Do wide ratio cassettes for lower gears have any place on performance road bikes? Why the pros are moving away from smaller sprockets

Years ago, the choice of gears available on performance road bikes was pretty much made for you, with a standard 53/39t chainset often the only way to go, and cassette choice limited to whether you wanted a measly 23 or 25 teeth on your back sprocket... or even a 21. Ouch!

Today, road bikes now come with increasingly wide cassettes and seemingly more gearing options than ever, with the leading groupset manufacturers now offering at least 12-speed cassettes to reduce the gap between each shift. So, why has the move to wider cassettes as a default setting happened? Are there still some circumstances where a tighter cluster is the way to go, or is something like an 11-34T truly better in all circumstances? Let's weigh up the pros and cons. 

Before we get started, if you're new to all this: a bike cassette is a cluster of sprockets (gears) attached to the rear wheel of a bicycle. It works in conjunction with the chain, chain rings and derailleurs to provide different gear ratios, allowing you to adjust your cadence and therefore effort, to the terrain.

Gravel bike gears for the win?

The trend for cassettes to offer more gearing range is by no means new, and the largest sprockets have been growing in size over the last few decades. Whereas performance bikes of old typically came with 11-23T cassettes, it's now common to find 11-34T cassettes on Shimano-equipped road bikes, and 10-33T or even 10-36T cassettes on SRAM-equipped performance bikes.

This shift reflects a broader move towards providing road bikes with a greater range of gears. Take the Trek Madone SL 6 Gen 8, for example. This lighweight aero offering features an 11-34T cassette with a 23-tooth range that wouldn't have looked out of place on a gravel bike a decade ago.

Similarly, the Specialized Tarmac SL8 Expert comes equipped with SRAM's 10-36T cassette, providing an even wider 26-tooth range. 

Why wouldn't you fit a wider range cassette?

You might be asking, then, why wouldn't you fit a wider-ranging cassette? A wider cassette offers a greater range of gears and therefore can make the hills easier, but there are a couple of drawbacks. 

The first drawback is that wider-range cassettes are typically heavier. For example, a Shimano Ultegra 12-speed road cassette weighs 291g for an 11-30T setup, while the 11-34T version comes in at a claimed 345g.

Likewise, SRAM's Red 12-speed cassette weighs 175g for 10-26T and 210g for a 10-33T cassette. Although this weight may seem negligible to the majority of us, bike manufacturers and pros alike are still keen to shave off every possible gram.

> 10 reasons why your bike's gears aren't working as they should, and how to fix it

The next drawback is that a wider range cassette will typically has larger gaps between sprockets, which results in bigger jumps in cadence as you change gear. 

For example, the Shimano Ultegra 12-speed 11-30T cassette features sprockets sized 11, 12, 13, 14, 15, 16, 17, 19, 21, 24, 27, and 30T, while the 11-34T cassette has sprockets sized 11, 12, 13, 14, 15, 17, 19, 21, 24, 27, 30, and 34T.

For SRAM Red 12-speed cassettes, the 10-26T version has sprockets sized 10, 11, 12, 13, 14, 15, 16, 17, 19, 21, 23, and 26T, while the 10-33T version includes sprockets sized 10, 11, 12, 13, 14, 15, 17, 19, 21, 24, 28, and 33T.

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Elite cyclists, or just very particular amateurs, might find that the precise gear they want to keep to their perfect cadence isn't available to them with a wider cassette, or want the jumps between gears to be as small as possible to avoid losing any momentum. Examples where very close gearing is favoured include time trialling, where having the perfect gears for the course could be crucial to putting in your best possible time against the clock.  

Why is this happening?

Today’s pro road racers are provided with equipment significantly more advanced than what was available 20 years ago, but it’s the range of gears that has been the most interesting trend as the groupsets have evolved. As the number of sprockets has increased, the gear range has increased. 

It's now possible to offer riders a broader range of gears without compromising the quality of shifting or the reliability of the drivetrain. While wider-range cassettes from Shimano and SRAM introduced slightly larger jumps between some gears, they still offer smooth and reasonable progressions thanks to having an increased number of gears. For example, take Shimano’s 11-34T cassette from it’s latest Dura-Ace and Ultegra groupsets. It has a 23-tooth range between the biggest and smallest sprockets, which on average works out as less than a two tooth jump for each gear change. Compare this to the 5 or 6-speed groupsets of 50 years ago, and a cassette with the same range would result in an average jump of over four teeth per gear change, making it no surprise that these cassettes don’t really exist any more. 

