Road Bike Gear Ratios: All You Need to Know

Modern road bike gears can take an age to get your head around! Gone are the days of pushing the lever forward for faster, and backward for slower!

Now it’s all about sprockets, and cross-chaining (don’t do it!), and cranksets and goodness knows what else.

I’ve been trying to get my head around all the technicalities all the (long) time I’ve been cycling, and in this article, I’m going to walk you through what road bike gear ratios are all about.

I’ll take a look at:

• What are gear ratios?
• What road bike gears look like today
• Road bike gears at the front and back – how they work
• How many gears do you need on a road bike
• Common setups for your gears
• Does the number of gears matter?

Understanding The Two Types Of Gears For Road Bikes

Let’s start with the easiest bit to get your head around and then expand from there!

A road bike usually has gears at the front and gears at the back. Let’s take a look at what that’s all about…

Front Gears

The front gears are known as chainrings, cranksets, or “the front ones” by riders with little jargon knowledge.

In actuality, the whole assembly of the crank arms together with the front gears is referred to as the crankset.  

The majority of cranksets contain either two (referred to as double or 2x) or three (3x) chainrings.

Single (or 1x) cranksets are rising in favor, especially among mountain cyclists and cyclocross riders, although they remain a niche application. They’re not very common on road bikes though.

The smallest chainring on the crankset is nearest to the frames. 

The lower the chainring, the simpler pedaling becomes.

As we push the chain further from the centerline of the bicycle, the pedaling becomes more difficult, but the speed increases.

Usually, chainrings are referred to either by their location or by their diameter. On a triple, they are often referred to as outer, middle, and granny gear (I kid you not!) for the smallest gear.

Rear Gears

The gearing on the back wheel is known as “cogs,” and when many cogs are assembled in increasing size order and attached to the rear axle, they are alluded to as a “cassette.”

The cassette on the majority of road bicycles manufactured in the previous several years is usually between 8 and 11 gears.

The gears are counted from the inside out, with the biggest cogs closest to the wheel. The bigger the cog, the “lower” the gearing and the simpler the pedaling, but the slower the speed.

I found a brilliant Youtube video that really explains and demonstrates in detail everything you need to know about bike gears:

Road Bike Gears History And What They Look Like Today

The first bicycles only had one gear. By the middle of the 19th century, it had expanded to two, and the amount of gears has climbed steadily ever since, so that a bicycle may have 81 gears today.

A top tip though – more is not always better. 

In gearing, the variation – the proportions – is what matters most, and we’ve never felt more spoiled. The challenge is to determine which gear combination will actually work for you.

Not that long ago, the majority of road bikes included a “standard double” device (or crankset). Thus, a large band with 53 teeth as well as a smaller ring with 39 teeth. 

Then, in the early 2000s, FSA popularized the ‘compact’ crankset with 50/34 chainrings.

Since then, the ‘mid-compact’ 52/36 crankset and the ‘super-compact’ 48/32 crankset have been introduced, along with several variants on the theme.

While all of this has occurred in the front portion of the drivetrain, there has been an extremely fast increase in the number of sprocket variants in the back. The previously widespread 11-23 cassette has been replaced by a variety of choices, ranging from a 9-tooth to a 42-tooth sprocket. 

It’s pretty unusual for a road bike to come equipped with a 10-33 or alternatively an 11-34 cassette, but a gravel bike may sport a 10-36, 11-40, or any number of other possibilities.

If none of this makes any sense to you at all at the moment, please keep reading – because all will be explained!

What Are Gear Ratios?

In the simplest possible terms imaginable, this is what a gear ratio is…

It means the number of times the back wheel will rotate when you rotate the pedals once.

If you get two wheel turns for one pedal turn, then this is a ratio of 2:1.

The gear ratio is determined by the number of teeth on the chainring and the number of teeth on the sprocket.

It’s all a bit technical!

Eleven gears on the rear sprocket and two in the front ring provide a total of 22 choices.

The variation in the number of notches between the front ring and your chosen rear gear (the little, pointed pieces that loop through the holes in your chain) is the most important factor in determining how hard you work. 

The gear ratio is determined by the chosen chainring and cog combination. The gear ratio, in conjunction with the wheel and tire circumference, defines how far one will ride with each rotation of the cranks.

How Many Gears Do You Need On A Road Bike?

When discussing the number of “speeds” a bicycle possesses, there might be a misunderstanding.

Multiplying the number of cogs by the number of chainrings is a marketing department favorite since large figures are impressive. 

However, there is a great deal of overlap, thus a 92 does not technically have 18 gears. 

People that ride bicycles exclusively refer to the number of gears in the cassette, such as an eight-speed, a nine-speed, etc. They may additionally specify whether their crankset is single, double, or triple, or they may just state “92” or “29.”

I hope this is all making sense so far!?

What Are Derailleurs?

The term ‘derailleur’ is difficult to say! But thankfully it is simple to comprehend.

A derailleur moves the chain from one gear to another or from one chainring to another. (Simples)

The front sprocket is a very simple mechanism that only displaces the chain from one chain so that it may be “caught” by the next.

The back derailleur is somewhat more complicated due to its dual function.

Similar to the front, it directs the chain from cog to cog, but it is also tasked with keeping chain strain and picking up the slack when shifting from larger to smaller gears. 

The back derailleur has 2 minor gears (technically known as “pulleys”), and the chain forms an “S” curve across them.

The higher pulley is known as the “jockey pulley,” and the bottom pulley is known as the “idler pulley.” The pulleys’ position is maintained by the cage.

