Bikes As Art, Building As An Artist

Making near sighted one-liner observations and more or less doing the blog equivalent of sitting on, is not what I like to do here. If you go back a couple weeks in this blog, you’ll notice a patch where the writing wasn’t really there. Like an attack that doesn’t go anywhere, all I could muster was a stab. It didn’t go unnoticed. One reader went so far as to post the comment “Ur blog is lame” after I poked fun at Bradley Wiggins repetitive tour interviews and compared Alberto Contador to Ryan from TV’s The Office. Touché!

I think there’s a finite amount of creative energy in my camelback. Some goes to my work. I make all the things that make you turn off corporate radio stations and listen to NPR: commercials, jingles and goofy things for commercial radio stations. It might be a step above greeting cards, maybe. What’s left over, I try to drizzle into this blog. Writing about cycling is way more fun than finding another way to convince you to trade in your clunker for a new Yaris. Unfortunately, it doesn’t pay as well. I also think it’s fair to say that creative thought gets spent on building a bike. In a way, it is an art. The process is very similar. Whether it’s audio, a rhyme, paint, clay or stuff from Easton and Sram, you’ve got a bunch of parts that need to get put together in a functional, yet emotional effective way. Between work and the bike, we certainly had a bout with blog lameness a few weeks ago.

Three weeks ago, amongst snippets of cables, ferrules and dead leaves, I sat on my workshop floor for a good twenty minutes stared at the pieces like a kid with a box of 64 Crayolas. Across the room leaned an IF Planet X and a Jamis Nova both with aging Ultegra 9sp, a Jamis Xenith road bike with Sram Red, and (I am so lucky) two sets of carbon wheels, one without tires. How do I get the Sram Red on the IF, CX tires on the 2^nd set of wheels, spend a minimal amount of money on cassettes and cables and brake pads while keeping the inevitable pain in the ass of having two different drive trains (Ultegra 9sp and Red 10sp) on my CX bikes to a minimum? With my hands on my chin, I stewed over needed parts and the costs, only later discovering I had smeared grease on my cheek.

Sell it. Sell the Nova. In less than a day, thanks to Facebook, I sold the Jamis Nova. Friggin’ genius. Sure it was my pit bike, but it was also aging and would be the crux of having two bikes with different drive trains. The fair deal produced enough lettuce to buy tires and a glue job for my 2^nd tubular wheelset as well as purchase new cables/housing, chain and cassette to put the road bike Sram Red on the IF. It also gave a friend an inexpensive way to get back into cyclocross. With the hundred or so I had budgeted earlier to buy tires with, there might be enough to afford a carbon fork and cover incidentals. Sure I wouldn’t have a pit bike. However, traditionally I’ve only used it on average about twice a season. My wife was elated that we actually reduced the steeds in the corral. I now had the makings of one sweet cyclocross bike and two sets of sweet wheels. The first splash of color hit the canvas, and then the 2^nd stewing began, along with a week and a half of non-functional bikes.

Which tires? Which fork? What gears on the cassette? With cables/housing, I should do new bar tape. What color? I sculpted. I arranged. I tried white & blue bar tape, threw it away and went with black. I went with the white saddle over blue. I tore through bins, boxes and file cabinets to find the IF sticker set that came with the bike so I could adorn the fork. I cleaned and lubed. The entire process from the first stew on the garage floor to the finished bike you see pictured took two weeks, help from a lot of friends and made at least one person post an anonymous poke.

Cyclocross Carbon Fork Brake Shudder: I’m No Engineer But I Think I Have This Figured Out

I inadvertently performed a bike experiment last night after work. I took my cyclocross bike, an Indy Fab Planet X with an Easton EC90x carbon fork for a spin at a nearby park. Since the glue job on the Zipp 404 CX tubulars was fairly new, over the past week I kept the air pressure high to make sure the glue cured and stuck to riding the roads and bike path while I dialed in the fit. Yesterday was my first cyclocross style ride with the tires at cross pressures. Instead of driving the mile to the park, I decided I’d just let some air out of the tires in the parking lot at work and ride over to the park. I guessed at it and let air out until I could squish the Vittoria file tread really good with my thumb. The ride in the park for the most part was fine, although the pressure was probably a tish too low on the hard ground. The bike felt like it was pushing to the outside in corners (as if the tire was sort of rolling under the rim.) Since my pump was a mile away, I just dialed back the cornering speed and went on with my ride. Coming down the steep road back to my car at work, I hit the brakes, and I felt the familiar tug-tug-tug of brake shudder. I could see the ends of the fork blade move. Son of a!

I had been riding this bike for at least a week and a half with the tires over 60 psi with no brake shudder. Now the tires were at the extreme opposite (guessing around 28-30-remember I let air out without a guage), probably a few PSI too low for hardpack causing a little shudder when slowing at the bottom of a paved hill. I knew about the possibility of brake shudder with carbon cyclocross forks and consequently hung on to my trusty steel fork in case this was to happen. However, I hardly think it’s time to ditch the carbon fork. You have to admit, it’s pretty rare to have a paved descent in a CX race. I didn't feel a single bit of shudder or snap while riding in the park and I even bombed a few grassy downhills where I had to brake into a corner.

It was a long hill; long enough to hit the brakes and watch what was happening. The brakes were slowing the wheel, but the tire was spinning just a bit faster. When I hit the brakes, the tires traveled a little further than the rim, causing the sidewall of the tire to give a bit and in reaction, causing the fork to flex under the bike with the grabby pressure. Ah ha!

Of course, putting the steel fork back on would reduce the shudder. But, I don’t think the problem is severe enough to add a pound back to the bike. I also think brake shudder isn’t the correct description. It’s more like fork snap. I think Carbon forks are stiffer and snappier. We all know steel has a very soft and easy flex to it. I think the steel fork flexed too, but it never snapped back to shape as quickly as the carbon. It’s like the difference between bamboo and pine. Both forks will flex under braking pressure. It’s just that the carbon fork will snap back into shape while the steel fork will flex, stay in the flexed position longer and go back to it’s original shape more slowly and less noticeably when the pressure if relieved. In addition the IF steel fork has a greater degree of rake, (48mm compared to the carbon’s 45mm). From the beginning the steel fork puts the contact area of the tire more forward than that of the Easton EC90x.

You can do a few things to minimize the “snap.” The usual fix is to try toeing in the brakes which will put less initial brake pad in contact with the rim surface, which I assume reduces initial braking power, makes braking more linear or gradual, and consequently reduce the fork flex at the other end. However, I think that’s only half, or more likely a quarter of the solution. I think tire construction, the grippiness of brake pads, tire pressure, fork rake and even the hardness of the ground play an equal role. I would go even as far to assume a tubular with a soft cotton sidewall and latex inner tube (like a Challenge or Dugast), would cause more carbon fork snap than say a Tufo or Vittoria with a thicker sidewall and standard rubber inner tube. The ground was hard yesterday, I really only needed to run low enough pressure for comfort and keep the tires from rolling in the corners. I think a few more PSI would’ve made all the difference. The other thing to note is that I didn’t feel any fork snap during the CX practice. It didn’t snap until bombing down a long paved hill.

I think the trick is to keep enough air in the tires so that they hold their shape in the given conditions. This optimal pressure will change with the course and conditions. If the tires hold their shape, that’ll give the contact patch of the tire less opportunity to get under the fork and pull it backwards. The fork snap should be reduced. Air is the least expensive of the possible combination of solutions.

Ahh. Fhew. Time to put on my smoking jacket and ease into my high-backed leather chair with a snifter of brandy.