That's quite surprising. For 100 mi (160 km), that means you are in the saddle for more than 8 hours! That's pretty impressive in itself. I helped my wife tr

That's quite surprising. For 100 mi (160 km), that means you are in the saddle for more than 8 hours! That's pretty impressive in itself. I helped my wife train up from nothing (not having ridden a bike in 20 years) to a 90 km ride in 4 hours. Admittedly we were riding 5 days a week, but it only took 3 months. One thing you might try (if you are keen) is riding shorter distances at higher intensity (say 25 km in 1 hour). As for clipless pedals, I'll agree with the other poster who says that they have limited value for power. Their main use (IMHO) is safety. Never again have your foot slip off the pedals when it is raining. Never again have to concentrate on your feet when you are riding over uneven surfaces. I've spent a fair amount on my bike and nothing has come close to the value of clipless pedals in terms of increasing the enjoyment of my ride.