IS ONE SHIFTER, CHAINRING AND DERAILLEUR ENOUGH FOR ROAD BIKES?
As Monty Python’s Flying Circus, the 1970’s British comedy troupe famously said… “And now for something completely different.” Different, at least, for road cycling enthusiasts, the kind of cyclist I am and write for in these In The Know Cycling reviews.
The completely different things I’m writing about in this post is the SRAM Force 1 and Rival 1 groupsets for road bikes which both use only one shifter, one crankset ring and a single, rear derailleur. These 1X or “one by” sets had previously only been offered by SRAM for Cyclocross and MTB riders.
While SRAM states a lot of potential benefits for roadies of the 1X – eliminate shifts, no dropped chains, simpler to operate – these are not issues that most enthusiasts worry about that I’m aware of. Recreational riders, weekend warriors, commuters? Maybe. But roadies?
Since SRAM and their Zipp and Quarq divisions have been innovators and changed some of the conventional thinking in our admittedly conservative part of the cycling world over the years, I wanted to evaluate the 1X and see if there was something in it for my fellow road cycling enthusiasts.
By the way, this post is also completely different, at least for me and this site. I always review and compare products with similar design, performance and cost characteristics in the same post and have never reviewed just one product in its own post. I do it this way, even though most cycling gear reviews don’t, because this is the way I and most enthusiasts shop for gear. So maybe In The Know Cycling is also completely different. (My wife has certainly told me that I am.)
In a sense, however, this review will still be a comparison. An early mentor of mine used to tell me, life is all relative. Or, as he jokingly said to make his point, “When someone asks me how my wife is, I answer ‘Compared to whose?’” (RIP DD)
We all have experience with “2X” groupsets from SRAM, Shimano and Campagnolo that have two shifters, two chain rings and front and rear derailleurs. I wrote a post comparing those a while back (here) and will update it soon with some of the new models that have or are coming out from those three as well as new ones from Rotor and FSA.
So how well does the SRAM Force 1 (best prices, in stock at top rated stores Competitive Cyclist, Wiggle, Chain Reaction Cycles, JensonUSA, Merlin, Ribble) and Rival 1 (Competitive Cyclist, Wiggle, Chain Reaction Cycles, JensonUSA, Ribble) work for cycling enthusiasts?
Fortunately, I was able to ride the SRAM Rival 1 groupset with a Force 1 crankset over a two month period on my road disc bike. To immerse myself in the SRAM 1X, I rode this set-up 3-5 days a week during this time but also rode and tested out other gear on my rim brake bike equipped with a conventional 2X, in my case the Shimano Ultegra 6800, the other days I rode.
Initially I thought it was kind of cool only shifting with my right hand. It took me just a few rides to reestablish the feel and muscle memory of the SRAM Rival 1’s Double Tap shifting system. With the Double Tap, also used on SRAM’s other mechanical road groups, you tap or push in the shifter paddle with your finger a little to get the derailleur to move the chain down the cassette to a harder gear. This is the ‘single’ tap. When you push it in still further, during the same tap, the chain goes up the cassette to an easier gear. You don’t tap once or twice. Instead you essentially double the distance of the tap you would make if you wanted the harder gear to get to the derailleur to move the chain up the cassette for an easier one.
So yes, it seemed having one shifter that you only needed to tap a little or a little more to get all your shifting done across your entire range of gears indeed made the 1X simpler. But, because the amount of force you need to use to move the shifter paddle to get to a harder and easier gear varies depending on how much tension you have in the chain, it turns out the shifting wasn’t so simple after all. Actually, I found myself making mis-shifts at exactly the wrong times.
Here’s what I mean. Riding fast on the flats, say at 200 watts, required a certain amount of tap force to get the derailleur to shift down or up the cassette, to make the riding harder or easier respectively. But, riding uphill at a 300 watts tensioned the chain more than on the flats and required more force on the paddle to get the derailleur to shift both ways.
Going uphill, if I didn’t tap in the shifter paddle far enough to make up for the added tension in the chain, I would end up moving the chain to a smaller/harder cog exactly when I wanted a larger/easier one to keep my cadence up. On the flats however, if I tapped too hard or too far, I’d go to a bigger/easier cog when I wanted a smaller/harder one to go faster.
This is really about the Double Tap system more than the 1X but having only one shifter didn’t make shifting any simpler, a benefit I had read I’d get with a 1X. Because of the greater gaps between rear cogs in the cassette that I’ll detail below, getting the shift wrong because of the cassette you use uniquely with the 1X made these shifting mistakes worse than if I were make them on a Double Tap with a 2X Red, Force or Rival groupset.
Of course, there’s a similar kind of chain tension difference when I’m riding with a Shimano 2X groupset. However, I know that if I tap the right shifter paddle, I’m always going to get a harder gear at the cogs through the rear derailleur and if I push the right brake lever in, I’m going to get an easier one regardless of how much tension is in the chain. I still do have to push it more or less depending on the tension, but I push it until it clicks in and don’t have to worry about the chain going down the cassette when I want it to go up and vice versa.
And yes, I have to use the reverse logic to move the front derailleur on a Shimano 2X but I do that maybe 1 time for every 25 shifts I make with the rear. That’s less often that I have the chance of screwing up and I’ve got that reverse logic pretty well wired at this point.
