• Di2 project for the TT bike.

    I was doing some reading about di2 hacks, seen the guy that managed to partially reverse engineer the canbus protocol of it, the guy that printed custom circuit boards for it...etc. The thing is, on a TT bike its a huge convenience if you can shift both from the base bar and the extensions, so why not try to make that work? The biggest prohibitive cost for me was the cost of cables. You can always just wait it out and grab a bargain on the components (still very expensive when accounting for TT levers etc), but it'll still be £250 for cables, battery, and junction box. Best case scenario. Given how often I'll use my TT bike, its reasonable to just move the battery over.

    Heres the plan: I bought a GRX di2 LH shifter that has a broken hydro part, di2 is functional. Ill take out the circuit board and the switches. Once its out, essentially all the built in buttons are just momentary switches just like on the sprinter "dummy" port, but the wires for these are soldered onto the circuit. I'll splice into these, and have two on each switch parallel. Shift RD down on basebar and extension, shift RD up on basebar and extension.

    Im planning to 3D print the housings for the switches that go on the basebar and the extensions, and there will be a small box housing the circuit board, Junction A, and the battery that goes in the seatpost. From here, one cable will go to the RD, and 2 more (housing 4-4 wires each) will go to the front of the bike through the downtube. Not planning to have FD on this bike, but if I will, it should work in syncroshift mode so no need for additional buttons for that.

    Ill also have a custom circuit board to eliminate the need of a Junction box B, and cut down on the number of di2 standard wire connections. It will need only 4 actual di2 wire connections (RD, Junction box A, Battery, "shifter" (circuit board from grx shifter).

    Given that I'll do a bunch of circuit testing and my race bike probably wont be complete before next year anyway, I made a board to make testing easier:

    Oh by the way I already have a groupset on it with mechanical shifters. So why this project?

    ...Why not?

  • Some top tinkering going on here

  • I'm not sure mounting everything to a board is the most aero solution.

    Is it for testing alignment or something?

  • Tinkering with the electronics, designing the housing, soldering the connections..etc will likely be a few weeks long project (or one weekend? Depends on the mood), and I just didnt want the mess of cables and parts in a shoebox or on my desk for that time.
    This will have a single cable coming off the board that I can connect with my frankendi2 shifter's latest iteration for testing.

  • I've got the working switches out of crashed TT shifters and was going to put them under bartape but I've not got around to it yet. I still have some busted up deraillers here that I've saved in case anything can be salvaged from them. Good luck.

  • Got my hands on my GRX shifter, and managed to non-destructively break it down to get the Di2 stuff out of it. Now I just need to take off the last piece from the lever but need my mini torx set from the office tomorrow for that.
    At the same time if anyone needs a right hand side ST-RX815 grx di2 lever for parts, let me know, its yours. It leaks oil after a crash, but the body is intact, and all other small parts on it, including lever and the rubber hood.

    I also sold my BMC frame to a friend of @hma, and it will be roaming the streets of Budapest, putting the "fast" in fast food :D

  • the chap is well chuffed. i don't think people ever saw their food teleport before..

  • reverse engineer the canbus protocol

    Something I've been interested in for a while now. Any more info?

  • @kiskubai
    Hi, I just broke the derailleur hanger of my spacechicken and planetx does not have any in stock.
    What derailler hanger did you use and where did you buy it?

  • Probably due to NPNG-s emails, planetx suddenly found some derailleur hangers in stock, in case anyone needs them, theyre on their website.

    @psg1ben Never really looked into canbus, thats a whole can of worms I dont want to open.

    Updates: The Di2 module from the GRX shifter is working perfectly, so thats good! Tried the flat momentary switches I got for my road bike to go to the bottom of the handlebar on the roadbike as climber switches, they work great. Not much progress with the di2 stuff other than that.

    In the meantime after selling the BMC, the next stage of the "It'd be nice if all of my bikes actually fit me" project I picked up this frame from @50pcoin :

    I figured they must have left the original paintjob under that beautiful black layer that its been blessed with :) So I got started:

    And about 3x3 hours and a pack of sanding paper later:

    Unfortunately thats not with a new clearcoat yet, just wet from water when washing it after sanding. But its looking pretty decent, most of it is finished to 800 grit.

