Friday, December 18, 2009

derailleurs and gearhubs

It has become fashionable for various internet gurus to decry the unreliability and/or onerous maintenance requirements of this gizmo:

What you see here is a Shimano LX rear derailleur, "Rapid-Rise" (i.e. low-normal or reverse-action) version, from about 3 years ago. It started as HC inventory way back when, but came to me this time in used-condition (from a coworker's bike?) and is now installed on the Pugstigator. At HC, we occasionally use road derailleurs (Tiagra, 105, Ultegra, Dura-Ace, Campagnolo, etc), but for the types of bikes we usually build and fix, mountain bike parts generally make more sense, and for various reasons, Shimano is the brand we use the most. From the economical Alivio/Acera all the way to bling-bling XTR, I have used them all on personal bikes and customer bikes, and I think it's safe to say that Shimano makes rear derailleurs that work well, are easy to adjust, and that take the use, abuse, and neglect that folks tend to heap on them. Anytime you read an opinion that derailleurs are inherently unreliable or require tons of maintenance, you should immediately question the credibility of the author of that opinion.

Of course, derailleurs get a bad rap from people who haven't used one made in the last 20 years, or from those who attribute minor mis-adjustments to an inherent design flaw. Of course, a legitimate case can be made that the derailleur, being exposed/dangling as it is, is subject to getting bent, say, if you back your car into it or slam it in the trunk (this happens A LOT). The case could also be made that derailleurs can't shift while coasting or while the bike is stopped, which is a real drawback in certain applications (especially cargo bikes). And, last but not least, it's a strange-looking mechanism, and not every cyclist understands how it works, how to adjust it, or how to keep it reasonably well-maintained. (if you are a local customer of ours, and don't know these things, we will be HAPPY to give a free hands-on lesson - just ask).

Regardless of whether the problem is with the equipment or with improper use/abuse, it seems clear that much of the trend of the past 10+ years toward single-speeds, fixed-gears, and more recently, internal gear hubs (IGH) is the result of folks being frustrated or intimidated by derailleurs. Personally, I think single-speeds make a lot of sense for a city bike in mostly-flat Minneapolis, and I really enjoy riding fixed-gear. I could also list a number of applications where the IGH has some real advantages over derailleurs, primarily: you can shift at a dead stop (imagine riding a loaded Big Dummy up to a stoplight only to realize you're in a too-high gear) and often there are benefits to having a chainline that doesn't change. If you come to HC looking for a bike for which an IGH is the best choice, I will certainly suggest that option, but I will also make sure you understand not only the advantages, but also the drawbacks (yes, there are drawbacks, and they are significant).

Yesterday I received a call that started with some words that are now familiar to me: "I really like the idea of an internal gear hub..." Of course, the "idea of an internal gear hub" that the caller was talking about is the mythical drivetrain that requires almost no maintenance, is guaranteed to be reliable under even the most extreme circumstances imaginable, and almost never needs to be repaired or even adjusted. This is simply not a realistic expectation of any IGH system, though the fantastic (and fantastically expensive) Rohloff comes close. Anyway, he went on to tell me about a lengthy bicycle tour he was planning, much of it through some pretty remote places. Would, he asked, the popular Shimano Alfine 8sp hub be an appropriate choice under those circumstances? My answer is no, probably not. He suggested to me that, while he planned to stay mostly on paved roads, there was the chance that he would go offroad, and that he didn't want to risk mud jamming up his derailleur. Well, I ride offroad quite a bit, and I have had problems with mud jamming up my wheels, but I never had mud jamming up my derailleur. In fact, if mud somehow gathered around the derailleur, it most likely would also jam up the tiny, somewhat delicate parts that comprise the Alfine cassette joint, which is the external moving part that shifts the Alfine hub. Even if this wasn't a wildly contrived scenario, unlikely to really happen, I'd much rather wipe mud off a derailleur than try to extract mud from the recesses of the Alfine cassette joint...

Of course, when I hear "long bike tour", I also hear (in my head) "50 flat tires in the dark or the rain". With derailleurs and quick-releases and a little practice, fixing a flat is EASY and FAST and generally requires NO TOOLS (aside from the pump and maybe a tire lever). With the Alfine, fixing a flat is relatively difficult, time-consuming, likely frustrating, and is best accomplished with a 15 mm wrench, a 2 mm allen wrench, and a small flat-bladed screwdriver (plus pump and maybe a tire lever, of course). If I thought it likely that I'd have to repair more than one flat on a tour, I would trade all the alleged advantages of an IGH for the ease of fixing a flat on a derailleur bike. But maybe that's just me.


dd said...

If any of your customers are looking for an 7sp internal shimano hub, I've got one that's just collecting dust. I can conceivably bring it with me to MN next week too :)

Paul said...

