Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

That’s an excellent video, never seen anyone stretch springs like that.
User “mybikeparts” on ebay sometimes has Shimano spares not available through dealers. Alex Japan as well.

I intelligently decided to wash my tt bike with di2 at the weekend and now it’s dead. How do I identify what’s broken and needs replacing?

I removed the battery and there’s some rusting around the connectors so my first thought would be that? Is there any way I can confirm it’s that as I really don’t want to spend £100 on a new one if I don’t need to

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This also looks a bit fucked…

It’s run 1x. The cable next to the one with the blue rust (!) on it goes to the rear mech. The opposite end, one goes to shifters and one to charger and battery (I think)

Can I test any of these elements separately for fuckedness so I only order what I need?

No lights come on the charger when plugged in

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Ah, I’ve plugged the charger directly into the battery and got a flashing orange light. Does that mean battery not fucked?

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Weird, let it charge a bit, plugged it all back in and it’s working again. Fun morning that was.

Anyhow, what’s the best way to waterproof those elements before I put them back in the frame? Just bubble wrap and tape?

Odd that you've got two junctions there; I'd get rid of the one with the corrosion on the unused connector, and the short cable connecting the two, and plug all three remaining cables (rear mech, battery, shifters) into the other one.

Gross.

Plug it into other Di2 bits and/or the software to see if it detects any component.

Odd that you've got two junctions

I wonder if they just used it to create a longer cable? Maybe whoever built it had spare bits but not a long enough cable.

Obvious answer is to never TT in the rain.

Could be sweat from turbo too, so don't train indoors either.

A blob of vaseline under each plug and a big blob in any open sockets. Even better, dummy plugs.

blob of vaseline

Use proper silicone based dielectric grease unless you're sure that the plastic and rubber parts are safe with petroleum based lubricants.

Yes, it is odd. thanks for pointing that out, I'll give that a go. If the cables are too short then so be it.

@gbj_tester do you mean I could put this grease https://www.screwfix.com/p/arctic-hayes-silicone-grease-tub-100g/968PA between the plug and socket then plug it in? Or put it on once it's all connected up?

Does it matter what sockets plugs go into on a junction box or is it just a connector so any plug can go in any socket?

Apologies for the noob di2 questions. This is why I trust sram

It's just a connector, it doesn't matter which one goes where.

I was thinking of getting some TT shifters for my ultegra R8070 setup aero bars. The problem is that ultegra 8070 only has two ports per shifter and between the two I'm using 3 already (shifter to shifter, shifter to junction in downtube).

Can I just use a junction box I have already (shoved inside the bars) to connect them together then connect that to my shifter? Will di2 accept 2 junction boxes?

Yes. You can use as many Junction B connectors as you like.

Am thinking of a 3-port SM-EW90-B... I assume that "B" means it'll be okay?

a TT bike!

https://www.lfgss.com/conversations/399168

I use a 5-port junction A under the stem for this. At least I did, until someone at GLS stole my Mason.

This way you can fit them and remove them very easily rather than sticking junc B internally.

No, if it has a charging port it's a Junction A. You can only have one of those. "Junction B" means a dumb junction with just E-tube ports.

The SM-EW90-B is a Junction A with 5 ports, because Shimano.

Alright cool. I'll just get the 4-port box and put the dummy into one port when I buy the shifters. More unused shit in the spares box.

The bike has a downtube junction so replacing that would be more fuss than a 4-port junction (I think, it's all theoretical)

This is my general experience with Di2 - occasionally it borks itself, and disconnecting/reconnecting/charging it will randomly come back to life.

but @hippy is right, riding outdoor in the wet on a TT bike is for hardpeople/madness

Would an XTR di2 rear derailleur work with Dura Ace 9150 shifters?
I’m try to make a gravel/allroad using parts from a road bike I barely use and my mountain bike.
Or should I wait for the GRX 1x12?

Or put it on once it's all connected up?

Smear a thin layer on the part of the plug which ends up inside the junction box to seal it against water ingress. You don't need to be too fussy because electrical connections will eject any surplus as you plug them in and make metal to metal contact. If you're too liberal you can end up applying hydraulic pressure to sealed boxes as you insert connectors, so don't go mad🙂