Microspline, HG, XD and XDR what fits?
What fits? -sometimes the most challenging question on the technical side of bikes today.
With every major brand offering several generations of gears and hubs it can get confusing quickly. The easiest way to narrow this down is by Manufacturer / Brand and what each brand does then narrow from there. In general there is a lot of cross compatibility, but you have to really watch the details as there are a few exceptions that exist of outlier cases.
And just to note… 13spd… at the moment thats a Capagnolo only thing… everything that is 13 is specific to Campagnolo. Makes it a bit easier 🙂 …. 10, 11, 12 on the other hand ! read on.
Shimano style gears or technically called Cassettes – now make 2 styles, HG and Microspline or “MS”
- 10spd and 11spd are called “HG”
- 10spd and 11spd have always used the same cassette to wheel combination, with 10spd requiring an additional 1.8mm spacer on the freehub body.
- 12spd is the newest and is a design for best use on a Microspline (MS) wheel interface, but it will fit on a HG shaped freehub body (with some caveats from aftermarket companies)
If you look close at the inner splines on above two photos the difference is small but the inner spline pattern on the MS 12spd is different than the 11spd. Having said that Shimano state their 12spd cassettes are backwardly compatible with 11spd Wheels (freehub bodies). *
*if its not shimano hub its worth checking with aftermarket wheel / hub manufacturers
Shimano Freehubs / Freewheels
This is where the cassette slips onto the wheel. Shimano just released Microspline or MS for Road (12 spd Road)
The Microspline hub / freehub body is 12spd ONLY for both road and Mountain
SRAM is a little clearer on compatibility. But understand that SRAM make Shimano compatible and specifically SRAM only cassettes so be careful which you choose.
Shimano compatible will say Shimano is referred to as HG
SRAM only systems are referred to as XD or XDr
- SRAM Cassettes which are 9, 10 spd work on Shimano’s HG Freehub body as show above.
- SRAM 11spd cassettes can work on Shimano or SRAM wheels, its really dependent on which specific cassette
- Some SRAM 11spd cassettes only work on XD hubs. So look out for the details. 1150, 1175, 1195, 1199
- SRAM 12spd cassettes for the most part only work on XD or XDr Wheels / Freehub bodies (as shown below) there are two exceptions the 1210 and 1230 cassettes which are very e bike focused and work on Shimano wheels.
- XD is more common in the mountain bike world and XDr in road.
To note: XD /XDr is a mechanical interface that slides and twists on vs just sliding on like Shimano. Details also here
SRAM Freehubs / Wheels
On the freehub / freewheel side, SRAM owns two proprietary technologies XD and XDr, both can be used for 11spd or 12spd SRAM gears. the main reason why its important to note this is that XD/ Xdr allows the use of a 10 tooth smallest cog. This 10T cog is very specific to SRAM.
- The “r” in XDr designates road. but a lot of places now are using the same XDr driver for both mountain and Road, since the only difference is a spacer.
- The XDr body is 1.85mm longer than a regular XD body
- You can use an XD cassette on an XDr body with a spacer. doh I kinda said that already, sorry.
As you can see on the photo above, XD / XDr both use a mechanism where the cassette slides onto splines first for a short distance then theres a threaded section that twists and locks on. SRAM went this way for a better, tighter fit and to ensure they could get a 10t cog to work.
A good thing to note here is that it’s not just SRAM that make this style of attachment. The shape has been licensed out to over 250 wheel and hub manufacturers in a similar way that Shimano licence their HG and MS designs.
I hope this guide was useful. And if you have questions please post in the comments – jbucky