Weight limit 90 kilos? Maximum system weight 100 kilos? XXL bikers can only smile wearily at this. Together with the weight of the bike and equipment, many riders can easily reach 120 kilos or more. If you are particularly tall or heavy, you can't just reach for the shelf to select MTB parts. The search for suitable bikes and parts often leads into the manufacturers' small print. Of course, there are weight restrictions for good reason. Mountain biking is a high-risk sport and the material has to withstand a lot, especially for heavy riders. To find out how the brands react to the requirements of XXL bikers and what tips insiders can give on the subject, we asked the manufacturers of particularly heavy-duty parts. DT Swiss, Schwalbe and Maxx answered our questions in an interview.
DT Swiss on wheels for heavy riders
Wheels have to cope with a lot when the rider weighs a lot. After the tyres, they are the first to take the strain. There is hardly any other part that influences the handling of a mountain bike as much as the wheelset. We wanted to know what Andreas Tschanz, Head of Engeneering Wheels And Components at DT Swisshas to say on the subject of XXL bikers.
BIKE: How do you determine the maximum possible system weight for your wheels?
Andreas TschanzOver the years, we have developed a comprehensive factory standard that defines the requirements for our wheels depending on the area of application (ASTM) and the maximum system weight. The factory standard goes well beyond the existing standards in the bicycle sector and is based, among other things, on field load measurements and our decades of experience with wheel components and complete wheels. For riders over 100 kilos, the loads on components are significantly higher. This makes correct design all the more important.
What is your recommendation for such a rider with a body weight of over 100 kilos?
In any case, the customer should pay attention to the manufacturer's intended area of application and the maximum system weight. If necessary, it makes sense to choose a product that is intended for a higher ASTM category. For cross-country bikes, for example, an all-mountain model or even an enduro model.
29ers have established themselves and are often better suited to taller riders. In a 2013 buyer's guide, we rated them as problematic for heavy riders due to their lack of stiffness. Is this still an issue ten years later?
In my view, not any more! This may still apply to very heavily weight-optimised wheels and components. As a rule, the maximum system weight is then also correspondingly low. The use of wide rims in all areas of application and the market launch of Boost hubs has permanently alleviated this issue.
Which component of a wheel is particularly sensitive at high rider weights?
You cannot look at a single component here. The sum of the components must function as a system and be designed accordingly. The optimum combination of wheel components in combination with good wheel construction produces the perfect result.
Schwalbe tyres for heavy riders
XXL bikers put much more strain on their tyres when mountain biking than lighter cyclists. Nonetheless, they must be able to rely on the grip and puncture resistance of their tyres at all times when they are riding their MTB on a trail. We find out how tyre manufacturers deal with these requirements and what tips they can give particularly heavy riders Carl Kämper, Product Manager at Schwalbe.
BIKE: Does body weight play a role in the choice of my tyres?
Carl Kämper: First of all, tyres with a larger volume are preferable due to their better load-bearing capacity. Body weight plays a decisive role, particularly when choosing the tyre casing, but also when setting the air pressure. Heavier riders should opt for a more stable tyre casing in order to avoid punctures and have sufficient lateral stability. The air pressure is then used for fine tuning.
Is it possible that a tyre tread no longer plays along above a certain rider weight and, for example, outer lugs buckle?
This definitely plays a role! The grip of the tyre depends on the weight load (downforce) and the coefficient of friction (compound and tread). In theory, a heavier rider can therefore build up more grip, but the movement of the mass relative to the ground is disproportionately limiting. On an MTB, this means, for example, that the tyre will reach its limit sooner when cornering at high speeds, even with a higher weight load. A certain amount of flex in the shoulder lugs nevertheless contributes massively to the tyre's controllability. This is referred to as "wheeling" or controllability at the limit.
Contrary to popular belief, maximally stiff side lugs are not desirable. Instead, the compound and tread are matched to each other in such a way that the effect of etching is achieved in a specific area. The Magic Mary, for example, is known for its good-naturedness and the particularly large limit range due to a pronounced wheeling effect. Tacky Chan, on the other hand, has much more stable shoulder studs with significantly more counter support. Developed for use in the World Cup, it offers more precision, but requires an active riding style with a lot of vigour.
What influence does the driver's weight have on tyre wear?
On the one hand, a higher weight load allows the tyre to build up a high level of grip, especially on hard surfaces. Since grip is ultimately nothing more than the tyre sticking to the surface, a higher weight also leads to greater wear. On the other hand, higher rider weights require greater braking power, which must be transferred from the tyre to the surface. This also leads to increased wear.
For which weight range does Schwalbe develop MTB tyres?
Most of our 29-inch MTB tyres are designed for an axle load of up to 120 kilos. This means that a system weight of 240kg is theoretically possible! For tyres with a larger volume (2.6 inch), even higher loads can be achieved.
Maxx to bicycle frames for heavy and tall people
If bikers are tall and heavy, they place high demands on their equipment. This applies not least to MTB frames. Even simply constructed hardtails have to withstand heavy loads for XXL bikers. The issues of durability and handling become even more complicated with heavy riders and fullys. Defective frames are not only a safety risk, but also cost money. Andreas Weigl, member of the Maxx management team, reveals what MTB frames for tall and heavy riders need to be able to do.
BIKE: How come you also have mountain bikes for extra tall riders in your programme?
Andreas Weigl: Maxx is a bicycle manufacturer that specialises in ergonomics. We want to build bikes that fit our customers perfectly. Riders taller than two metres have different demands on a frame that cannot be met with just a longer stem or other attachments. This is why we included a wide variety of sizes in our range at an early stage. XXL bikes are now an important sales driver for us. In recent years, we have been able to position ourselves well here thanks to our large range for mountain bikers.
How do your frames in size XXL differ from size M, for example?
With an XXL frame, both the geometry values are adapted to tall riders and the material thickness and therefore also the stiffness are improved. We attach particular importance to ensuring that both meet the requirements of tall riders. The rider should immediately feel comfortable and the frame should be able to withstand the loads.
Are the requirements of tall drivers also taken into account in the choice of equipment?
The XXL bikes also differ here. For example, there are some mandatory upgrades in the configurator for tall and heavy riders, such as brake discs and wheels, as these have to be adapted to their needs. When selecting components, we also make sure that they are suitable for tall riders. For example, we specify forks with longer steerer lengths and indicate in the configurator if a possible spacer selection is not compatible.
What advice would you give a two metre tall rider before buying an MTB?
In general, the model should meet the biker's requirements, and then it should be ergonomically customised for the biker. Our configurator helps with this. If the biker has any further questions, we recommend seeking professional advice either directly from us or from one of our MAXX dealers.
Jan Timmermann
Editor
