i have a thing about chainline Sunday, 30 May 2010 link

And now, another digression into bike geekery.

Like most wheeled transport, bikes have gears. Gears control how much the rear wheel moves when you push the pedals around. Some bikes have a single, unchanging gear ratio; the BMX you had as a kid, or the fixie your overly trendy mates keep falling off, for example. So, for example, imagine a bike with a single chainring at the front with 42 teeth, and a single sprocket on the rear wheel with 21 teeth. For each turn of the pedals, the rear wheel goes around twice.

But most bikes you see these days have multiple gears. A typical set-up would be for three chainrings at the front, and nine or ten sprockets at the rear. Two derailleurs work to move the chain from ring to ring, or from sprocket to sprocket. So if you're riding on the flat, you can use the big ring at the front to give you high gears for speed. When you come to a hill, you can shift down to the middle or small rings to get a lower gear to help you climb.

Derailleurs aren't perfect, though. For one thing, you don't actually get as many gear ratios as you'd think. In the set of possible front ring/rear sprocket combinations, you get a fair bit of duplication. 32x16 is the same as 44x22, and 22x12, 32x17, and 44x22 are either identical or near as damnit. Plus, you want to avoid extreme chainlines - having the chain on your outermost ring but your innermost sprocket means that it's at an extreme angle, which wears the chain faster, is less mechanically efficient, and is pointless anyway (as you get basically the same gear by going for a more middle/middle effect). The result of all this is that on a nominally 27-speed gear system (3 chainrings, 9 sprockets) you end up with around fourteen or fifteen usable gears.

Plus, derailleur systems are a pain to keep maintained. The mechanism is hanging there, out in the open, so gets a lot of problems from dust, grit, water, and road muck. Offroad, derailleurs are pretty vulnerable to sudden impacts (cough cough). It's quite easy for the settings to get slightly off, so that the gear runs noisily in some gears or jumps between sprockets. And the need for chains to be able to flex laterally to move to different sprockets means that the chains are weaker than chains designed not to flex.

So why are derailleurs used on the overwhelming majority of production bicycles? Well, they're (relatively) cheap, they're maintainable when they go wrong, the gear change is extremely fast, when maintained in mint condition they're more mechanically efficient, and - crucially - they're reasonably light. They're perfect for racing bikes, which get a lot of mechanical attention anyway. They're also very customisable - you can change the gear ratios easily by changing the set of sprockets on the rear wheel. It's straightforward to set up derailleur gears so you get a gear pattern you like. The main problems with derailleurs show up if you use them day in, day out. Derailleurs make a hell of a lot of sense if you're racing, but less so if you're thrashing a bike day in, day out.

The main alternative to derailleurs if you want to actually be able to shift gears (which not everyone does) is a hub gear. This holds the gear mechanism inside the hub of the rear wheel, and changes how fast the rear wheel rotates relative to the pull of the chain. Hub gears were very popular in the 50s through 70s; the name Sturmey-Archer may stir memories of old 3-speed Raleigh Choppers. 3-speed is how most people experienced hub gears; in the 70s, one of the reasons that 10-speed derailleur bikes were so popular was that the alternative hub gear available was the 3-speed. There, it made sense to prefer the derailleur - a 10-speed system usually gave you around 7 usable gears, and a greater range of gears (that is, higher top gear, lower bottom gear).

But times have moved on.

And hub gears are slowly making a bit of a comeback, particularly for the kind of bikes you just want to ride without having to worry too much about maintenance. Somewhere in their lineup, most manufacturers will have one or two hub geared bikes - usually around the "city/comfort" end of things.

Whereas in the 70s, you were looking at a 3-speed hub gear - maybe a 5-speed if you pushed the boat out and bought top of the line - these days a 7 or 8-speed is relatively affordable. The current standard Shimano Alfine has eight gears, over a 300% gear range (that is, the top gear is three times the size of the bottom one). That's better than the old models, but it's still not quite up to derailleur standard. A standard 9-speed mountain bike gear has about a 400% range, for contrast.

But that's not impossible. The gold standard of hub gears has, for the last decade or so, been the Rohloff speedhub. 14 (unique) gears, 500% gear ratio, incredible precision German engineering. That's up there with top end derailleur gears, though it's slightly heavier. What's the catch? The price. An aftermarket Rohloff will set you back around UKP1,000 (NZ$2000) just for the hub. That's considerably more than most whole bicycles.

