Double or Triple crankset for a Road Bike?

A "double" crankset refers to one with two chainrings on the front, representing a mid and high gear range option.

A "triple" crankset refers to one with three chainrings, the extra chainring being a very small one on the inside that gives you a considerably lower gear range than available with the double. This small chain ring is commonly called a "granny gear" as in even your granny can climb a hill in this gear.

Triple Chainring Crankset	Double Chainring Crankset

In general, a "double" crankset bike will have either 14, 16 or 18 gears, and a "triple" will have 21, 24 or 27 gears.

Things to consider

If you climb in lower gears, you’re not necessarily going to go slower up the hill. In fact, the opposite may occur, as the lower gearing of a triple might be more optimal for your own physique. Not everybody was built with massive muscles, and in most cases, higher RPMs at lower gears will be more in sync with your body than big massive gears that you might barely be able to turn. A bike with a triple usually has about the same high-end (your go-fast gears) range as a double. So in general you’re not giving up anything at the high end but rather adding on at the lower end (meaning that you’re getting new gears to make it easier to go uphill while keeping the high gears that allow you to go fast downhill). Way-cool high-end bikes are now available with triple cranks right off the showroom floor! It’s no longer the case that the only way to get a super-high-performance frame and wheelset was on a bike with a double crankset. The market has dramatically changed, and there are now as many options with triples as there are with doubles and if the bike you want isn’t available with a triple, chances are that the bike shop can install one on it. Triple-equipped bikes are not just for wimps!!! Even hot-shot riders come across incredibly-steep hills that make him/her think (although rarely aloud) "It sure would be nice to have a lower gear right now!" And besides, just how comfortable do you feel calling every mountain bike rider a wimp? Virtually 100% of them have triple cranks, and they USE the lower gears all the time! In fact, it’s probably the widespread success of triple-equipped mountain bikes that’s helped fuel demand for the wider range gears on road bikes.

So why wouldn’t everybody get a triple-equipped bike?

Many people (particularly men) have this macho-thing about being strong enough to climb a hill without the help of so-called granny gears There’s not much you can do about this type of attitude. The only "cure" is a pair of busted knees, and that "cure" usually ends the cyclists' riding career. It’s still the case that the very highest-end component groups are not available with a triple crankset (specifically Campagnolo Record and Shimano Dura-Ace). So if you want a $3000+ bike with the very hottest components, it requires a bit of improvisation if you want it with a triple. There remain a number of cyclists that believe tradition is more important than progress, and since early, classic road bikes didn’t have triples 30 years ago, they still shouldn’t now. This is frequently the same type of person who feels that "steel is real" (meaning that any other material, be it aluminum, titanium or carbon-fiber, just isn’t what a bicycle is supposed to be made out of) and probably doesn’t wear a helmet. And there are truthfully some people so strong that they don’t need a triple crankset, or for inexplicable reasons just don’t have a whole lot of trouble climbing in very tall gears at very high speeds. Alas, there are few of us so afflicted. Finally, there are slight trade-offs in terms of weight (figure an extra half-pound or so of weight) and shifting performance. Not much decline in performance, but the longer chain makes for a bit more work for the rear derailleur, and on the front, shifting between the inside and middle chainrings isn’t quite as precise as the shifting on a double.