Friday, May 29, 2009

New Wheels

Just got done building and installing some new wheels on my 1981 Fuji Gran Tourer SE, the bike that has been the serious object of my attention in recent months.

The hubs are a really nice set of 36 hole Campy Nuovo Tipo high flangers. Although they hardly needed it, for good measure I replaced the bearings (grade 25, natch, 1/4" in the rear, 3/16" in the front) and repacked. The rims are the ever classic 700c Sun CR-18's, spokes are DT 14/15 stainless.

Here are some closeups of the front hub. You can see the retro straight quick release levers.

You may have also noticed the slightly fatter tires. These are Specialized Armadillo Nimbus 700 x 35. One of my motivations for going with 700c rims rather than the original 27" was to be able to run something slightly larger than a 32. With 27" rims and fenders, this bike was running out of clearance, even were there much of a selection of tires larger than 32mm in 27" (there isn't...).

I don't build many wheels, since I only do it for myself. But I always enjoy it and always have gotten good results having faithfully internalized the Sheldon Brown instructions on the topic some years ago. I don't have a truing stand, just use a bike frame with brake calipers installed. If you are careful with this rudimentary approach, you can easily get results that are well within 1mm true on radial, lateral, and dish.

I also always use the Spocalc spreadsheet on the Harris Cyclery website, it has always given good results.

This is the last wheel I will build inserting the spokes through the hub one at a time as they are laced. I managed to scratch up the front a bit, plus it is a bit of struggle getting the leading spokes into position without bending them too much. I found this to be especially true with a high-flange hub, as the spokes and clearances end up a bit bit shorter.

The Specialized Armadillos have a fearsome reputation for difficult installation, their wire bead being very tight. This is my second set, and I was determined not to have the two pinch flats I suffered when installing my first set. But I didn't want to spend an hour wrestling the tire onto the rim.

Normally, when installing the tube, I'll get the valve in place and give the tube a bit of air to give it some shape. This makes it easy to fit into the tire, just pops right in, but does leave the tube rather close to the bead even if all the air is let out. With this set, I figured I would have to use tire irons to get the second bead into place, so I just put the tube in with no air whatsoever, being very careful about the orientation around the wheel. I then levered the bead on with tire irons, even using these required significant grunt - these are very stout tires, at least the bead tightness is.

Following this, I inspected the bead looking for pinches. I did find one potential one and rectified it, then partially inflated, deflated, broke the bead, looked for problems, then took up to full pressure.

Voila, no pinch flats, I'm quite proud of myself.

This morning, I took a spin on the bike. The wheels are holding true. The 35mm Armadillos are my compromise between cush and convenience. I loved not having flats on my previous set of 32mm, but this required keeping them pumped above 100 psi for full protection. That sort of pressure defeats the purpose of having thick tires and is bone jarring/teeth shaking on the gravel paths I frequent.

These tires have a minimum pressure of 75 psi, which, while still a bit high, definitely smooths things over a lot. I could probably cheat a little and run them down around 60 psi. The word on the street is that this reduces the flat protection, but I'm willing to gamble a little. My previous daily rider, my now-sold Trek 620, had sprung Brooks Conquest saddle, this one does not, so I need to compensate elsewhere for a little comfort.

The front brake threatened to be a big issue. A Dia Compe 610 centerpull, its pads were near the bottom of the slot with the 27" rim and really didn't have enough reach for 700c rims, with the pads ending up at the very tippy-top of the rims. Technically, this could have barely worked, but I'd have to be very vigilant about pad wear creating a situation where the tire sidewall could be rubbed. Plus, for almost any part on a daily rider bike, I avoid setups that require parts to be at the absolute limit of an adjustment for the bike to work - this limits options for field repairs, in general makes for a less reliable, serviceable machine.

I considered, then abandoned, the notion of filing some more clearance into the slots. Then, I started thinking about getting a Dia Compe 750 caliper for the front until I remembered that I had some tektro canti pads with threaded posts and elliptical spacers. This worked excellently, leaving much adjustment options.

Well, I'm delighted with the results and the slightly fatter tire look. I have a few fender line issues to address on the by and by, but these are now in service.

Given the high flange hubs, I suppose it is ok to violate the taboo against non-drive side pictures:

1 comment:

Matthew said...

That is just a great looking bike.