Silver Case

Luke, Ling, Woei, and I did a short bike run for breakfast today. I was riding my Favorit fixed-gear bicycle. On the way back heard a repeating noise. Unusual. Single-speed track-gears make almost no noise, because there are no freewheels or derailleurs. When I looked down I could see a wobble in the rear tire, so I figured a spoke broke.

When I inspected closer, I saw that the spoke was fine, that in fact the cheap aluminum spoke nipple had snapped its head off. At least that will be easier to fix, but no wonder quality wheelbuilders refuse to use aluminum nipples on wheels. That wheel has literally seen less (far?) than 100km on it.

The wheel issue reminded me that I needed to have a follow-up appointment with my road wheel I rebuilt back in January. It is running true but I was more interested in the spoke tensions and how they’ve held up since I first built the wheel.

Wheel

The results look pretty good. Not perfect, but liveable.

When I did the math

January Measurements:

Drive Side tension (mm of deflection) averaged 1.85 with a std dev of 0.08mm (or 4.17%)

Non-Drive Side tension averaged 1.22 with std dev of 0.08 (6.76%)

March 2010 Measurements

Drive Side: 1.82mm average with std dev 0.09 (4.80%)

Non-Drive 1.13mm average with std dev 0.10 (8.60%)

So the wheels loosened up a bit and slackened a bit, but still quite ok. The worst drive-side spoke deviated by 10%. On the non-drive side, I had three spoke unacceptable (-14%, -20%, +11%).

This should be quite fast and easy to tune up, and then I’ll check again in a couple months. I guess I’ve probably ridden a little over 700km on this wheel so far?

Interesting, I was talking to Brian Roddy, president of Rolf Wheels at the NAHBS. I told him that my friend had been using a Rolf wheel forever and claimed it was the strongest wheel he’d ever used. Brian told me that how they built the wheels is (1) build the wheel (2) press the rim from each side with 400lb force (3) re-tension (4) press again with 400lbs (5) do a final retensioning. That means the spokes are really well seated in. Pretty cool, and it makes results. I guess I make some sort of jig to press wheels like that myself — just need a big lever and a proper die to press against it.

Think it’s finished, after more than a few hours of tinkering. Lateral deflection is around 0.2mm. Axial deflection, 0.3-0.4mm. The dishing is correct to a mm or two. I got all the spokes tensioned to within +/-10% of the mean. At 107kgf, I’ve got the tension on the drive side rear wheel towards the high side of the Mavic specs (according the Barnett Bicycle Guide), but I think my first wheel failure was from under-tension, so I’d rather err on this side.

Now I have no excuse not to ride a lot this weekend.

Cornholio joined us in sending Mom and Dad to the airport at 4:30am

Well Mom and Dad are back in Pittsburgh. We certainly enjoyed their visit. I think they enjoyed it to (everything except mom’s late night curry-refund at Mt. Alvernia). Hopefully we can make a visit back to Pennsylvania during 2010 Summer. I was really dreading so many flights to the USA this year, but already my business trip scheduled for next year was cancelled today, so that’s one less punishment-journey I have to make.

I changed color schemes for Auntie Mary. Let’s see if that is any easier for her to read.

The indentation into the aluminum flange is normal. The broken spoke is not.

Spent the evening lacing and tensioning a new rear wheel for my bicycle. I think I did a poor job the first time I built it, then never checked the wheel. Subsequently it went slack, fatiguing the spokes. They started popping furiously on my last big ride. Somehow we (Michel) managed to true the wheel salvageably so I could finish.

When I got home, the spokes were clearly junked, so I threw them all out and am rebuilding the wheel again. I laced it in about 25 minutes tonight without too much drama.

Mistakes made? Looks like I must have twisted the hub in the wrong direction because my pulling spokes are inbound spokes instead of being outbound spokes. A small(ish) detail but it annoys me. I know Sulaiman will notice.

Other mistake? When I bought my spokes (288mm and 290mm) my brain wasn’t working and I ordered 32 of each, rather than 16 of each. So I have exactly twice the spokes I needed for this project. I guess if I break the wheel again(!), I’ll have a third set of spokes to build. Ugh. Hoping that doesn’t become necessary.

The wheel is reasonably ok already. I’ll finish it tomorrow when I’m fresher. I spent about two hours on it tonight which (I know, I know) is about double as long as it should take a skilled wheelbuilder. But I’m not skilled; I’m barely even a wheelbuilder at this point…It’s just me and my Jobst Brandt.