So, silly me putting together a trail/XC build for the summer thought I'd try being fancy and high-tech, and splurged on XTR Di2, because I hate money and am an idiot.
Word of warning: the SW-M9050 Di2 Firebolt shifter is the single worst piece of mtb tech to come along in a very long time. Currently, after 3 weeks of riding, I'm on my 3rd shifter after sending the previous two back for warranty.
Problem 1: The ergonomics are terrible. Now, depending on your hands you may prefer normal Shimano over SRAM, or vice versa. I prefer the feel of SRAM with the multiple-shift stroke of Shimano, but it's not a comitted thing or anything. Basically I'll use whatever. But this Firebolt thing is objectively terrible. The upshift and downshift are switched from what they should be, but that's an easy fix with software. The real problem is threefold: a) the top button is much smaller than the bottom button, which is the reverse of every single other shifter on the market, SRAM or Shimano. It is also quite difficult to find when you are doing anything other than cruising along on smooth track. Better hope you don't need an easier gear after that chundery downhill, because you aren't getting it. b) The shifter throw is kind of a "rotates around the axis of the bar" movement, which, again, is unlike the straight swivel of every single other shifter on the market, SRAM or Shimano. This doesn't sound like a big deal, but after a couple of hours of shifting, will cause your thumb to start cramping due to the unnatural movement. Finally, c) the giant bulbous spring housing makes it impossible to fit near your brakes, regardless of brand. This means the crappy rotation movement of b) is further complicated by having to do the thumb war stretch just to shift.
Problem 2: The shifter is a flimsy, plasticy POS. So, if you take the time to actually read the dealer's installation manual, they tell you to install the shifter with a torque spec of 0.9 N-m. Without carbon paste. Since I am such a nerd that I actually own a torque wrench capable of doing decimal fractions of newton meters, I happily dialed in the torque and discovered that 0.9 N-m is nowhere near enough to secure the shifter. It will rotate the second you try to shift. Okay, time to add carbon paste- Nope! Still rotates. Okay, maybe double the torque to 1.8 N-m? *SNAP* The damn thing breaks. Specifically the screw that tightens the band cracked it's housing and caused the band to lose any ability to hold tension. It's worth pointing out this was on a Pro Tharsis Trail Di2 bar- so Shimano's own bar designed specifically for this shifter. Warranty #1. Fortunately this happened right before a race Shimano was doing support for, and they were able to warranty it on the spot, A+ for service there. They handled the install, telling me they made a running change to the shifter because of that flimsy band/screw interface. Fair enough. New shifter actually holds on to the bar, which is nice. Whats not nice is two days later the return spring that pushes the lever back to neutral (both buttons use the same spring) breaks. Warranty #2.
Finally have a third functioning shifter (installed by me, at 4 N-m with carbon paste, which is what it takes to keep it from rotating) but this one seems to have some binding with the return spring, and it occasionally catches and keeps on shifting.
Overall, while I am happy with the rest of the drivetrain, it's rendered completely worthless by a shitty shifter. Seriously Shimano, what the hell? How can you fuck up a shifter this badly? Contemplating just going with Eagle.
TL;DR- don't buy Di2 XTR (or XT) untill Shimano fixes the mess that is the Firebolt shifter.
Word of warning: the SW-M9050 Di2 Firebolt shifter is the single worst piece of mtb tech to come along in a very long time. Currently, after 3 weeks of riding, I'm on my 3rd shifter after sending the previous two back for warranty.
Problem 1: The ergonomics are terrible. Now, depending on your hands you may prefer normal Shimano over SRAM, or vice versa. I prefer the feel of SRAM with the multiple-shift stroke of Shimano, but it's not a comitted thing or anything. Basically I'll use whatever. But this Firebolt thing is objectively terrible. The upshift and downshift are switched from what they should be, but that's an easy fix with software. The real problem is threefold: a) the top button is much smaller than the bottom button, which is the reverse of every single other shifter on the market, SRAM or Shimano. It is also quite difficult to find when you are doing anything other than cruising along on smooth track. Better hope you don't need an easier gear after that chundery downhill, because you aren't getting it. b) The shifter throw is kind of a "rotates around the axis of the bar" movement, which, again, is unlike the straight swivel of every single other shifter on the market, SRAM or Shimano. This doesn't sound like a big deal, but after a couple of hours of shifting, will cause your thumb to start cramping due to the unnatural movement. Finally, c) the giant bulbous spring housing makes it impossible to fit near your brakes, regardless of brand. This means the crappy rotation movement of b) is further complicated by having to do the thumb war stretch just to shift.
Problem 2: The shifter is a flimsy, plasticy POS. So, if you take the time to actually read the dealer's installation manual, they tell you to install the shifter with a torque spec of 0.9 N-m. Without carbon paste. Since I am such a nerd that I actually own a torque wrench capable of doing decimal fractions of newton meters, I happily dialed in the torque and discovered that 0.9 N-m is nowhere near enough to secure the shifter. It will rotate the second you try to shift. Okay, time to add carbon paste- Nope! Still rotates. Okay, maybe double the torque to 1.8 N-m? *SNAP* The damn thing breaks. Specifically the screw that tightens the band cracked it's housing and caused the band to lose any ability to hold tension. It's worth pointing out this was on a Pro Tharsis Trail Di2 bar- so Shimano's own bar designed specifically for this shifter. Warranty #1. Fortunately this happened right before a race Shimano was doing support for, and they were able to warranty it on the spot, A+ for service there. They handled the install, telling me they made a running change to the shifter because of that flimsy band/screw interface. Fair enough. New shifter actually holds on to the bar, which is nice. Whats not nice is two days later the return spring that pushes the lever back to neutral (both buttons use the same spring) breaks. Warranty #2.
Finally have a third functioning shifter (installed by me, at 4 N-m with carbon paste, which is what it takes to keep it from rotating) but this one seems to have some binding with the return spring, and it occasionally catches and keeps on shifting.
Overall, while I am happy with the rest of the drivetrain, it's rendered completely worthless by a shitty shifter. Seriously Shimano, what the hell? How can you fuck up a shifter this badly? Contemplating just going with Eagle.
TL;DR- don't buy Di2 XTR (or XT) untill Shimano fixes the mess that is the Firebolt shifter.
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