from Rookie’s keyboard
Hello, friends
The other day, I had a weird experience with an 11-28 (11spd) cassette that I was trying to install on a friend’s 10-speed hub.
In short, it didn’t work well. I was quite surprised and decided to perform a thorough investigation as to why.
I learned the truth. And today, I will share it with you.
But before going into the details, I will first present some general bike transmission info as some rookies out there might not know it:
- Cassettes with extra gears are not all that much wider than cassettes with fewer gears.
- To ensure easy upgrades without replacing the rear hub, producers try to keep the overall width of most cassettes the same.
- As the number of gears goes up, the sprocket thickness and the space between the cogs decrease. Ergo, cassettes with more gears require thinner chains and may sometimes fit on hubs designed for narrower models.
Well, this was my thinking when I tried.
But there was one thing I didn’t know at the time – 11spd road cassettes are weird animals.
The “secret” is that Shimano’s 11-speed road cassettes are 1.85mm wider than the 10-speed models.
The goal is to create some space between the larger cog (smallest gear) and the spokes of the wheel.
Road bikes have much higher gearing than MTBs and even the lowest gear could be quite high in comparison to an MTB cassette (e.g., 25-28T vs. 34-51T).
For that reason, the largest cog is in great proximity to the widest part of the wheel – just above the hub flange (the place where the spokes insert into the hub).
Therefore, some modifications are required to prevent contact between the spokes and the largest cog.
11-speed road cassettes with a 1st gear that has fewer than 34 teeth are 1.85mm wider than 10-speed models.
Why?
Because small sprockets are more likely to touch the spokes. Larger sprockets (34T+) are also wider/taller and can’t come in contact with the spokes because the distance between the spokes gets narrower towards the rim.
An 11-speed Shimano road cassette that doesn’t have at least a 34T cog cannot fit on a 10-speed hub. The freehub’s body is too short. And that, my friends, was my problem too.
But 11-34T 11-speed cassettes and models with an even bigger low gear fit on a 10-speed hub.
11-speed 11-34T+ cassettes often come with a 1.85mm spacer. The spacer makes it possible to install the cassette on a standard 11-speed hub. A 10-speed hub, however, doesn’t require the spacer.
The 11-speed cassettes that meet the criteria, in this case, are Shimano HG700 and Shimano HG800.
MTB
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.
SRAM
11-speed cassettes that aren’t labeled as XD will also fit on a 10-speed hub.
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 10-speed hubs are too narrow for them too.
Also, 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
Campagnolo’s 10-speed hubs can readily accept 11-speed Campagnolo cassettes. But the cassettes cannot be installed on non-Campagnolo parts.
Other Brands
11-speed cassettes produced by other less popular brands are designed to be compatible with the largest number of hubs out there and follow the same principles as the models made by SRAM and Shimano (Campy is always different).
That said, it’s highly recommended to read the description. It should indicate the type of hubs that the cassette can work with.
And there you have it, friends.
My problem will hopefully not be yours thanks to this information.
Until next time,
– Rookie
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