You may have heard of this thing called XDr, So what’s all the hype? I decided to lay down some practical XDr knowledge.
The bike world is all about engineering and this can drive new features, making better things for the user. The terminology “XDr” refers to how your rear gears connect to your wheel (specifically the cassette to your hub) XDr is specifically Road, (XD is a similar thing but for mountain bike). So we are talking about that interface where the gears sit on your back wheel. Another thing to note, the manufacturer SRAM invented this technology, so there is no Shimano XDr, its a SRAM thing.
XDr allows 12 gears, More gears give you more choice, but also more variety in gear sizes gives you different ease /speed of peddling. This is key, XDr allows you to use a very small cog on your cassette all the way to a large cog. In the past it has been standard to use 11t to say a 28t cassette or less, so adding an extra gear (12 spd) and dropping to 10tooth plus going up to 33 tooth is a large range change. Allowing you to ride fast on the flats and spin up the hills.
new XDr – 10t – 33t
vs. Shimano HG – 11t-28t
If this all sounds confusing, it kinda is, maybe the FAQ’s below will help your mind sort it out.
Below is a chart that shows the gear ranges using the new XDr cassette vs a Shimano cassette.
XDr has several benefits of different magnitudes depending on your outlook.
Do you want more gears? 12 speeds! yes thats 12 on a single and 24 gears on a double.
Are you looking for the perfect gear ratio? with 12 cogs and the new range from 10tooth, means there are less steps between gears on the cassette meaning you can find the perfect gear for your cadence.
Do you have a gravel bike? – and because gravel bikes have drop bars, most gravel bikes use road shifting systems, some have one chainring and others two. For the cases with one chainring (1x), with XDr you can use an 10t to 33t cog which allows you to go fast down hill and have an easier spin uphill. Thus easier to explore more terrain and also have 12gear options.
In the cases of two chain rings you now have even more range since you have 2 in the front and better range in the back. (see graphic above)
Do you have a road bike that you want to simplify? – now you can convert your road bike to a single chainring setup and have more gear range than a previous 1x. In fact SRAM say you can have a very similar gear range as a 2x chainwheel. Here is a propaganda article for 1x for the road here
- How many gears does XDr have? 12
- Do Shimano have 12 Gears for Road/Gravel? – No not yet. They do have 12 for mountain bike it uses a system called Microspline here
- Will I need a new parts for my existing hub/ wheel? yes – you will need the XDr part, as seen in the pictures below. Its called the freehub body or Chris King call it the Driveshell
- Will I need a new wheel / hub? – probably not, XDr supports a lot of manufacturers, they engineer their own XDr compatible version – see list below. The best way is to contact the manufacturer of your wheels / hub.
In general if you are going from 10spds to 12spds you will probably need to get your wheel re-dished (aka rim running in the center of the axle). If you are going from 11 to 12 there will be no problem, just switch in the XDr part.
- What about XDr compatible gears, are there choices? – yes there are currently 6 SRAM cassette options at two performance levels Force and Red largest range is 10-33t
- Will XDr work with shimano road shifters? – Technically Yes but practically you will be missing a gear as Shimano shifters are set for 11 shifts
- Can I use Shimano HG cassettes on my XDr setup? – No, the two are not compatible and the Shimano cassette wont even slide on an XDr hub.
- Can I use a XDr Cassettes on my Shimano wheel setup? – no the two are not compatible, see #7
- Are XD and XDr Cassettes the same thing? – Yes and No – they both use a similar system where the cassette screws on, but XD cogs are spaced out from each other to work with mountain bike components, XDr are spaced out to work with Road shifting components. So you will need to decide what shifting system you are using.
- What are Shimano going to do? – there has been Shimano’s solution called Microspine in the works for a while to get to 12spd and 10t gears. This was rumored to work on both MTB and Road/Gravel and the only Microspine to see public light has been in conjunction with DT Swiss here and Industry 9 here -maybe in the future it will go wider.
XDr Tech Talk
Straight from SRAM: The XDR driver is 1.85mm longer than an XD driver. Made for Road specific 11-speed rear wheels; it occupies the same space as an 11-speed HyperGlide (Shimano) road driver. The XDR driver allows XD cassettes that are part of SRAM’s 1x road and MTB groups to be installed on a wheel that is spaced and dished for 11-speed road HyperGlide freehubs when used with a 1.85mm spacer behind the cassette.
- 1.85mm longer than XD Driver to properly fit on 11-speed road HyperGlide hubs
- More stable hub connection means better axle and bearing durability
- Improved cassette/driver interface: cassette will not cut into aluminum driver over time
- XDR Driver is 6-8g lighter
- 10-tooth cog compatibility allows for expanded cassette range
- Licensed to more than 80 wheel and hub manufacturers
- Cassettes are still installed and removed using standard tools and practices.
What are you planning on doing? let us know in the comments below…
Also -For a look at an XDr setup I just built and reviewed… click here