986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post

berty987 · 03-03-2012, 04:56 AM

Reading up on bearing failures it's normally a result of the race guide or the balls suffering damage. Typically this damage is caused by either foreign particles entering the bearing races or the bearing race/balls fragmenting as a result of excessive heat from running at too high a speed /load or with insufficient lubrication. The advantage of ceramic or composite materials is they are less affected by temperature or foreign particles. Assuming Porshe specced the bearing correctly for speed and temperature the only realistic cause of failure is that the lubrication is washed away or that foreign particles enter the bearing causing deterioration. Either way, there is a very strong case for fitting a bearing that can operate with less lubrication or oil lubrication rather than grease and that is more resilient to foreign particles in the race guides.

A question for Jake and flat six innovations at this point. With full ceramic bearings available , why is the solution offered using a hybrid rather than full ceramic ? Is there an issue with full ceramic bearings in terms of load or shock resistance that is required in this application ?
For instance the bearing listed below meets the temp requirements for the application
6204 Full Ceramic Bearing 20x47x14 Ball Bearings

Or the full compliment Silicon nitride bearing
6204 Full Complement Ceramic Bearing 20x47x14 Si3N4 Ball Bearings

I assume the bearing offered currently is something like this ?
6204-2RS Hybrid Ceramic Sealed Bearing 20x47x14 Ball Bearings
SKF - Product data

03-03-2012, 04:56 AM	#7
berty987 Registered User Join Date: Jan 2008 Location: Uk Posts: 31	Reading up on bearing failures it's normally a result of the race guide or the balls suffering damage. Typically this damage is caused by either foreign particles entering the bearing races or the bearing race/balls fragmenting as a result of excessive heat from running at too high a speed /load or with insufficient lubrication. The advantage of ceramic or composite materials is they are less affected by temperature or foreign particles. Assuming Porshe specced the bearing correctly for speed and temperature the only realistic cause of failure is that the lubrication is washed away or that foreign particles enter the bearing causing deterioration. Either way, there is a very strong case for fitting a bearing that can operate with less lubrication or oil lubrication rather than grease and that is more resilient to foreign particles in the race guides. A question for Jake and flat six innovations at this point. With full ceramic bearings available , why is the solution offered using a hybrid rather than full ceramic ? Is there an issue with full ceramic bearings in terms of load or shock resistance that is required in this application ? For instance the bearing listed below meets the temp requirements for the application 6204 Full Ceramic Bearing 20x47x14 Ball Bearings Or the full compliment Silicon nitride bearing 6204 Full Complement Ceramic Bearing 20x47x14 Si3N4 Ball Bearings I assume the bearing offered currently is something like this ? 6204-2RS Hybrid Ceramic Sealed Bearing 20x47x14 Ball Bearings SKF - Product data Last edited by berty987; 03-03-2012 at 05:30 AM.