I spent part of Sunday setting up the new SRAM e-tap system on my M5 Highracer, but I'm wondering now whether it was a good move. My confidence was eroded when I couldn't get both front and rear derailleurs to work simultaneously. If I got the blip-box to communicate with the rear derailleur, then the front wouldn't work, and vice versa. The instructional videos produced by SRAM didn't address this problem at all. Local dealers were of little help, saying only that they'd never encountered this issue. It was only after I found an instructional video posted by some random user that I realized that both front and rear derailleurs had to be paired with the blip-box at the same time. After that, everything worked as it should. But by then I'd done quite a bit of research, and I was a bit alarmed to find so many complaints posted on various forums describing e-tap malfunctions. I've been using mechanical shifters since 1970, and I can't recall even one case of a failure. There were of course cable tension adjustments that needed to be made on occasion, but I've never experienced a total failure to shift gears. And when such failures occur in the case of the e-tap system, the problem can't be easily corrected with a screw driver. Invariably the units has to be shipped back to SRAM for repairs, and that means significant downtime, not to mention the inconvenience of suddenly finding yourself unable to shift gears in the middle of a ride.
Something else that has irritated me about electronic shifting since the first time I tried them, is their relative slowness in performing the gear shift. With a mechanical shifter, changing gears seems almost instantaneous. The moment I apply pressure to the shift lever, I can hear the chain moving to the next gear. But with the e-tap, I noticed that the derailleur arm wouldn't even begin moving until I'd taken my finger off the shift button. This seems to happen with the Di2 system on my other bent as well, and it's especially annoying when executing several shifts in rapid succession. Why this has to be the case is beyond me.
Another thing that bothers me about the e-tap system is the sheer size of the blip-box. The one on my Di2 system is very small and can be easily concealed. The blip-box for the e-tap is three times larger, and can't just be tucked away somewhere. The problem isn't just it's bulkiness, but the fact that because of it's size, I'll have to mount it someplace where it's plastic housing will be exposed to the searing Florida sun 100% of the time. Anyone who has lived here knows what happens to plastic or rubber when it's exposed to the hot sun for significant periods: it becomes brittle and disintegrates. I've had plastic mirror housings fall apart, I've had plastic straps dry out and snap, and recently my plastic Garmin GPS mount split across the top and nearly fell off. To prevent that from happening to the e-tap's overpriced blip-box, I'm going to have to design some kind of cover to keep it out of the sun. The designers really should have anticipated this. Or perhaps they did and just saw it as an opportunity to sell more replacement blip-boxes.
