Bike knowledge: What you should definitely know about MTB tyres!
What are the benefits of tyre combos?
The front and rear wheels fulfil different functions: At the front, you need guidance and above all want to be able to brake, for this you need grip and traction. In other words: a softer rubber compound and a stronger tread that can interlock with the ground. The rear tyre should roll well, so the rubber can be harder and the tread can also be tamer. Special case: downhill. Here, the rear wheel also fulfils a braking function, which is why the same tyres are often used at the front and rear for downhill.
How important is the carcass?
The carcass is the tyre's skeleton. It should be as stable as necessary and as flexible as possible. Flexible to adapt to the unevenness of the terrain, but stable enough to prevent constant punctures. Downhill tyres have a multi-layer carcass, which provides high puncture resistance and better damping.
Tubeless? Advantages and disadvantages
Tubeless is more puncture-resistant, reduces weight, improves rolling resistance, allows lower tyre pressure and therefore provides more traction and comfort. The disadvantages are more complex assembly, burping with greater lateral forces, a higher price and air escaping from time to time. Special tubeless rims are also required.
When is a tyre worn?
There is no rule of thumb for this. If the edges of the studs are round, racers reach for new tyres, often after just a few runs. Hobby bikers can theoretically run the studs all the way down. The rule of thumb is: the lower the lug height, the worse the tyre interlocks with the ground. The tread is much more important on the front tyre than on the rear tyre. Rear tyres can safely be run all the way down - to a semi-slick tyre. By the way: tyres with a soft rubber compound provide a lot of grip, but wear out much faster (eraser effect) than harder compounds.
Are plus tyres dead?
Yes, plus tyres from 2.6 inches to even 3 inches wide are almost extinct. Only a few manufacturers still specify chunky 2.6 tyres. This is because the disadvantages outweigh the advantages, such as a spongy ride feel. Tyres around 2.4 inches wide make sense for gravity use.
Do I need mud tyres?
Racers swear by mud tyres on muddy, deep ground, as their long lugs provide noticeable advantages. For hobby bikers, special mud tyres - and therefore an additional set of wheels - are a superfluous investment. Hobby bikers should make sure that the tyre has good all-round capabilities and works well in a wide range of conditions. More tips on the right MTB tyres for wet and cold conditions >>
How do you recycle tyres?
There is a good recycling chain for bicycle inner tubes: bike dealers take back defective inner tubes, which are then returned to the manufacturer (e.g. Swallow) can be 100 per cent recycled. Old tyre casings, on the other hand, often end up in household waste or at the recycling centre - depending on the federal state regulations. There is currently no effective recycling system for tyres. As tyres have a high calorific value, they are usually incinerated in waste incineration plants.
Does a tyre have an expiry date?
Yes, unfortunately. Tyres harden or become brittle. The more they are exposed to the weather, the faster the rubber ages. Ozone is particularly responsible for this. If the tyre is new and stored properly (dark, dry, as airtight as possible, for example in a plastic bag), it will easily last 5 years without losing performance.
How important is tyre pressure?
Very important. A low pressure provides more comfort, traction and therefore riding safety. Unfortunately, the lower the tyre pressure, the higher the risk of punctures. Low tyre pressure mainly has a negative effect on rolling resistance on the road or on gravel paths - but less so off-road, as scientific studies have shown. DH World Cup racers often run 1.8 bar at the front and 2.0 bar at the rear. The high pressure is due to the much higher speed at which racers are travelling. The high pressure makes the tyre more puncture-resistant and it flexes less. The rule of thumb for tyre pressure is: as low as possible without risking punctures and with sufficient lateral stability so that it does not smear. Rule of thumb for hobby bikers (approx. 75 kilos): 1.5 bar at the front, 1.7 bar at the rear. If you tend to ride slowly on mountain tours, you can even go as low as 1 bar. Such a low air pressure provides enormous traction and the tyre is very wide. Tubeless tyres can be run at 0.3 bar less pressure, but at some point the limit will be reached and these tyres will also puncture. More about optimum tyre pressure >>
Rolling resistance: What do the values say?
The rolling resistance is given in watts and indicates how much energy a tyre "swallows". A normally sporty person can achieve 250 watts per hour. If they have to constantly exert more energy because the tyres swallow a lot of watts, they will be knocked out sooner. The values are measured in the laboratory on a smooth steel drum, but may be slightly different off-road. As the front tyre is less loaded, the rolling resistance of the tyre is less noticeable here than on the rear tyre.
Which value is more important: puncture or penetration?
Clearly, the puncture resistance is more important. It tells you how robust a tyre is. Punctures are rare, but punctures are the big enemy of mountain bikers.
What do wide rims do?
Wide rims increase the lateral stability of the tyre at low pressure, and the tread becomes flatter overall, so more lugs grip the ground. This leads to more traction.
What do the different rubber compounds do?
As a general rule, the softer the rubber compound, the greater the grip, traction and wear. Tyres with soft rubber have the greatest effect on the front wheel in particular. Hence the rule of thumb: soft at the front, harder at the rear for better rolling resistance. In racing, soft rubber compounds are usually used on both wheels. The rubber compound also influences the damping properties of a tyre. This rebound elasticity has a major impact on handling behaviour. Downhill compounds have very high damping values and therefore stick to the ground. Disadvantage: low durability, not very sustainable!
What are the benefits of two-chamber systems and foam inserts?
Dual-chamber systems are used in conjunction with tubeless tyres. The tyre is pressed into the rim bed in such a way that it cannot jump out and lose air, as happens with pure tubeless tyres, for example during cornering compressions or burping. The biggest advantage is the enormous puncture protection, as the high-pressure tube armours the rim. In dual-chamber systems, the air pressure can be reduced to below 1 bar, depending on the intended use. Foam inserts such as Cush Core and Co have a similar purpose. Both systems are mostly used in DH and Enduro races. Disadvantage: more weight and wheel inertia.
Do lightweight tyres make sense on enduro bikes?
Yes, of course it depends on where. In rocky bike areas such as the Vinschgau Valley or Lake Garda, you need puncture-proof tyres with good damping. If, on the other hand, you are riding in low mountain ranges, on softer ground and undulating trails, then lightweight tyres with a rather hard rubber compound make sense. This is because they generate a lot of propulsion and lively handling. The lower tyre weight significantly changes the character of the bike - the tractor becomes a sports car.
