First impressions: wide carbon clinchers

Just short of 100 miles on the new wheelset. Impressions so far using the wheels on the cross rig, with 700 x 25 clinchers, 80 psi & 90 psi (front/rear), 11-28 cassette.

Stiffness: carbon rims have no issues here. These are very stiff, especially with CX-Ray spokes.

Ride: not bad considering the stiffness.

Braking: good! This was a surprise. I won't be riding these in the rain, or bombing sustained descents. Using DT Swiss yellow fronts and Gigantex cork rear.

Aerodynamics: they don't feel fast, but they're also not susceptible to crosswinds.

Looks: head turners thanks to the 12k cosmetic weave.

The test rig.

It's hard to capture the luster of the 12k weave. It does look sweet--take my word for it.

The brake track uses the 3k weave.

38 mm, U-shaped profile, Sapim spokes, DT Swiss brass nipples. Black everywhere.

Carbon everywhere!

And yet more carbon...

Head tube badge. Carl Strong is the man.

The relentless pursuit of insanity

If you happen to be a perfectionist, wheel building is not for you. You'll never get perfectly uniform spoke tension and perfect roundness, so the best you can hope for is close enough on both measures. Adding quantitative measurements can either improve your wheel building by providing additional feedback, or drive you to madness with the pursuit of perfect numbers. I use a tensiometer and that's been 90 percent positive. Today I build my first wheel with the aid of lateral and radial truing gauges from Morningstar tools. We'll see if this is a good thing.

I will say that the experience thus far has been good. The tools shipped quickly from California, and they included a handwritten note from the owner, Paul. That's awesome, right? Gauges now mounted to my TS-2, I'm diving in...

Update: first build--Powertap G3, 38 mm wide carbon clincher, Sapim CX-Ray spokes--is done. These gauges are very useful and well worth the $120. The accompanying instructions could be clearer, but soon enough you'll figure out the logic of the setup.

One trip around the dial equals 0.1" and each unit is 0.001".  The wheel I just completed indicates a tolerance of +/- 0.005". This thing is fucking brilliant. (I can't say the same about building with CX-Ray spokes. More about spokes in the subsequent posting.)

Update two: this setup may be too accurate. I can now detect flat spots on the rim that are due to manufacturing defects. The current rim has 3 and they're about 0.002". Doesn't sound like much, and it's probably not, but it's annoying knowing they are there.

Nerd alert: Rim measurements

I'm cleaning my room today. It's where I sleep; it's where I build wheels; and it's where I store wheels, rims, hubs, and spokes. I've got other work to do, but it's not as much fun as wheel building. So to procrastinate, I decided to measure the internal/external dimensions of the rims on hand.

Yoeleo U shaped 25 mm carbon clincher
25 mm external/18 mm internal

Yishun 23 mm carbon tubular
23 mm external

Gigantex/Equinox carbon tubular
20.5 mm external

Velocity A23 clincher
22.8 mm external/17.5 mm internal
(This is equivalent to the HED Belgian and H Plus Son Archetype. The Pacenti SL23 measures 18.5 mm internally.)

DT Swiss 450 (double eyelet)
19.5 mm external/14 mm internal

Flashpoint FP60 clincher
18.4 mm external/13.4 mm internal
Can you say pinch-flat? Can you say 125 psi limit?

Velocity Arrowhead
20.25 mm external/14.2 mm internal

Wide carbon clincher rims

Captain Ahab: Moby Dick
Me: wide carbon rims

The sin of omission is commonly practiced by purveyors of carbon bicycle goods. It manifests when describing carbon rims and wheels. Taller was the old trend; wider is the new trend. WIDE CARBON CLINCHER RIMS! They'll tell you 23 mm wide. The problem is that is the measurement at the brake track. The measurement that counts is the internal bead-to-bead dimension. That is the dimension that will change your tire's profile from a lightbulb to a rounder and wider profile. Once you get over 17 mm for the internal dimension, you can legitimately claim wide rim status.

I recently received a 25 mm wide U shaped carbon rim from a new supplier in China. I put the calipers on it and--holy shit--truth in advertising. Outer: 25 mm; inner: 18 mm. It is 38 mm in depth with a 12k cosmetic weave. The set is, of course, 20/24 hole. It even has a u-shaped profile, which should add some stability in cross winds.

This will be a Powertap G3 wheelset for my road bike.
Scheduled build: in two weeks.

Destro's cross wheels

This morning I finished a set of carbon tubulars that will be fitted to a friend's new cross bike. The rims are second generation Yishun carbon tubulars, which measure 23 mm and have a nice deep center channel for your sew-ups. Gluing and mounting tires on these rims is very easy.

