Choosing the Right Bike Chainring
The right chainring depends on your drivetrain, riding style and terrain. You would replace chainrings if you're upgrading worn chainrings or re-tuning your gear ratios.
1x vs 2x and 3x Chainrings
Most modern mountain bikes use a 1x drivetrain. A 1x system relies on a single narrow-wide chainring for simplicity and chain retention.
Road bikes and some hybrids may still use 2x systems, offering a wider gear range for climbing and speed.
If you're running 1x, a narrow wide chainring is essential. For 2x or 3x setups, compatibility with your front derailleur and cranksarms becomes much more important.
Narrow Wide vs Standard Chainrings
Narrow wide chainrings are designed to hold the chain securely on rough terrain, making them ideal for MTB and gravel riding.
They are called narrow-wide because a narrow tooth is followed by a wide tooth design. This significantly reduces the chances of chain dropping on rough terrain.
Standard chainrings are used on multi-chainring setups where a front derailleur manages shifting.
Chainring Sizes Explained
Chainring size is measured in teeth (T), such as 30T, 32T or 34T.
- Smaller chainrings (28T–32T): Easier climbing, better for steep terrain
- Mid-range (32T–34T): Balanced climbing and speed
- Larger (36T+): More speed on flat terrain, harder on climbs
Choosing the right size depends on your fitness, terrain and cassette range.
1x mountain bike chainrings have either a 32T or 34T front chainring. Gravel bikes go up to a 40T chainring.
Road bikes have different chainring combinations.
A 50T/34T chainring combination delivers the easiest climbing gear. This combo is designed for new riders or those riding up a lot of elevation.
A 52T/36T chainring set is the most popular, especially paired to modern wide-range casssettes. It delivers a good balance of speed and climbing ease. Perfect for riding variable terrain.
Lastly, a massive 54T/40T chainring set is designed for strong riders who are spending time on flatter roads.
What is BCD (Bolt Circle Diameter)?
BCD refers to the spacing of the bolts that attach the chainring to your crank. Common standards include 104 BCD, 96 BCD and direct mount systems.
It’s critical to match your chainring to your crankset—otherwise it simply won’t fit.
Oval Chainrings – Are They Worth It?
Oval chainrings are designed to smooth out your pedalling stroke by varying the effective gear ratio through each rotation. Some riders find they improve climbing efficiency and reduce fatigue.
They’re a popular upgrade for riders looking for marginal gains, especially in MTB and endurance riding.
When Should You Replace a Chainring?
You may need a new chainring if you notice:
- Skipping under load
- Poor chain retention
- Visible tooth wear (shark tooth shape)
- Reduced shifting performance
Replacing a worn chainring can dramatically improve drivetrain performance and extend the life of your chain and cassette.