Posted 20 January 2024

A thread on how to possibly get Shimano 105 Di2 Cheaply?

So I wanted to open up a discussion because I have managed to find links, some allowed some not, that could potentially bag a bargain di2 12 speed groupset. Something I want but don't need so I doubt I'll buy it but I went down a rabbit hole. I have a top budget of 550 for this kind of thing and that kinda doesn't exist.

Or does it..........................?

So (running totals in brackets)
rear derailleur is 95 delivered at Ribble
Front derailleur is 84 delivered at SigmaSports (179)

Front and rear shifters (and I think flat mount calipers and hoses) at Wiggle/CRC (not allowed on HUKD)
Left Shifter is 107 (286)
Right shifter is 134 (420)

Chainset c100 from various outlets/ebay with patience. personally don't mind 2nd hand/near new (520)
Cassette c45 from various (565)

So now we get into the small bits and it potentially becomes a little bit less attractive, di2 cables, battery, charger, chain and junction box.

Now I already have a charger for my TT bike and the battery is also really accessible so I could in theory plug and play but is that worth the cost of a di2 battery to me, not sure. My road bike frame isn't di2 ready but I can make it work, I'm somewhat Heath Robinson about these things!

This link is most helpful for building and FAQs as well as highlighting (and I need to read more) that the shifters are wireless?????

So I guess my thoughts are, is this worth the multiple parcels and general hassle? I think with some further shopping around it can be had for close to less than 700 and I can't see a new groupset for less than 940 and I am not sure that comes with everything. I don't think a groupset (e.g. from Merlin) comes with a junction box but I could be wrong and would appreciate anyone who has bought a di2 groupset recently might say what does and does not come with one. I think they come like this:

  • 105 Di2 Shifters (ST-R7170)
  • Flat Mount Brake Calipers (BR-R7170)
  • 105 Chainset 172.5mm 50-34T (FC-R7100)
  • 105 Cassette 11-34T (CS-R7100-12)
  • 105 12 Speed Chain (CN-M7100)
  • 105 Di2 Front Derailleur (FD-R7150)
  • 105 Di2 Rear Derailleur (RD-R7150)
  • 2 x 140mm Rotors (SM-RT70)
  • Di2 Battery (BT-DN300)
  • 2 x 900mm E-tube Di2 electric wire (EWSD300IL090) (is that enough?)
  • Charge cable (EW-EC300)

I am not a mechanic, I've built 2 bikes (not hydro) and am just keen on cycling, shiny things, convenience, tech and bargains. So don't shoot me down and it's just a discussion so...

Happy riding all.
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  1. Johnmcl7's avatar
    With the current generation of Di2 (R7170/R8170/R9270) you don't need the junction box since the shifters are wireless and you only need two cables, one from each derailleur to the battery.

    Something to be aware of is that the R7170 shifters do not have the hood buttons nor can you connect satellite shifters, I'm not saying it's worth the money for the R8170 shifters but it's something I wasn't initially aware of.
  2. jr007's avatar
    I tend to shop around but I paired slx callipers with Road 105 shifters.

    I’m not a fan of batteries in frames and tempted to go SRAM now they have improved their brakes.
  3. horstachio's avatar
    I have historically built up a few Di2 bikes, and it is always cheaper to buy across multiple retailers in parts. Most the time it will be OEM but you don't need the boxes really.

    In terms of wire length, usually the frame manufacturers in manual will spec the lengths they use. if not, estimate using string and add a decent amount more. It is very easy to store excess wire in the frames. (edited)
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