Which wheels?

I thought the advantages of ceramic wheel bearings over decent quality stainless steel were meant to be tiny - like  fraction of a watt - most of us would probably get more with a new chain.   If you have Mavic hubs often they (well the rear anyway) have a rubber seal inside which adds a bit of drag - if you aren't riding your wheels much in the wet if you space that out with a small washer that'll give you a little bit of improvement too.

IronCat5 in the Hat wrote (see)

I don't know much about anything Eng....

However, Mr Eng will hopefully back me up here. If you know the size of the bearing, you can get ceramic replacements from SKF or a similar bearing supplier.

Yes and no. You can buy bearings from SKF quite easily, and I have done in the past (though in high torque actuation applications, not bikes). I recall a discussion with the tech guy from Zipp a while back who was talking about this though, and essentially not all ceramic bearings are created equal - this is because the most common application is not fancy bike wheels, it's high temperature industrial applications.

I'm not sure I recall the technical differences in gory detail but the essence of the discussion was that the ceramic bearings specifically for bikes differed in more than just material selection (given that thermal expansion is less of an issue). Commonly I've seen ceramic feature more balls of a smaller diameter - presumably as the manufacturing tolerances are tighter? A good chunk of the benefit may well be through simple stuff like sealing rings being toleranced to optimise friction at the service temperature intended, rather than for a generic application.

Note also that there exist both fully ceramic units and those with silicon nitride coated balls in a steel race. I'd have to read a bit more about them (and reach a level of performance where 1W made a difference) before going shopping, personally.

What would concern me is the maintenance interval. The SRAM red kit with ceramic bearings needs an clean and oil every 200 miles.

I'll stick with the OEM bearings in the PX wheels I have until they inevitably fail, then replace with aftermarket normal bearings.

Fulrum quattros were recommended to me as a semi aero wheel at a decent price.

How long do bearings last in OEM wheels, or the ones that you chaps are talking about?

And how challenging is it to replace them? I mean, including the inner cups.

One of the bike mags tested deep rim wheels last month and they reckoned the PX 52mms were the best under a grand.  And I think they're about £400 !

It was on one of the PX weekly emails anyway.

Lifes too short to maintain bearings every 200 miles !  I've a Dura Ace hub that was on my best bike and now is on my winter bike. Never had to mess with the bearings and the wheel is at least 20 years old now. OK so it only gets 50 miles plus a week in the winter - but its not nice miles. 

Blisters wrote (see)

How long do bearings last in OEM wheels, or the ones that you chaps are talking about?

And how challenging is it to replace them? I mean, including the inner cups.

If they're balls then easy to change. And if you check them every now and then you may not need new cups and cones.

Sealed bearings are harder to change - you need a puller or some kind of drift to knock them out. Advantage - no cups and cones.

cougie wrote (see)

One of the bike mags tested deep rim wheels last month and they reckoned the PX 52mms were the best under a grand.  And I think they're about £400 !

It was on one of the PX weekly emails anyway.

Lifes too short to maintain bearings every 200 miles !  I've a Dura Ace hub that was on my best bike and now is on my winter bike. Never had to mess with the bearings and the wheel is at least 20 years old now. OK so it only gets 50 miles plus a week in the winter - but its not nice miles.

I'm sure 220 or TriPlus reviewed them and said they were great for the price. I have the 60mms; can't fault them for the money.

The 200miles was for the Red bottom bracket! on review it may have been 200 hours. I have the tech doc somewhere but can't be arsed to find it...

I've just been into the rear wheel bearings. One side has gone rusty (honest). Both cup and cone are wrecked, and the balls were visibly mis-shapen. This is not good on a bike that's Barley (sp) a year old.

I've done a temporary fix, but I'm not a happy bunny.

I had some planet X 52mm clinchers. They were ok, but I wasn't overly happy with the quality. I opted for some American classics in the end.
Part of me really wants a disc, just for the noise.

I will go and see TigerFrog at some point and look at their deep wheels

I had a pair of Ksyrium Equipe wheels for many years. I did the Etape Du Tour, all sorts of UK sportives, duathlons, club rides and 10 mile time trials using them and really couldn't fault them as they were robust, responsive and well priced. Then last year I splashed out on a pair of PX 52mm clinchers and sold the Equipes for 60% of what I paid for them, which was a bonus. I've done hilly sportives (Dragon Ride) and flat OD triathlons using the PX wheels and will use them for IMW this year.

Both Mavic K's and PX are superb all rounders for the money, but I go  for the PX if forced to make a choice as the aero advantage is certainly noticeable.

http://chasethepotato.wordpress.com/

This thread has made me investigate what wheel bearings actually are - bit by bit I'm learning my way around a bike . Cheers all!

Cougie,
They are the stock wheels on a Specialized Allez Elite, branded as DT Swiss, I believe. Here's what is a bit frustrating: hang the bike up and tap the wheel round. Tick tick tick stop. My knackered touring bike is 30 years old, but has got Campag hubs. I've never been into them, and there's no need. Tap them and they still go tick tick tick tick tick tick tick tick until you get bored and make a coffee. When you come back they are gently swaying too and fro based on the extra weight of the valve. There's no way in God's planet that I will have paid a fortune as a student.

cougie wrote (see)

I think all deep rims take on water. My Mavics did and my mates expensive FFWD wheels do too.

What Cougie said. The rattle is more likely the valve or extender rattling on the carbon fairing. Clearance is tigher there than on the spoke holes.

I can follow the logic there, both for the rattle and for the deep rims taking on water. Logically, it would appear that the maintenance task necessary would be to deflate the tyre and just let it out after a wet ride. There's no point having expensive/light wheels and adding aqua-ballast!