- Cassettes with more gears are not necessarily wider than cassettes with fewer gears.
- To encourage upgrades without the need to replace the rear hub, brands try to keep the overall width of most cassettes the same.
- As the number of gears increases, the sprocket thickness and the space between them decrease. Consequently, cassettes with more gears require thinner chains and can sometimes fit on hubs designed for narrower models.
Shimano’s 11-speed road cassettes are 1.85mm wider than the 10-speed models. The purpose of this engineering is to create some space between the larger cog (smallest gear) and the spokes of the wheel.
Road bikes tend to have lower gearing and consequently the lowest gear could be quite high in comparison to an MTB cassette (e.g., 25-28T rear cog).
Due to this property, the periphery of the largest cog is in great proximity to the widest part of the wheel which is just above the hub flange (the place where the spokes insert into the hub).
As a result, some modifications are needed to prevent contact between the spokes and the smallest cog.
11-speed road cassettes with a large sprocket that has fewer than 34 teeth are 1.85mm wider than 10-speed models. [The goal is to push the largest sprocket away from the spokes.]
Consequently, an 11-speed Shimano road cassette that doesn’t have at least a 34T cog cannot fit on a 10-speed hub. The hub is simply too short.
That said, 11-34T 11-speed cassettes or models with an even lower gear fit on a 10-speed hub because the large cog can be dished and taken further away from the spokes.
For that reason, 11-speed 11-34T cassettes come with a 1.85mm spacer. The spacer is there to make it possible to install the cassette on a standard 11-speed hub. On a 10-speed hub, the spacer is not needed.
Note: The 11-speed cassettes that fit the bill, in this case, are Shimano HG700 and Shimano HG800.
An 11-speed Shimano cassette can be installed on a 10-speed hub because 11 and 10-speed MTB cassettes are of similar width.
MTB cassettes do not have to be dished nor do they require a longer hub because the lowest gear is larger and doesn’t interfere with the spokes.
11-speed cassettes that aren’t labeled as XD will also fit on a 10-speed hub. However, SRAM PG-1170 11-36 is an exception to the rule as it’s a road cassette. SRAM’s 11-speed road cassettes are wider and thus10-speed hubs are too narrow for them.
Additionally, the 11-speed XD cassettes need an XD or an XDR driver and will therefore not fit on a standard SRAM or Shimano hub.
Campagnolo’s 10-speed hubs can accept 11-speed Campagnolo cassettes. However, the cassettes cannot be installed on non-Campagnolo parts.
There is a fair number of 11-speed cassettes produced by other less popular brands. Usually, those models are designed to be compatible with the largest number of hubs out there and follow the same principles as the models made by the big names.
That said, it’s highly recommended to read the description. It should indicate the type of hubs that the cassette can work with.
The Advantages of Installing an 11-speed Cassette On a 10-speed Hub
If your hub is compatible with a 10-speed cassette, you will save a decent amount of money and labor because you won’t have to buy a new hub and rebuild the rear wheel.
- Smoother Transitions
Cassettes with more gears offer smaller transitions between the cogs and make it easier for the rider to maintain a steady cadence. The term cadence refers to the rotations of the cranks per minute. In general, high cadence (e. g., 90RPM) is associated with greater average speeds and reduced energy expenditure.
The Disadvantages of Installing an 11-speed Cassette On a 10-speed Hub
The only major disadvantage of 11-speed cassettes is that the upgrade will require you to spend extra money on parts without being a game-changer.
The parts needed for transitioning from 10 to 11-speeds are:
- New hub + wheel rebuilding (if the current hub isn’t compatible)
- 11-speed shifter
- New cable and housing (recommended)
- New derailleur (if the old derailleur can’t cover the new cassette)
- 11-speed chain
- 11-speed cassette