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Old 01-15-10, 03:25 PM
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letsgetsandy
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Originally Posted by dealingwithit View Post
Sheriff stars are c-record.
+1

Stolen from another thread.


"We've collected at this point 211 high-end road and track hubs that had flange failures, all in an effort to differentiate fact from urban fiction. Obviously any results from them are conditioned by the fact that we aren't taking statistically valid samplings of each brand or model. Of the hubs, only 17 were track hubs but the results may still answer your question. 14 of the hubs (both road and track) were C-Record (sheriff's star), and 10 of those were rear, 4 front.

Out of those 211 hubs, we were only able to identify 27 where the failure wasn't related to an extraneous event. The most common event was a crash or fall in which there was strong lateral (sideways) stress applied to the wheel very near the hub. Most typical was a car driving over the wheel. One of the classic photos of the C-record hub floating on the internet doesn't show that there's a substantial cement grind spot on one side of the hub where broken, that there are automobile tire tracks on the opposing flange, and the hub appears (though we couldn't tell any longer for certain) to have been laced to somewhere north of 1300 N (we could only measure this from calculations of spoke length plus the distance the nipples were threaded onto the spokes, plus generally the fact that several spokes were torn right through the spoke holes of a Velocity Deep V rim). If all that has happened, it's not unreasonable for the hub flange to fail.

Most flanges fail by unzippering of the spoke holes. This typically happens with low flange high-spoke-count hubs where you have a number of holes, close together. It's exacerbated if the flange is rather small and unreinforced. An example is a 36-hole Chris King hub; King does not warranty radial spoking for this reason and no longer offers higher spoke counts. A DT or current Dura Ace hub is just the opposite -- the spoke hole circle has a higher diameter so the holes are not quite as close and there's more flange outside the spoke hole circle. They still have some limitations on how high they can be tensioned radially. However, high flange hubs create more spacing between holes so of all the examples we have, only 28 were high flange. None were Phil Wood, none were old Campagnolo Record or Super Record, and none were Dura Ace 7600, Sansin, or Superbe Pro. We had one Miche front track and one Suzue Promax rear track, but both showed evidence of lateral strikes so we don't feel inclined to blame the hub.

We did notice that the flanges of the C-record "Sheriff's Star" design were unduly fragile. Two such hubs did appear to break without external inducement but we also saw flaws in the metal at the break. Cutting one of them apart further, we were not entirely surprised to see that those hubs were not forged or spun like most track hubs, and that the metal blanks used were full of pits, inclusions, and other flaws. We can't say whether all C-record hubs have such problems but the one examined certainly did. This doesn't mean they'll break, but the metal may have been more to blame than the design. Either way, C-record equipment was at rather a low point in Campy's life and they have bounced back with much better engineering and manufacturing after that brief lapse. (And we wouldn't curse C-record either -- it's still very good equipment.)

A quick note about spinning and forging. The blanks can be treated in any number of ways to increase the strength before milling, which creates a strong hub, plus the design can be a little more conservative -- Phil Wood is a good example. The downside is that this approach typically is heavier. The higher-end Japanese hubs have typically been produced by spinning. A blank is mounted on a metalworking lathe and a special set of tools are used to actually push the metal into shape. This strengthens the metal itself and allows for a very weight-efficient design. If you look closely at some hubs such as many Superbe Pros, you'll see a join in the middle, showing how the left and right flanges were spun separately and then joined in an extension of the spinning process. We've heard (but not confirmed) that Shimano dropped the 7600 high flange track hubs for a while not because of demand but because they couldn't find metalspinners in Japan to handle this process; that problem was resolved and the hubs are back in large-batch production. Others such as HotBlack should please chime in as well, but of all the methods for hub design and manufacture, the higher-end spun Japanese hubs have certainly in our experience had the highest level of reliability and performance at the lowest weight.

All told, however, there's no reason not to use C-record on the track (or on the road for that matter). Some street riders treat their fixies like stunt bikes so it's not surprising that equipment fails. As Gord pointed out, this equipment has an incredibly long service life (nowhere near as long as Gord, of course) and no one should abandon a pair of C-record wheels in expectation of failure. Just be reasonable about lacing tension and the kind of riding one does. If you go over the rail in a crash and your hub breaks, don't write Campy about it."
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