4K miles on 2015 TARMAC, have Praxis Works crank, getting replacement Praxis bearings.

HAWK Ceramic seemed way too expensive, don't even know if it could be retrofitted.

Is there a difference ceramic vs standard ?

I'm sure it's subjective.

Not one which is important at bicycle crank rotation speeds. Just a difference in cost, one of which (ceramic) is inflated beyond all reason. It is just **** and pillage.

So why are you replacing the bearings? Just bored?

Waste of time and money.

Noisey ..... it's time.
Not impressed with SPECIALIZED stock bearings.

Headset was contaminated & replaced 4 months ago with upgrade bearings.

Yes there is a difference, but not one you'll ever notice. Ceramic bearings make a difference in performance at very high speeds, but a bicycle crank never spins that fast.

Save the $$ and get the standard bearings.

There are tons of brand name bb30 bearings on ebay for cheap.

Save your money. I put ceramic bearings in a Campy BB -- no difference.

They might be worthwhile for something like inline skates. Those small wheels must turn very fast.

Or your next jet engine.

Same with SRAM. There was a definite weight difference, but mostly in your wallet.

If you're going to get ceramic BB bearings, be sure to get these ceramic bearing rear mech pulleys. All that friction will slow you waaaaay down.

A friend of mine insists that his ceramic BB saves him 7 watts over steel. Good trick, since even a crappy BB consumes less than 1 watt. Here is an article with tests that say ceramic is no better.
Friction Facts: measuring bottom bracket drag - BikeRadar USA

Your crank spins at 100ish rpm. Do you think the friction change makes a lot of difference at 100 rpm?

I've used wheels manufacturing/ enduro stainless steel bearing BB on two bikes and really like them. I don't have much to compare them to though. You can get them on ebay or amazon fairly cheap too. They also offer ceramic, but I'm under the impression it isn't worth it. I went for the angular contact ones because I'm gullible, but I haven't had any issues with them.

Can someone explain to me why pressed fit BB's fail so often? Is it rain? The old DA7800 BB's last a lifetime.

r The same thing happens here in Phoenix AZ, and we get very little rain. I think the DA7800 BB is just far superior to the bearings used in other BBs.

hollowtech 2 style outboard bearings failed all the time, contamination is relatively easy, moreso with cheaper outboard BB like the ones from FSA. BB30 fail in 2 different methods, creaking from the cartridge in the shell which is usually an easy fix with the correct loctite, and from the bearings themselves, oftentimes from the use of inferior cartridges.

In the past I have had to replace the balls in a cup and cone BB after a few thousand miles.

I second [MENTION=391744]catgita[/MENTION]'s post. I'm so happy that friction facts put together a few studies on this topic. Since then I just open the reports and decide wether I want to invest in something better. The bottom line: there are better and worse BBs and you can save some power by picking a good BB. On the other hand it's very subjective if it's worth to pay that much for such a small advantage. And also based on the reports ceramic BBs not necessarily better than steal ones.