Anyone got any experience of these cheap ceramic bearings?

leonlikestrees

As you can see in a thread below, I'm servicing a tired old Ksyrium SSC SL wheel, and I need some new bearings (6902).

Having a quick search, I found a ceramic/stainless hybrid bearing for a fiver (well, nearer £8 with postage, but hey!)

http://www.bearingshopuk.co.uk/6902-2rs-9442-p.asp

This seems pretty cheap to me. Any used these? My thoughts are that if it is ceramic and stainless, it can;t go rusty, and that's where 90% of the problems are with bearings. If I pop them apart and put new grease in from new, it should be fine?

By comparison, one from a bikey brand at £30

http://www.sjscycles.co.uk/product-Whee ... -17081.htm

mtbhenry888

hi again!

i would go for it, you cant go wrong for a fiver and look at it this way if they last a shorter time just buy some more and you'll still be in pocket over £30 a bearing!

Monty Dog

My experience of ceramic bearings is from inline skates - when you use 16 at a time, it's a little more noticeable. I agree that they're worth a try, particularly at only a few quid more than the standard ones. For speed, many people use oil rather than grease. Water and corrosion is what kills bearings IME.

softlad

Monty Dog wrote:

Water and corrosion is what kills bearings IME.

in my experience, what kills bearings is ingress of dirt and grit. Either way, you can't go wrong at that price..

leonlikestrees

Well, I've bought some. The wheel is going on my cross bike, so I'll report back on how it goes.
I checked with them, they are lower grade (10-20), but still expectthem to be better than the steel ones.

pliptrot

Slightly off-topic, but how many wear out bearings before rims? I assume the cost and hassle of getting new rims on Ksyriums and the like makes such an exercise prohibitive, and the supposed quality of sealed bearings should easily see them out-last any (particularly light weight) rims. So why the need to change?

Now if wheel manufacturers actually put some decent sealing on their hubs, ingress of anything would not be a problem. It really isn't rocket science, but since Maillard 700 hubs only Shimano have tried to do it right (and largely succeeded in their off-road hubs).

Rockhopper

You should never take the seals out and fill new bearings with grease, apart from the risk of damaging the seals the extra grease will make the balls skid around the race rather than rolling. This will overheat them very quickly.

leonlikestrees

Rockhopper wrote:

You should never take the seals out and fill new bearings with grease, apart from the risk of damaging the seals the extra grease will make the balls skid around the race rather than rolling. This will overheat them very quickly.

Hmm. I've popped the seals off plenty of times on old bearings to give them a new lease of life. Don't think Ive damaged them.

Point taken on the grease.

leonlikestrees

pliptrot wrote:

Slightly off-topic, but how many wear out bearings before rims? I assume the cost and hassle of getting new rims on Ksyriums and the like makes such an exercise prohibitive, and the supposed quality of sealed bearings should easily see them out-last any (particularly light weight) rims. So why the need to change?

Now if wheel manufacturers actually put some decent sealing on their hubs, ingress of anything would not be a problem. It really isn't rocket science, but since Maillard 700 hubs only Shimano have tried to do it right (and largely succeeded in their off-road hubs).

Well, one of my bearings has sort of fallen apart. The rim is on the way out too, but I'm sure there are quite a few mils to go on it yet. Going to pound it to death on my cross bike to finish it off.

pawlfreehub

Rockhopper wrote:

You should never take the seals out and fill new bearings with grease, apart from the risk of damaging the seals the extra grease will make the balls skid around the race rather than rolling. This will overheat them very quickly.

Does that apply in most bike situations?
I frequently do that and have got much better life out of BB and headset bearings as a result, I can't see my headset bearings ever overheating, I think water and muck considerations will outweigh heat and bearing function through overgreasing on a bicycle. In many automotive applications I'm sure you have a point though.

Rockhopper

Headset bearings are not really stressed very much though comapred to wheel bearings. I've had two hope hub bearings fail,on both occasions because a previous owner had damaged the seal with a screwdriver.