|Anyone Using Silicon Nitride Ceramic Ball Bearings?||PsyDoc|
Oct 8, 2003 6:42 AM
|I was thinking about replacing the steel ball bearings in my DA hubs with silicon nitride ceramic ball bearings. I have heard they are more durable and provide less resistance. Anyone try this? If so, do you still use grease or simply a light coating of oil as the ceramic bearings are durable up to 1800 degrees?|
Oct 8, 2003 4:30 PM
|If you decide to use them, I would still grease them. The friction still exists, therefore you need to lubricate them. Note, if the balls are too hard, they may eat your bearing races and wear em out faster, because they're made of steel.
The only production wheelset that uses them is the Zipp Z3 wheelset. I think it costs about $3000!! But I think the entire bearing is silicon nitride, not just the balls.
|Try Sildenafil Citrate||pedalAZ|
Oct 8, 2003 6:10 PM
|along with a light coating of oil, and you'll ride like the wind.|
|Kind of pointless, don't you think?||Kerry Irons|
Oct 9, 2003 5:02 PM
|Are you saying that you could tell the difference in rolling friction? Are you wearing out the bearings in your current hubs? I didn't think so.|
Oct 10, 2003 4:02 AM
|...because I have no idea what would the "practical" effect would be by swapping them out. Would the harder ceramic bearings destroy the races in 2-3 years? Would the wheels feel "psychologically" faster? Hell, I do not even know how much a set of ceramic bearings for both wheels would cost, which might make such a swap too expensive. I just posed a relatively simple question after my interest was sparked from reading this: http://www.zulau.com/news/skf%20ceramic.htm
As for wearing out my hubs...I doubt I ever would. I had a set of ultegra hubs from the late 80's/early 90's that appeared to be eternal. Those hubs went with the wheels when I sold my bike in 2001.
Oct 10, 2003 12:40 PM
|If you have the $$$ and simply want a psych boost, then go for it.
The ceramic bearings boast some insane spherical consistencies from which your steel hub races would not benefit. For this reason, I can only see an advantage using a ceramic cartridge bearing set mounted on super high precision bearing seats and spindle. Even then, bicycle rpms are too low to realize the full potential of the bearings.
Seal drag, grease viscosity and pre-load has a much greater affect than ceramic bearings. Aerodynamic improvements will be far more noticeable.
|Thanks for the additional info...nm||PsyDoc|
Oct 11, 2003 10:48 AM
|Friction in perspective||M_Currie|
Oct 11, 2003 6:26 PM
|Just to get a rough idea here, I refer back to my "New Departure Handbook" of 1932 (Ball bearings haven't changed much really), where they note that "The frictional torque of a 1202 bearing, operating under a load of 150 lbs., at 1140 r.p.m., has been found to be .00062 h.p." A 1202 is a plain radial bearing with 15 mm bore, 25 mm outside diameter, 11 mm thick - somewhat larger than a typical cartridge bearing in a bicycle hub.
That's not a whole lot of friction to start with.
|re: Anyone Using Silicon Nitride Ceramic Ball Bearings?||scorpionking|
Oct 15, 2003 8:05 PM
|No, but recently I have been adding a bit of helium to my tires for races with long climbs. It makes me a lot faster. Now I just need to find some plutonium based nuclear bearings for my wheels, that must be what has been slowing me down.|| |