Where’s My Granny? The Mysterious Disappearing Triple

Why do new road bikes have only two chainrings in front?

It was only up until a few years ago road bikes were equipped with the fabulous triple. Otherwise known as the “granny gear.” Three chainrings up front meant more room to spin, less burning in the legs, less pain to suffer.

And although the market recently is pushing for higher gear ratios, you’ll only find two chainrings on most road bikes. Granny is gone.

Bicycle gearing has come a long way. These days, your Ciclismo Classico bicycle won’t have three chainrings. It’ll have two.

Are we just evil?

What gives? Why are bike companies making it so hard to go uphill these days?

Well, if you’re having trouble riding uphill, you should reconsider how you approach climbing. But maybe you can do something about your bike even if you no longer have the granny gear. Let’s take a look at gearing and the amazing, disappearing triple:

Getting Geared Up: Physics 101

First, let’s take a look at gears and how they work. Briefly put, if a smaller gear in front is spinning fast, a larger gear in the back spins slower. This is your lower gear. On the other hand, a larger gear in front will turn a small gear on the back of the bike multiple times. This is high gear.

Thus, according to Explain That Stuff, I need increased force on the front to increase speed on the back (high gear). So the bigger gear I have in front, the more force I need to apply to it, to turn the gears in the back.

Obviously, all of these gears have teeth (that’s how they turn the chain – and each other – around). The relationship between one gear and another is called the gear ratio. How Stuff Works has a fantastic explanation of gear ratios.

The great Sheldon Brown – guru of all that is biking – has a great online calculator for figuring out gear ratios. This will help you understand how gear ratios are set up between “Standard” and “Compact” crank setups.

Granny Got Run Over by a Chain Gear

In the mid-2000s, component manufacturers like Shimano invented the compact crankset. Simply put, the diameters of cranksets (and thus, the number of teeth) has gotten smaller. Today, a typical compact setup will have gear teeth of 50/34 (except Campagnolo). Smaller diameters call for smaller numbers of teeth on the chainring.

Standard setups, however, are much larger. A typical standard setup can be 53/39 with diameters approximately 20mm bigger. It may not seem like a lot, but three extra teeth can make a major difference. If a larger crank requires more force to turn it (as we’ve seen above) then I’m going to need more force to turn the pedals, burning up precious energy sources. Steve Hogg has great research and an excellent Q&A on this topic discussing everything from speed to force differences.

Some pundits suggest Shimano trashed the whole triple idea to cut costs. They removed the smaller gear to make cycling a lot easier for the everyday cyclist.

Lesser Material = Cheaper Product?

Not quite. Keep in mind a lot of bicycle component companies are trying to reduce the weight of their product. Shimano is not trying to cut corners, they’re trying to improve their technology. They discovered removing the triple and changing the crank diameters was a great way to reduce weight and maintain ergonomic gear ratios. If they were to make cranks bigger, you’d need a hulk to pedal those gear ratios. Anything smaller would be inefficient. 50/34 works perfectly for the average working cyclist.

Closer for Comfort

Getting rid of that third chainring eliminates unnecessary space. I remember in the late 90s trying to adjust front derailleurs to cover all three chainrings. What a mess. There would be that awful tic-tic noise as people would try to move the chain up or down the chainrings.

Now, with that “granny gear” gone, there is less space to move a chain. The bike chain has two places it can go. And dropping the chain is less frequent. With more precise derailleur limits you don’t waste any energy when changing gears.

Take it Easier

You’re still looking for easier gears to turn? Don’t touch your chainrings. Change out the rear cluster.

These days you can put a 32-tooth cog on your rear wheel. With a compact 34t chainring and a rear 32t cog, your gear ratio is nearly 1:1, and that’s great. Shimano also makes a 105 34t cassette, making hills a lot easier to climb. But be sure to check with your local mechanic about doing any of these changes to your bike. A larger cassette means you may need a longer cage on your rear derailleur.