A Look At Gearing For Gravel – Part “2X” – by Grannygear
Note- The first article about gearing can be accessed by clicking HERE.
Grannygear’s 2x gearing thoughts, opinions, and wild assumptions.
So now that I had things shifting well at both ends, I needed to decide how to get lower gearing. First of all, how much lower is ‘lower’ going to be? I am not sure, but I expect that unless I get to a 4 tooth gain (basically like having a 12th cog added on to the 11-36 cassette) that I will not be getting enough to make it all worth while. However, I am going to try a half way approach first to see how that works out, but that will be more of an experiment than the final plan.
But before any tools get fit to the hand, let’s look at what my options would be if I stayed 2×11.
Getting Cranky: What about Sub-compact or ‘Adventure’ geared cranks?
I remember Suntour Micro Drive from back-in-the-days of early MTB. It gave us a reduced BCD crank with a 42/32/20 triple and allowed for some pretty low gearing. Maybe Guitar Ted has some insight as to why this did not catch on, but it made some sense. Perhaps SunTour was in the process of being steamrolled by Shimano’s indexed shifting and programmed cogs that made everything else off the back. (Editor’s Note: SunTour ballyhoo’ed the Micro Drive system as having the same wide ratio as 110/64 BCD cranks but with lighter weight. Typical MTB cranks before this were 46/36/26 or some variation thereof. Micro Drive reduced this to 42/32/22, more or less. Cassette ratios could be smaller with Micro Drive as well. In typical Shimano fashion, they took the idea of a “micro-drive” drive train, made it better, and the industry followed suit.)
Now we have that reduced chainring size happening again in the gravel world. FSA was at the forefront of this with cranks sporting 48/32 and 46/30 chainring sets. Praxis offers a 48/32 combo as well and Easton just jumped in with similar gearing to FSA. The bigger news however is Shimano’s new GRX line of gravel stuff. It was only a matter of time until the big “S” jumped into the fray and gave us options to the silly 50/34 set-ups we have been seeing. So let’s see what the Adventure gearing options are.
- FSA: 48/32, 46/30
- Easton: 47/32, 46/30
- Praxis: 48/32
- Shimano: 48/31 (FC-RX810), 46/30 (FC-RX600)
- SRAM: I am going to set aside SRAM AXS for now, but I will circle back around to it.
This approach has a lot of appeal as it offers lower overall gearing across any cassette yet retains the basic relationship between chainrings that you would have with a standard road compact double in a 50/34 (16T difference in a 46/30). Interesting that Shimano, a company that loves to have close ratio cassettes, etc, has the biggest ratio difference in the 48/31 crank. With these new tooth counts and ratios the capacity of the normal front derailleur is not too challenged although you need a frame and front derailleur mount that can go low enough to accommodate the 46/30 version.
If I went to a 48/32 instead of my 46/36 and kept the 11-36 cassette, I would gain that 4 tooth difference in my lowest gear. Nice. But, I would be increasing the big ring to the point where I doubt the standard WiFli Rival 22 rear mech could handle the 16T span and keep tension in the smaller cogs/small ring.
There is such a thing as ‘derailleur capacity’. Basically it specifies how much difference the rear mech can handle between all the gear sizes. For instance, consider this scenario: Say you add a bigger cassette over stock so now you need to add some chain length to accommodate that so when you select the big/big combo…big ring and top cog (and you know you will)…you don’t break things. Good to go, right? So now that you can survive that extreme gear combo, you shift into the small ring and begin working your way down the cassette. But now you find that the rear derailleur is beyond its ability to take up the chain slack and by the second to last cog it is out of range and the chain is a floppy mess. Granted, the extreme combos are not something we should do as a rule, but it happens. When I went to an 11-36 cassette, I also reduced my big chainring size, increased my small chainring size, and kept things more or less equal as far as the chain length was concerned and the rear derailleur was able to deal.
