Hi

I built my bike last year with Dura Ace Di2 and used the internal wiring harness which was a treat to fit and use.

I would like to have a new frame for 2013 and reuse the Di2 groupset and wiring harness.

The only dilema i have is removing the heat shrinking tubes which go over the junction box connectors
to weather proof them.

Does anyone have any experience removing the sleeves ? or can suggest a way that would enable me to re use the harness
rather than have to buy a new one.

Thanks.

Nelson

Carefully cut them with a sharp razor blade. I have did this a couple of times and no issues. Just make sure you cut in to out.

Thanks for the advice.

What do you mean exactly "Just make sure you cut in to out." ?

I wondered about re heating the tubes to re activate the glue and then perhaps they would pull off.
Can you get new heat shrink tubes from Shimano or did you use commercially available heat shrink tubes from an
electronics store ?
Thanks

Nelson

I've done this a lot as well, upside is right just use a sharp razor blade. I think he meant to say just make sure you don't cut into the wires themselves.

You can buy more from Shimano but it's easier to just buy it locally from an electronics supplier.

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Thanks for your advice i will remove the groupset and use it on my
new build in the spring.

Nelson

You can purchase the shrink wrap at a local hardware store. The stores usually have it in different diameters. Have fun

Just make sure you buy the glue lined double wall heat shrink. That's the same type used in the di2. The regular stuff is not water proof.

I've never seen adhesive lined heat shrink at any hardware store, or electronics store for that matter. Google and Amazon worked for me in the past, though.

do what the pro teams do--just use a few wraps of electrical tape on the connectors.

seriously--how much water do you expect the INSIDE of your frame will see?

Is there such a thing ? I fixed the Di2 harnesses myself, never noticed that there was glue on the inside. Didn't notice it when I took them apart last month either.

In any case, there is no need for 'double walled' heat shrink, you may encounter some issues with some frames if you do that. But just make sure you get those that are ~6.5mm diameter, with a 90% shrink capacity ( they cost almost 3x the normal 50% shrink types) .

Also, note the o-rings that are already on the harness, just don't damage them as they help to seal off the heat shrink for you.

Get the stuff at auto parts stores. And just cuz its "double walled" doesn't change its diameter or shrink. But of course this is the good old interweb, where people love to express definitive opinions about stuff they don't actually know. If you read the shimano instructions for the wiring harness you will realize they use glue lined heat shrink. Whether you want to take a chance with a wiring harness inside your frame and is a bitch to remove is your business. As for water in your frame, well that depends on the frame and whether you ride in the rain and wash your bike. I certainly drain water out of my frame after that.

Nobody implied a corollation between wall thickness and shrink ability.
Separately, I doubt Shimano's own heat shrink reduces 90%, I would have assumed it's typical 2:1, 3:1 at most. It is quite a bit thicker than off the shelf stuff, but as mentioned earlier, some entry holes are a tough fit as they are.

"You may encounter some issues with frames if you do that"
The 3M thin walled adhesive lined stuff has a 3:1 shrink ratio.

Dug up my old harness instructions and yes indeed there was mention of glue being on the tubes.
But its something which I have never noticed seriously as I've done and redone the same set of harnesses 2 times and helped another friend set up his.


As for the double thickness types, its a fact, that some frames will have barely enough clearance for the connectors, with a double thickness heatshrink, you'll get into problems, especially in the chainstay portion. A thin walled, high shrinkage heatshrink tube would be the best.

I doubt they do either. But its a claim I saw at a local electronics supply shop I saw a few ago. As far a quality heatshrink goes, the best available ones are about 4:1.