Tuesday, April 28, 2009

Alan Gets Double Chainguards

After the experience of the "Hell of the North" (documented below), during which my poor front derailleur became so completely clogged with mud as to become unusable, it began—another project.

First I considered getting a set of TA cyclocross cranks. Since Alans of my kind were produced for almost 30 years unchanged, I thought the TA cranks (which have been made unchanged for longer) would be a good fit. But that would require buying a new set of arms, a new bottom bracket, and tracking down some rings. More importantly, TA only ever made them down to 43 teeth—a bit bigger than ideal. And nearly impossible to find in that size.

So I decided to use my Ritchey cranks, which are very nice looking, have world champion strips, and which set up the chainline such that the small ring more or less centres on my freewheel (my wheel is set up as a 130mm 6/7 spd.) Next I needed chainguards. The TAs are too expensive, as are the Salas. BBG guards, however, are beautiful and extremely cheap. For $28 including shipping, I had two black 110/42 rings in the mail.

Clearance was my main concern. With essentially a triple setup on a 109.5mm BB, one would expect the inner guard and bolts to rub on the chainstay. Luckily the Alan has seriously indented chainstays, likely to deal with this exact problem.

As it turned out, these took an incredible amount of work to install. Mostly because the old Stronglight triple chainring bolts needed lots of modification to work with the spacers I got, and because the Ritchey cranks use a system where the fifth bolt screws directly into the arm. I've documented some of this fun below, followed by photos of the actual guards.

I got all this set up yesterday, and immediately took Alan on a ride in High Park. (Not a ride I'll repeat: as I was repeatedly told by angry park-goers, bikes aren't allowed off-road there!) The guards worked perefectly: no rubbing, no hopping chain, and no front shifting to think about. Right now I have a 6-speed 14-24 freewheel installed, and that probably doesn't give me an ideal small gear. I have a 13-26 7-speed I may swap in. Indexed shifting might be nice if I actually ever race. For now, though, this is good! Alan is quickly achieving the status of the Platonic form of the cross bike...

The joys of bicycle projects. Lately I have spent a lot of time shortening bolts! This is all done in my bedroom, among my books, using a very cheap hacksaw and a vise I don't have anywhere to mount...

Filing spacers: tricky and tedious! I had to shave 1.5mm off of this one, and then increase the ID so that the bolts would pass through... I could have saved myself time by visiting a well-stocked bike store, but I prefer doing things myself if I can.

Attaching three rings and spacers directly to the crankarm required a very long bolt, which I didn't have. But the threading matched that on my old Stronglight triple bolts (they came on the Raleigh I converted for my sister below; I turned the Stronglight 93 into a single-ring, and it now lives on my city bike). But just the one bolt wasn't long enough. So I cut the head off of the inner bolt (it still can be tightened via a 5mm allen bolt inserted inside) and made a two-part mega-bolt. This works well: I tightened the inner bolt all the way in by sticking a 5mm allen key through the outer bolt. Then I tightened the outer bolt with a chainring screwdriver. It's nice and tight!

Through the outer to the inner.

On to the fun stuff! Alan looking very nice all set up.

Losing a left shifter gave me a chance to use this lone World Championship-strip bar-end plug I've had laying around. The stripes match those on the frame, the cranks, and the Mavic VTT logo on the hubs and headset. The chances of my actually winning a World Championship on this bike, I fear, are somewhat low.

From the front. I may shorten the chain, but I'll wait until I settle on my gearing.

The Ritchey cranks with BBG guards. I used an old SR 42-tooth 110bcd chainring from Marta's Bridgestone 500 (I traded for a Sugino 36!).

I used two tricks to get perfect chainline and clearance. First, I used a BBG "superlight" inner guard, not for weight but because they're 1/16" thinner. Then I used a 1.5mm BB spacer to pull everything toward the drive side. Getting the BB out of the Alan to install said spacer was a bit of an adventure, however. Fearing loosening, I had very stupidly installed his Italian BB using blue loctite rather than grease. It required literally all my force to get the BB out. Here's a trick to those who find themselves in a similar situation: use a QR skewer inserted through the axle to hold the BB remover tool in place. Then stand on the longest wrench you can find! It took me about an hour to unthread the BB, and there was a strange pile of sandy-looking dried thread locker on the ground when I was done. I used LOTS of grease when I re-installed it, and lots of torque.

Anyway: my reward: excellent chainline!

BBG guards: very highly recommended! They shipped very quickly, and for very little money (even internationally!) They have lots of colours, and almost every imaginable size. $12/ea!


OAP said...

You mentioned my blog! Fame at last! The Alan looks really sharp. And good luck finding those 821 shifters :)

AH said...

Some fame!

For the record, Olivier offered me his 44-tooth TA cyclocross rings. He's a good fellow!