Originally Posted by
pesty
Should work... this is where si.shimano.com is your friend.
2018-2019 SHIMANO Product Information Web
Looking at the compatibility chart for e-Tube it does show that SW-R600 should work as shift buttons. I've also heard of people cabling them directly into the junction box, which suggests the same.
The two thing to keep in mind with these is:
1. The cables are short, they are only designed to be run from the stem to the levers, so you may not have enough cable to get from the brake levers to your junction box. If you're handy with a soldering iron, you could splice a longer cable, or possibly open the shifter and solder directly to the board. I had to splice some e-tube cables to run Di2 in my bike without modifying the frame, it's not that bad, just two wires, similar to CoAx cable, but much smaller.
{edit** I do realized that there are junction tubes to join multiple wires, but didn't think it would be a good solution given that this will likely be under bar tape or just outside of it.
I was under the impression that the junction box could be mounted under the stem, but I'm just learning about this.
All of that being said.... is there a reason you're opposed to Shimano's own hydraulic Di2 levers or do you already have the TRP's in hand?
Yes, I already have the Hylex levers, which are currently retrofitted with Gevenalle 10 speed shifters. I've found that I want to shift from the drops a lot more often than I anticipated when I got the Gevenalle upgrade kit though. I think the remote switches may be reachable from the drops based on where they mount on the levers, so the idea would be to remove the Gevenalles then install the climbing switche(s).