Besides the capacity issue, I do not want a taller gear range at all so the jump up to a 48T ring from my 46T is no bueno. And I really only want a single, ‘extra’, lower gear and not a 100% reduction in gear inches across the entire cassette although a 32T ring does get you to a 1:1 low with an 11-32 cassette.
Now consider that a 32T ring is getting pretty small for road work and would mean I would be shifting up into the 48T sooner. Now take that even further and go to a 46/30 combo in that adventure crank. Now that 46T is a sweet spot for me but a 30T small ring is teeny. Man, that would spin out really fast on the road, so the 46T would be used a lot of the time with a good bit of cross chaining I bet. It does allow the 11-32 cassette to give you lower than 1:1 and the 11-34 11spd cassette will get me that 4 tooth gain I am looking for.
Also, that 30T ring may not play well with your front derailleur adjustment. That is not what any road bike parts designer had in mind when they were drawing up a standard road 11spd front derailleur so the cage shape and derailleur swing path is likely less than optimal for a 30T ring. You may find that you do not have enough vertical adjustment in your system to get the derailleur right, even for a 46T, but I have a clamp on type so that is not an issue for me.
But frankly neither one are what I want. What would I want? How about a 46/36 or 46/34 with an 11-40 rear cassette? Not with the components I have though, unless I could make it work with something like Wolftooth’s Road Link, but with 2x, I still have to deal with the capacity of the rear derailleur to handle chain slack.
So that is where SRAM 2×11 leaves me wanting. There is not really a great solution to getting SRAM 2×11 to be wide enough in range. But, Shimano has been busy. The new, longer cage rear derailleurs in Ultegra and 105 that they now offer have much more capacity. I have been told that they will handle an 11-40T cassette with some massaging to the B Tension screw. It is very likely that I could run a 46/36 and an 11-40 combo as stock bikes are running 48/32 and 11-34 combos off the showroom floor with the new Ultegra clutched der (pre GRX). I have not tried this however, so you are on your own here.
If that works, it actually would be quite good I think, although of course the cassette does begin to get a bit gappy at 11-40.
I will not go quietly into that dark night…
So what if I wanted that crank combo, the one that does not exist, in what I consider to be a modern shifting system (I’m not that interested in some of the esoteric stuff with a square taper interface or the White Indutries crank)? What if I stepped outside the boundaries of programmed shifting and combined a 34T or 32T cog with a 46T big ring? Basically, the way no mainline manufacturer offers it. Well, if I understand this right, a 34T is the smallest ring you can mount to a typical Shimano road crank (110 BCD) so a 32T would be out. But the other day I was riding with a guy on a gravel bike that had an 11-36 rear with a standard Ultegra mid cage and a 46/34 chainring combo (all Shimano). He said he could barely tell the difference in the front shifting.
I mention this because in the world we live in, all the main players do not support chainring combinations that are not ‘factory’. So the 46/34 combo is coloring outside the lines. No one will say it will not work, but no one says it is just fine either.
So to play with this a bit, I asked Praxis to send me a 34T chainring as well as the standard ‘approved’ combo of the 46/36 that I had just installed and was a proven shifting system. We talked on the phone at length about this and they were fine with the experiment, but of course they do not promise that the results will be at the same level as what they sell as matched sets. If I was ready to accept that a 34T small ring and a 36T top cog was enough of a low gear, then this could be a way to go, although I will be pushing the capacity of the rear derailleur to handle chain slack.
Results? Shifts great. Can I tell a difference? Yes, but it is soooo slight that I would call it just fine. How has it been as far as getting a lower gear? Well we are only talking a 2 tooth difference here but yes, it is noticeable. It makes nose-of-the-saddle climbs more doable and yet the 34T ring is fine on the road, speed wise. For my area, and if I had a Shimano crank, it is what I would do if that was the limit of things. 46/34 and 11-36.
But here is the rub, for me at least. Praxis does not sell 2x chainrings separately, so you cannot buy a 46T and a 34T (or 32T, etc) as a set. You would have to buy both sets that had what you wanted in them and use only half each time. Hardly reasonable cost wise.
