Wednesday, October 27, 2010

Techie Tuesday - Wheels & Wheels of Details

My spare rear wheel arrived at the local Performance Bike Shop - shipped free of charge from the online store - in good shape, but with a 100mm front skewer instead of a 130mm skewer. I walked around the store and picked up a few items, especially, a new pair of gloves, squeezing the spokes to relieve them, and then handed the wheel back to the mechanic to have it trued.

It was in pretty good shape, so I am very happy with the purchase, as the cost was a screaming deal at $118 - about half of $205, plus shipping, from Colorado Cyclist. In their defense, my CC wheels were custom built by hand with DT Swiss's Revolution, 14/17 super-butted spokes, so I expected to pay more for them. The PBS wheels use double butted 14/15 Wheelsmith spokes, which as you will see in the photos, have much more abrupt butts. Spokes with abrupt butts usually fail at the butt, if and when they fail.

As indicated a few posts back, the CC wheel has developed a serious flaw at the SUP weld, so the catalyst for buying the PBS wheel was as a spare I can use to keep riding while my CC wheel gets shipped back for a warranty inspection.

I took a lot of pics to get these, which I think are quite good, and highlight contrasts between these two wheel builds. I went through a lot of trouble to get some good shots of the manufacturer's trade-mark stamp on the spoke heads. Once you know what to look for, this makes identifying the spoke mfg quick and easy.

Without further adieu then...

Sorry there are no captions, but BlogSpot's captions currently screw up the HTML so badly that you lose the ability to click on the pics and get full-resolution click-throughs..

Pic #1: Note the prominent "W" stamped on the spoke head for Wheelsmith, the manufacturer. Also, if you look closely you will see the butt area quite distinctly about 30mm out from the spoke head. The transition is done in about 4-5mm.

You might also notice a characteristic of 3-cross spoking - that adjacent spokes are pulling in opposite directions and form an almost unbroken and unbent line from one side of the rim to the other. This arrangement limits stresses on the flange to those pulling along the curve of the flange, nearly eliminating forces pulling away from the flange directly towards the rim. (which is characteristic of radially spoked wheels)

Pic #2: Shows a close-up of the flange and spoke head.

Pic #3: Shows a shot along the drive-side of the wheel, with the halographic Mavic OpenPro decal in focus.

Pic #4: Shows the same shot, but with the Shimano Ultegra 6700 steel freehub body in focus. You can see the butting quite clearly on several of the spokes in this shot.

Pic #5: Shows the DT Swiss head stamp and the very tapered butting. It is very hard to see the butting, it is so gradual. It is easier to feel it, but you can see it somewhat here, and the butting is all over by about 20-25 mm from the head. The same is true on the nipple side, leaving almost the entire length of the Revolution spoke at a very thin 17 gauge.

Pic #6: Shows a close-up of the head stamp and flange.

1 comment:

Gotta Run..Gotta Ride said...

You need to work in this cycle field. Seriously!!!