Blog

Are you ready for a free bike theory less from the brainy bike master?

Let’s go.

Geared entry-level bikes often come with a triple crankset combined with 6,7 or 8-gear cogs at the back. The combinations provide 18-24 theoretical gears, but not all of them are usable due to cross-chaining resulting in a loss of pedaling efficiency and friction against the cage of the front derailleur.

Meanwhile, more expensive, higher-level bicycles have a double or single crankset offering fewer gears. The bikes with a single chainring at the front do not even have a front derailleur.

Naturally, people ask themselves – why aren’t the expensive, higher-end bicycles the ones providing more options? Why do cheap bikes have more gears than luxurious models?

Cheaper bikes have more gears because they rely on a basic and mass-produced triple crankset technology naturally resulting in a large number of chainring to cog combinations.

Conversely, 1x and 2x drivetrains are more optimized, trendy, and use sophisticated materials and rear mech. Subsequently, their price is significantly higher.

Why Are 3x Drivetrains Cheaper?

Note: The term drivetrain refers to the system of components transferring power to the rear wheel. 3x equals a triple crankset (three chainrings) whereas 2x and 1x drivetrains use a double and respectively single crankset.

The factors behind the lower price of 3x drivetrains are:

Mass production

Triple cranksets have been a mountain bike standard for a long time. The infrastructure needed for high-volume manufacturing and the necessary distribution pathways are already present and operating.

The never-ending demand for low-end bikes reinforces this mechanism and creates a healthy environment for the continuous production of triple cranksets.

As expected, mass production lowers the price of those products because the lines are optimized, and the producers can buy the necessary materials in bulk.

Lower Grade Materials

The triple cranksets found on entry-level bikes are often quite generic and come with chainrings made of non-sophisticated stamped steel.

Metal stamping is a highly efficient low-cost manufacturing process during which flat metal sheets are turned into parts of various shapes. The method is fairly inexpensive and has a quick turnaround – properties that make it perfect for mass production of chainrings.

Conversely, the chainrings found on 2x and 1x drivetrains are often made of high-grade machined aluminum which requires a more sophisticated production process.

The crank arms on triple cranksets are also of lesser quality than those on 2x and 1x drivetrains. One of the reasons for the structural difference is the style of riding that the bikes are designed for.

A triple crankset is oriented towards trekking and Cross Country whereas a single chainring is geared towards more aggressive disciplines e.g., downhill. Hence why the crank arms on many single cranksets are reinforced and built of stronger materials.

Another characteristic of cheaper triple cranksets is that they are riveted together. This assembly streamlines the production process but also makes it impossible to remove and replace the chainrings once they wear out. Subsequently, nothing from the old crankset could be used…except for the bolts.

Below is a table that summarizes the major differences between the low-end triple cranksets and the higher end 2x and 1x cranksets:

Low Level Craftsmanship

As expected, more expensive cranksets showcase a greater level of craftsmanship. The design and the lines are more elegant and complex.

Cheaper Cassettes

Triple cranksets can offer a wide gear range without a high number of rear cogs at the back. The lower number of cogs simplifies the production of cassettes and lowers the expenses.

For example, a typical 8-speed cassette with a 34-tooth large cog such as Shimano CS-HG31-8 offers a reasonable range of low and high gears at a very affordable price.

To provide an adequate gear range, 1x drivetrains need more cogs at the back of the wheel. The results are 11, 12, 13, and even 14-speed cassettes with ultra-large rear cogs designed for hill climbing. The production of those cassettes is more complex and expensive.

Affordable Low-Gearing Targeting the Untrained Public

Most people buying entry-level bicycles are new to the sport and probably untrained too. A triple crankset combined with 7, 8, or 9 gears at the back offers a very wide range with plenty of “climbing gears” that allow even inexperienced cyclists to climb big hills without getting out of the saddle.

Marketing

The higher number of gears adds marketing points to entry-level bikes. Uneducated people could easily conclude that a bike with 24 gears is significantly better than a bike with 14 gears.

Cheaper and Simpler Rear Derailleurs

The cheaper derailleurs designed for 6,7,8 and 9 speeds do not have the necessary capacity to work with larger cassettes and won’t be able to shift the chain onto the largest cog of a cassette with more gears.

