mobil aviation grease e1664053783850

Lubes, oils, greases and fluids for your bike

Let’s start with a very, very hard to differenciate terms: what is a lube, or lubricant, and what makes it different from an oil ?

That’s quite hard to distinguish, so follow me: Lubricant is a general term, which also covers oils. Oil is a misnomer, which was already available before synthetic oils, which is a misnomer, too(!). There is no such thing as “synthetic oil”, for a start: it’s a synthetic lubricant, as “carrier base” is not oil. Oil is …very, very petroleum-related thing. So, forget about “oils”; they are total misnomers, but here is some handy stuff to know: if some lubricant has “oil” in its name, that means it is used internally! Like, engine oil: it’s in the engine crankcase, you don’t wash your engine with engine oil. You pour it into engine. (right?). Like gear oil. Or transmission oil. A thing to note is, oil is not just a lubricant, it’s also a cooling agent, UNLIKE grease: grease don’t like heat and oxidise pretty quickly compared to oils and other lubricants.

Guess what? It is not even that simple: for example, if you have an automatic transmission in your car, it’s not “transmission oil”, but “transmission fluid” – but why? Because they are very different chemicals. Manual transmissions oils cool gearboxes and lubricate them, while transmission fluids’ main role is to drive some hydraulic actuators, like your disc brakes does.

Ok; now we know oil and lubricant is, so what is grease anyway? …it’ s a lubricant, too. But it’s more solid, more viscous. A grease has to stick on surfaces which is meant to lubricate.

Why do we need to know about lubricants, when using in bicycles ?

Mobil XHP 222 grease
For 5-6$, you get Mobil XHP 222 cartridge, which is 390gr’s, and good enough for few decades of use.

I’m interested in lubricants, because I’m also interested in many mechanical devices from cars to hand tools: if you follow OEM recommendations, you need to stock a few thousands of dollars worth of lubricants filling your whole home. That is not possible, acceptable and efficient in any way. It’s not practical, too: I’d like to use 2 types of grease to lube my bikes’ headset, bearing in my cars, and probably my wheelcart too, without having to carry / switch between 35 types / brands of grease, doing the same thing and probably manufactured by the same company.

But I’m not the type that dip chains in olive oil with confidence, and then make a salad with same bottle, admiring my work. The real world is something in between the OEM’s directions and blissful ignorants’ way. I also like to use anything I have to its full potential, while enjoying longevity, and I’m cheap.

Looking for substitutes, as we don’t want to keep many items, and also they’ re expensive…

Lubrication is complex, but not something on a quantum mechanics level. So why there are soo many varieties? Actually, there aren’t much as we perceive. There are certain types of lubes, intended to be used in certain scenarios, having some viscosity, and certain base (“carrier fluid”) with additives each serving a purpose. When you want to replace an OEM fluid, you have to know all about these, but doesn’t need to be very frantic about matching every aspect of the original fluid / lube.

So, lets talk about what we have to know:

Viscosity of grease

Viscosity is important, as the correct replacement have to fill the moving parts, but not be too thin to run. For example, if your bearing grease is too thin, it may easily flow out from bearings. This is not to be confused with stickiness, but certainly, viscosity is a factor in stickiness, too.

A too viscous grease may add extra friction and can promote wear. Greases are rated with “NLGI grade” to describe its viscosity, hence consistency. Very thin greases have 000,00, and 0 designation. 000 is considered very soft, having consistency of ketchup, while 00 is more like mayonnaise. Today’s side topic is salads and dressings 😉

Then comes 1,2,3,4,5,6. 6 ise very thick, and anything between 1,2,3 and 4 is fit for almost everything. I use 2 and 3 for bikes. If I don’t have a car, or some heavy grade equipment, I’d probably use 1 and 3, or maybe even 0 and 2, if I was feeling light-headed. There is an extra advantage to using 2 and 3: they are abundant and cheap, and also much easier to find. I think the yellowish-green Shimano grease is probably has NLGI grade 1.

Main parameter to choose a grade in bike application is, load. Forget about speed and temperature, as these both is non-existant in the equation when bikes are considered. Any speed is considered “extremely slow” when it comes to bearing terms. You need THICK grease in high load. So, what is a high load? A ton? 10 tons? 1 kg? It’s about bearing parameters, but believe me, considering their size and construction, bearings in bike applications abused pretty badly. So, a more viscous grade is needed. I’d easily pick grade 4 for everything, if someone else does the pedalling! But I think Grade 2-3 is a good compromise between friction and protection, for bicycles.

If you have 2 grades like me, use the thickest one on your bottom bracket bearings, and also in headsets. You can get away with the softer one in hub bearings, especially if they are cup and cone like Shimano. Bigger the balls, softer the grease can be. The OEM grease comes in Shimano hubs is a superb choice, yet I’d never use it in GXP or Hollowtech bottom brackets.

DOT fluids for hydraulic bicycle brakes (Sram and others)

Luckily, every fluid used in bikes are either automotive or motorbike related. Take DOT brake fluids, mineral brake fluids, or chain lubes. Even suspension oils. They are nothing very original. And luckily, viscosity doesn’t matter much here, as compared to these vehicles, bikes are simple and subject to much less demanding conditions.

If you have brakes using DOT fluids, like Sram Guide’s, or any other Sram (formerly Avid) go and buy DOT 4 or DOT 5.1. In fact, be cheap, and get cheapest DOT 4, it’s still an overkill for bike

Motul ATF VI: a near-perfect replacement for mineral brake fluids, if not better...
Motul ATF VI: a near-perfect replacement for mineral brake fluids, if not better…

brakes. Rule of thumb is, DOT fluids attract water from air, and your brakes only need a minuscule amount of DOT fluid. When you break the seal of the bottle, clock starts ticking. Never seen any DOT fluid comes less then a 1/2 liter, so it may be a good idea to buy one and share with friends, or get a big syringe and fill them it in service stations, or maybe, change your cars’ brake fluid and bike’s fluid at the same time! When you open the bottle, you have to use it in 6 months. Dumping 90% of a DOT fluid is not so eco-friendly, and using DOT fluid for brakes is a bad engineering practice in many ways, sorry Sram.

Mineral oils (Shimano, Magura, Tektro)

For mineral world of brakes, its not hard to choose, either. Basically, mineral brake fluid is automatic transmission fluid. When you look at the specs, they are almost identically the same. I buy a liter of the best ATF 6 fluid available, and use it on my bike, but also for my steering box in my car. It’s dirt cheap.


For suspension, I use motorbike fluids! I’m not a shock fan; only shock I have is a Rock Shox SID, and it uses 15w and 5w suspension oil – you can get away with only 15w, but I do it by the book. 15w is known as “medium grade oil” in motorbike-speak. Original ones are super expensive (Sram stuff is 3x-3.5 more expensive compared to Eni 15w I use. For 5w, I use Liqui Moly, premium stuff but still lot cheaper than Sram), so I use motorbike fluids, as they’re easy to find and still more cheaper.

What about chain lube ?

Chain lubes deserve a post on its own. I wax my chains whenever I can. If I can’t I use dry lubes. Without going into detail:

  • Use dry lubes when you can, as they attract much less dust
  • Do not use aerosols. You’ re damaging the environment, and your wallet too.
  • Cleaning is almost as critical, if not more. Properly clean your chains.
  • Do not overpay for premium stuff. A proper brand with an entry level product is ok. Chains won’t last forever, even with OSD-level waxing. Some guys spend more money on chain lubes then chains, and this is not a worthwhile investment in any way!



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