This way I can upshift using the index finger and downshift using the thumb – all from right side, no left hand involved – just like on Shimano.
BHPian amol4184 recently shared this with other enthusiasts:
A while ago I made a usability mod on my beloved CAAD 10, a bike which I have vowed never to sell. I built it up with a first-generation completely wireless SRAM Red eTap 11 last year. As many of you will know, the SRAM shifting method is different from Shimano’s. The right shifter upshifts while the left shifter downshifts the rear derailleur. To shift the front derailleur you have to press both shifters simultaneously. It’s not bad but I much prefer Shimano’s style of upshift/downshift from one side.
The beauty of this groupset is that it allows adding extra shift buttons that mimic the functionality of actual shifters. SRAM calls those buttons Blips and sells an entire suite of hardware for a handsome fee. That price stopped me in my tracks. But digging a bit on some forums I found out that the system can be easily “hacked” with a simple wire and push button toggle switches that you see on electronic appliances.
My plan was to route that cable-button combo all the way from the left shifter to somewhere near the right shifter. This way I can upshift using the index finger and downshift using the thumb – all from the right side, no left hand involved – just like on Shimano. While it’s still not a 1:1 replication of the Shimano style, it’s close. Good enough for me! The DIY commences.
Most important bit for this mod:
Once I figured out the cable routing it was fairly easy but slightly destructive DIY.
The button that will do the downshifting:
Approximate location to cut a hole in the shifter hood so that the button can stick out of. I used an Exact Knife with a brand new blade to cut a tiny hole in the hood. This was probably the hardest part of this.
The Red eTap has 2 ports on each shifter:
We just need one to be used:
Poorly drawn schematic of the wiring. The cable (and button) would go from the left side and come out from the right side. 
The cable routing was somewhat of a pain for a couple of reasons. The cable is delicate and couldn’t be manhandled. Secondly, the cable holes in the bar are at an angle and small. Eventually, I had to grind the holes slightly to make them smoother and larger.
To pull the cable from the other side took about 20 minutes but with some help from tweezers and cussing the button eventually emerged on the right side.
The cable for brakes also goes in the same holes – that took some effort too but since brake cables are pretty stiff you can push them in the desired direction easily.
Once the cabling was done, I put the bar tape on by carefully winding the tape around the port and button.
This is how the left side looks:
And this is the right side. Put a dab of glue under the button to keep it in place:
Pull the hood over the button and align the hole so the button comes out. Final result:
What this accomplishes:
Complete shifting of the rear derailleur without using your left hand.
Bonus accomplishment:
With some practice, you can press the thumb switch + shifter button with your index finger simultaneously thereby shifting the front derailleur too! Basically your right hand now can shift both derailleurs.
Extras:
- You don’t have to route the cable from inside the bars. Much easier way is to just tape that cable on the outside of the bar. But if it is inside the bar, you don’t run the risk of pinching it.
- You can do it the reverse way and shift both derailleurs from left hand side.
- You can have them placed anywhere on the bars e.g. middle of the bars.
- The shifter remains active, so you can still do traditional SRAM style shifting.
- You can go a step further and build the cable switch yourself if you have the right parts and soldering skills. I would definitely like a bigger button and plan to do just that this summer.
Check out BHPian comments for more insights and information.
