This post presents the differences between 130BCD and 144BCD cranks and chainrings.
What is BCD?
BCD stands for Bolt Circle Diameter (BCD) and represents the diameter of the circle that goes through the center of the bolts supporting the chainring.
The BCD value determines what size chainrings a crankset can accept.
The Advantages of 130mm BCD Chainrings and Cranks
130mm BCD chainrings and cranks are the current road bike standard. Their advantages are:
- Smaller Chainrings
You can use smaller chainrings and get a lower gear making it easier to maintain a higher cadence. The term cadence indicates the rotations of the cranks per minute (RPM). RPM such as 90 is associated with greater efficiency and higher average speed.
The smallest chainring that a 130mm BCD crankset can accept has 38 teeth.
Since 130BCD products are the road standard, one gets to choose from more products on the market. The higher availability results in lower prices too. And if you’re stuck in the middle of nowhere in need of a new crankset or chainring, you have greater chances of finding one that fits.
- More Bottom Bracket Choices
Another side benefit of choosing 130BCD products is that you’re more likely to find cranks that can work with your current bottom bracket whatever it may be. Most 144BCD cranks, on the other hand, are designed for square taper bottom brackets.
- Don’t need as much frame clearance
Smaller BCD cranks do not require as much frame clearance as larger models. Thus, they can fit on more frames.
The Advantages of 144mm BCD Chainrings and Cranks
The advantages of 144mm BCD parts are:
- Track Standard
144 BCD is the track standard and thus it is easier to borrow or replace existing components if you are already a part of this cycling segment.
If you plan on using higher-end track components, 144mm is the way to go. Otherwise, you won’t be able to find decent chainrings.
It is believed that the large BCD of track cranks makes them stiffer. Stiffness is a good thing when it comes to cranks because the lack of flexion eliminates power transfer losses during pedaling.
It’s highly questionable whether people can truly perceive the difference, however.
- Compatible with Thicker Chains and Chairings
A standard single-speed chain has a 1/8″ (3.3mm) inner width and about 9mm outer width.
Single-speed chainrings are therefore thicker to fill up the extra space. The additional thickness makes the chainrings stiffer and more durable. That said, road chainrings are still durable enough.
Note: Most road (130mm BCD) chainrings are designed for 3/32″chains. It’s possible to find road chainrings made for 1/8″ chains, but the options are limited due to the lower demand.
High-quality 144 BCD chainrings tend to be truer. In other words, they’re closer to a perfect circle than other chainrings. This is necessary because track bikes have no derailleurs to tension the chain and if the chainring, cranks, and the rear cog aren’t as round as possible, the irregularities will result in inconsistent chain tension and make it harder to pedal smoothly.
That said, the differences in roundness are too small and remain unnoticeable by recreational riders.
Note: Today, 144 BCD is reserved for track bikes, but older road cranks from the 70s, 80s, and even 90s could be of the same size too. One example would be Campagnolo’s cranks from the 80s. The advantage of using 144 BCD road cranks (besides the vintage look) is the option to install a second chainring and acquire a 2x drivetrain.
What to get?
130 BCD and 144 BCD components are designed for different bicycle segments. 130 BCD works best on road bikes whereas 144 BCD will give maximum performance on the track. Thus, it makes sense to base your choice on your riding style.
That said, it’s worth mentioning that 130 BCD is more versatile because you can use multiple chainrings. It’s also possible to install 130 BCD cranks on a track bike.