Grease Compatibility
 

I used to own a old Benz and service it myself whenever possible. I wanted to add some grease to the wheel bearing one time, but stopped when I read in the workshop manual that using generic wheel bearing grease will destroy the wheel bearing because such grease is not compatible with Benz's factory packed grease. The manual went on to say mixing factory grease with generic grease might cause a chemical reaction that turns the combo grease into liquid that leaks out.

I just pulled apart the head set on my bike and noticed the bearings might do well with a little more grease. Can I use regular bearing grease from Autozone and just add it into whatever grease is on the bearing already? I have to ask to be sure after the enlightening experience thanks to Benz's technical writer.

I'm one of those anal types that will use solvent and remove all bearing grease then re-grease bearings whenever I change grease types or do not previously know what type grease was used.

It is true that some greases don't play nice together, however, this is probably rare. If you read the label on most greases it warns against using them with other types.

To be safe, you can clean out all the old grease and re-pack with the grease of your choice. I prefer to use a sticky grease like StaLube marine grade.

That's what I was thinking too. Once you have the headset open it takes so little extra effort to clean out the old grease that not doing so just feels wrong.

I tried to learn about this subject awhile back but there was not a ton of info. available online. The one thing I did learn is that it's the different bases that greases are made that can make them incompatible.

I have also read in the Barnett's manual not to use automotive grease in bike bearings. Unfortunately he did not say why. The only thing I can figure out is that auto bearing grease is too thick and will cause excess drag.

I'd like to hear more about this subject from someone who is a grease expert.

Marketing BS is ALL that is.
I have tried a couple of those synthetic "bike specific" greases that causes a LOT of "drag".
Nothing but automotive type greases for me.

It's not all BS. There are greases incompatible with other types but you are unlikely to have the problem with the standard over-the-counter brands.

That said, why not give the bearings a decent cleaning and add all fresh grease? You don't have to get them surgically clean, just wipe off as much of the original grease as you can and replace with fresh stuff.

Automotive grease is fine but lithium based lighter greases are usually the recommended type for bike bearings.

Just to be clear, the Barnett's manual didn't say why you shoudn't use auto grease and he wasn't marketing any specific grease. The grease drag theory came from somewhere else. That's why I said it would be nice to hear from a grease expert.

Why do you use auto type grease? Does it last longer or is it just cheaper? I've never tried it because I work at a bike shop and bicycle grease is more easily accessible for me.

Auto grease is a hell of a lot cheaper and the same stuff. +1 on the cleanout - it's worth it.

The Benz warning is probably 10% fact and 90% a marketing ploy. However you should clean out and replace all the grease is to get rid of grime and metal particles that will wear down the parts.

Do you know that they are the same thing for a fact or are you just making things up?

http://www.bestsynthetic.com/edu-grease.shtml
http://www.pecuniary.com/faq/grease-compatibility.html

The Park Tool grease tub can be found for $7.99 and some auto bearing grease as low as $5. 1+ lb tubs should last a home mechanic for a couple years. That's not a huge difference to me. I won't buy tubs of grease since it is virtually impossible to prevent it from getting contaminated once you open it. I only use grease from a tube.

I buy tubs or the large 14-oz tubes of Phil Grease but I pack the bulk grease into a Duelco grease gun and use that to apply it. That way the grease stays clean, the Duelco meters just what I need and I can buy grease in large enough quantities to keep the price reasonable.

It's the soap used in the mixture that makes differing types of grease incompatible. Most automotive-based grease use lithium soap but you can still have compatibly problems between synthetic and vegetable based lithium grease. Then there are the grease types with additives such as Teflon. Considering how little pressure and heat bicycle bearings are subjected too most any grease will work as long as there is no contamination present from incompatible grease or petroleum products. My favorite is Aircraft approved red synthetic grease available from aircraft supply retailers. It's impervious to water infiltration, extreme heat, and it's super slick. It's also compatible with any other aircraft approved grease types. For my bicycles I had been using it but having retired I ran out of my personal supply of that stuff and purchased a tub of green colored marine grease. In any case when I service the bearings of anything the bearings get a through cleaning with mineral sprits to remove all traces of the old grease (compatible or not) dirt, and grime. Bicycle Coaster brakes need grease that can survive high temperatures especially if the bicycle is used in an area with long steep hills. When servicing a coaster brake hub I use red colored synthetic automotive grease made for disc brake hubs as this grease is made for very high temperatures.

