Which Chainrings Do I Need?

What to do if you need a new chainring for your road bike, mountain bike, or crosser. The first thing you do is contacting our customer service, of course, but to make things easier, we wrote this blog about the outer chainring, so you can find the right components for your crankset.

Chainring - crank type

First thing you do is checking the type of crankset you have. There are four possibilities:

• Single: One chainring in front. You mostly find them on MTBs and crossers.
• Double: The classic set where you can choose between a heavy gear or a small one (53 or 52 and inner chainring of 39t)
• Compact: Between a triple and a double: 50/34 chainrings.
• Triple: Offers three choices: large, smaller, smallest. You can take on all roads; flat roads and all the steep mountains on your to do list.

Second step is checking the amounts of gears: 9-, 10- or 11-speed mostly. You can check by counting the sprockets of your cassette.

BCD

Then you check the axle of your crankset. Simply: it is the diameter of the circle in the middle of the bolts, also BCD = Bolt Circle Diameter.

Sometimes this is hard to measure, so below an image that hopefully makes things clearer.

Chainring - numbers don’t lie

The left image shows a chainring with a BCD of 110mm. Sometimes this is hard to measure, although it probably is easy to see if it is a 130 BCD or a 110.

Below we offer an extra check to make things easier. Take in mind that you check if you have a 4-arm or 5-arm crank! If you have a 4-arm, use the image on the right, if you have a 5-arm use the image on the left!

Measure distance “x” (See illustration). From this follows:

• Race: x = 76mm (5-arm), BCD = 130
• Race: x = 64mm (5-arm), BCD = 110
• ATB: x = 74mm (4-arm,), BCD = 104

If you have a Campagnolo groupset:

• x = 77mm (5-arm), BCD = 135
• x = 65mm (5-arm), BCD = 113

Then you determine how many gears you need. This depends on your preferences and the surroundings of your rides. In the mountains you use smaller chainrings than on flat roads.

A 53/39 is fine for flat roads, for example, but if you ride in the hills a compact 50/34 would be better perhaps.

You can find the images below in our webshop if you search for chainrings. You can check the qualities you want and that fit your bike on the left side of the webpage, so you only see the chainrings that meet your demands.

Budget

Finally, the last thing you need to do is set a budget, for obvious reasons. If you have Dura-ace outer chainrings, that doesn’t always mean that Ultegra and 105 components are impossible, though.

This wouldn’t look as sleek, however, and you could also use other, cheaper brands which are often just as durable. But this depends on your personal priorities :)