Wednesday, June 13, 2018

Different Ways Of Crankin'

Is "Super Compact" the future for adventure/gravel bikes?
I am in the midst of considering parts for my build of the forthcoming Black Mountain Cycles MCD frame and fork. So far I have wheels lined up, through axles, a head set in mind, and now I am considering crank sets and bottom brackets.

That link above takes you to the frame tech page for the MCD and there will see that the maximum chain ring configuration is 46T/36T, or a standard CX crank set ring combination. This is what Ive used most often and what I will likely do again. However; if you haven't noticed, there is a move afoot to bring radically different gearing to gravel and adventure bikes, spearheaded by FSA, who provides a LOT of OEM parts to builders.

Their idea is called "Super Compact" and it is wide range double chain ring set up. I know a lot of you think 1X is the solution, but a LOT of riders don't like it. Too big a jump between gears, for one thing, but there is more to it than that. However; I am not delving into that subject just yet.......

Super Compact gearing is kind of like what the old randonneuring gearing was like. Basically you have a "drive" gear, (outer chain ring) which you use more often. The inner ring, the "bail out gear" or "grannygear", was used on steep climbs or when there was a tough headwind or like circumstances where a low gear was desirable. The modern form of this gearing utilizes wide range rear cassettes to keep jumps between gears closer and more efficient.

I tried such a set up on the old Gen I Fargo, using a 48T outer and a 28T granny, if memory serves. Modern Super Compacts wouldn't have that much disparity between chain rings, but it is close. FSA is pushing 48T/32T or 46T/30 as options I could use. My experiences with this sort of gearing wasn't positive. Oh, it's just fine when you are in the big ring, but when you dump out to that smaller inner ring your cadence goes haywire and I, at least, lost a ton of momentum when I switched gears. As a "native single speeder", I loathe losing momentum. So, that was a big reason I bailed on that experiment with that gearing.

New Ultegra CX crank set
This is why I am seriously leaning toward going to traditional cyclo cross gearing, which is 46T/36T. I like to use an 11T-36T cassette with that gearing, and I have a few reasons why I really have gravitated toward this gearing. Of course, the minimal jump between chain rings helps preserve momentum, which you probably already guessed.

The other reason that is important to me is probably pretty weird. I admit to a bit of a "Princess and the Pea" syndrome here, so bear with me on this one. See, I have very often been riding and thought, "Dang! This gear feels awesome today!" I can feel more power and just a more efficient pedal stroke many times in certain gear combinations, and probably 99.9% of the time when I bother to check, I have a dead straight chain line.

You may think, "So what?", and I get that, but a straight chain line is the most efficient one to pedal in. This is maybe something I tuned in to from my single speed days, but cross chaining makes me feel like I am working harder, many times. Not always. But every time I feel awesome about a gear, it is a straight chain line. So, I don't like the thought of running a "drive gear" and a "bail out gear". When the chain starts climbing the cassette, I like to switch to an inner chain ring and not jack my cadence up way over 100/minute when doing so. Obviously, I also can keep the chain straighter.

Now, some of you may be thinking, "Aha! We should still be riding triple chain ring cranks!" I would partially agree with that. In fact, I set my Badger custom bike up with a triple. That said, these newer gravel bikes, by their nature, are trying to also give us the shortest chain stays, (not really that necessary) with the widest tire clearances with an eye toward 650B mtb width tires. (Again- not all that necessary) So, triple cranks are a non-starter there.

I know that I could maintain a straighter chain line with a triple, but to some degree, the narrower chain rings and cogs we run now in combination with the best materials technology cyclists have ever enjoyed make a triple crank not quite the "no-brainer" that it used to be.

I haven't gotten back to that 1X commentary yet, but I'll save it for another day. Suffice it to say that since both SRAM and Shimano have filed patents and are working on chain sets that adjust for chain line misalignment inherent in 1X set ups, you can bet that your 1X system has too many inefficiencies. Otherwise, why would they bother? 

Stay tuned.........................


17 comments:

Iowagriz said...

I am similar gearing concerns and problems on my MTB that I use for gravel, singletrack and bikepacking. Ideally a 2x(11-36) with probably 30-38 up front (but that was 10speed).

I recently made the jump to 11, with hesitation on the big jumps of gear spacing on the back. I believe I now have 10-42. Again, if I could pair with a 30-38, that would give me the bailout gear and something high enough for tailwinds and downhills.

Ari said...

46x36x11x36 seems to me perfect. Are you going 11 speed?

Tyler Loewens said...

Really curious to see your final build here! Are you leaning more towards Shimano like your photo, or something else? Get spicy/weird and go full Rotor Hydraulic? :)

Guitar Ted said...

@Ari- Yes, this will be an 11 spd bike

@Tyler Loewens- I might go White Industries, since the shop is a dealer. Shimano is a workhorse choice that won't let me down mechanically but it is ugly! Shifting will likely be Gevenalle. I may use their hydraulic brakes, (rebranded TRP's), but I already have a set of Spyre brakes sitting here, so........

bostonbybike said...

I started with a cyclocross setup of 46/36T with 12-30T cassette but it wasn't working for me. Now I embrace Super Compact wholeheartedly, although my setup is even more "super". I run 42/26T crankset with 11-32T 11sp cassette and it gives me all the gears I need.

As of triple cranksets - I don't see much sense in going back to that. Yes, you can fine-tune your chainline better, but you end up with so many overlapping gears that it's just too complex and confusing. I think for most people a wider range 2x10 or 2x11 setup is pretty much optimal.

Guitar Ted said...

@bostonbybike- If "overlapping gears" is a reason folks don't use triple crank sets then, in my opinion, the most important purpose of a triple crank set is lost on them. The Keith Bontrager "Rules of Gearing" (I may have that title incorrect, but the intent is the same) would help in this instance.

