Larger diameter wheels roll over pebbles,- which cause falls,- better than small wheels, so why not make them standard equipment?
To address your question about wheel size let's take into consideration the purpose of rollerskiing. Rollerskis primarily exist as a training tool for the offseason by simulating the sport-specific movements associated with cross country skiing. Large wheels do not simulate cross country skiing as well as standard-size wheels. When performing freestyle technique, large wheels encourage the skier to place their weight in between the wheels rather than over the wheels. By ineffectively transferring your your weight over a single leg, you will devalue your offseason workouts, and make it harder to transition onto skis when winter rolls around. This is because you are not only training your body, but your brain's connection to your body.
Most folks understand that they are training their heart, lungs, and muscles to adapt to training. What is not always emphasized is the role of the nervous system in athletic performance. When you train, you are strengthening your brain's ability to tell your muscles what to do by building insulation around your nerve connections (also called your myelin sheath). Check out this video, and read this article by clicking the links. The same applies for learning any skill whether it be learning a musical instrument, or a new sport. When performing a sport with poor technique, your brain encourages further poor technique through training. This means every season you may have to unlearn the bad habits from using large wheels before you can begin improving your technique again.
There is a place for large wheels in training. In freestyle technique, large pneumatic wheels should be exclusively the domain of recreational skiers as they offer little for improving one's technique. For classic technique, large wheels are acceptable and sometimes encouraged as they make excellent skis for double poling workouts, and give little interference to developing technique over their alternatives when striding.
Category Manager - Nordic and Endurance Sports
Bliz Eyewear, Start Ski Wax, Swenor Rollerskis