Fullforce

Back in the early 90's, I bought a Diamondback Approach hybrid bike for around $250. I have been riding it pretty regularly now about 4 to 5 times a week for around 30 - 45 minutes at a time. Since I have little spare time, I have to ride as fast as I can. I have only added Ergon hand grips, slimmer tires, & replaced the chain twice. Recently, I had a bike shop modify the rear cassette to give me a higher gear. I am 47, & despite loving my cromoly framed bike that is still in great shape, I now am running out of gears. I only use the three highest gears 90% of the time. I want to go faster, maintain a decent comfort level, have a bike that is not going to have a flat once a month, and a bike that can handle in the wind. Does anyone have any ideas? Mainly, I want to go FAST because I am getting bored. My LBS suggested a Trek 4.5 or Specialized Roubaix. I have been scouring the internet and Craigslist for used bikes, but I'm totally baffled.

Longfemur

If you're running out of gears, all you need to do is to have a shop change the largest ring in front to a slightly bigger one. Hybrids have mountain bike gearing, and the largest ring might not be large enough when riding really fast downhill or with a tailwind.

On the other hand, are you sure you're pedalling fast enough and not using gears that are too high? You want to spin the pedal at about 80 rpm, not mash them down on each stroke. Even many road riders who aren't racing swap out the large ring that came with the bike for a smaller one in the same range as what comes on a hybrid.

Everything you want to do you can do with your hybrid. It's not the bike itself that handles wind, it's the rider's position on the bike. No particular reason you couldn't replicate a more road-bike-like position on your bike. Saddle higher and handlebar lower might be what you need. I mean sure, any LBS will suggest something they can sell you if you want, and that's up to you. But I would suggest experimenting with riding position on your current bike first to see how that feels. Drop bars are desirable for serious cyclists, but you can make do with a flat bar and bar ends. I'm primarily a road bike enthusiast, but I used to have hybrids I used for riding in the woods but with long road stretches, and I always set them up road-bike style.

Fullforce

How do I calculate rpms? I read about this all of the time, but no one mentions the process.

Machka 

rpms ... rotations (of a pedal) per minute. How do you think you'd calculate that?

Fullforce

Thanks.

Now can anyone else please offer an opinion on my original question (I do like the first answer, however).

envane

Buy a cyclocomputer to find out how fast you are really going. If you are maintaining a 20+ mph speed as you are implying, then go out and buy a kick-ass roadbike and join a club.

Fullforce

My largest chainring has 48 teeth; what should I go to?