Thursday, January 8, 2009

A wheel or two

A few more parts showed up at my door in the last week or so. All my drivetrain parts arrived, including my long-awaited spokes. So this last weekend, I had a wheelbuilding day. And let me tell you, it was the WHOLE day. But not a bad way to spend some time!

I've gone into some great detail on my Ramby wheel build...but here, not so much. It's sufficient to say the build was pretty much the same, except for the spoke quantity. Only 32 for these wheels, but they are still cross-3 lacings so the same rules apply.
It didn't take me quite as long to get these wheels laced up this time. I still referred to Sheldon Brown's wheelbuilding web page (I'm not building bike wheels every day), but my memory served me well. I can definitely say wheel building is a science, a skill, and an art and by no means am I an expert. Hence the reason why it took me an entire day (and then some) to get these wheels built. It was more important for me to take my time and ensure I did the best job possible within my limited skill set :>).

Building wheels, to me, is a delicate balancing act. There are three basic parameters, lateral trueness, vertical trueness, dish, and tensioning. The first parameter I'd naturally focus on would be lateral trueness. However, you have to balance that with all the other parameters as well. This time, my method would be to tighten all my spokes to an even tension. I purchased a Park Tool spoke tensioning gauge for this purpose, and it works very well. I tensioned all my spokes to an even 20 on the gauge, then checked lateral trueness. Of course, it was off but at least I had a good starting point. I alternately tightened an loosened spokes appropriate to bring the wheel into lateral true, or a least a good approximation. Then I checked my vertical true (roundness). I tightened and loosed adjacent alternating spokes appropriately to make my wheel 'less lumpy'. After all this was done, I checked my dish using my dishing tool. At this point, it was probably about 1/4" or so out of dish.

So loosening spokes on one side of the hub, and tightening on the opposite brings the hub closer to center. And after getting the dish close to where it's needed, guess what? Lateral and vertical true needs to be readjusted. After alternately loosening and tightening spokes for hours, I finally got my wheels to a state of decent trueness. The front wheel trued up very nice. The rear took a bit more effort. I rounded off several nipples and had to cut those spokes out and start again, but that's why you always order a few extra, right? :>)

Like I said, it's a science, a skill, and an art. Throw in a bit of luck as well. I'm sure professional wheelbuilders do wheels in just an hour or two and do several sets in a day. I'm definitely not a professional, and I am definitely slow, but I try to be thorough! Picture time!
72 291mm DT Swiss Competition spokes, in black, ready for lacing

Starting the lace-up

Truing up

On the bike


Travel Gravel said...

Looking good so far. Is this a shifting bike or a single speed? Keep at it! said...

It's a shifter bike, 3x9. I have everything on the bike now except for the drive train. Shouldn't be much longer!