After a few rides, I got the shifting pretty well sorted out and stopped making mis-shifts. While I still prefer Shimano’s separate paddle and brake lever actions for shifting for the reasons I’ve just mentioned, I imagine the learning curve for people moving from a SRAM Double Tap to a Shimano two lever system would be much greater than the other way around.
With the derailleur now moving the direction I wanted with the Rival 1, I often found that my cadence changed more dramatically, as much as 5-8 rpm more, after shifting in the 1X than with the 2X. In addition to messing with my rhythm, this affected my effort to keep my power output going up and down evenly and in a certain training range. It also caused me to want to shift less to avoid the big cadence and power changes when ideally I should be shifting more frequently to keep my cadence and power steady as the road turned up or down.
What was causing this? Was this due to having only one front ring? Why? How?
I selected a gear ratio on the 1X (44 tooth front ring and 11-36 rear cassette) that would give me essentially the same range and top and bottom end ratios of my 2X (50/34, 11-28). I knew there were different gaps as you stepped up and down the cogs in the two cassettes, but I tried not to think about that during the time I was riding the 1X. I didn’t actually detail them until I began to write this post. I wanted to feel the difference riding between the 1X and 2X rather than think about it and being biased by that knowledge. Certainly, I had a hunch about what was going on but tried to keep a potential explanation in the background so I could better describe what I was feeling in my legs and seeing on the bike computer.
I normally ride in my larger 50 tooth ring on my 2X unless I’m going up a steep or long climb. The 25 and 28 cogs in the back give me enough to get over most hills with a cadence still in the 70s. (I’m light, not strong). If the pitch is going to be steeper than 5% or a long climb near or just below that pitch, I’ll switch into my 34 ring to keep that cadence up and avoid tiring. On the steepest climbs with the 2X I’d be using a 34 tooth ring with a 28 tooth cog for a ratio of 1.21 and on the 1X, a 44 ring and 36 cog for a 1.22. No diff. I’d be working just as hard either way.
At the other end, if I was pedaling full-out going downhill or sprinting full-gas on the flats, I’ll be at 50-11 or a 4.54 on the 2X and at 44-11 or 4.0 on the 1X. Sadly, I don’t often find myself in those situations so this difference was something I never really noticed.
With the 1X you can get more range by using a different cassette and ring. If, for example, you are climbing really steep mountain pitches and want more range on that end, you can go with a 10-42 in the back. If you want to avoid spinning out going downhill, you can go with something like a 46 or 48 tooth ring in the front. Using a 46 and 10-42 will get you a 1.1 ratio going uphill and 4.6 on the downhill or flats, a wider range than the 11-28 2X set-up.
To match this with the 2X however, you can go with an 11-32 with the same compact 50-34 up front to get you 1.06 going up and the same 4.54 going down.
So the same range and top and low end ratios can be achieved with the 1X and 2X.
What is different, of course, are the steps you take between the cogs in each cassette across those similar ranges.
Let’s go back to the set-ups I rode in my comparisons, an 11-36 with the 1X and an 11-28 with the 2X. Of course, both have 11 cogs because they are 11-speed cassettes. While they both start with an 11-tooth cog at the small end, because you end up with cogs having different teeth at big end you have shifts where the number of teeth or “gaps” between adjoining cogs or gaps is different.
Here are the number of teeth in each cog of the cassette:
- 11-36: 11-12-13-15-17-19-22-25-28-32-36
- 11-28: 11-12-13-14-15-17-19-21-23-25-28
What you see here explains why my cadence and power was varying so much between shifts on the 1X vs. the 2X. With the 11-28 you get 1-tooth gaps for first four shifts, 2-tooth gaps for the next five and a 3-tooth gap only for the last shift between the 25 and 28 tooth cogs.
With the 11-36 however, you only get two 1-tooth gaps shifts and three 2-tooth gaps. When you get to the middle of the cassette, you start shifting through 3-tooth and 4-tooth gaps. As I ride most of the time in the middle and upper range of my cassette, the gaps between shifts with the 11-36 turned out to be 1.5 to 2X what I normally experienced with the 11-28.
As a roadie trying to ride a steady pace whether going on the flats or up and down the hills, I noticed these differences. You would think you shifted twice with the 1X when you hadn’t. Heck many roadies bemoan not having a “16” in the middle of the cassette and forego the safety of have a 28, preferring to ride an 11-25 just to pick up that 16.
I can imagine riding a CX or MTB course where the pitch and pace is constantly changing, often in greater amounts than what we roadies see on the pavement. As a CX or MTB rider, you’d probably welcome the 11-36’s or 10-42’s bigger gaps as it might take you two shifts on an 11-28 to get the new gear ratio you want and you can get there in one with an 11-36 or 10-42.
Shimano has introduced their own 1X groupset recently as part of a play for commuter bikes. While commuters ride the same road terrain that by many enthusiasts do, they may have more reason to shift up and down in big steps however, to match the traffic speed changes on the road. Having only one shifter, ring and derailleur is probably less maintenance, a bigger issue for commuters, CX and MTB riders.
In the end though, the 1X may be a bridge too far, or have gaps too big, for road cycling enthusiasts.
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