Are 8 And 9 Speed Cassettes The Same Width?

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At first look, the 8 and 9 speed cassettes appear to be very similar, but can they be interchanged with maintaining the bike's regular operation? A novice's ability to differentiate these components is limited, and even experienced riders are frequently perplexed and unable to make decisions. Their breadth is commonly questioned in search of an answer to the possible substitution between 8 and 9 speed cassettes. Is the width of 8 and 9 speed cassettes the same? The page provides an overview and instructions on how to use the required components.

What are speed cassettes, and how do you use them?

When you're not a pro, it's difficult to discern between bike parts, but even if you are, it's difficult to tell apart cassettes because they have various speeds and similar appearances.

Cassettes are cog-shaped components mounted on a bicycle's rear wheel, where the chain is connected to the pedals and ensures the bike's operation. 

The more speeds you add, the narrower chain becomes. However, if you wish to reduce the width of the chain, it will be less durable, will wear out faster, and will require a bit of a slower shifting action. But it will still work.

What are speed cassettes, and how do you use them

What are speed cassettes, and how do you use them?

Is the width of 8 and 9 speed cassettes the same?

Is it possible to confirm that 8 and 9 speed cassettes are the same widths? This will necessitate a thorough examination of several factors. And once you've answered this problem, you should be able to make the best component selection possible.

8 Speeds

The cassette size is the same as with 6 or 7 speeds. The sprockets are placed at a distance of 4.8 mm between them, with each sprocket having a thickness of 1.85 mm. Cassettes are compatible with both Campagnolo and Shimano 8 speed shifters and derailleurs.

9 Speeds

There is no combining with any standard. Each cassette has its own unique sprocket thickness and spacings. Campagnolo has its own standard, incompatible with Shimane's. Cassette sprockets are placed at 3.5mm spacing, with each sprocket being 1.6mm thick.

8 and 9 speed cassettes have the same width but differing gear spacing

8-speed and 9-Speed have a freehub body width and are both slightly wider than 7-Speed, but the distance between the gears of 8-Speed and 9-Speed is different. This means that the chain of 8-speed cassettes can work perfectly fine with 9-speed. Of course, for the 7-speed cassettes box to be suitable for 8-speed or 9-speed operation, there will be a small spacer behind the 7-speed cassettes box.

8 and 9 speed cassettes have the same width but differing gear spacing

8 and 9 speed cassettes have the same width but differing gear spacing

Because the space between the teeth is comparable to 8-speed, but the distance between the gears is slightly narrower, creating the biggest drawback of 9-speed cassettes is that the durability is not really sup

Campagnolo 8-Speed Cassettes used a slightly different Spline Pattern than the current pattern used for the 9- and 10-Speed systems. 8-Speed Campagnolo Cassettes will not fit on new "9-speed" or "10-speed" Hubs. 9- and 10 Speed Campagnolo Cassettes won't fit on 8-speed Hubs. It is theoretically possible, but in practice, the parts aren't usually available.

The difference in width created by the brand

The same 8-speed or 9-speed, but slightly differing designs, resulting in unequal distances. The fact that 8-speed cassettes from Campagnolo and Shimano have different spaces is proof of this. This accidentally complicates parts replacement because an 8-speed Campagnolo wheel with a Shimano cassette will not deliver ideal performance. The same is true for speeds in the same class but not at the same distance as those from another brand.

The difference in width created by the brand

The difference in width created by the brand

The number of gears on the cassettes can vary depending on the brand, although the overall diameter remains constant, requiring you to change the chain while utilizing. This occurs with Shimano 9-speed cassettes because they have one more gear than 8-speed cassettes. However, the overall width remains the same, resulting in a tighter jagged gap and the need for a different chain for installation.

To be able to overcome some inconsistencies of speed cassettes types with sprocket spacing of different brands, you can refer to some tips below:

  • Replace your gasket for a more consistent installation
  • Use alternative cable routing
  • Using a special pulley adapter increases the compatibility of sprocket and cassettes.

Should you go with an 8-speed cassette or a 9-speed cassette?

There is no uniform formula for determining whether an 8-speed cassette or 9-speed cassette is better for you; it depends on your demands and experience. The best fit comes from the perfect combination of Cassettes with chain and Chainring.

To determine the proper speed cassettes, you must do numerous tests and rigorously adhere to the manufacturer's guidelines to obtain the best components.

Should you go with an 8-speed cassette or a 9-speed cassette

Should you go with an 8-speed cassette or a 9-speed cassette?

In addition, you need to consider the dropout spacing at the rear to be able to find the right speed cassettes. For example, your bike is 126mm while 8-speed and 9-Speed are 130mm, so neither is suitable for your bike.

If your bike has an aluminum frame, some advice would be to limit the stress created by using larger wheels. In this situation, you need new shifters, a new chain, and a new derailleur on the rear if necessary.

The statistical estimates width of various sections of a bicycle

You must evaluate the compatibility of the component, which needs to change with the rest of the elements to be able to choose the suitable part to perfectly support your bike. Choose speed cassettes are the same too. Cassettes are deemed appropriate if the width of the cassettes is commensurate with the width of the other sections of the bike.

The statistical estimates width of various areas of a bicycle

The statistical estimates width of various areas of a bicycle

Here are some estimates that will help you in this selection process:

  • Distance width estimates: 8 speeds (3.00mm), 9 speeds (2.56mm)
  • The width or GNU estimates: 8 speed (1.8mm), 9 speed (1.78mm)
  • String width estimates: 8 speed (7.1mm), 9 speed (6.6 to 6.8mm)

Based on the estimated width of these components, you can find the right speed cassettes for you. This distance compatibility will assist the bike in having rhythmic motions, boost the bike's performance, minimize the loss of strength while cycling, and increase the bike's durability.

Other things to consider include

You should know that there are two types of gears, single speed and double speed. Single speed means one gear, while double speed means two gears. Your bike needs a new chain, new shift levers, and possibly a new derailleur.

Frequently Asked Questions

Can I use a 9-speed chain on an 8-speed cassette?

Chains with +/- 1 speed tolerance can be used with any other chain within that range. However, because 9-speed chains have a narrower cog pitch, they are more likely to break if you try to fit them into an 8-speed cassette (or vice versa).Chainring design is important when choosing the right bike. A thicker chainring means less friction and better performance.

Can I use a 10-speed derailleur with an 8-speed cassette?

A 10 speed derailleur can work fine with an 8 speed cassette only if it is a road model made by Shimano. All other derailleurs do not match the ratio of the cassettes used, thus making a 10 speed derailleur useless.

Can I use a nine-speed derailleur with a seven-speed cassette?

Yes, since the rear shift ratio of both brands is the same, a 9-speed bike will work fine with a 7 speed cassette.

Will a 9- speed derailleur work on an 10-speed cassette?

A 9-speed Shimano Derailleur will work on an 8/9 speed MTB Cassette if the shifter is made by Shimano and is designed for Road Bikes


Because 8-speed, 9-speed, and even 10-speed cassettes have the same overall width, they can all be fitted on the same hub, so you don't have to change the rear wheel to change cassettes. However, additional compatibility features should be used to pick the type of Cassettes to replace.

The information above about the width correlation between 8-speed and 9-speed cassettes should have helped you choose the sound cassettes somehow. Fit and compatibility in interacting with another component is a top priority to choosing which Casseter you should buy and whether you can use it at maximum efficiency. For more useful information about bicycles, follow other posts on our website.

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