“Without getting too far down the bike nerd rabbit hole I’ll break it down like this.”
Like many people who have been riding for a long time, I have a tendency to get set in my ways. This was absolutely the case with my mountain bike. For starters, I only recently finally gave up my dated 27.5” wheeled bike for a new Norco 29er. I was on a budget and decided to reuse as many parts off my old bike as possible with the idea that as things wore out I would continue to upgrade. Makes sense, right? Right.
"Well, sort of."
I elected to reuse the 2x10 Shimano XT parts I had. After all, I liked them just fine. When I originally switched to a double crank years ago it was a revelation. Ditching the triple crank was great. I chose gearing that allowed me to shift my front derailleur less and focus on the trail.
I don’t consider myself a particularly fast mountain bike rider but at the time I was enjoying participating in racing and would occasionally get a decent result in a “sport” class race. I was convinced that the 38/24 combination of chainrings was the perfect mate to the cassette cogs on my rear wheel that ranged from 11 to 34.
"Turns out, I was not exactly correct in my assessment."
After very little time on a mountain bike over the past few years, I had been hitting the trails more and more this spring on both solo rides and with a group. Again, at the time, I had myself convinced that my setup was great. I managed to ignore that I often found myself over-geared on the downtown trails when confronted with the short steep pitches. My mediocre skills often meant I was fumbling to find the right gear, and sometimes grinding to a halt.
I convinced myself I was fine but began to write the internal narrative that when I finally wore out my current chainrings I would probably upgrade to 1x. After all, I had no excuse. It’s simple to do and I could even reuse my shifter and derailleur.
There was just one thing that bugged me. I really liked the overall range of gearing that I had. Without getting too far down the bike nerd rabbit hole I’ll break it down like this.
Using a gear inch calculation chart I determined that the range on my double was 20.65” on the low end and 100.35” on the high end. That’s a big range. When you use the formula Sram uses to hype up the range of their “Eagle” 12-speed system it sounds even better. My old double gave me a range 719%! Sure that’s far better than the 500% that a Sram Eagle cassette paired with a single ring gives? Right?
"Well, not really. The numbers don’t always tell us how much of that range is actually being used."
I knew that If I went to a 1x and used the more common 11-42 cassette standard that was compatible with my old parts I would have to decide where I wanted to make sacrifices. The range of an 11-42 was only 381% after all. Barely more than half of what I had before. After doing the math I saw I would need a 30 tooth chainring to pair with that 42 tooth cassette cog to get the same low gear I had. While I did not use this lowest gear super frequently, I knew that I did, in fact, NEED it at times. This meant giving up quite a bit of top end gearing. In a nutshell, it meant my three hardest gears would simply vanish. Not a prospect I was excited about.
Sram all but eliminated this problem with their 12-speed system by creating a cassette with teeth ranging from 10 to 50 but it comes with some drawbacks. To go from an 11 to a 10 tooth cog for the hardest gear required a complete redesign of how the cassette attaches to the rear wheel. While it’s a clever design it is not a switch that can be made to every hub out there. While this additional upfront cost to convert a wheel to work with Sram’s XD cassette system is frustrating, it is the ongoing additional cost that really bugged me. Sram’s XD cassettes simply cost substantially more than an equivalent part that uses the classic “HG” wheel interface. Given that the cassette is a wear part the prospect of paying 2-3 times as much every time I wear one out was not appealing.
"All of this aside, it also meant going with Sram’s full 12 speed Eagle drivetrain system. Again, an additional cost that I was not all that excited about."
But then, out of the blue, my problem was solved. SunRace had been somewhat quietly making cassettes with expanded gear options for a couple of years. It started with bringing the 11-42 range to 10-speed drivetrains at an affordable price point. We had been using these for some time to keep the cost down for converting customer bikes to 1x10 with great success. Low and behold they released a new 11-50 cassette for 11-speed drivetrains.
After taking a few measurements I was pretty sure that this would work just fine with a Sram 11-speed derailleur despite the fact that Sram only rates their parts for use on a 42 tooth low gear. I ordered the parts I needed and waited.
"A few days later it was time to see if things would work."
A short time and a quick test ride later everything seemed to be good to go. Set up was easy and actually less fussy than the similar 12 speed Eagle system and all its proprietary parts. All that was left to do was hit the trail.
The next evening I met a few friends and did just that. I had done the math and the 11-50 mated to a 34 tooth chainring should give me everything I wanted in gearing. I would actually be getting a slightly lower gear than I had before and only give up what was essentially my hardest gear. Given that I almost never rode in the 11 tooth cog before, I was OK with that small sacrifice. We rolled out from the shop and dropped in at the top of Forest Hill Park. Immediately I noticed how crisp and precise the shifting was. I had installed Sram’s somewhat budget oriented GX series derailleur and shifter rather than throwing down the extra cash for the higher end parts. I was not let down. Things felt every bit as good as higher end 11 and 12-speed parts from Sram. Compared to the Shimano XT parts I had removed the shifting was actually better. The action on the thumb shifter for downshifts had a lighter action but still gave good feedback. While I did briefly miss the ability to upshift with my index finger that my previous Shimano parts allowed I quickly acclimated. By the time I exited Forest Hill to hit Buttermilk east I had forgotten about it.
The real icing on the cake was not having to even think about the shift to lower gears. No quick decision to shift chainrings or not. No miscalculations and hitting a steep pitch over-geared. I simply continued to downshift and easily found the gear I needed. By the time we finished up North Bank, I knew I had made the right choice.
While single ring setups may not be right for every type of bike, I can say with confidence that they are absolutely the right choice for mountain bikes and I will never go back to a two ring set up. Ever.