Replace grease with oil?

[david roth]

As an inline speedskater, I cleaned my bearings weekly since I replaced the grease with high speed oil. It may have been a bother but the difference in speed made it a no brainer. Does anyone do this? Any special tools required to make sure bearings are aligned? I've read an article on this site about overhauling hubs and repacking the grease but is it too major of a job in bike hubs to do once a month. I don't expect to have to clean them weekly since the hubs are much farther off the ground and away from the dirt than speedskates. Any speedskaters out there who can relate?

[DaveM]

No personal experience...but supposedly some track bike racers use oil instead of grease. I assume it would give you some improvement. However, the downsides are obviously that you need to repack the wheel often. With a couple hand tools and practice, this shouldn't take any more time than your skate bearings. However, I would say that the risk of damaging the bearing races is higher in that if you mess them up, it can mean buying a whole new hub instead of just a new bearing. Most bikes have one bearing surface built into the hub itself. Also the issue of the oil leaking out and getting everywhere (on braking surfaces?).

The benefits may be questionable. A bike wheel turns at much lower rpms than a skate wheel so grease doesn't create as much drag here. Probably the two biggest factors in bike speed (beyond the rider) are aerodynamics and rolling resistance of the tires. Tires are probably the most overlooked aspect and different makes can have very different levels of resistance and higher price is no easy guarantee of a faster tire.

I'd say spend the 1-2 hours/week you'd spend re-oiling your wheels either riding or earning money to buy better tires. Probably have a bigger impact on your speed.

[david roth]

Good point about the rpm's...i didn't. onsider that. btw, what are some fast wheels if you wouldn't mind providing me a short cut?

[Joe_W]

Tyres: depends what is "fast" for you. If you get a flat on the bike leg of a triathlon you'll lose more time than if you had used the slightly slower but more durable tyres. I like Conti GP 4000s (they are now replaced by the Attack / Force combo), they are sturdy and fast rolling (several tests showed this). Schwalbe is preparing a new tyre for 2013 that is supposedly as fast and maybe better. Additionally, tubeless technology is improving for road bikes, might be a good thing to check out. For tyres, also read:
http://www.slowtwitch.com/Tech/All_About_Tubeless_j2799.html
http://www.slowtwitch.com/Products/Things_that_Roll/Tires/Fast_Tires_for_2012_-_2_j2686.html

Fast wheels: Zipp Firecrest 404 or 303 in the front and maybe a disk in the rear... but this can really depend on the frame! There was a test in Tour-Magazin (German cycling rag) two or three months ago, where they had that effect: another wheelset was much better in one frame than the Zipps.

Oh, and most of the high-end bearings cannot be repacked since they are "sealed" bearings, that is not cup and cone but rather a cartridge (note that sealed does not mean they are more waterproof than cup and cone bearings)
I recently found this article
http://www.slowtwitch.com/Tech/Bearing_Breakdown_2822.html
could be interesting for you, too

For non-racing I would use something like:
- high-end Shimano cup-and-cone hubs (serviceable)
- Halo Mercury rim (reasonably fast + light + no carbon)
- DT double butted spokes (or maybe "aero" spokes), stainless steel
- laced cross three (reliable pattern), maybe radial in the front (not too much lateral load, not-measurably-decreased drag, almost no weight reduction.... but looks better?)
Now I need to go and find them... and tell my wife I bought bike stuff again.
And it is your fault ;-)