I have yet to do the headset on my bike and probably won't for some time since it's completely fine
But I did repack a pedal. I tried Finish Line w/Teflon and it was simply too thick. I tried thinning the grease -many times with varying amounts of each of the following
chainsaw oil- that helped ..Once I squirted in quite a bit of some Pedro lube to the concoction the pedal turned very smoothly -nearly as well as the perfectly greased pedal which I hadn't yet touched ..although, the sound of the pedal revolving wasn't as dampered as the untouched one. Hard to describe the sound created -not a grinding one, though. I then added Crisco to the mix for it's thicker consistency to match the appearance of the untouched pedals grease ..but it didn't do anything for the noise.
I went out and bought red Mobil synthetic grease to try
It looked right except for the color
Too thick. Too much drag like the FL w/ teflon grease only.
I also bought some cheap amber and white lithium grease
I tried the amber one first
barely coating the bearings in the grease before placing in ..CAREFULLY. The grease isn't thick enough to hold the bearings in and too much grease just adds to the drag
Perfect. Still isn't QUITE as smooth as the untouched pedal but it's not noticable to anyone but me. No noise.

I'm thinking a light coating is all that's needed. Too much and stuff just doesn't move as nicely.
The grease isn't the same as what's on the other pedal ..that pedals grease is thick
This lithium turns very liquidy as did all my other experimental grease mixtures ..but none ran out.

For bike purposes don't worry about mixing greases
Ordinary lithium grease is the cheapest I found and works very well. If your headset turns well I'd leave it ..putting in more may make everything appear to be better taken care of
but it may just be a waste that increases drag.

I've never had any problems using automotive grease and my LBS actually recommended that I just use that anyway. I've even done quick jobs where I mix the old with the new and haven't once had a problem.

Do you know what makes a grease a "high temperature" grease? Does it just resist liquification at high temps? Does it protect just as well at "low temps"?

What would make a grease "bicycle specific"? I'm guessing it's a combination of water resistance and viscosity but I'd love to know for sure.

High temperature automotive grade grease is a synthetic blend capable of withstanding very high temperatures generated by automotive disk brake hubs. It performs well in extremely low temperatures as well. Most all this type of grease is the same stuff approved for aircraft use, which needs to endure extremely low temperatures encountered at high altitudes. It costs less in that it does not go through testing for aircraft use, which would add considerable and unnecessary cost.
You just package the grease in a tube labeled for use with bicycles. Typically, this grease will be the same as marine grade grease as most bearing on bicycles are not equipped with rubber seals that seal in the grease and seal out water, dirt, and grime. Most of them also contain Teflon in an effort to make it very slick and tacky and having Teflon listed on the package promotes purchasing that tube of grease on the shelf of your LBS.

You should service the bearings on your bike at least once a year. Not because the grease will be bad in a year but simply to remove any collected dust, moisture, dirt, metal shavings from the bearings and balls, and general grime.

ATB and MTB bikes used off road and do not have sealed cassette type bearings should have the bearing serviced every three months or after a ride where you got mud and water around the axels and bottom bracket.

Grease compatability chart:

http://www.mpclubricants.com/GreaseCompatibility.pdf

This of course assumes we are aware of the grease's base/soap/thickener that is already in the bearings. Always an excellent practice to wash and flush completely any unknown grease before adding fresh grease.

My credentials include factory bearing schools and the selling of these products for, well for a little bit.

High Temp means it resists liquification (thinning) at (you guessed it) elevated temperatures. How hot does it get where you ride?

Bicycle Specific means it was purchased in high volume and re-packaged in small containers and re-sold at obscene mark-ups.

Don't be a sap; grease is grease (really!).

Contaminated? What do you do, pee in it? :eek:

I know what Pete Hamer is saying. If you dip grease out of an open tub with your fingers or a small brush, dirt and crud from the parts can be carried back into the tub as well as general dirt from the surroundings. That's why I repack grease from a larger container into a Duelco grease gun. It keeps the bulk grease clean and keeps the grease-in-service clean too.

When you work at a shop it is much harder to keep tubs of grease from getting contaminated. There are other people that might use it and they might not be very careful. I would never use a tub of grease at a bike shop for bearing o-haul. I wouldn't buy at tub of grease for home use either because it would get too old before I use it all up.

