Carbon Toe-in

If I'm going to Hell, my punishment will be listening to improperly maintained, noisy bikes for eternity. Breaking in this carbon wheelset was a scared-straight visit to Hell: no matter what I did, I couldn't silence the squealing brakes. I sanded the brake pads (they build up a glaze), I meticulously cleaned the brake track with alcohol and acetone, and I even tried riding the brakes thinking it was only a matter of breaking-in the new rim's brake track. Nothing. The brakes were screeching loud enough to make neighborhood dogs howl. I concluded: this is the difference between a $200 Chinese carbon rim and a $800 Enve or Zipp rim.

As I was about to throw down some mad cash on different brake pads--a last attempt before writing off the wheelset--I researched the squealing carbon rim problem. There are three prevailing opinions: 1) it's a problem with cheaper rims; 2) it's  problem with certain rim/pad combinations; and 3) it's a problem related to improper pad toe-in. I had assumed #1 and #2, but hadn't considered #3.

So I toed in my yellow Swiss Stop pads on my road bike. Now my braking is quiet.

Who knew? From cross racing I was familiar with the cursed cantilever tendencies to howl unless toed-in. I never thought the same technique would work for a road bike with carbon rims. Lesson learned.

Only the finest brake pads that 60 bucks can buy.

That's some aggressive toe-in, son.

Carbon rims!

Question: Why does it cost 90 bucks to ship these things from China?
Answer: Because Vivian puts them on an airplane so they get here in 8 days.

My order of carbon rims has arrived:

• 1 set of 20/24 hole 50mm carbon tubulars
• 1 set of 20/24 hole 50mm carbon clinchers

I measured the ERD of the clinchers last night and they were within 1mm of factory claims. I've seen more variation on aluminum rims, FYI.

This batch of rims looks a little higher quality than the ones I ordered a year ago. Those were a unidirectional finish, and had the unlikely claim of being able to tolerate 250 Kgf spoke tension. Something may have been lost in translation.

This new batch is matte finish 3k carbon weave and carries a more realistic claim of 180 Kgf spoke tension before failure. This set is also lighter than the originals. The claim of 400 grams seems conservative.

I have ordered the spokes for the carbon clinchers/Chris King setup. That'll get laced and built this weekend. I hope.

Something to look at until those are together....

A harder, higher friction treatment for the brake track. Braking during cross season was sufficient. Not sure I'd bomb an Alpine descent on them.

The rentless pursuit of even spoke tension

Last night I finished off the dynamo wheel I have been building for my dad since his last birthday in August 2012. This wheel, like most I build, has a unique story. The rims (Velocity A23, 36 hole) were originally procured for a friend who was attempting her own build. Once she realized 26 inchers were needed, the 700c Velocity rims reverted to me. Building a super sweet dynamo wheel for my dad seemed like a great birthday present.

Several month, and several other wheel builds later, I am in the home stretch for this project. As I was in no particular hurry to finish this one, I decided to get it as technically perfect as I could. So I:

• Constructed my own spoke tension map. The Park Tool one doesn't work with my new tensiometer.
• Soaked the brass nipples overnight in Triflow. The point of doing this is to minimize the potential for spoke wind-up due to friction on the spoke threads, and friction between the nipple's shoulder and the rim.
• Used my new Wheel Fanatyk tensiometer. It was much easier to use than my old Park Tool tensiometer and much more accurate.

The result.

Red graph line indicates the right side spokes; blue is left; and gray is the average of both sides. This wheel is straight and true.

No too shabby. The average spoke tension varies +/- 1.5%. This 36 spoke wheel should last a lifetime even under my 200+ lb dad.

Now I can move onto other more exotic, low spoke count projects!