While the chain is pulled very tight, it will be much more difficult to move the front gears, thus you should decrease your stroke when switching chainrings.

When pedaling vigorously, the back derailleur is significantly more effective in shifting gears. It is vital to remember, however, that the belt must be going forward in order to shift gears.

When the shift wire is pushed on both the front as well as rear derailleurs, the chain is moved to a greater gear. When the connection is removed, the chain will shift to a lower gear. 

Remember that bigger rear ratios make pedaling easier but increase torque, whereas larger front gears make pedaling more difficult but increase speed.

Going from “easier” gears to “harder” gears is referred to as “upshifting,” whereas the opposite is “downshifting.”

Common Setups For Your Gears

Crank Set (Front Gears)

Sometimes, cranksets are characterized as “compact” or the default standard on most bikes. Typically, a compressed crankset has a 50-tooth (50T) large ring and a 34-tooth (34T) small ring.

Typical crankset ratios are 53T/39T. 

In most circumstances, you can modify your cranksets to have various tooth tallies, but as a standard guide, you shouldn’t have a greater than a 16-tooth differential between your largest and smallest chainrings; otherwise, shifting troubles may arise. 

Common triple crankset designs include 26T/36T/46T and 52T/42T/32T, which provide gear ratios that are even closer together.

With 10 and 11-speed drivetrains becoming the standard, triples are becoming obsolete and even single-ring cranksets are gaining popularity because of the broad variety of gear ratios an 11-speed sprocket can provide.

Cassette (Rear Gears)

As discussed above, modern bicycle cassettes often have eight to eleven gears. You have the option of selecting cassettes with a restricted range of ratios and closely spaced gears, or cassettes with a broad range of proportions but larger leaps between cogs. 

Choosing a bicycle with more speeds mitigates the trade-off and increases your adaptability.

If you spend most of your cycling on flat terrain, you should definitely choose a narrow-range sprocket with tiny ratio jumps, as this will let you fine-tune your rhythm and effort level. 

If you reside in a region with more diverse terrain, a cassette with a greater range may be the best option for climbing hills.

Wider-ranged cassettes with more gears often feature more closely spaced ratios on the smaller “climbing” cogs and larger ratio leaps on the larger “range” cogs, giving you the best of both worlds.

Why Do Gears Matter?

If your ratios are too low, you will be dropped when you spin out on the flats. However, if they are too high, you will not be capable of maintaining an effective cadence on steep inclines.

Having the appropriate gears may affect the following:

Output Of Power

Your output of power, in terms of watts, is the single most important determinant of your speed.

The resistance offered by bicycle gearing permits the conversion of leg strength (through torque as well as cadence) into forward motion. Your gears should let you maximize your power, which varies from cyclist to cyclist.

Cadence

Cadence is the number of times per minute that your foot accomplishes a complete pedal stroke.

You must first choose your chosen cadence range. Do you prefer to pedal with a lower cadence and a higher gear, or a lower cadence and a lower gear?

Different Gearing And Use Cases For Road Bike Cyclists

Preparation For Hill Climbs

In order to maintain a more effective cadence when ascending, an easier ratio is the ideal choice for riding or races in mountainous terrain.

On a climb, you will virtually never regret having simpler gears unless you anticipate an exceptional downhill sprint.

If your climbs are reasonably brief (less than a few minutes) and not too sharp, a mid-compact crankset is excellent.

If your treks are steep and lengthy, you should choose a small crank.

In both instances, a cassette with big gears containing 28 to 32 teeth will provide a wide gear range and a great gear ratio.

Check the rear derailleur’s capacity, since some can only accommodate gears of a specific size.

Preparing For Open Roads

If you are a physically imposing athlete who mostly rides on flat terrain, a conventional crankset may be an excellent choice for you.

This gearing focuses on top-end power and may offer you an advantage in a very rapid sprint, but you will be unprepared for large hills. 

For this reason, even on flat terrain, mid-compact cranks are an excellent choice. Although they may not provide exactly the same racing performance as a normal crank, they provide more versatility when traveling or riding on diverse terrain.

On flatter terrain, cyclists may use cassettes with a smaller radius than the ones used for climbing. Like regular cranks, these cassettes are not good for hills despite being significantly lighter and featuring a more gentle transition between gears. 

Modern drivetrain components have added additional gears to each sprocket, so even wide-range mountaineering cassettes provide a rather smooth transition between cogs.

Preparing For Underage Riding

Under 18?

Riders under the age of 18 are limited in their gear selection.

This is meant to level the competitive balance between young athletes and their less-developed opponents.  

In the United States, junior gearing cannot exceed 312 gearing inches.

Depending on the size of the crank, cassettes with 12 or 14 tooth (instead of the normal 11) are employed for this reason.

How Do Cyclists Shift Gear Sets?

Bicycles often include many gears, enabling the rider to adjust the gear ratio to suit varying riding circumstances. The biker uses the shifters on the handlebars to change gears.

On road bikes, they are normally built into the brake levers, whereas mountain bikes have separate levers. 

When a cyclist wants to make cycling easier, he or she will change to a lower gear using a smaller chainring and a bigger cog. When they wish to increase the difficulty of pedaling, they will move to a higher gear with a bigger chainring and a smaller cog.

Bottom Line

Bicycle gears function by altering the gear ratio between the front chainring and rear cog.

By changing the chain between chainrings and cogs of varying sizes, the rider may alter the pedaling resistance.

By utilizing the shifters on the handlebars, a cyclist may simply change gears to accommodate diverse riding circumstances and increase the efficiency of pedaling.