Modern expensive racing bikes can be worthwhile for serious cyclists who are looking for top-of-the-line performance, advanced technology, and lightweight materials. These bikes are designed to provide the best possible aerodynamics, speed, and handling, which can make a significant difference in competitive racing. However, for casual riders or those on a budget, the high cost of these bikes may not be justified, as there are plenty of more affordable options that can still provide a great riding experience. Ultimately, the decision on whether a modern expensive racing bike is worthwhile depends on the individual's cycling goals, budget, and level of commitment to the sport. **

Racing bikes are generally faster than road bikes and mountain bikes. Racing bikes are designed for speed and efficiency, with lightweight frames and aerodynamic features. Road bikes are also built for speed, but may not be as specialized as racing bikes. Mountain bikes, on the other hand, are designed for off-road terrain and are not typically as fast as racing or road bikes. **

In general, road bikes have better acceleration than mountain bikes. This is because road bikes are designed for speed and efficiency on smooth, paved surfaces, with lighter frames and thinner tires that allow for quicker acceleration. On the other hand, mountain bikes are built for off-road terrain and have heavier frames and wider tires, which can make acceleration slower compared to road bikes. Therefore, if quick acceleration is a priority, road bikes would be the better choice. **

Rims from road bikes are typically not compatible with mountain bikes or city bikes due to differences in wheel size and tire width. Road bike rims are usually designed for narrower tires and higher tire pressure, while mountain bikes and city bikes require wider rims to accommodate their wider tires and lower tire pressure. It is important to ensure that the rims are compatible with the specific type of bike to ensure proper fit and performance. **

I don't have a personal preference as I am an AI and do not have the ability to ride motorcycles. However, some people may prefer super sports bikes for their high speed and performance on the track, while others may prefer supermoto bikes for their versatility and ability to handle a variety of terrains. Ultimately, the choice between the two depends on the individual's riding style and preferences. **

Some secure bike locks for expensive bikes such as E-bikes or Downhill bikes include U-locks, chain locks, and folding locks. U-locks are made of hardened steel and are resistant to cutting and leverage attacks. Chain locks are also made of hardened steel and are flexible, allowing you to secure your bike to a variety of objects. Folding locks are compact and provide a high level of security due to their hardened steel construction. It's important to choose a lock that is rated highly for security and to always lock your bike to a secure and immovable object. **

Some of the A2 super sports bikes available include the Yamaha YZF-R3, Kawasaki Ninja 400, and the Honda CBR500R. For A2 naked bikes, options include the Yamaha MT-03, KTM 390 Duke, and the Suzuki SV650. These bikes are designed to meet the A2 license restrictions while still providing an exhilarating riding experience. **

Road bikes and mountain bikes each have their own unique advantages and are designed for different types of riding. Road bikes are great for long distance rides on smooth pavement, offering speed and efficiency. On the other hand, mountain bikes are built for off-road trails and rough terrain, providing stability and control. Both types of bikes have their place and it ultimately comes down to personal preference and the type of riding you enjoy. Whether it's the thrill of speeding down a mountain trail or the satisfaction of a long road ride, both road bikes and mountain bikes offer their own exciting experiences. **