The Bike List

Standard Road Double Chainsets – The Complete Guide

What is a standard road double chainset?

A standard road double chainset (the crank arms and chainrings combined) always has two chainrings. The big (outer) ring typically has 53 or 52 teeth and the small (inner) ring most commonly has 39 and sometimes 38 teeth. The most common combinations are 53/39 or 52/38.

Standard road double chainsets offer bigger (harder) gears compared to compact chainsets which typically have a 50 tooth outer ring and a 36 tooth inner ring. For this reason standard road double chainsets often feature on racing bikes where higher average and top speeds are common.

With two chainrings rather than three, there is also the advantage that the chainline (how straight the chain runs from the chainrings to the cogs on the rear) will be straighter more of the time, which is mechanically more efficient. The chain on a road triple chainset, typically with 50/39/30 tooth chainrings, is forced to cover a wider area which is mechanically less efficient. It will also be heavier with that third chainring, but does offer more gears - ideal for less fit riders, those riding consistently hilly terrain and cyclists carrying heavy loads such as on touring trips.

A compact chainset offers a middle ground between a standard road double and a road triple chainset and features on a wide range of bikes. To find out more about compact chainsets read our complete guide.

What bikes do standard road double chainsets typically feature on?

Standard road double chainsets offer big gears for going fast and for this reason they feature on road racing, time trial and triathlon bikes. In fact, if a bike features a standard road double, then this is an indication that the bike is probably intended for speed over comfort and is likely to also have a more aggressive geometry.

For the average club / sportive road cyclists a compact chainset is likely to be a better all-round option, offering more useable gears on a variety of terrain.

Click here to see all bikes that feature a standard road double chainset.

What is a semi-compact chainset and how is it different to a standard road double chainset?

A semi-compact chainset (typically 52/36 teeth) offers gear ratios that are in between those found on a standard road double (typically 53/39 teeth) and those on a compact chainset (typically 50/34 teeth). Where as a compact chainset is a good all-rounder option found on a wide range of bikes, semi-compact chainsets, like standard road double chainsets, are typically found on road racing and triathlon bikes. This is because the larger chainrings on both semi-compact and standard road double chainsets are better suited to riding at higher average and top speeds.

The largest chainring on a semi-compact (52) offers gears ideal for high speed riding or racing and the smaller chainring (typically 36) offers gears that are well suited to climbing. This combination makes a semi-compact a good option for those who plan to race and participate in undulating or hilly endurance events such as sportives using the same bike.

Click here to see all bikes that feature a semi-compact chainset.

What is BCD and why is it important?

BCD stands for Bolt Circle Diameter and is the diameter of the circle created by, in this case, the five holes at the end of the arms on the spider - the multi armed piece that connects the chainrings to the crankset.

BCD 110 And 130

The BCD number must be the same for both the crankset and the chainrings otherwise they won't be compatible.

A point worth noting is that the BCD on the majority of compact and semi-compact chainsets is 110mm whereas the BCD on the majority of standard road double chainsets is 130mm. This is significant as each BCD places restrictions on the maximum or minimum size of the small chainring. The small chainring must have 38 teeth or less on a 110mm BCD chainset and must have 38 teeth or more (usually 39) on a 130mm BCD chainset. This means you'll need a 130mm BCD if you want to run a 52/39 or 53/39 or 54/42 racing / triathlon / time trial specific chainring combination and if you want to run a 52/36, 52/38 or 50/34 etc you'll need to opt for the 110mm BCD crankset.

What are the limitations of standard road double chainsets?

For amateur racers and professional road cyclists a standard road double or semi-compact will make sense most of the time. For those less concerned with going as fast as possible, a compact (the most common choice) or road triple chainset is likely to be an ideal alternative. Compact chainsets are very popular as they offer a broad range of gears and are covered in more detail here. Similarly road triple chainsets are well suited to hilly terrain and those carrying heavy loads whilst touring - covered here. On seriously hilly stages in races such as the Tour de France even professionals will opt for compact chainsets to help them climb long arduous ascents.

Compared to a standard road double chainset, a compact chainset will allow you to spin your cranks faster uphill (thanks to the easier gears available) which will make climbs feel easier to pedal up. This is especially useful for long or steep inclines where spinning up hills with a higher cadence (revolutions per minute) is generally considered to be more efficient, although perhaps slower. A higher cadence also means it is much easier to stay seated whilst going uphill.

