Di2 components are pretty tough - I have a Di2 hardtail and two road bikes, and they haven't failed me yet. Still, these Di2 components do wear just like other bike components, and eventually, they'll break.
Some of these can be repaired, or have parts that can be replaced. Derailleurs are pretty good in that regard - almost every part can be replaced:
- The pulley wheels
- Tension springs
- Derailleur plates
- Limits bolts
- Charge port cover
Hydraulic shift levers on the other hand, are harder to repair. Shimano just don't offer a lot of replacement parts for them.
So how do you know whether or not your component can be repaired or has any replaceable parts?
Shimano's documentation site has the answer to that, and I'll show you where to find this information.
Shimano's documentation page, si.shimano.com, is basically a search engine for all their documentation on anything Shimano has made in the last 20 years or so.
It lists Dealer Manuals (DM), User Manuals (UM), Service Instructions (SI), Catalogues (SM), and Exploded Views (EV).
Dealer Manuals contain all the information on how to install components on your bike, and the user manuals are the (usually useless) small paper manuals you get in each Shimano component box.
If you're looking for spares though, exploded views is where you want to look. This is where you can see the individual parts that make up any given component.
There's one catch - Shimano only lists the parts that are offered for sale. The EV will only show the replaceable parts that can actually be bought.
Let's open a couple of these and go through them.
Ultegra RD-R8150 Exploded View
Click search, and it'll show you the search results page.
On the far left, you'll see a number of filters you can use to narrow down your search. This is useful when your search query returns a very long list of files.
Since we're searching for a specific component here, there isn't much point in filtering the results any further. It's already a pretty small list.
The main section lists all files related to the search query ('RD-R8150'), and the file types.
There are two methods of displaying most of Shimano's documents: a PDF file, and the web version.
To open the PDF file, simply click that PDF icon at the far right of the screen. These files are pretty basic, but I like them.
The web version of the files is a more recent development. Let's open the one for RD-R8150 now.
Click the document title, 'RD-R8150-4864'.
Let's say you've broken the derailleur's charge port cover. As you can see in the EV above, that is part #6, with the Shimano part number Y3J145000.
You can now paste this into your favourite search engine, and it should return a bunch of sites where you can buy the part. Of course, your local bike shop can also order these from Shimano directly.
Here's something cool the web view can do, but the PDF files can't.
Let's say you're looking at the list of parts and come across #7, 'boot'. I have no idea what a derailleur's boot is, and don't know where to look for that in the EV.
You can click the part number/description, and it'll highlight the part for you in the EV.
This is what that looks like:
Pretty cool, right?
EW-RS910 11-speed Junction A
Now let's look for a spare part that I needed myself, about a year ago.
I had a silly accident while riding and crashed. Apart from some bloody elbows and bruises, I was fine. The bike was too, but the left side of the handlebar scraped along the ground, damaging the left shifter and RS910 handlebar dummy plug.
And yeah, you don't need that part. A regular handlebar plug will work just as well.
I decided to replace the part anyway, so I looked up the EV, ordered part Y71J98020, and that was that.
Sometimes when you open an Exploded View, you'll see a mention of 'Interchangeability' in the list of parts.
It also uses the same Clamp Bolt as its mechanical sibling, the FD-9000.
The interchangeability is 'A' for all of these parts, meaning that they are exactly the same.
There's also 'B-interchangeability', which means that the parts are the same functionally but differ in appearance, or materials used. You can safely use them, but they'll look different.
Line-up charts and Compatibility
While the Exploded Views are pretty good when it comes to finding spares, there are other methods too.
Let's say you need new brake pads for my 105 Di2 hydraulic disc brakes. Where could you find what brake pads are designed to work with your calipers?
The line-up charts page is where I'd first look for this information.
Open productinfo.shimano.com and click the 'Line-up Chart' button.
If you're looking for information on older products, by the way, click the '2004-2022 Archive' button right above the search box.
The 'Line-up chart' main page looks like this:
You can either navigate to your groupset using the filters on the left (MTB, Trekking, BMX, Gravel, E-Bike, Urban, Road), or find the correct button In the main section of the page.
I clicked the '105 R7150 Series' button, and that brought me to the line-up chart for the R7150 series.
Scroll down a bit, and you'll find the correct hydraulic brake hose for the BR-R7170 brake caliper, as well as the 105-level disc brake rotors.
Scroll back up a bit, and click the brake caliper, BR-R7170. The caliper specifications will now open.
This will show you the compatible brake hoses, as well as the brake pad options we were looking for. As you can see, the recommended pad options are K05S-RX Resin, L05A-RF Resin, and L04C-MF Metal.
There is another way to get that information, of course. You could open the specifications page, browse to your groupset, and you'll find the component's specs.
The compatibility information is a bit harder to navigate, but generally lists more information than the component specifications and line-up chart.
You could click the relevant sections to eventually find the information you're after, but I prefer searching for the components I'm interested in.
To do so, move the mouse over the magnifying glass at the top right of the screen. A search box will open.
Type 'BR-R7170' and press Enter.
The right section of the page lists all the search results by category. The main window automatically scrolls to that specific information when you click it.
For example, in the image above I clicked 'Disc brake caliper and disc brake rotor compatibility'. The page shows the BR-R7170 and other calipers, and all the rotors they're compatible with.
There's also a section on compatible brake pads, and it's worth looking at. Besides the three compatible brake pads we found earlier, there are quite a few other compatible brake pads.
This section also shows the difference between the brake pads, making it easier to decide which ones to buy.
Found the parts you're looking for?
So there you go - you should now be able to find spare parts for any of your components, and brake pads, hoses, rotors. Anything you need really.
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Need some more help? Feel free to leave a comment below or send me a message. I'll get back to you as soon as I can.