One option is to use a rear derailleur hanger extender which effectively lowers the derailleur and allows it to encompass the entire range of the cassette. The downside of this method is that it doesn’t always work.

For that reason, single cranksets come with more expensive rear derailleurs with greater reach and a clutch technology that keeps high tension on the chain.

The result is a more secure and silent chain that doesn’t bounce as much. Also, the “luxurious” derailleurs offer a smoother and more premium shifting experience.

Cheaper Chains

The 6,7,8 and 9-speed chains are more common and tend to be cheaper than the ones designed for 10+ speed transmissions.

Why? It’s hard to give an adequate reason other than the fact that 10+ speed chains are part of the 1x and 2x “premium package”.

Smaller Incentive to Save Weight

Since 3x drivetrains are usually installed on entry-level bicycles, there’s a smaller incentive to make the components as light as possible. This alone saves costs because it’s always expensive to lighten a bicycle.

Why Do High-end Mountain Bikes Use 1x Drivetrains

The main reasons why high-end bicycles, primarily MTBs, rely on 1x drivetrains are as follows:

Simplicity

1x drivetrains eliminate the front derailleur. All the shifting happens at the back. When you need a lower gear, you go up; when you need a higher one, you shift towards the smallest cog. There’s no need to think of different combinations because there is only one chainring at the front.

Efficiency

In theory, 3x drivetrains provide 18-27 gears (the number of rear cogs multiplied by the number of chainrings).

In reality, there’s significant overlap, and the actual number of usable gears is many times lower.

The chart below presents the gear ratio of a 3×8 drivetrain with 34 as the largest cog at the back.

The gear ratio illustrates the number of turns that a rear cog makes for one turn of the cranks.

The formula for calculating the gear ratio of a bicycle is:

Gear Ratio = Number Chainring Teeth/Number Rear Cog teeth

For example, if the chainring has 32 teeth, and the rear cog has 24, then the gear ratio for that gear is: 32/24=1.3

Casette: ShimanoCS-HG31 8-speed
Cogs: 11-34 (11-13-15-17-20-23-26-34 teeth)
Chainrings: 42/32/22

Conclusions:

1. The 22×11, 22×13, 42×23, 42×26, and 42×34 gears are technically not usable because they result in noticeable cross-chaining which reduces the efficiency of the transmission and creates rubbing against the cage of the front derailleur.

2. Many combinations have a very similar gear ratio and are marked as “overlap”.

3. These combinations of chainrings and cogs leave us with 15 usable gears once you remove those that overlap and the non-usable ones.

1x drivetrains aim to make the transmission of a bicycle as efficient as possible by eliminating redundant gear ratios while still offering plenty of choices.

Below is another table presenting the gear ratios offered by Shimano Deore XT CS-M8000 11-46T 11-speed cassette when coupled with a 32-teeth chainring at the front.

Conclusions

An 11-speed cassette with a big 46-teeth gives us 11 usable gears. The lowest one has a gear ratio of 0.69 whereas the highest one is 2.9.

When we compare this system to the 3×8 drivetrain analyzed above we find the following differences:

1. The 3×8 drivetrain offers extra high gears (42×11, 42×13).

2. The lower gearing of both systems is pretty similar (0.69 vs. 0.64 in favor of the triple crankset system)

3. The 1×11 drivetrain comes with higher jumps between the gears – 0.2 on average.

Since mountain bikers rarely use the highest gears on a 3x drivetrain, the two main downsides of a 1x drivetrain are the higher jumps between the gears and the potentially lacking low end.

Having said that, the price difference between the two systems is quite large.

An 11-speed cassette produced by a reputable manufacturer is over USD 100. And that’s just the cassette. For the same, money you can buy an entire high-quality 3x drivetrain.

Aesthetics

1x drivetrains look cleaner and subsequently more aesthetically pleasing. For many, the looks alone make them worth it.

Weight Savings (potentially)

In general, a 1x system should be lighter because the front derailleur, the front shifter, the left shifting cable, and two of the chainrings are removed, but in practice, that doesn’t always happen because some low-end cassettes are quite heavy and the final weight cut isn’t that big.

