Joined: Jan 2010
Posts: 9,818
Likes: 1,790
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
The grease in all Dura-Ace components from at least 1988 effectively lasts forever.
The Dura-Ace hubset, even the freehub ratchet that's seen a lot of use, spins just like new.
The grease in Dura-Ace STI levers, even after sitting for 10 years or more, doesn't gum up like the Ultegra shifter installed in the '90's on the same bike.
The grease in recent Shimano cable housings, applied by the factory thoughout their entire length, is silicone-based and will never gum up, evaporate or permeate the housing liner.
Many other greases eventually thicken, and many do not.
I've known the grease in older Miche and Normandy hubs to thicken into a hard plastic, yet many of the Maillard hubs from the mid-70's still spin freely without service.
Contamination will kill any grease, but well-shielded parts like UN-5X-series Shimano cartridge bottom brackets are known to last over 40,000 miles with no apparent loss of smoothness and no discernable freeplay. That grease is a small quantity (I've looked) but works for an incredible amount of use around these very smooth bearing surfaces.