Several years ago, there were only two crankset models available for road bike : double and triple. Today you also have the option of the compact, as well as the new single speed. But it’s not easy to know where to turn with all these options available, particularly for beginners. So here are some helpful explanations about the different models and a few hints on how to use each one.
The oldest crankset model for road bikes. It has five arms (more recently tending towards four arms), and the spider’s spacing (where the chainrings are fixed) is 130 mm (Shimano and SRAM) or 135 mm for Campagnolo.
It’s the typical crankset for very hefty messenger bike or cyclosportive riders. It’s often supplied with 53/39 chainrings, but you can also opt for other combinations such as 52/42, 50/38, or 52/39.
But be careful: only the 130 mm spacing (Shimano and SRAM) lets you fit a small 38-tooth chainring. For Campagnolo, the 135 mm spacing doesn’t let you go below 39 teeth.
Long the crankset of choice for cyclotourists or anyone who isn’t a fan of hill climbs, the triple crankset is becoming harder and harder to find, even though Shimano and Campagnolo continue to sell specific drivetrains in their ranges.
With three chainrings, this crankset allows you to enjoy a wide gear ratio and thus helps you to tackle any hill at all. The 74 mm spacing lets you mount a small 30-tooth chainring. The most common combinations are 50/40/30, 52/42/32, 52/40/30, and 48/38/30.
With a small 30-tooth chainring and a cassette going up to 28 teeth, even the biggest hills are no match for this crankset. However, adjusting a triple drivetrain is a bit more delicate than a double chainring. What is more, the Q factor (distance between the two crank arms) is bigger than on a traditional crankset and can prove a problem to some people.
And lastly a triple drivetrain adds more than 300 g to your bike.
Like the double crankset, this crankset, which stems from mountain biking, uses two chainrings but has a spacing of just 110 mm. As a result you can mount much smaller chainrings on it, up to 33 teeth.
Although it doesn’t offer the same gear ratio as a triple chainring, the option of 10- and 11-speed cassettes with sprockets of up to 30 or even 32 teeth provides a fairly wide range. But there will of course be a bigger “gap” between each gear, with jumps of two or even three teeth at the top of the cassette.
On the other hand, the chain will be less likely to get crossed than with a triple crankset and you will be able to use a short cage rear derailleur when a triple crankset would have required a long cage.
The most common combinations are 50/34 and 52/36 (also known as a semi-compact).
It is without doubt the most popular model nowadays. It’s just as suited to cyclosportives (in 50/34 or even 50/33) as it is to messenger bikes with a 52/36 or 52/38 combination.
THE DOUBLE COMPACT
The latest crankset models from Shimano and Campagnolo offer four arms and let you mount both compact and double chainrings.
You no longer need to choose between a double and compact chainring because these latest models, thanks to their 110 mm spacing (except for Campagnolo, small chainring with 112 mm spacing and large one with 145 mm), let you mount chainrings from 34 to 56 teeth without losing rigidity.
Nowadays all crankset models are focusing on this capacity to fit double and compact chainrings equally well.
THE SINGLE CHAINRING
Let’s also take a look at the latest arrival in road cycling, the single chainring. This technology comes straight from mountain biking and, as its name suggests, has only one chainring.
Mainly used for cyclocross, gravel and city bikes, it makes the bike much lighter and also reduces maintenance (no front derailleur).
But this lack of derailleur means having a specially designed chainring with specific teeth that can deal with extreme cross chaining on the cassette’s sprockets.
For me, the single chainring is too limited in terms of gears for using when road cycling.
WHICH ONE IS RIGHT FOR YOU?
It all depends on what you will use it for. On tandems or if you want to cycle long, hilly routes with a load on your bike, you will want to go for a triple crankset. It’s the only drivetrain that can offer a wide gear ratio that is nicely spaced. The extra weight won’t be a problem.
For most cyclosportive riders, the compact is what you need. Particularly with the latest Campagnolo and Shimano group sets, which let you mount both 34-tooth and 56-tooth chainrings if necessary without changing the crankset.
We’d recommend the 50/34 and 52/36 combinations, with 11/25, 12/25, 12/27, 11/30 or 12/32 cassettes, which let you cover most needs.
The traditional double, in 53/39, would be best kept for very hefty sprinters and cyclosportive riders.
Finally, only very competent cyclists will know whether the single chainring is suitable for them or not, depending on the area where they live or cycle.