Road Bicycle Gears – Triple, Compact, Double, what does it all mean?

Bike Gears – Triple, Compact, Double. What do I need?

Road bikes come with variety of gearing combination. When purchasing a road bike you must know what configuration is the best one for you.

What are the gears (the speeds)? The gears are the chain-rings on your crankest connected by the chain to the cassette on the rear wheel. It works very simple. The bigger the chairing in front, the more speed you get, but it’s more difficult to push the pedals. The smaller the chairing in front is, the less speed you get but it’s easier to push the pedals. At the back, it works just the opposite. Bigger ring easier but slower. Smaller ring faster but harder. While riding we change gears to achieve preferred riding speed in various riding conditions. It’s usually the one he can sustain for a period of time. For example when transitioning from the flats to uphill we will adjust the gears to allow easier pedaling while giving up some speed.

The bikes today come in three main configurations: Triple, Compact, Double.
Triple (52/39/30)allows for the widest range of gearing combination (30 gears). It is the most versatile out of the three because it’s good for flats and climbs. However, the triple is not very popular and considered for “beginners”. It is also a bit heavier. You will have a problem to find a high-end bike with a Triple.
If you can’t find a triple but you still want to be able to climb hills your next choice will be Compact (50/34). Compact is trying to cover the most of the triple’s range with just two rings. Therefore there is some sacrifice at the end of the range. If you’re in a good shape you might want to use compact as it will save you weight, provide better shifting and you will only lose about 12% of your climbing power.
So what about the Double? The Double (54/39) is designed for speed and for strong riders. It has bigger chain rings than the Compact and therefore provides more speed. However, climbing with double is very difficult.
But what about the rear cassette? How does it come into the play?

Let me start by saying that if in front we have three possible configuration at the rear we can chose between six different cassettes from Shimano: 11-21, 11-23, 11-25, 11-28, 12-25, 12-27. All cassettes has a different purpose. For example 11-21 is the speediest cassette, but it will be very hard for climbing as the biggest cog is only 21. The 12-27 is good for climbing, but might not be the fastest. The one that covers the whole range is 11-28. This would be my choice.

Let’s look at the gears ration table I’ve created (click table to enlarge):

The Yellow marking represents the 11-28 Cassette at the rear and it’s ratios to the three crankest configurations. Since the Triple provides the widest range, I compared everything to it. The fastest speed combination 52/11 is denoted as 100% of the speed – green. The best climbing combination is 30/28 and it’s denoted as 100% climbing ability – pink. The table shows that when choosing a Compact over Triple you give up 12% of your climbing ability and 4% of your speed. When choosing a double you give up 23% of your climbing ability but gain 4% to your speed.

This is the decision flowchart you might want to use when choosing your gears:

1. Am I going to ride only flats? Get a double.
2. Am I going to do serious climbs? If yes and you are a not a strong rider – triple is a must. If you are in good shape get a Compact with 11-28 cassette.

So what do I ride? I am in good shape but my personal choice is the unfashionable Triple. Yes it weighs more, yes it’s not cool, yes the shifting is not as crisp as on the Compact or Double, but when I’m out with my bike I am know I am well prepared for anything I can encounter. Living in an area with daily climbs of 3000ft Triple is my best buddy.

I must provide a clarification that all my calculations were based on Shimano, however other manufacturers (SRAM or CAMPAGNOLO) might have other similar configurations. If you understood the theory, you will be able to choose your gear from any manufacturer. I would recommend not to mix and match between them as they are not 100% compatible.