Some people might question whether 11-34T cassettes that Joe Public use truly belong on high-end road bikes, but when it comes to cycling equipment, the pros often set the standard.

Although pro riders are travelling much faster than the average chopper, they still require a setup with the ability to handle a range of terrains, from steep climbs to fast descents, without compromising on performance. 

The most common chainset size in the pro peloton for typical stages of a Grand Tour, such as the Dauphiné, is 54/40T for Shimano and 52/39T for SRAM chainsets. Shimano neutral service bikes are fitted with 52/36T chainsets. At the rear, we've seen the widespread adoption of 11-34T cassettes amongst Shimano-sponsored athletes, and the use of 10-33T cassettes from SRAM-sponsored riders. 

> Should you run a 1x set-up on your road bike?

Given that professional cyclists are amongst the most discerning users of bike equipment, the fact that the 11-34T cassette meets their rigorous demands suggests that the disadvantages we’ve discussed may not be so significant after all.

Despite many pros using this cassette size, their bikes still weigh around 6.8kg, which meets the UCI's minimum weight limit. This also indicates that the gear ratios are well-suited for these athletes, who prioritise both efficiency and performance.

As we mentioned earlier, the disadvantages of having larger gaps between gears on wider range cassettes has largely been mitigated by the increased number of gears on modern 12-speed groupsets. Although we recommend not copying everything that the pros do, going to wider-ranging cassettes is almost always one of the things that we would recommend doing. 

Recently, we compared the Pinarello Dogma X with a Colnago CT1 Titanio Lux from 2000 on a rolling ride. One of the most significant advancements we've noticed in the past 20 years was the improved range of gears. Today's road bike gearing is far better suited to the needs of the average rider.

What about 1x?

As well as the shift to wider cassettes, an increasing number of bikes now use 1x drivetrains, which essentially means the bike has a single chainring with no front derailleur. These setups typically have even wider range cassettes, although the gearing range may not be as extensive as 2x setups. Notably, Jonas Vingegaard and his Visma Lease a Bike teammate Wout van Aert have used SRAM 1x setups for certain stages of the Grand Tours. 

> Are single chainring set-ups the future of road cycling?

We've also recently reviewed Van Rysel's NCR road bike, the first mainstream pure road bike that we've tested that ships with 1x setup. We can see this trend becoming more popular in the future, especially on beginner road bikes where simplicity is a priority.

So, should you choose an 11-34T cassette?

Is an 11-34T cassette better than an 11-25T? For almost all riders, the answer is certainly yes, but it won't be required by absolutely everyone. If you live in a flatter area, you might not need the extra low gears that an 11-34T cassette offers. However, for those riding on varied terrain, the added range can be a game changer, and as the pros prove, without significant downsides. 

We're now seeing much wider range groupsets with more realistically usable gear ratios for those of us that don't race. Having the gears to help out on challenging terrain and conquer more hills sounds like a good deal to us. Realistically, on my local group rides, it's more about ego than performance that stops people from switching to a larger cassette.

Can a bike shop swap your cassette out?

> Check out the gearing choices of the pros at the Tour de France

If the bike you’re considering comes with an 11-34T cassette that you don’t want or need, many bike shops will swap it out at the point of sale. This typically depends on whether they have your preferred cassette in stock and if it’s compatible with the other components.

It's generally much easier to go down cassette sizes than up, as you will most likely require a new longer chain to facilitate the larger sprockets if you decide you need a bigger one. 

What's coming next?

There is a practical limit to how much bigger cassettes can get. Beyond a certain point, the added weight will become disadvantageous, and without further increasing the number of gears, larger jumps will make it harder to maintain a comfortable cadence. If you've ever ridden your mountain bike on the road, then you'll be well versed in this. 

Personally, I think an 11-34T cassette is about the sweetspot for 2x setups, and I think we'll see more and more performance bikes follow suit. It is probably unlikely we'll see much larger cassettes in this configuration without compromising performance. 

What size cassette do you ride? Let us know in the comments section below.