Originally Posted by cyccommute

If you want to maintain a similar speed at a similar cadence, there is. Consider the following. The 50/39/30 with an 11-34 cassette is the gearing I have on my fast road bike. Comparing it to a 50/34 with the same cassette, let’s assume that you are riding in the 23 tooth gear on both bikes at 90 RPM on the same 28mm tires. Speed is 15.7 mph. If I shift off the large ring to the middle one, the speed difference at 90 RPM is 3.5mph. A slight increase in cadence will bring me back up to the same speed.

With the compact double the speed difference between the two ranges is 5 mph. To maintain the same speed, the rider has to increase cadence to over 120 rpm or the rider has to upshift twice to get the same speed/cadence as the closer ratio triple gives.

Road riders will go on and on about how they want close ratios so that they can find just the right gear for the right speed but then they ride a drivetrain that doesn’t allow for that kind of close ratios. I don’t get it.