent repair method.

Why Spoked Wheels Are Particularly Suitable for Enduro and Off-Road Motorcycles

• Spoked wheels are especially well-suited for off-road use due to their flexibility and shock absorption. They can absorb impacts and vibrations better, making them less prone to damage from bumps on uneven terrain.
• The ability to replace individual spokes makes repairs in the field easier and faster compared to cast or forged wheels, where often the entire rim needs to be replaced.