CD? Ceramic??? Road rims for the mile eaters?
 

I cannot seem to be able to get a good answer from older posts on the same subject. So i know that mavic CD is NOT the same as their Ceramic2, the latter being what most of us refer to simply as ceramic rims. So is CD the infamous crack prone 'hard anodizing' widely discussed by Jobst Brandt?*

That being said i am looking to build a set of training wheels around Chris King Classic hubs. Mavic Reflex tubular will most likely be my rim of choice, however, unlike the Open Pro clincher, it is only available as regular silver and CD coating. Here it rains a lot so if i judge by the wear on my commuter rims (about halfway through the wear strip in about ~4000miles) i will most likely eat through regular rims in no time. So i think some kind of coating (like CD) might help me... Also changing rims/rebuilding a wheel with a new rim once a year might also be an option, however, i prefer to have to do that due to a worn rim not because of cracked hard anodizing.*

What is your experience? If Ceramic2 is what they say it to be, i could consider Open Pros but i'd rather go with tubulars.*

-Carcinogent

yes, CD is their code for the hard anodizing,
My Koga '04 WTR came with ex721 CD rims,

abrasive brake pads [magura HS33 green] and wet hill braking,
evenly wore thru the anodizing ,
then I went back to the stock pads, and braking was 'normal'

A pad like Kool stop salmon colour, 'rim friendly' as they say
may give you longer wear,
my black pads wore down in a couple years, which was OK
as the friction goes somewhere,
better to wear out the brake shoes than the rim.
last replacement, Magura Red, they hire KS to make the inserts,
the 'Salmon' FeO2 stuff,
so will see how they do ..

The sand in the road grit is a separate wear problem, hosing down the wheels ,
and checking for embedded grit in the pads will help.

Clear anodizing will be adequate, just from a no need to polish,
perspective, I suspect.

If i remember my Mavic technical data catalog correctly the annodizing process makes the exterior 6 times stronger than bare metal, and the ceramic process, which is both on the surface and imbued to 20% into the metal is 10 times stronger than the annodized surface.

I have never had an issue with "CD" rims cracking and even after the annodizing is gone they still be have like normal wheels.

Don't sweat about the technical drawbacks of hard anodized rims, they're exaggerated, and folks have been riding hard anodized rims on road bikes for almost 3 decades with no significant issues. Initial braking, especially wet, will be worse, but that breaks in pretty quickly.

As far as wear goes, you can't compare sport road use with commuting. I do both and can assure you (if you didn't already know from your own experience) that brake use per mile is vastly less on the open road as compared to stop and go commuting. In about 100,000 miles of all weather biking I've never worn a rim from braking, or had one stress crack. All my rims have lasted until they fell victim to unforeseeable road hazards, usually rain filled potholes at night.

There were some of the MA 40s that cracked around the doubled spoke ferrules ,
but if anyone were to put their hidden stash of NOS MA 40's up for auction
they would still sell for a good price..

I also note cycling news http://www.cyclingnews.com/
displaying amazement that, the Pro's team mechanics,
bring out their hard anodized box section 32 spoke 3 cross tubular wheels
for the roads and Pave' on the way to Roubaix , each spring..

Thank you all for the input. So i'll be sticking with Mavic Reflex as initially intended. If i decide to go CD i will need ceramic specific pads, right? Or just regular ones that i will have to change more often? Or ceramic first and once the coating is worn, use regular?

@FB

Shortly after posting i got thinking and realized what you said. *To be honest i never think about how much i break when in traffic. On the other hand i live in an urban(ish) setting so i'll have to do some commuting style riding before I get out and back to the city...quite some traffic lights. I'll take your word and won't be so skeptical towards hard anodizing anymore.*

-Carcinogent

brakeing improves as quickly as the hard anodizing wears off.

You've been al lot luckier than I have. In 150,000 miles of mixed riding, I've worn through the rims of at least three wheels to the point of cracking at the brake track. The earliest failure was with an Open 4CD Mavic rim which cracked at 12,000 miles. Since then I've run Mavic CXP33 (Not CD treated) for as much as 30,000 miles with no failure under the exact same riding conditions. I'm one of the nay-sayers about CD rims.

I've got Mavic ceramic on my "nice" mtb-xc wheels, which see a fair amount of muddy use and are holding up very well.
I bought several sets of ceramic specific pads of various brands when I built the wheels, and somewhat embarrassingly I haven't gone through that stash yet.
But yeah, I've also heard that it's possible to switch over to regular pads eventually. But unless it's a question of having to replace the pads while on tour, I'll probably stick with ceramics. Avids have become a favourite.

brakeing improves as quickly as the hard anodizing wears off. [/QUOTE]

Yes, braking does improve quickly and materially, I might have been clearer. IMO braking is a non-issue when considering hard anodized rims.

It's not all luck. I hate applying my brakes and giving up that hard won momentum. Actually most of the 100k was open road biking and touring so less breaking was needed. Also I ride tubulars on all but the city bike, so there's more forgiveness since I don't have a cantilevered flange to crack. OTOH, I ride 305 gram rims, so they're fairly thin walled to start with.

On my city bike I have a fairly deep box-section and set the shoes on the box not the flange as much as possible. That's important because it isn't only wear that cracks rims, it's fatigue from flexing when brakes are applied.

Anyway you live in Pittsburgh and have lots of descents that end at intersections so probably don't have much choice about braking.

No, hard anodized rims use standard shoes, only ceramic coated rims take special ceramic pads. If you want to wear through the hard coat faster you might start with ceramic shoes, but I wouldn't bother, the rims break in fast enough anyway.