  • The boardman is alive and well, inherited the Chorus 11s group from the BMC, and for now a Kinlin-Powertap wheelset on it. Havent got a PF30-campa BB so running a sram crank on it for now.
    Shitty bike picture, but really popping Lizardskins bartape:

    TT bike project!
    Flatmate just got delivery of a rear disc, looking good and got it for a good price. Paired with my tubular Zipp 404 front it comes to <1550g for the pair.

    Redesigned the TT extension shifter for Di2, a lot more simple. Slips to the end the extension, and further held in place with the bartape/grip tape. Simple momentary switch glued into it (and topped off with a rubber cap), and cable is routed down the side to the original shifter cable hole of the extension. Now that I typed this out, realized I could have routed it through the front. Back to the drawing table I guess :D

    Edit: And the way this will work with the Di2 system is that those momentary switches will be connected to the circuit board from the GRX shifter above in this thread.

    Got my aero bottle as well, 2 for 1 price basically so got a 600ml and a 900ml. Main event Im doing on this bike this year is the 90km bike leg of a triathlon race.

    Either Im gonna buy the stock Profile design mount, or if my compression moulded carbon skills live up to my expectations I might come up with something. I need to raise the front even more anyway, so need a bridge. That will be the starting point, then the bottle mount, then a garmin. Drawing is definitely not to scale, havent got the bike with me so just eyeballed the distances between extensions, and the length is just like 15cm or something.

  • Looks like a great deal on that disc. Maximum wom per £ those profile straws are pretty hard and I've cut my mouth on them hitting even the smallest bumps while drinking from it. I put a camelbak bite valve on the tip of my profile HC straw and it works brilliantly.

  • They are tough - I got some flexible tube and attached it to the ends of mine for that reason.

  • Good shout guys, I'll grab the bite valve off my camelbak!

  • Shaping up.

  • Cool Bikes! That DuraAce/Sram Crank/Chainring combo looks fantastic!

  • Looking fast already 👍 What frame is that? Mine is a very similar open mould Chinese import and I've been really happy with mine.

  • Thanks, I was quite happy with how the crank-chainring combo turned out! Although for proper use it'll have a black Force22 crank on, because thats what ive got with a powermeter.

    @Retro_Bastard Its a Vitus Chrono TT from around 2014-2016. Previous owner already took off most of the stickers, but I cleaned the rest. Selcof basebar and TT extensions, and it'll have the TRP mini-v brakes both front and back.

  • Nice that's the same frame as mine then inc the fiddly trps mine just looks a little different as my top tube is horizontal as its a medium. Loads of manufacturers were using those moulds at the time some of them Italian and really expensive just with flashy paint jobs and branding but they won't be any faster. Ryan Mullen rode that frame branded as a Vitus to a national 10 mile record so no excuses for going any slower than 17:51 especially now you've got a disc 😉

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  • he can always say he's missing the trispoke.. :)

  • looking good! especially the aero cable hoop - that's for eliminating vortices created by your ankle, right? :D

  • Naaah thats for not wasting a shifter cable on this setup that I just mocked up so I can use it on the turbo :) And if I need excuses, dont worry, I'll find one :D

    Todays progress:

    Why the bridge? there will be an extra 2cm spacers in there -which, looking at the pics above isnt that bad-, and this will connect with a -hopefully- more elegant solution than the factory one to hold the Profile design bottle between the TT extensions. At the end of that there will be a garmin console too. Maybe.

    Im planning to make these from compression moulded carbon, mostly from "forged" carbon with a few sheets in the middle running all across. Following this tutorial:


  • Todays progress. Still figuring out how Im gonna fix the bottle in it, but the original rubber bands are strong contenders.

  • This thread deserves more credit. A proper project thread!

    .... searches internetz for 3d printers ....

  • You can usually get a barely used "xmaspresent" Ender 3 off FB marketplace under £150. They are easy to mod & upgrade. But be careful, just like cycling, this hobby is a slippery slope...

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Kiskubai's Garage (Solving problems I've created - formerly unexpected Space Chicken)

Posted by Avatar for kiskubai @kiskubai