|Re: Mavic Open Pro CD rims||sam-g|
Jul 30, 2002 9:41 AM
|I have a chance to upgrade my wheel set and am considering Open Pro rims with D/A hubs. I'm currently riding Open Pros with Ultegra hubs on a lugged steel mainly D/A equipped bike. So far I've put on over 1000 trouble free miles on this wheel set and can move these wheels to my daughter's bike. My question is; what is the main difference and benefit of the CD spec and is it worthwhile? Also will I notice any benifit from moving up to D/A hubs from Ultegra?
Thanks for your advice.
|re: Re: Mavic Open Pro CD rims||curlybike|
Jul 30, 2002 10:14 AM
|There is no real short term advantage to the change you proposed other than a slight weight loss in the hubs and your wallet. There have been a lot of recent complaints about Open Pro rims developng a dreadfully annoying click after a little ageing. I am in the process or replacing 2 of them for that very reason, the wheels are fine but the riders friends keep complaining about the noise and he isn't strong enuff to ride away from them.|
|CD actually a disadvantage.||Quack|
Jul 30, 2002 10:53 AM
|I wouldn't go with the CD rims. The coating on the braking surface doesn't seem to brake as well. And if you get caught in the rain, the CD coating will last about 10 minutes before being ground away by grit and will leave your rim looking like crap. I have 2 CD rims currently and one of them is a clicker. Give the Sun ME14A rims a try or something from Velocity as an alternative.|
|CD vs Ceramic?||DougSloan|
Jul 30, 2002 12:13 PM
|Are you confusing the CD treatment and ceramic coated rims? I don't think the CD rim has any coating on the brake surface; the ceramic rim does. The CD rim is anodized in the colored part of the rim. A rim can be both CD and ceramic, though.
|CD vs Ceramic?||sam-g|
Jul 30, 2002 12:41 PM
|OK. So if the CD is just an annodized coating, why is the CD rim sold separately and at a higher price point than the standard silver or the colored red, black and blue Open Pros? I've heard about problems with the ceramic coating degrading in time, but still have no clue as to what the CD coating or treatment does.
Any advice on D/A over Ultegra hubs?
|CD vs Ceramic?||DougSloan|
Jul 30, 2002 1:10 PM
|CD must be some "special" anodizing process to harden the surface of the aluminum. Ceramic is on the brake surface only. The Mavic website explains it.
I like D/A over Ultegra hubs. I think they are smoother and are lighter. The Ultegra's seemed to leak out grease much faster, too.
Jul 30, 2002 5:09 PM
|If the CD is "hard anodized" and not just "color coated" then I would steer away from it. Hard anodized rims have a thicker layer of anodization than a normal rim, and this makes them more prone to failure. The anodization layer is relatively brittle, and if it cracks (at a spoke eyelet), the brittle layer will propogate the crack more easily. This problem arose in the early '80s when HARDOX rims first came out. That's why the were only popular for a couple of years, and now are not common.|
|Hard anodized||Tim Field|
Jul 31, 2002 1:31 AM
|Hmmm... we're talking about 20 microns thick as opposed to 3 on standard annodising (if I remember correctly), certainly not large amounts!. Have you evidence of failure with modern techniques. 80's technology is hardly current...
|Hard anodized and braking efficiency.||Quack|
Jul 31, 2002 5:30 AM
|From what I understand, a couple of the major wheel building books bash anodized rims like the CD due to a fear of the rim being brittle and more prone to cracks. The only evidence I remember supporting this claim was the older 80s anodized rims. Another claim is that the CD coating insulates the rim from dissipating the heat from the pads and therefore will end up braking poorly once the pads overheat. Personally, being from Minnesota, I never have descents long enough to actually have to use brakes longer than a few seconds. All I know is that the CD coating is very thin and only took one hour riding rain to absolutely destroy the coating at the sidewall and leave the rim sidewall trashed. They are now reduced to my winter-riding salt rims.|
Jul 31, 2002 12:20 PM
|Regardless of how thick the anodized layer is, it is an inflexible coating of a flexible structure (like paint on an elastic band). Consequently it is likely to encourage crack propogation into the rim, as was said earlier in the post. The cracks are there before you buy the rim, as the anodizing is applied before it is rolled into a hoop.
Nothing has changed since the 1980's when Mavic MA40's were failing everywhere, excepting that the manufacturers have moved rim mass from the sidewall to the rim bed to reduce their susceptibility to this. We now have pretty rims which wear out fast from braking. Unfortunately even silver rims are invariably anodized also.
Your local bike shop will have a few anodized rims lying around which have cracked around the spoke holes, I am sure. Perhaps they might even consider this a feature, illustrating as it does a "race-only" use.
Jofa (returned from the abyss)
|I have both CD and Ceramic||johnnybegood|
Aug 1, 2002 7:39 AM
|Mavic offers several finishes on their Open Pro rims. I own several sets of Open Pros. One is black with machined rims, one has the CD finish, and I have one front wheel with the ceramic coating on the braking surface which I bought because I thought it would have better stopping power. The CD rim is anodized with a ceramic coating over the entire rim, inside and out. The braking surface is machined before the coating is applied so the brown coating is on the braking surface, too. The coating is very hard, and Mavic's literature says it does help to dissipate heat. With any wheel, if the brakes pads have imbedded abrasive materials (impurities in the rubber or sand/dirt from riding in the rain) the braking surface will get scratched. I think that this CD coating on the braking surface would be less susceptible to scratching because it's harder than then base metal. However, when scratched it is very visible because the coating is a diffrent color than the underlying metal. The Open Pro CD with Ceramic is coated the same way as are the normal CDs, but has another, very rough, ceramic coating applied to the braking surface. It makes the braking surface feel like sandpaper. This coating is applied to increase the coefficient of friction when wet. I would think that it would be less susceptible to scratches from impurities imbedded in the pads because of its hardness and extra thickness. But, it can still be scratched (one of mine has a radial scratch from banging it into something while handling the wheel in the garage). I have read that once scratched the ceramic application is susceptible to flaking off. Haven't experienced that yet. They do stop better when dry (normally don't ride in the rain in San Diego). The biggest disadvantage to the ceramic coating is that it is so abrasive it EATS BRAKE PADS at an UNBELIEVABLE rate! Koolstop makes green pads for ceramics which is better, but still goes fast. I am currently running a set of Shimano pads from an old model of cantilever brakes which are very hard. The hardness somewhat compromises the increased stopping power, but at least they will last more than 500 miles! Would recommend the CD coating, but stay away from the ceramic coating unless riding in the rain.|| |