FREEHUB & CASSETTE COMPABILITY
There are two brands that dominate the freehub/cassette market - Shimano and Sram.As standards evolve, the number of compatibility issues rise. We have created this simple manual to explain the history and talk through the various formats available.
If you have a Campagnolo cassette, you require a Campagnolo freehub, they are not compatible with Shimano or Sram.
SHIMANO
Shimano’s Hyperglide (HG) freehub design was introduced in the 1980s. It is distinguished by its 9 splines, with a keyed (wider) slot in order to align the cogs so they shift properly. There were several variations of these HG freehubs to be aware of.
Shimano HG “8-10” Speed Freehub
When 9 speed was introduced, they used narrower chains and had less spacing between cogs compared to 8 speed. The overall cassette width was exactly the same and you do not need to run spacers with either cassette. Shimano had a mind for 11 speed, so when they introduced 10 speed, they made the spacing much narrower than 9 speed. A Shimano 10 speed cassette is even narrower than a 9 speed so you need to run a 1mm spacer behind the cassette in this case. When 11 speed mountain cassettes came out, they would fit on the 8-10 speed freehubs without the use of a spacer. Road 11 speed, however, would not fit unless you were to remove one of the inner cogs.
Shimano HG 11/12 Speed Road Freehub
Since 11 speed mountain cassettes fit on 8-10 speed freehubs, this HG road freehub is intended for road 11 speed AND 12 speed cassettes. You can, however, run an 8, 9 or 11 speed mountain cassette on these with a 1.85mm spacer. If you want to run your Shimano 10 speed cassette, you can add a 1mm and 1.85mm spacer. A handful of hub manufacturers used the “road” 11 speed spacing and included a spacer as they assumed Shimano would be releasing 12 speed mountain cassettes and would require this wider freehub. However, when Shimano released their 12 speed it ended up using a completely different design (MicroSpline, explained later).
Shimano MicroSpline (MS) 11/12 Speed
When Shimano mountain cassettes grew to 12 speed, they introduced a long-awaited freehub revision - MicroSpline. The MS freehubs are characterized by being much shorter and having 23 splines (HG-type has 9 splines). The increase helps distribute forces thus allowing for lighter alloy freehubs to be used.
MS freehub splines and cassettes are mounted differently and can’t be combined with other standards. The largest cogs are mounted to an alloy spider, while the four smaller steel cogs slide onto the freehub body individually. The smallest cog is only 10t (11t was a standard). The spacing is the same between 11 and 12 speed MicroSpline cassettes, there is just 1 less sprocket with 11spd.
Shimano Hyperglide+ 12 Speed Road Cassettes
In 2021, Shimano launched the all-new 12-speed Dura-Ace (R9200) and Ultegra (R8100) road groupsets for faster and smoother shifts. They applied the Hyperglide+ technology (first introduced in off-road cycling) to their road cassettes. The 12-speed cassette is designed to be backwards compatible with the existing 11-speed road freehub.
SRAM
Shimano HG-Style (SRAM PG Cassettes
SRAM has 8-11 speed cassette options that fit on the Shimano HG freehub body. This is their PG series, or Power Glide series.
Sram PG cassettes are largely the same spacing as Shimano, with the 10 speed exception. The Sram 10 speed cassette is the same width as 8/9 speed, whereas with Shimano it’s 1mm narrower.
The PG 8-10 speed cassettes will fit on on the Shimano HG 8-10 speed freehub without a spacer. On 11 speed Shimano HG freehubs, the PG 8-10 speed cassette will usually require a spacer. The 11 speed usually do not, and will not fit on the 8-10 speed freehub.
XD 11 & 12 Speed
Sram XD driver is created to allow the smallest cog to be 10 teeth for high gear ratio. It’s lighter and more durable than HG freehubs because cassettes won’t gouge into the splines. The SRAM XD is commonly used for mountain bike wheels. XDR Cassettes are not compatible with the XD freehub body.
XD-R 11 & 12 Speed
The road version (XD-R) is compatible with mountain cassettes if you add a 1.85mm spacer. There is no spacer required with a road XDR cassette. As it relates to the freehub, there is no compatibility difference between 11 and 12 speed Sram cassettes. SRAM RED eTap AXS and Force eTap AXS road cassettes use the XDR freehub.
ROL FREEHUBS - Different Kinds and Availability
Over the years, we have used a couple of different designs for our hubs to keep up with technology and cycling trends. Our hubs prior to 2014 were 8-10 speed and no upgrade to an 11 speed freehub is available.
Our 2014-2019 hubs have 11 speed freehubs and can be used as a backwards compatible with a spacer or combination of spacers. Most of these freehubs are wither red or black in color. The availability of these freehubs is very limited. Please reach out and we will let you know if we are able to get a new freehub for you,
From 2019, most of our freehubs are gold/tan color and look lik the below photo (these are fairly available):