I agree, many folks are confused by triple crankset use and purposes, and this is one of the reasons why 1X is very popular. It eliminates having to think more critically about your choices. You just pedal. In a way, 1X users are 3/4's of the way toward becoming single speeders. ;>) Nothing wrong with 1X if it works for you, but it isn't as efficient as a 2X or as a 3X system with the ability to use straighter chain lines and to have closer ratios on the cassette.

james said...

Hey GT,
really curious about your brake choice. Why not use full hydro from Shimano or Gevenalle (TRP)?

BluesDawg said...

I'm totally sold on super compact gearing, running 46/30 with 11-28 on my road bike and 46/30 with 11-36 on the gravel bike, both are 11 speed.

I did experience the problem of lost momentum when I first tried a similar approach back when I was running 2x7 with friction shifting, but it is so easy to quickly shift a few gears on the rear with modern shifters that I don't really notice that. It just took a short time to get it programmed in my head that I need to shift up a couple of gears when I move to the small ring or shift down a couple when I move to the big ring.

That won't solve the chainline problem, but while I do avoid cross-chaining, especially on the small ring, it hasn't been a bother for me.

BluesDawg said...

Overlapping gears is the best feature of a triple setup, not a drawback.

Guitar Ted said...

@james- In my opinion, disc brakes- ANY disc brake for drop bar- is total overkill for gravel. Especially where I live and ride. Modulation is king here. Since I am a mechanic, I can massage almost any mechanical brake to my tastes. Hydraulic brakes less so, and in some cases, not at all.

The TRP/Gevenalle "HYDRAULICS" system is awesome for sure. I have it on my Raleigh. However; it is not very easy to modulate and is WAY too powerful for riding on Iowa gravel.

Shimano/SRAM hydraulic brakes are okay, but again, since they require bleeding and are more technical to work on, and the need for them being slight here, I don't feel led to choose either system.

TRP Spyre brakes have been flawless for me. Easily set up for lots of modulation, pad wear is excellent, and they are not tied to a specific lever. They are quiet, reliable, and cheap, (relatively), so I see no down side to using them.

Ultimately I see no reason not to use rim brakes other than that all the latest, greatest materials tech and product is going to be disc brake going forward. So, I am moving on and converting everything over to through axles and disc brakes in my main fleet now. That's also going to keep what I do for RidingGravel.com relevant to the readers as well.

Skidmark said...

GT, maybe you can have a celebrity charity auction for all your now ancient obsolete out of date over the hill old school equipment!?
ps- I’m riding mine to the very end of the road.

DT said...

@GT - I have had a lot of luck mixing the Shimano chainrings. My favorite setup for gravel and road is the 46/34 combo. Run it on 3 or 4 bikes and haven't had any issues, let alone a decrease in performance.

@Boston - I love that combo. I have 36/24 (SRAM) on my Cutthroat with 11-32 in the back. Plan on upgrading to 40/28 (XT), but keeping the same spread on the cassette. I just don't find myself needing more than a 40T big ring with those big honking 700c/29er gravel tires.

grannygear said...

I agree. Cross crank and an 11-36 is pretty excellent. If I could I would make a 46/34 crank with timed rings as that would give me a bit lower gear without a bigger cassette or a tiny, circus clown, small ring. We have gotten too used to that big drop into the small ring from the typical compact crank. When I first tried a 50/34 road crank I was struck by that big change. Ugh. You get used to it but it is not great. Shifting a 36/46 crank is lovely.

I am a general fan of the Adventure crank approach, but the issue I see with something like a 30T small ring is you would spend a lot of time in the lower part of the cassette if you are in that ring and not climbing a steep grade. 30T is pretty small to live in, so then you would be in the 46T cross chained more IMO.

That 36T cross ring is pretty efficient feeling and paired with an 11-40 (if you need that), is pretty low and still high enough in the 46x11 to satisfy most gravel needs. Now if Shimano would only give me a 2x rated, long cage, road brifter compatible, rear der that hits a 40T, has a clutch, and keeps me from a Frankenstein approach...perfecto.

Derek Teed said...

Gearing has a lot to do with where you live and whether you're a spinner or grinder. Living in B.C. and having long steep gravel climbs around (often climbing for 1 1/2 to 2hrs) and subsequent fast descents 1x doesn't work for me. I went with a White Industries G30 crankset with 28/46 gearing. This allowed me to use a closer ratio 11-32 or 11-34 cassette and I couldn't be happier. The crankset with the stainless bearings also happens to be one of the smoothest spinning cranks I have ever felt and I also have the opportunity to easily change my gearing to what suits my current needs with their VBC.

Kenny Ness said...

In these Arkansas hills, 42/26 up front with 8 speed 12-30 works like a charm for me. 95% of my time is in the 42, but sure glad I have the 26 up front. ADDED BONUS—a new chain and cassette every 1000 miles is $30.

Andy Rae said...

I'm using the video FSA 46/30 and love it.
Combined with a 11-30 Ultegra cassette I get the low end 1:1 climbing gear and still have nice very close ratio gearing for flat and false flat cycling.
Just remember to simultaneously drop a couple of cassette gears when dumping from 46 to 30 on the chain ring so you don't start spinning.

RonDog said...

I am going with the Olive MCD frame. I will be running old Retroshift ( Gevenalle ) levers with 11 speed Shimano bar end shifters. White Industries crank with 44x30 chainrings and 40x11 or 42x11 cassette. Using the new Ultegra front and rear 11 speed derailleurs. Mechanical Spyers for brakes. I will have a 650b and 700c set of wheels. H-Bars will be Cowchippers. Really looking forward to this bike!!!