I don't have a scale so I will take them at their word on 400 grams/rim. The weave is 3k with a matte finish. They are round, except for one or two high spots from the mould. This lack of roundness is a problem I've noticed on every carbon rim I have sourced from China. (By way of contrast, the Gigantex/Equinox rim I built up was round.) If an alloy rim arrives out of round, it is a mere annoyance. When the rim is carbon, it is a major headache and the wheel will never be radially true.

Details for Destro's wheels
Front uses a White Industries T-11 hub, black. 20 hole
Radial lacing, using 2.0 DT Swiss spokes, laced to DT Swiss brass nipples

Rear uses a White Industries T-11 hub, black, 24 hole, Shimano/SRAM
DS is 2-cross, using 2.0/1.8 Sapim Laser, laced to DT Swiss brass nipples
NDS is 0-cross, *elbows out*, using 2.0 DT Swiss spokes, laced to DT Swiss brass nipples.

Notes

• I went with elbows out/radial for the rear NDS to increase lateral stiffness. I learned the hard way that not every hub is tolerant of this spoking pattern. Advice: make sure that hub is forged, not machined.
• I went with straight gauge on the NDS for the same reason as above. Now that Shimano/SRAM has gone to 11 speed, the DS flange has moved inboard with the effect being a drop in lateral stiffness. This can be compensated for with lacing, spoke diameter, and rim choice.
• The plus side for all manufacturers moving to 11 speed is that cassette bodies can now be swapped without redishing the wheel. To complete Destro's wheelset I had to swap Campy for Shimano. Took 10 minutes. That White Industries stuff is really nice.

Update: these are lighter than Mateo's cross wheels. In yo' face, Zartan!

Carbon rims and radial trueness

Lateral trueness is easy; radial trueness is hard. I'm always looking for better tools, and this morning I was researching Morningstar tools. They offer a dial-based truing gauge that will fit to a Park TS-2. Slowtwitch was the first review that popped up. Buried within an article on wheel building is a point about the difference between carbon and aluminum rims:

This is also the point where carbon and aluminum wheels differ. Carbon rims are much stiffer than aluminum. Put simply, the amount that you can radially manipulate a carbon rim is MUCH less than aluminum. As such, when adjusting radial trueness, you need to adjust many more spokes. Think of it as shifting the entire rim up or down – rather than bending a part of that rim to be more straight. Instead of adjusting 4 spokes, I might adjust 8 or 10. This also brings up the point that carbon wheels rely much more on roundness of the rim itself for a straight wheel; an imperfect rim cannot be manipulated very much (unlike aluminum). 

This is why cheap carbon rims are a really bad idea. There are plenty of other reasons why cheap carbon is a bad idea--labor conditions in those Chinese factories, for starters. Next up would be a total lack of warranty coverage for manufacturing defects.

Want a legit rim and customer service? See Brandon at the Bike Hub Store. Always great service and they're the only consumer source of Gigantex rims that I've found:

http://www.bikehubstore.com/category-s/124.htm

Getting back on that horse

It is almost July, and that means cross season is almost upon us. That means taking a break from riding all the wheels I've been building, and returning to the truing stand. What have I been riding? On the road bike, a lovely Pacenti SL23 wheelset with a 20 hole White Industries H2 on the front, and a 24 hole Powertap SL (with G3 internals) on the rear. These are shod with 700 x 25 mm Contis. Life below 90 psi is splendid.

Ongoing impressions of the Pacenti:

• They work very well with standard size road brake pads, exhibiting none of the pulsing I was experiencing with V-brakes. I suspect this has something to do with the length of the pad.
• Mounting tires is a real challenge. I suspect this is because of the tubeless rim design. Once I get a frame with the proper clearance, these will be an excellent candidate for the 28 mm Hutchinsons.
• My initial concern about the low spoke count was unfounded. These rims are plenty stiff for someone who goes 175.

What I am working on today:

• Relacing a rear 24 hole White Industries T-11 (Campy) onto a 50 mm Yishun carbon tubular. This will be straight gauge spokes in 2x (drive), 0x (non drive) pattern. This will be my rear wheel for cross.
• Relacing a rear 24 hole White Industries T-11 (Shimano) onto a 50 mm Yishun carbon tubular. This will be the same pattern as the above wheel. 
• Lacing a front 20 hole White Industries T-11 onto a 50 mm Yishun carbon tubular. This will be 0x with straight gauge spokes. This will be my front wheel for cross.

I'll go into the relacing in a separate post.

Here's the assembly line for today:

• T-11 hub--titanium cassette body--no gouging, unlike Chris King.
• 12mm brass nipples drying out after soaking overnight in triflow. Lube those nipples when building with carbon!
• Spokes and the all important spoke ruler.
• Lastly, my trusty and calibrated Park Tool TS-2 stand.

Updates to follow!