How to maintain, clean and look after your Di2

[@Di2_GP]

Thank you to @horststorkebaum6475 for pointing out my mistake! Free - stroke adjustment is to compensate for brake bite-point, 'reaction time' the time or distance of brake lever before brake pistons in the calliper are moving. It does not move calliper pistons itself. However, if you have new brake pads, and free-stroke is fully backed off, turning free stroke clock-wise, and compensating lever position with reach adjustment will reduce lever movement before brake pads are touching the rotor. This may be helpful when your pads wear down, or if you're wearing your front and rear pads in different ratios, but want to keep lever movement the same.

[@bradallen8643]

Thanks for brake reach and pad ware adjustment explanation. Good to know when replacing brake fluid 👍

[@brunoj6146]

Great video and very helpful. Thank you.

[@hmudesign]

Another great video sir. I see you tackled the front mech issues, I have one 6800 series front mech I got from somebody, where the shaft had snapped. I was thinking about casting or machining a replacement. Where do you get your replacements, from other mechs that are beyond repair and only for parts? Would you do a video about di2 batteries at some point, and common problems etc. thanks again for the awesome content.

[@Di2_GP]

I use other derailleur for spares. I did try making that actuator arm out of sheet aluminium, but it wasn't working well. I did get my friend to tig weld one that broke, but as that's cast alloy, it was quite contaminated. Weld wasn't pretty, but it held ok. I used it for a couple of rides and then found replacement. Battery video coming soon, just need to find a time.

[@hmudesign]

@@Di2_GP No rush, I look forward to your videos, this is so up my alley. It combines my love for fixing stuff, with bicycles which I also love.

[@jamesplumb644]

Very useful video thanks !

[@Di2_GP]

Thank you

[@YTOnlineReviews]

Very helpful video.

[@Di2_GP]

Thank you

[@horststorkebaum6475]

Hello Pawel, I suppose your explanation of the "free stroke" mechanism and adjustability is wrong. It's not intended to reduce the lever travel before the pads start touching the brake rotor. It's intended for the opposite. (I never met any person who ever wanted to have more "free stroke", but that's how it works.) When you turn in that bolt completely the master piston is right at the edge of the first communication opening in the master cylinder. If you start pulling the brake lever that opening is shut and the reservoir and the master cyclinder do not communicate with each other anymore. The pistons in the caliper start moving towards the rotor. Turning out that bolt lets the master piston move further back in the master cylinder. Which means the pistons in the caliper will start moving later in the brake lever stroke. The position of that adjustment also doesn't affect the bleeding process as you cannot turn in the bolt far enough to prevent the reservoir and the master cyclinder from communicating with each other.

[@Di2_GP]

Thank you, I may not be 100% correct, but free stroke bolt does move piston out, which in turn applies brake, as a result brake pads will touch the rotor sooner. If that bolt is fully done up (You will have reduced total volume of brake fluid shifter can take) and then you bleed brakes, after undoing it, you will be able to top up the fluid (add more fluid). That is what I had in mind, maybe I should have explain it better.

[@horststorkebaum6475]

​@@Di2_GPI have to check on a 12s brifter like the one you used in the video. I haven't yet as I have found that adjustment to be superfluous so far. That said on all 11s brifters it works as I described above. The default position is bolt all in and thus free stroke reduced to its minimum value. Any turning of the adjustment bolt will increase the free stroke. The only useful application of that adjustment that I have found have been the rare cases where the bite point was significantly different in-between the two levers. Then I use the free stroke adjustment and the reach adjust in conjunction to make both levers feel similar. BTW the dealer manual for Shimano's 12s brifters describes the process in the same way as it has been for all the 11s brifters.

[@Di2_GP]

I do agree I made a mistake, pistons do not move when free stroke is adjusted. I've made a video, as it a lot easier than trying to describe it in comments. Have a look, I still stand by the recommendation to back off free stroke before bleeding. Finally I should have said that 'assuming' your free stroke is fully backed off with the new brake, pads, a combination of free stroke and reach adjustment will keep lever position and travel the same despite worn pads. In my defence I don't think I dealt with factory Shimano brifters, I always bought 2nd hand ;-) kzbin.info/www/bejne/nKPOnHejm82jmcU

[@frankdelarosa9527]

I'd like know what cleaning agents you're referring to when you mentioned 'with salt'.

[@Di2_GP]

I don't want to end up in court, so I won't mention any specific names. In general, I'm referring to mainstream bike specific cleaning products. As an example, bike cleaner label states “

[@dsinsuatable]

do you have video how to disassemble 6870 RD, FD? Thank you.

[@Di2_GP]

Here is a link to 68070 GS disassembly, but the same process applies to 6870 SS and 9070 kzbin.info/www/bejne/hpq2pICIbJh4d9E . I don't have a specific video on 6870 FD. What is the problem with your 6870 FD.

[@shankeong6753]

why will Shimano want to make the DA jockey wheels 3mm slimmer than their Ult and 105 counterparts? Is there any mechanical advantage?

[@Di2_GP]

Tooth profiles and tooth count are the same. Bearings are the same. There is no mechanical difference in the axial load. DA jockey wheels are just lighelter. However, as the jockey wheels and the cage itself is narrower on DA, you may get some minimal aero gains.