CD comes from the French language of manufacturer , Couche Dure,

http://www.mavic.com/en/technology/rims/CD

It's not the ceramic2 plasma spray treated stuff, just a harder anodizing treatment.

I see ceramic 2 only offered in Open Pro road rim and XC 717 race mountain rim..

Forget about the hard anodized. It like much of the stuff sold in our hobby is hype. I can't make the rim stronger and does have a bad effect on the braking. It's a waste of money.

Thanks for ignoring the typos. I was in a hurry when I wrote my original posting. :)

Yes, frequent braking is the norm around here, at least if you want to survive. So, my rims do take more abuse than those of flatlanders and riding in all kinds of weather makes the situation worse. That said, my only "premature" rim failure was with an Open 4CD so that left me with a distrust of the CD process in general.

In case anyone wasn't aware (or cares), all aluminum develops a layer of aluminum oxide on the surface. Aluminum oxide is a very hard ceramic used for some sandpaper or the white part of a spark plug. Normally, this layer is extremely thin. Anodizing increases the thickness of the layer (and porosity so it will hold dye better).

Apparently, the CD process increases the thickness and density more than regular anodizing. So the anodized surface really is ceramic, it just isn't applied like a "real" ceramic coating.

Mavics Hard-anodizing treatment.
This is a low temperature electrolytic process which is carried out in a sulphur filled bath. Parts are connected to the anode (+) pole, and are submitted to a voltage varying from 0 to 120V.
The duration of the treatment depends on the thickness of the anodizing desired and the alloy used.
The anthracite grey color of the anodization results from the transformation of aluminum into aluminum oxidde.
This surface treatment is not simply a coating as it propogates 50% in the base and 50% in extra thickness.
Benefits
As its name indicates, an extremely hard outer surface is produced which can attain a degree of hardness of 700 Vickers, i.e. 10 times the hardness of the lightweight alloy normally used.
This layer has the following properties:
•high resistance to corrosion
•enhanced rim rigidity
•reduction in friction generated heat

Nice post on what hard anodizing, except that the last either doesn't apply, or may be undesirable.

The total kinetic energy of the moving bicycle is converted to heat. It doesn't matter what the materials are or their coefficients of friction. the heat energy released is in direct relation to the weight and speed reduction of the bike (discounting hills).

The vast majority of the heat produced goes into the rim because the rim is a better heat conductor and much larger heat sink than the rubber shoes. The lower friction property of a hard anodized rim, doesn't change the heat produced, it just means that the shoes have to squeeze press harder on the rim to get the same amount of braking force, de-acceleration and heat.

Or anyone else's. There is nothing Mavic does that isn't a standard process used by dozens of industries.

Do you work in Mavic's marketing department?

Your first point is of little consequence since brake wear rubs off the CD layer in short order and corrosion isn't a significant factor in rim life anyway.

The second claim is just not true. The CD layer has no significant contribution to rim rigidity. If anything the anodized layer is brittle and if it cracks it can act as a stress raiser and increase the tendency of the base metal to crack also.

Your third point is really a negative and FBinNY has disposed of it nicely.

I just copied it from the rim catalog of 1993. I am not a Mavic employee nor do I play one on TV.

I've heard from a friend that the OP ceramics are nice in the rain, but that might be exaggerated and should be taken with a grain of salt. I think the only true, practical benefit of rims with such surface coatings are aesthetics (they look cool), but the look doesnt last forever once the miles add up.

Remember, ceramic coated rims and CD (hard anodized) rims aren't the same. CD is primarily an appearance item with little durability and has no beneficial effect on brake performance. Ceramic coatings are far more durable and do indeed improve braking performance, particularly in the wet, but they eat standard brake pads like jelly beans. There are specific pads intended for ceramic coated rims and they should be used but, conversely, these pads are quick death on standard rims.

I know you didn't ask about disc brakes as a possible solution but I'll throw it out there. They are not a perfect solution but as far as decreasing rim wear, you won't find a better option.

The downsides of disc brakes that I've found:

1. heavier fork than non-disc fork and fewer options
2. heavier system than caliper brakes
3. feel cannot be fine tuned as much as caliper brakes can
4. noisy when wet
5. initial set up takes a lot of care

For me, they've been worthwhile trade offs. I commute in all weather and ride a route requiring a lot of braking and lots of it going downhill. I'm almost at 8000 miles on my wheels built using American Classic hubs and IRD Cadence rims (one of lightest aluminum clincher rims made). I only run a front disc brake (canti rear) and I do the vast majority of my braking with the front.

They sure are. Not quite as consistent as discs/drums, but still a lot better bite than regular alloys.

A ride on a bike thus equipped would quickly disperse that illusion.

Well, that is true. For a MTB being thrown about in rocky terrain, or maybe taking a landing hard enough to dent the rim, the ceramic coating has a tendency to flake off at the impact point.

For bicycles seeing less violent use the killer is oftenthe type of bicycle racks where you jam the wheel into something wedge-shaped. This together with a narrow tire is a "foolproof" way of knocking flakes out of the ceramic.
Not that the bare patches are by themselves critical, but they lead to grabby braking which gets quite tiresome eventually.

My experience with bikes ridden in all-weather conditions is that the rear rim and rear brake pads fail first despite the large majority of braking being done with the front brake. I've always concluded it's because the rear wheel lives in a far dirtier, grittier environment. So, if I were trying to save rims I think I'd use a disc for the rear.

Depends on how much you brake with the rear. I barely use it (certainly influenced by only having a front disc) so my rear rim is practically new with plenty of miles on the bike. A rear disc would have greatly limited my frame choices and made mounting a rack and fender more difficult (minor relative to the frame issue).