Sorry, I'm not a grease specialist. I suspect you aren't either. There might be a bit more to this subject than you or I know. As a professional bicycle mechanic I consider it worth investigating claims made by people with no credentials on public bike forums before I apply them in my work. Especially when they contradict what I read in credible bicycle repair manuals. Here is a quote from the Barnett's manual Volume 1, fifth edition, page 1-8, "Not all greases are suitable for bicycle use. Bicycle bearings operate in a relatively low temperature range, so grease designed for automaotive use often does not become effective at bicycle operating temperatures.". And from the AMSOIL site "Base Oil - Many different types of base oil may be used in the manufacture of a grease, including petroleum (napthenic, parafinic) and synthetic (PAO's, esters, silicones, glycols). Just as with motor oils and transmission fluids, the viscosity of the base oil is the most significant property. A lighter, lower viscosity base oil is used to formulate low temperature greases, while a heavier, higher viscosity base oil is used to formulate high temperature greases." If you know something that can convince me that you are right and the Barnett's manual is wrong I would like to hear it. Until then I'll continue to listetn to the experts. Whining about price isn't a valid argument either.

Wow this thread has become rather testy. The OP wanted to know if a general purpose grease at their local auto parts store was ok to use.

The short answer is yes, it's ok. The long answer is it depends on the grease and how tacky it is (because of the thickener and additives used and the greases stated/designed purpose) and what temperature range you want or the environmental conditions you will face in your local area.

It may surprise many that most "Bicycle Greases" are NGLI "2" greases, the same as automotive grease. Just look up Finish Line Teflon Bicycle grease (Here's a link to the specs - pdf) or Park's PolyLube 1000 Lubricant. To put into perspective, competitive in-line skaters and skateboarders use a NGLI "1.5" grade grease on their bearings.

I don't think anybody is going to buy a tub/tube of hi-temp disc brake grease or CV grease and use that on their bike bearings and it isn't designed for that purpose. Within the NGLI 2 spec, there is a relatively wide range of fluidity allowed. If one buys Slick 50's Grease One or Mobil One synthetic grease, you'll find those greases consistency and fluidity is closer to the minimum spec and seems more like a 1.5 rated grease because of the carrier oil and thickeners used.

The old DuPont Teflon Bearing Grease you used to see in bike shops has been replaced with Dupont's Krytox grease and I don't think many would buy a grease, even if it's considered the best money can buy, that's costs a minimum of $30 for a 2 oz tube of grease that's good from -95°C to +343°C and is slick regardless how thin the coating is, will stay there without shearing or washout, and not feel like it's dragging or holding you back because it's too tacky or thick. According to DuPont, Krytox has been used from the Mars Rover to Nascar and the Tour de France as well as precision miniature/micro machines and electronics. Although hard to find DTBG, you can still buy the old formula and it comes in an injector, Calhoun Cycle for example, and here's a picture of the packaging.

Most of these grease arguments are just over-thinking it. Even over at Bob's the Oil Guy forums, you'll see reps and techs from various companies argue for and defend their products over what is best for a particular application. The bottom line to to find a product, in this case grease, that meets your needs/satisfies the requirements while allowing you to get the maximum amount performance with the least effort from your bike and lasts/is durable.

It's a bicycle headset, not the high-heat environment of a motor vehicle front axle. As already noted, simply clean out the old grease with a solvent or just a rag if you want, until everything is shiny clean... then use a grease of your choice. I might even consider petroleum jelly if that's all I had. But just about any clean grease you have in the workshop will work. After all, you could probably use the most viscous soap grease you can find in the headset and still not notice the difference -- especially if it's on an everyday utility bike. Just don't go overboard in applying -- a good smear on the cups, races and the balls is all you need.

And a thought if it is a utility bike that you aren't concerned about offending the OCP crowd... cut a piece of MTB inner tube and slip it over the bottom of the headtube before you refit the fork, then lap the inner tube over the bearing to stop dirt and water from working its way in. The rubber won't last a lifetime, but probably long enough before you decide to service the headset again.

I was told by an auto mechanic who has an insane depth of knowledge about way too many things NOT to use solvent on bearings because there is a chemical coating put on at the factory which causes grease to adhere to the balls. Solvent removes said coating. He said just really hot water, dish soap, and a cleaning brush is the thing. I tried it and the bearing is clean as a whistle at way lower cost than buying solvent.

Anybody else hear about this chemical coating? Was he pulling my leg?

Anyway as I said, the bearing is shiny, like new now. Ultra Dawn, cheaper than solvent.