Bike List Top Tip: it pays to look after your components

Keeping your chainset, cassette (the group of smaller cogs on your rear wheel) and chain clean and well-lubricated can make a big difference to how efficient your bike is. If your chain is dirty it can be up to 7 or 8% less efficient - the equivalent of being 5 or 6 kgs heavier on a climb. Source - The Obree Way, A training manual for cyclists, Graeme Obree.

Converting your standard road double to a semi-compact or compact chainset.

Shimano 22 Speed Dura -Ace FC-9000

Converting from one double chainring chainset to another is much easier than converting from a double chainring setup to a road triple. The reason being that if the number of chainrings stays the same, then only the chainset needs to be replaced.. There are exceptions such as Shimano's 22 speed Dura-Ace FC-9000 chainset, pictured on the right, where the Bolt Circle Diameter is the same on all cranks meaning only the chainrings need to be swapped. On the majority of chainsets, a change from a standard road double (typically 53/39) to a semi-compact (52/36) or a compact ratio (50/34) requires only a new chainset. See article on BCD for more details on this. If changing from a compact to a standard road double a longer (new) chain will also be required however it is good practise to replace the chain anyway if putting on a new chainset.

Converting your standard road double, semi-compact or compact to a road triple chainset.

Changing from either standard road double, semi-compact or compact chainset to a road triple or vice versa will typically require a new left shifter, front derailleur, chain as well as chainset which means this type of change is usually not cost effective.

The Bike List Top tip: replace instead of converting

Price up a conversion from two to three chainrings or vice versa, and include labour costs as well as the parts mentioned above, as in some cases it can be cheaper to replace the bike with one that has the setup you want and sell the one you have.

What cassettes are standard road double chainsets typically paired with?

Standard road double chainsets are typically paired with cassettes (the group of smaller cogs on the rear wheel) that have an 11 tooth small sprocket as the smallest cog giving you a 53 + 11 biggest gear.

They will also typically come with a cassette that has one of the following sprocket ranges: 11-21, 11-23, 11-25, 11-26.

To work out gear ratios, speed at cadence or cadence at speed visit for more information.

Changing A Cassette

These gear ranges are relatively narrow compared to others that are available as racers and time triallers typically prefer small incremental changes which allow for smooth gear changes with minimal difference in pedalling frequency or RPM (revolutions per minute).

That's not to say you can't change the cassette to one that has a broader range. Changing a cassette is a cost effective way of adapting your bike to make it more suitable for different terrain. A simple change to a cassette with a wider range of sprockets such as 11-26, 11-28, 12-28, 12-30 or 11-32 will make the same bike noticeably easier to pedal on hillier terrain.

If you shop around you can usually find a good cassette such as Shimano 105 (which strikes a good balance of value and quality) for around £25-£35. A like for like cassette replacement will usually be around 3-4 times cheaper than a like for like replacement chainset.

Read our guide to changing a  Shimano 10 speed cassette here.

The Bike List Top tip:

Most rear derailleurs will be capable of running a number of different cassette ranges. If the largest sprocket on the cassette is changing significantly in size make sure your rear derailleur can accommodate the larger sprocket. Most road bike rear derailleurs are available in a short cage (small gear range), mid cage (middle gear range) and sometimes long cage (wide gear range) designs.

Summary of standard road double chainset:

  • 53/39 is the most common chainring tooth combinations.
  • Will have either 10, 12, 14, 16, 18, 20 or 22 gears.
  • Offers bigger (harder) gears than semi-compact and compact chainsets making it ideal for riding at high speeds such as when road racing or time trialling.
  • Weighs less than a triple chainset.
  • Not as efficient as a compact or road triple chainset when pedalling up hills.
  • The smallest cog on the cassette will typically have 11 teeth.
  • Well suited to pairing with a cassette with a small range to allow for small incremental gear changes and therefore smooth pedalling when changing gears.
  • The chainline will be straighter more of the time than on a road triple and therefore more efficient.
  • Much easier and cheaper to change to a semi-compact or compact chainset than it is to change to a road triple chainset.
  • Standard road double chainsets typically have a 130mm BCD where as compact and semi-compact chainsets typically have a 110mm BCD.
  • Changing from a standard road double to a semi-compact or compact only requires a new chainset and chain.
  • Changing from a standard road double to a road triple chainset is often not cost effective as it requires a new chainset, left shifter, front derailleur and chain. So, buying a new bike and selling your old one can be a better option.

To find out more about compact, semi-compact and triple chainsets click below to read our comprehensive guides.

Compact Chainsets - The Complete Guide

Semi-compact Chainsets - The Complete Guide

Road Triple Chainsets - The Complete Guide