You can get Shimano rings separately for a Shimano crank, so there is that and frankly Shimano is what 95% of riders out there have anyway, right?
So in Praxis land (and others), really it makes more sense to go with the 48/32 crank and the 11-34 rear gears…easy to buy, you know it works. It’s just not to my wants.
So let us move to the other end of things. What can I do with cassettes?
I am already at the limit of that standard SRAM WiFli Rival 22 rear derailleur. An 11-36 is about it. Now I could run that Wolftooth Roadlink but here is the problem…that does not expand the derailleur capacity which, if you remember, is the ability of the derailleur to handle the chain slack when in the small ring and lesser cogs while still not tearing things off the bike when in the big/big combo (Roadlink was intended more for 1x). As well, I am not crazy about the idea of stacking bendable aluminum bits between my frame and my derailleur which is what is happening if you add a Roadlink to an existing replaceable hanger. It does work though and there are many happy riders on Roadlinks.
Well then, let us just swap to a rear derailleur with increased capacity, like a MTB one with longer cages and geometry that is happy with 40T cassettes. Not so fast. Almost none of this turn-y, gear-y, shifty-bits stuff plays well together. It’s like no one thought of this adventure/gravel bike stuff and never imagined that we would want this range of gearing on a road based system. You have to match the amount of cable pulled with each *click* of the shifter to the amount of travel each *click* moves the rear derailleur or it’s a catastrophe.
The amount of cable pulled by the SRAM 2×11 road shifters is the same as the older SRAM 10 speed MTB stuff, so you should be able to mix and match certain road and MTB rear derailleurs across SRAM groups (more on this later). Shimano does not allow for that. The Shimano 11 speed road shifters do not speak the same language as the Shimano MTB 11 speed rear derailleurs. Further, MTB and road SRAM 1×11 is not the same. And Campy is different. Really different. And…it’s like this dysfunctional family where everyone can only deal with their own stuff and cannot tolerate anyone else’s stuff. Talk to the hand! It makes it really hard to get wider range 2x gearing on a gravel bike by simply bolting on a longer cage rear MTB der. Now Di2 makes it easy. Road Di2 brifters will talk to an MTB Di2 mech. Kind of handy, that.
Getting back to SRAM, I had heard that you could run a SRAM 10 speed MTB rear derailleur with the Rival 22 road shifters, allowing for bigger cassettes due to the longer cages and bigger chain capacity of MTB stuff. So I grabbed an 11-40 Shimano cassette, put it on the Lynskey and unbolted the Rival 22 mech. Now one awkward thing in my quick experiment was that SRAM 10 spd MTB rear derailleurs have no cable tension adjustment barrel, or at least the ones I have do not. The cable tension adjustment is at the bar mounted MTB shifter. Road shifters do not have this. So for this experiment I would have had to cut my rear shifter line and splice in a barrel adjuster to make it right. For the time being I just went without and left the chain length as is. I grabbed an old XX SRAM rear derailleur from the 10 speed days and bolted it up. Was there ever a rear derailleur that had a more frustrating cable fastening screw position? (Editor’s Note: Maybe old SunTour Accushuft rear mechs, maybe…..)
Anyway, that done, I found it shifted the 11-40 pretty well even though the chain was a link too short for big big. I think this would have worked fine actually, but I got to thinking. When was the last time you saw a SRAM 10 speed rear derailleur for sale? In a bike shop? Bet it is dusty. So that did not seem like a way to go if I am thinking of the future. But it would have been interesting.
So there we are with 2x and SRAM. The only reasonable way I see to get the low end I want with my SRAM stuff would be with a crankset I am not all that jazzed about, that being the 46/30, or perhaps creating my own with a 46/32 combo and that is hard to do unless you can get the chainrings separately.
Where that leaves me with SRAM is on the doorstep of 1X’s house, ready to press the doorbell. ‘Ding Dong’…The secret password is “One”. And that is where we go next. But let’s look at Shimano based systems, which offers more flexibility in 2×11.
Stay tuned for Part 2X (part duex) coming soon.