So for the last five years I've been slowly getting more and more fed up with mechanical shortcomings and fussiness of derailleurs. And I've been looking wistfully at a Rohloff-equipped bike (I once saw one parked on Lambton Quay; I nearly licked it). But I've been sensible. And I've been slowly thinking, maybe I should get a bike with an 8-speed hub gear as a day-to-day commuter - something I can ride through shite winter weather without having to worry about what it's doing to my gears.

And then I found out that Shimano is releasing an 11-speed version of their Alfine hub gear, with a gear ratio of 409%. It's relatively light, and seems to be up to pretty high performance. It looks pointlessly crisp, and hits the market in September. I think you'll definitely be seeing quite a few of these starting to creep into the more performance-orientated ends of manufacturers lineups.

So it would seem that a high-performance hub gear was becoming achievable without breaking the bank. I started mentally specc'ing my "realistic ultimate commuter" - road or cyclocross bike frame, running disk brakes for decent stopping power in the wet, with an 11-speed Alfine hub gear on the back. I even started checking out frames, in a daydreamy kind of way. And then I got an email from On One, informing me that they were about to start producing a disk-compatible version of their legendary "Il Pompino" road frame, and shipping it with disk brakes and the current 8-speed Alfine hub gear - specifically as an "ultimate commuter" build. And from asking them, they're going to offer an 11-speed version when the upgraded one becomes available.

So now I know what I want for Christmas.

  yes, i know these are getting repetitive Wednesday, 5 May 2010 link

Your first tattoo is a huge deal. You are going to be maimed, and bleed, and marked for life. You will never look the same again. It will hurt. It's gigantic.

I remember my first tattoo. It was back in 1994, from memory; my flatmate at the time (Maire) and I went into the small storefront on upper Cuba St (it's an antique shop now) that Shane Gallagher had set up as a studio. We'd made the mistake of telling a couple of friends that we were going to get inked, and they'd turned up to support us. For the values of "support" that include making jokes about needles. Maire very firmly went first, while I made small talk and tried to stop people making the aforementioned jokes, getting more and more nervous as time went on. Then it was my turn. The design I chose was a freehand (that is, custom drawn on and then inked in) anklet on my right leg, influenced by some of the spikier flash on offer on the walls. Though to be honest, like most people getting their first tattoo it wasn't so much that I wanted that particular pattern, it was that I wanted to be the kind of person who had a tattoo. I left the outside of my ankle unfinished (it still is) because I ran out of ideas. Afterwards, we all went off to a cafe, bleeding slightly and swearing we had the most awesome endorphin highs. For the next few weeks, I kept rolling my trouser legs up so as to show off the new tattoo. It was, as first tattoos should be, a great big occasion and a tremendous deal for me.

After a while, though, it becomes familiarised by repetition. It still hurts. You're still going to be marked for life. But after a while, the days all start to blur together a bit. It's just another day at the office. It's another day where you have to break off at 5 o'clock to go get the kids.

So I had another session on my leg yesterday. And since I'm sure that these posts are blurring together a bit for everyone, I'll just say that we spent 4 1/2 hours designing the tentacles for the octopus that's now taking up most of my left leg, then another 2 1/2 hours actually inking the outlining on. I can confirm that having the back of your knee tattooed is extremely painful, but that it's nothing as compared to having your inner thighs tattooed. Absolute agony. Now we've got all the outlining done; next session is filling in the linework areas in the design, then shading. A fair bit to go yet. But now that the tentacles are on in outline, it's very unmistakeably an octopus, rather than a lozenge-shaped abstract design - the concept of "it's an octopus, but we haven't got around to putting legs on it yet" is not one that leaps immediately to the average observer's mind. Next session in four weeks.

One fun thing about the design is that I need to have my trousers more or less off for you to see the whole thing, as the head comes up right onto my hip and one of the tentacles is quite high up my inner thigh. In shorts, you should be able to see some of the body and about four or five tentacles. I'm quite happy with having a design that's mostly concealed most of the time. Adds a touch of mystery, innit.

Actually, I went into mild shock yesterday evening after getting home. Interesting, but not much fun. Next time I'll need to be a bit more careful about keeping my blood sugar up after the session; severe nausea two hours later was not something I want to repeat.

Times have definitely changed. Not only do my tattooists text to confirm appointments, they've got a page on Facebook. Pacific Tattoo's page is here; they also advised me to check out the page for Monk3ys up in Auckland. Monk3ys is run by Cory Weir, who spent over a decade working in Japan (working with the Life Under Zen crew). Looking at his work, it's definitely the sort of Pacifica that I really like; might be worth popping in next time we're up with the in-laws in Auckland.