Moreover, most of the extra weight that comes with a 3x drivetrain is positioned at the bottom bracket – the place where you feel it the least.

Another reason why the weight savings aren’t all that significant is that sometimes people use a chain guard when running a 1x drivetrain to prevent the chain from dropping.

In conclusion, people often over-hype the weight reduction that comes with a 1x drivetrain.

Clean Cockpit

The handlebars look a lot cleaner once the front shifter and the shifter cable are removed.

Many riders often use the extra space to clamp on their dropper post remote.

More Freedom When Designing a Frame

Since 1x drivetrains have a single chainring at the front, there’s no need to design the frames around a front derailleur. The two main benefits are shorter chainstays and more possibilities when constructing frames with rear suspension.

Why aren’t 1x drivetrains available on cheaper bikes?

More observant people may ask a very logical question – can’t companies produce a cheap 1x drivetrain made of less sophisticated components?

In theory, manufacturers can do that, but you also have to take into consideration the market.

The entry-level segment isn’t a place where a lot of experimentation takes place because the prices have to be kept as stable as possible – an incentive to keep the infrastructure intact.

Switching from 3x to 1x on low-level bicycles would require a very intensive restructuring of the sector while offering questionable benefits.

Even if component producers come up with an affordable and reliable 1x transmission, it may not have a positive effect on sales because the targeted customers (beginners) don’t recognize the value behind 1x drivetrains.

If anything, unaware cyclists may conclude that bikes without multiple chainrings are of inferior quality and less technologically advanced.

Innovations are appreciated the most when they satisfy the needs of more dedicated riders who understand the game and have the knowledge and experience to fully grasp the opportunities that new tech can give them.

1x Drivetrain Shine the Most On Expensive Bikes

Single chainring systems are more suitable for higher-end bicycles for the following reasons:

Innovation Points

Technically, 1x systems are not new. They’ve been available for a long time. They were present before the 3x drivetrain. The difference is that modern 1x drivetrains offer more range and sophistication.

Bicycle lovers, especially mountain bikers, like new tech. Bike manufacturers know that and try to deliver.

Higher Quality

Putting a USD 300 drivetrain on a USD 500 bike makes no sense. However, the higher price points of more advanced bicycle models allow manufacturers to engineer drivetrains of better materials.

Higher Profit Margins

As already mentioned, dedicated riders are willing to invest more money into their machines. Hence why putting new components on higher-end bikes is often more lucrative than doing so on “department store” bikes.

Frequently Asked Questions

My bike has a 2x/3x drivetrain. Should I replace it?

Honestly, there’s no need to if everything is working fine. A 1x drivetrain may look “hot”, but 2x and 3x are not going to limit your riding regardless of what others may say. You won’t become a better rider upon switching to a more trendy transmission.

Having said that, you could consider moving to a different drivetrain when the current system wears out.

Prepare to spend a decent sum of money.

You will need to buy the following:

• A narrow-wide chainring (a special chainring with alternating teeth designed to stop the chain from dropping)
• A chainguard (if the derailleur does not have a clutch)
• A clutch rear derailleur with extended range or a derailleur hanger extender
• New cassette (potentially a new rear hub if the current one cannot accommodate the new cassette)
• New chain
• New rear shifter

As you can see, the expenses quickly add up. The same money could be used for more important upgrades like the suspension, the brakes, and the wheels.

Are 1x drivetrains overhyped?

They certainly have their place on higher-end bikes, but far too many people are expecting miracles from 1x transmissions.

I would even go as far as saying that many are needlessly switching to 1x from perfectly viable 2x drivetrains which offer plenty of range and close to zero redundancy.

In the table below, you can see the gear ratios of a typical 2×9 drivetrain system with 22 and 36 chainrings at the front.

The casette is Shimano HG300-9 11-34

Conclusions

The lowest gear ratio is 0.64 whereas the highest is 3.27. A 2×9 drivetrain system offers almost as much “high end” as 3×8 and the same “low end”.

Of course, 2x still requires a front derailleur, but the drivetrain’s functionality, the lack of redundant gears, and the acceptable jumps make it a very practical choice, especially if your bike doesn’t have a dropper-post with a remote eager to eat the spot of the front shifter.