Wednesday, July 18, 2012

Old Man, New Tech, Part 2: Cranky Guy Tries Compact Cranks

As with the first part of this Old Man series, I know that the compact double road crank is nothing terribly new -- even your geezerly narrator has been bodging them together on old mountain bike cranks since the early oughts. But my current road steed is the first I've ridden with an actual off-the-shelf compact road double, so I figured it was worth a more lengthy mention than the toss-off it got in the review linked above.

First, I should provide the ever-present disclaimer that gearing is a personal (and for some, damn near religious) choice, and that what works for me is influenced by the board-flat terrain of Iowa, my own substantial girth, and a pair of knees that have aged like a fine bottle of Boone's Farm. If you're a 20-something whippet with nothing to do all day but train, or if your area of the country has real geography, your needs are going to be different.

That said, I'm getting rather attached to the 34/50 double (with an 11-26, correction, make that a 12-26 nine-speed cluster out back). Coming off a touring bike with a 42-tooth big ring, I initially feared the "big meat" of a 50, but it turns out that 50 teeth puts my cruising gears right in the sweet spot of the cassette on a lighter road bike. As weird and gappy as it looks on paper, it plays well for me in practice.

Lest this be a one-sided (and even more dull than usual) review, there are some things to watch with a big-range compact twofer. While you can pretty much cross over the cassette with impunity on the big ring (a nice feature when you just need to power over a little rise without a front shift), the small ring is limited to the inside of the cassette. About halfway across, the chain will start to foul the ramps on the big ring, and pretty soon you're looking at an accidental (and noisy) front shift. Not fun.

Also, the compact double is NOT the gearing for gearchart nerds (I say this with love, having been a gearchart nerd for many years). It doesn't really shift in a logical "next biggest gear is right here" progression. The 34 is a stump-puller/hill-climber/get-the-wide-load-moving-from-a-stop gear, and once things are in motion, it's 50 time. If you're the sort of rider who wants to be able to go from your 70" gear to your 71" with one artfully-executed double-shift of your half-step-plus-granny (kids, that's how touring bikes used to be geared -- I can't explain it, so you'll have to look it up, perhaps by asking your granny), look elsewhere.

One last quibble -- a 16-tooth jump between chainrings is HUGE. I don't mind it as a downshift, since when I'm reaching for that 34, I expect (and usually want in a bad way) a very small gear. The jump up from 34 to 50 can be a shock to the system, though. I have to force myself to really get a hamster-spin going before I reach for the big stuff, lest I find myself grinding knee cartilage in a way-too-tall gear after the shift.

I'd also like to amend my quibble from the first part of the Old Man series regarding front derailleur trim on this particular crank. For reasons I can't explain, I don't really need to do that "up then down" shift and trim sequence I described any more. My guess is that cable stretch has taken just a skidge of travel out of the initial shift, so it positions in a non-rubbing spot and doesn't need a trim. Regardless, it's working just fine, and forcing me to rethink some of my grouchy Luddite tendencies regarding indexed front shifting.


Anonymous said...

Congrats for dipping your toes into another exciting type of gearing! Always fun to play around with new stuff, eh?

I set up my Borthwick with a 50-34 on a Sugino AT, and 12-25 eight speed in back. As you mention, the shift between rings is huge, and I usually followed with a change of 2 or 3 cogs in back. My issue with it was that the chainring change occurred around 13 or 14 mph, which could be pretty often in the hilly terrain around the Illinois river or such. With your 11-26, I think you could reduce the frequency of that chainring shift.

Compact gearing definitely has its place! If you are worried about competing for the townline sprint, it's not the right tool. If you are no longer a kid grinding up the hills on a 12-23 cassette, and just out enjoying a nice ride, then it's definitely worth consideration!

I'll admit that what caught my eye was the mention of a 11-26 nine speed cassette. Is this a Shimano offering?? I'm running a 12-27 on my go-fast 650C 'bent, and the 11T cog would be handy for those townline sprints into Washington, IL on Saturday mornings! I'm spinning out the 52 x 12 on those little 650C's, and the young guys have figured out that they can manage to draft me for quite a while. :-P

Steve in Peoria

Scott Loveless said...

My rSogn has a 34/48 up front with an 11-34 9-speed out back. I really like it.

The old Nishiki has a 34/50 with a 13-28 7-speed and it's quite possibly the worst gearing combination ever. It seems I spend most the time with the chain crossed at a pretty steep angle.

I may trade the 50 for a 44 and pretend I have a cross bike.

Jason T. Nunemaker said...

Steve -- I misspoke, the spec sheet says its a 12-26 SRAM, and obviously I never counted teeth. I'll correct the post in a sec. That said, it looks like SRAM does (or did) offer an 11-26 niner.

Whatever that itty cog is, the only time it's seen a chain is during the initial limit screw check in the workstand... but I'm one to let the town line come to me rather than sprint to reach it. :-)