I would also add that I haven’t noticed discs transfering a lot of heat to the hub itself. There’s a lot of aluminium and steel there, and when braking is hard, there’s usually a lot of wind and rotation to cool it all down. Would expect the discs to warp from overheating long before hub grease gets hot. Might put this to the test in the summer. 🙂 Of important criteria listed in paragraph 3.1. these greases only have problems with fulfilling Crit. 1. (for extreme conditions of bicycle use), while Crit. 3. is probably best satisfied of all the other grease types, except some enormously expensive ones.

Bicycle bearings don’t require any special grease IMO, as I’ve (tried to) explained in this post. Most any will do, while you can hardly go (measurably) better than a good quality lithium complex soap based grease with mineral base oil.Because it isn’t designed for prolonged water exposure, because it’s not designed for what you’re trying to make it claim, it’s NOT on the data sheets. There is no “ISO E” universal standard that all data sheets have so you’re looking for a statement that very few, if any, manufacturers claim.”

Further more this is long before you even consider that for headset bearings they generally have a range of motion of less than 20 degrees during a ride. You’d WANT a less viscous grease in the headset because of this short range of motion as the grease will have an easier time lubricating and protecting the bearings on this short arc when softer ala NLGI 1 or 1.5. I ride all year long, including winter when roads are full of very salty melted snow – no problems with bearing rust when using lithium (complex) grease. Another important thing is the speed. When a bicycle is ridden around 30 km/h, wheels turn about 250 times per minute (250 rpm). Pedals are rarely turning faster than 100 revolutions per minute, while the steerer bearings rpm is much lower. Also, the distances traveled by bearing balls are relatively small due to the small diameter shaft. When the tyre travels around one meter, hub bearings cover a distance of under 10 centimeters. Perhaps one of the referenced studies in the linked study would provide more information but I’m just evaluating what you linked. And frankly, it doesn’t actually state what you imply that it states/proves. This isn’t an argument against polyurea, it’s well known to be a great grease when you need a “sealed for life” application so it would be a good choice on non-serviceable bicycle bearings for that reason. But it’s also a fairly incompatible grease, Park’s formulation being an exception, presumably. So if you use it, then make sure to clean out all the old grease first. But superior? Why? Because Park uses it? Because it’s better in a given test without additives (ignoring incompatibility issues)?You have provided NO DATA AT ALL. NLGI2 is fine but is it ‘ideal’ or ‘optimal?’ No, because bicycles don’t need it. Please provide ONE study that shows NLGI2 is necessary for typical bicycle loads as thus far you haven’t provided ANY data so that would be a first. It is a common debate among cyclists (and mechanics) which is the best bicycle bearing grease – for use in hub, or steerer, brake pivot etc. bearings. Some swear by the old “axle grease” that “… my grandfather / father used …” Others recommend silicone, Teflon, graphite grease and so on.This postexplains important characteristics of various greases in terms of lubricating bicycle bearings. Similar arguments (or “arguments”) as Reason. Complete misunderstanding of the whole post (and subject), trying to find something to criticize. Don’t know why. Why do trolls troll? 🙂 Polytetrafluoroethylene is a fluorocarbon solid, as it is a high- molecular-weight polymer consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid.