Originally Posted by
XShifter
There is some incorrect information here about XShifter that I'd like to correct. First of all the servo does not rely on zip ties to maintain position. All the load is taken up in the Bowden cable. We have a video that demonstrates this on the Kickstarter page. Regarding shifting speed, it is as fast as di2 and eTap. We demonstrate the repeatability of within 2 microns. We are planing a significant speed improvement. Over shifting, XShifter has that capability on both front and rear. Furthermore, the user can tune the amount and timing if they like. No other system offers this flexibility. Please go to our Kickstarter page for all details.
We're getting off topic, but let's discuss errors and omissions since you're soliciting funds.
Use of Zip Ties
While the Bowden cable may maintain derailleur position in ideal conditions, the zip ties are less secure than bolt fasteners. On a 10 or 11sp drivetrain with tighter spacing, small movements in the battery assembly may be enough to affect indexing. Why use 8 or 9sp Acera drivetrain for your demo?
Shift Speed
The XShifter only provides electric assist in one direction (ie while pulling cable), and will be affected by dirty cables or sticky derailleurs. The XShifter can't provide faster shifting when for rear downshifts (large cog to small cog), or front upshifts (granny to big ring). It's hard to believe that the XShifter will match the speed of Di2 or eTap for all shifts, under full load (200-300 lb rider or tandem team), and in inclement conditions.
Poor Ergonomics
Most road bikes are equipped with STI-type shifters (aka brifters). The XShifter requires a road rider to move one hand from the brake hoods to the top bar shifter. This is not a good idea at high speed or in heavy traffic. On a mtn bike, the Shimano & SRAM trigger shifters make it easy to distinguish between an upshift of downshift. It's much harder to press the right button on the XShifter (1 of 4 positions), especially on bumpy terrain.
Protection from Water and Debris
The XShifter batteries are located in the dirtiest part of the frame: bottom of the downtube and the seatstays. For mtn bikers, the downtube location is vulnerable to rock damage. In contrast, most Di2 and EPS riders use internal wiring with the battery safely inside the seatpost. The eTap battery is integrated into the derailleur, so it's fairly protected. For the minority using the Shimano external battery, it's safely tucked away on top of the downtube (away from dirt, water, and debris). Not only is the Shimano external battery safely tucked away, it only has one small connector for the eTube wire. I have less confidence that the XShifter battery will stay dry when pounded by water at the USB charging port and removable battery interface interface.
Fast, Reliable Front Shifting
Di2, EPS, and eTap have powerful motors that can pull the chain in either directions for front shifts. The XShifter can only provide electric assist in one direction (ie. pulling cable instead of pushing cable). When shifting from the granny to the big ring, the XShifter must rely on the derailleur's cable tension to stop the cage from moving too far. When shifting from the big ring to the granny, the XShifter can't provide any electric assist. Your website video is misleading because it shows the front derailleur shifting a close-ratio triple crankset in a kick-stand while the crankarm is slowly rotated by hand at about 30 rpm. Virtually any derailleur will shift well in these conditions. It's a different story for double cranket (w 16T gap) under full load at more than 90 rpm with cable stretch or a dirty drivetrain.