ceramic bearings

[jersey flip]

any one ever build an engine with ceramic bearings if so how did it turn out.

[Rich250RRacer]

A buddy of mine used them in the CR250 motor in his microsprint. They were very expensive, but he praised over and over the extra .00001 horsepower he was going to gain from running them. They didn't make it through the first race before they blew apart. I remember him saying the bearings cost a few hundred bucks, plus the damage they did to the crank and other internal parts. This was the first time I've ever heard him admit a mistake. Basically what I'm trying to say is stick with factory bearings, since the gain is very minimal, but the cost could be VERY high.

[wilkin250r]

I've heard of several people trying them, all without success. Not all were catastophic failure, like Rich's story. But I knew a guy that tried them, and they would bind up at high temps and rob horsepower.

I've never heard of anybody that ran them with success.

[jcs003]

i know of them being used in drag bikes but they are replaced so often i can't say about reliability. but from a materials standpoint, ceramic can handle some extreme temps.

[jersey flip]

Originally posted by Rich250RRacer
A buddy of mine used them in the CR250 motor in his microsprint. They were very expensive, but he praised over and over the extra .00001 horsepower he was going to gain from running them. They didn't make it through the first race before they blew apart. I remember him saying the bearings cost a few hundred bucks, plus the damage they did to the crank and other internal parts. This was the first time I've ever heard him admit a mistake. Basically what I'm trying to say is stick with factory bearings, since the gain is very minimal, but the cost could be VERY high.

COOL thanks ! I herd a few dudes talking at the track... Ill stick with oem

[atvmxr]

ceramic may be able to handle high temperatures, but its very brittle in comparison to steel

[jcs003]

Originally posted by atvmxr
ceramic may be able to handle high temperatures, but its very brittle in comparison to steel

depends on the kind of steel and ceramic. generally speaking you are correct.

high speed steel is very brittle. for example.

but their are ceramics that can take a hit. zirconia and sialon are common ceramics used in the industrial arena.

zirconia is very tough and can withstand impact.

sialon has good wear charastics in a "slide wear" application like bearings.

does anyone know the type of ceramic used in bearings?

[Ruf Racing]

Chad502EX.com, uses them in the TRX450R. He would know
the material used.

[slomoe]

ceramic bearings typically are used for very high speed high precision things like machine tools. they dont have very high load ratings but will handel 25,000 rpm. I really dont think the expense of the bearing would be worth the gains in this application.
your best bet would be just loose 5-10 lbs that will make you faster!

[IcutMetl]

I'm not a 250r guru yet, but I would stick with OEM style bearings. I used to install and maintain high-end cnc milling machines, many of which had 40,000+rpm spindles and ran on ceramic ball/steel race bearings. They weren't in a constant bath of oil, but were under a constant flow of under race lubrication from a very light oil with almost the consistancy of kerosene which also served a cooling purpose.

Ceramic vs. hardened bearing steels are very hard and have a very low rate of thermal expansion (why they are used in machine tools accurate to microns), but treat them wrong and they are very expensive. Vibration, slight misalignment, or shock (i.e.- machine 'crashes'), and it's bye bye bearings. From a machine stantpoint, if you treated it the right way while programming and machining, they would last a long time and cut to rediculously low tolerances all day every day. Smack a cutter bad once, and it's a $30,000+/- spindle change. From an engine standpoint, it's still a lot of money if something explodes anywhere in the engine and grit, etc carries itself into places you can't see...

[machwon]

I have them in both my 250r and my daughters DRX50 for over 2 years now with no issues. I've yet to notice a difference on the dyno for the 250R but the little 50 does seem to pull 300 rpm more than the other builds I've done. I've been told of .75 HP increases on karts with 125cc motors, but yet to verify any gains on the dyno here.