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This article compares the advantages and disadvantages of 11-28 and 11-34 cassettes.

Let’s get into it.

The Advantages of 11-34 Cassettes

1. Lower Gear Range

The strongest advantage of 11-34 cassettes over 11-28 models is the lower gear range that the large 34T cog offers.

To illustrate the discrepancy between the two, it’s necessary to introduce a term known as gear ratio.

The gear ratio indicates the number of revolutions that the rear cog and consequently the rear wheel makes per 1 full-spin of the cranks/chainring(s).

To calculate the gear ratio of a specific gear, you need the number of teeth on the chainring and the rear cog.

The formula is – Gear Ratio = Chainring Teeth/Rear Cog Teeth

For example, a 36Т chainring and a 28T rear cog result in a 36:28=1.28 gear ratio. This means that the rear cog rotates 1.28 times per 1 spin of the chainring.

А 34Т rear cog and a 36Т chainring result in a 36:34 or 1.05 gear ratio. In this gear, the rear wheel makes ever so slightly more than 1 revolution per 1 rotation of the cranks.

Therefore, in this case, the 11-34T cassette provides a 19.61% lower gearing that significantly facilitates climbing.

How so?

The lower the gear ratio, the easier it is to pedal because each spin of the cranks triggers fewer rotations of the rear wheel.

A lower gearing can be achieved via the following methods.

• Smaller chainring
• Larger rear cog
• Smaller chainring + larger rear cog

The difference between a 34T and a 28T cog is 6T or 21.43%. Consequently, an 11-34T cassette would offer up to approximately 20% lower gearing than an 11-28T model when using a chainring with the same number of teeth.

The next table contains the lowest gear ratios of 11-34T and 11-28T cassettes when combined with chainrings from 32T to 46T.

(34Т and 28T are cogs designed for low gearing and aren’t meant to be combined with the “big ring” to avoid cross-chaining).

• More Suitable for 1x Drivetrains

An 11-34 cassette is not ideal for a 1x drivetrain. A larger model such as 11-42 would be better thanks to the extra low gears.

However, an 11-34 is still notably better than an 11-28T if the rider wants to run a single chainring.

• No Need To Replace The Chainring To Get a Lower Gear

A switch from an 11-28 to an 11-34 cassette provides 20% lower gearing without chainring changes.

If you have an 11-28T cassette and want the low gears of an 11-34 cassette, the only option is to install a chainring with fewer teeth.

If you go with a small chainring (e.g., 32T), you may acquire a very low gear, but the potential top speed of the bicycle will be severely reduced.

• Better for Gravel and Touring

An 11-34 cassette is better suited for gravel because offroad terrain increases rolling resistance. The low gearing of the 11-34 cassette counters that outcome to an extent and is, therefore, a better choice for gravel riding.

Touring cyclists would also benefit from an 11-34 cassette as it makes it easier to conquer hills. The low gearing is also helpful when hauling additional cargo over long distances.

The Negatives of 11-34 Cassettes

• Big Gear Jumps

When two cassettes have the same number of speeds, the one with the lower gearing always has larger gear transitions.

Big gear jumps hurt the rider’s cadence.

Cadence = rotation of the cranks per minute. A high cadence such as 90 is associated with greater efficiency and higher average speeds.

When the gears/sprockets are maximally close to each other in size, it becomes easier to keep the cadence high. If the drops and ups are large, it becomes more difficult for the rider to maintain the same cadence after a shift.

The tables below compare the gradations of 11-28 and 11-34 cassettes:

9-speed

Jumps in %

Conclusion: The gear transitions of 11-34 cassettes are about 4% larger than those of 11-28 cassettes (in the case of 9-speed models.)

10-speed

Jumps in %

Conclusion: The gear transitions of 11-34 cassettes are about 2-3% larger than those of 11-28 cassettes (in the case of 10-speed models.)

11-speed

Jumps in %

Conclusion: The gear transition of 11-34 cassettes are about 2-3% larger than those of 11-28 cassettes (in the case of 11-speed models.)

The difference between the gear jumps of 11-28T and 11-34T cassettes can’t be ignored, but it isn’t massive.

• Short Cage Derailleurs Won’t Cut It

A short cage derailleur often can’t reach a 34T cog. There are two ways to deal with this issue – replace the derailleur or install a derailleur hanger extender.

• New Chain 

If you’re switching from an 11-25/28 cassette to an 11-34, a new chain will be needed due to the large 34T cog.

The Advantages of 11-28 Cassettes

• Smother Transitions

11-28 cassettes have smaller jumps between the gears and make it easier to preserve a high cadence.

• No Unused Gears

It’s nice to have a low gear such as 34T, but if you never use it, it’s of questionable value.

If a 28T cog gives you all the low gearing you need, why bother with 34T?

The Disadvantages of 11-28 Cassettes

• High gearing

The gearing on 11-28T cassettes could be too high for riders who aren’t in shape yet and/or carry a lot of cargo over long distances.

• Less suitable for 1x Drivetrains

11-28T cassettes are not ideal for 1x drivetrains as the low gears won’t be sufficient unless you use a very small chainring. But in that case, you will lose a lot of top speed.

What to choose?

If you’re in good shape, an 11-28T cassette is a good choice, especially when combined with compact cranks.

11-28T cassettes will allow you to maintain a high cadence thanks to the smaller transitions. As a result, your efficiency and average speed will be influenced positively.

If you are a recreational cyclist who doesn’t obsess over riding cadence, then an 11-34T cassette is a more practical solution. Sometimes it’s better to have a very low gear and not need it than need it and not have it.