Agreed - after riding an IGH Dummy for the past year, my philosophy on flats is, "Don't get any". I've swapped out tires and have fixed serious flats, so I have some experience with the rear wheel, and can say with no reservations that it's a huge PITA. The Freeloaders don't help, obviously, but even when they're removed, replacing a tube is a huge chore.

On the other hand, you reference earlier my favorite thing about an IGH - arriving at that intersection distracted, realizing you're about six gears higher than you should be. Being able to gracefully get out of that situation has saved my ass a few times.

I doubt I'll ever get another IGH-equipped bike, at least until the pain of working around them is somehow dealt with. But on a heavy utility bike - not a 'convenient' bike by most standards, but tough and well equipped to handle most situations within a short range - I find that the hub fits the paradigm.

Champs said...

I came to a pretty similar conclusion commuting by bike last winter. I figured I could "trash" a cheap derailleur, but it was never a problem.

Keeping the chain in decent condition was a different story, and maybe that brings us full circle back to gearhubs, by way of belt drive. That's a whole new can of worms.

Bill said...

Changing a tire on an IGH wheel isn't that much of a PITA ... but enough so that I'd recommend running through the whole process at least once somewhere warm, dry and very well lit. Well, that and run something like Marathon Supremes in good weather. One tip: you don't actually need that 2mm wrench. I prefer the awl on a Swiss Army knife (I think the shape makes it easier to insert and the color makes it easier to see against a black hub/cassette).

Anonymous said...

I've been considering purchasing this interesting (and innovative) bike that I keep seeing on an infomercial. It has an automatic transmission that somehow senses your speed, measures the terrain and perceives your level of physical exertion before it automatically executes a shift into a lower/higher gear ratio. The people riding the bikes seem to have a happy, carefree ride. I seem to remember the bikes being very affordable, possibly due to the fact they don't use the complicated (and pricey) external derailleurs and shifters. Have you seen these bikes in your bicycle shop? Why aren't they sold in shops? Does this company have a monopoly on that technology?

Anonymous said...

to anonymous -

"affordable, possibly due to the fact they don't use the complicated (and pricey) external derailleurs and "

They aren't complicated, or pricey. That is still marketing BS.

You shift one direction to make it harder, another to make it easier.

And a decent rear derailleur is less than a hundred bucks.

Jim Thill said...

Jeff: I suspect "anonymous" is engaging in satire, but after some years in the bike business, I never know for sure.

"...a decent rear derailleur is less than a hundred bucks."

True. In fact you can get a decent one for under $30 (we use a lot of $25-35 Alivio/Acera derailleurs for repairs).

bloodline said...

bicycle technology is the only thing that keeps me intrigued lately, the derailleur in all it's forms from the 'coathangers' of the early years tohru the 70's to helical drive to 3 speed sturmy archer to schwinn approved two speed kick back,...BTW, what's a good day, i have a 3 speed hub that needs a little tlc

Boris said...

While not the best hub for touring due to relative unvailability of parts, for those considering an IGH for a utility bike and concerned with changing flats, the Sram i-Motion 9 speed coupled with disc brakes may well be your best option. You're looking at a quick release shift cable coupled with a 15mm spanner to remove the rear wheel. Pretty painless in all.

A close second is the Sram S7 (freewheel variant), with its quick release clickbox.

Sturmey and Shimano are more of a pain in the neck when it comes to removing the rear wheel (except for Nexus 3 speed).

rigtenzin said...

We have lots of choices when it comes to drive trains. You should own several of each kind.

jim_h said...

Great post. My observations after using a 3-speed hub for a couple of winters:

Carrying a hefty 15mm wrench is a drag, BUT... why bother? It's 20 degrees, I'm mushing around on the studded Nokians 5 miles from home and I get a flat - no way can I repair it in those circumstances - I'm going to pull out the phone, or maybe just build a fire and wait for rescue.

I actually only need 2 gears - seriously.

In the city, and especially in the winter, you get into situations where you really want to downshift immediately, without pedaling.

The 3-speed hub is great until something goes wrong inside, then it's a PITA and I don't want to take it apart.

Conclusions: after 100 years we still don't have the ideal bicycle drive train. When belt drives become inexpensive and easy to install, things will really change.

Jim Thill said...

It really depends on the definition of "ideal". To many, "ideal" means 100% reliable with little to no maintenance required. I think modern cars have really set the benchmark pretty high for this ideal. Maybe if folks brought their bikes into a decent shop every 2-3 months (like a car) to be cleaned, lubed, tuned up, and have worn parts replaced, reliability of ANY type of drivetrain would be less of a question-mark.

KM said...

IGH's really fall into two categories -- the 3 speed hub that has an easily disconnected indicator chain and needs a 15mm wrench -- and everything else. Having commuted a number of winters with the 3 speed and having more than one flat, the 3 speed wheel is relatively easy to change a flat on.

I have never had to change a flat on other IGH's on the road but having seen Mark do it many times in a stand at the shop and hearing him swear in French, I'm sticking with single speeds or derraileurs.