RiPHRaPH

does anyone have experience with ceramic bearing kits for wheelsets? They sell a $90 kit that you can turn your wheels into race ready ceramic's. I've got a guy in the club who put ceramics on all his wheelsets and swears that you'll never need to upgrade wheels again.

sch

If your wheels are perfect, they will last a little longer in the bearings with ceramics,
but wheels are disposable, rims get trashed or brake surfaces wear out, spokes break
etc. Hubs can last a lot longer. Ceramics are about 95% bling and 5% improvement.
They are meant for high speed and/or high heat bearings. Bike hubs, at 3-400 rpm,
and operating at 50-110F don't make much use of the advantages of ceramics. They
are low turning resistance, but wheel hub bearing friction is probably in the milliwatt
range for loose ball wheels. Sealed bearings have seal friction that adds to this.

HillRider

The guy in your club is a good illustration of the placebo effect. His wheels are better because he thinks they are better.

You can save $89.50 by buying high quality steel bearing balls the next time your wheels need to be overhauled and no one will be able to measure the difference. As shc noted, the rolling resistance of properly adjusted steel wheel bearings is in the milliwatt range. How much can ceramic bearings possibly save?

FLYcrash

+1

It's impressive how l-o-n-g a wheel with traditional bearings will rotate under its own rotational inertia as long as its bearings are clean and properly adjusted. I'm sure that air resistance (or grit in your chain, rolling resistance in your tires, etc.) is more important than bearing friction when you're at speed.

Save yourself even more money and get your steel bearing balls through non-bicycle avenues...McMaster-Carr will sell 100 of the best steel bearings ever used in bikes (grade 25, 52100 chrome steel) for $3-4 plus shipping. With such industrial suppliers, you can even do things like freak out and get stainless steel balls (to the same amazing sphericity spec) if you really want.

Coyote2

Is there an advantage to stainless steel in this application?

operator

Ceramic bearings offer a measureable difference in resistance tests - for non competition purposes it's probably worthless. ESPECIALLY if they just plop ceramic bearings into a wheel and think it's going to do anything. Ceramic bearings on steel races = much of the advantage of switching is gone already.

Look up '11.4' s posts if you want some good informed information.

operator

You can get and use better than grade 25. I almost say you shouldn't put anything LESS than grade 25 on your bike. Not worth it.

HillRider

Yes the difference is "measurable", if your measuring instruments are sufficiently sensitive. Is the small improvement in an already tiny value worth a lot of money?

operator

For competition in world class events, absolutely. Look at what the GB team equipment for the UCi track world championships. But for the average person who is not competing on the elite level... 100% waste of money. I'm with you on that point.

Roues artinsanles 2008 grand wheel test - there's going to be a section on bearing resistance. It'll be interesting to read the results, if and when they do post them (been waiting for almost 6 months now).

I've done repairs where the cone adjustment on loose ball hubs were literally so ****, it was hard to turn it when the wheel was off the bike. But when you put it back on, you can't really feel the difference even though you KNOW the hub is adjusted extremely poorly.

And I know, you know that too

HillRider

No question, poorly adjusted, tight and/or dirty hub bearings can be a noticable source of drag. I've seen then often enough that I certainly recognize the problem. However, nothing makes ceramic bearings immune to poor maintainance either. They just provide a more expensive form of drag.

But, clean, properly adjusted steel ball hub bearings have so little drag that ceramic bearings can't offer a significant improvement no matter how good they are.

The pros will, of course, take any improvement they can get, no matter how small and it helps that they aren't paying for it out of their own pocket.

operator

At some point I think the psychological (no matter how small the measured difference is) perceived advantage is almost as good as the actual advantage gained from using extremely expensive olympic events.

It's like if you are riding a bike. If you like how it looks and like how it feels, you will go faster almost irrespective of whether or not it actually IS faster. Psychological advantage is huge in competition.

FLYcrash

That's exciting to hear and news to me...

...where can you get such bearing balls?

FLYcrash

Probably not...if the balls are risking rust, a lot of other things are too. And it's not like 52100 will rust if you just look at it funny...it has a fair bit of chromium in it, which helps. If standard bearing balls were made of 1095 or some other extremely rust-prone steel, well, it would make a difference.

I'm just a steel junkie (I divide my hobby time almost evenly between bikes and knives) and was excited to see bearing balls offered in 440C, a common high-carbon stainless cutlery steel.

DannoXYZ 

https://www.mcmaster.com/

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