E30: Are Upgraded Wheel Bearings Available?

[Ben Carufel]

My left front wheel bearing went out on one of my early runs at todays BMWCCA autocross, forcing me to park the car and hang out for the rest of the day. Bummer.

I am curious if anyone has any experience with aftermarket upgraded wheel bearings (front and rear) for E30s. Or do any even exist?

Here's a photo of me and the car -- I decided at the last minute Saturday evening to have the vinyl graphics for the car die cut and found a local shop that could do them while I waited at 5PM Saturday! Came out well, and I won "Best Costume" at the autocross today and a neat 1:24 scale Z4 model...

The theme is Ricky Bobby, Will Ferrell's character from Talladega Nights.

[Steve J.]

You need the decal on the front windshield

Wheel bearings: http://www.rrtsuspension.com/catalog...Path=1213_1299

[Eddy@ApexRaceParts]

I think im going to do the "Me Tiger" version on my car

[vmwerks]

Take the new bearing apart and pack it with GOOD grease. FWIW my wheel bearings would run about a season of autox and HPDE's.

[theruss1an1]

What does RRT do different to their bearings?

-Serge

[B.Watts]

What does RRT do different to their bearings?

They take vmwerks advice.

Take the new bearing apart and pack it with GOOD grease.

[robweenerpi]

I would put stock wheel bearings in the car and be happy. Don't touch the grease. Bearing companies are very picky about the type and amount of grease that goes into a bearing.

[B.Watts]

I can tell you that the RRT bearings have lasted longer on our car than stock ones in the past. Have you seen failures or shorter life out of bearings with high performance grease?

[jrkoupe]

Ben......I would stay stock as Rob mentioned. I get easily 20 track days on mine.....maybe 30. 1990 325i....

[Ben Carufel]

Thanks gents. Sounds like stock is a fine way to go. I was thinking someone had a super-crazy overly-engineered never-going-to-fail solution, but it sounds like the best idea is just to replace them every year or two .

[Greg S]

What kind of grease? MoS2?

[robweenerpi]

In college my major was Manufacturing. For a high precision part like bearings, ball joints, CV joints, etc. The amount tolerance built into the bearings is insanely low. Everything is SUPER tight. In a way is actually cheaper to produce them this way. Quality control in this type of manufacturing is statistically controlled and a large part of what they do. They want these parts to last, their reputation depends on making a quality part.

The grease they choose is high quality in most instances as the is amount of grease used. Most of these bearing makers like SKF or FAG have many years of testing and experience with this. I think it's silly to assume that I could grab some grease off the shelf, take the bearing apart, and make an improvement.

You can modify a bearing with aftermarket materials to improve its performance but the gain is minimal and the cost is high. It's not something the average club racer would stomach, most people wouldn't like a bill of 350-500 dollars per bearing.

[Ben Carufel]

OK, let me ask you guys this: Is there a preferred brand of bearing? There is some price variation and several brands...SKF, Ruville, FAG, etc.

Also, it looks like the rear wheel bearings can be bought as just the bearing, whereas the fronts have to be bought with the hub. Is this the case?

[B.Watts]

In college my major was Manufacturing. For a high precision part like bearings, ball joints, CV joints, etc. The amount tolerance built into the bearings is insanely low. Everything is SUPER tight. In a way is actually cheaper to produce them this way. Quality control in this type of manufacturing is statistically controlled and a large part of what they do. They want these parts to last, their reputation depends on making a quality part.

The grease they choose is high quality in most instances as the is amount of grease used. Most of these bearing makers like SKF or FAG have many years of testing and experience with this. I think it's silly to assume that I could grab some grease off the shelf, take the bearing apart, and make an improvement.

You can modify a bearing with aftermarket materials to improve its performance but the gain is minimal and the cost is high. It's not something the average club racer would stomach, most people wouldn't like a bill of 350-500 dollars per bearing.

The guys who are marketing these re-packed bearings have degrees in engineering and materials science...they aren't exactly shooting from the hip either.

You're failing to mention that the stock bearings are designed to last on a car doing 70-100 mph with minimal side loads. Surely there's a bit more heat and other things at play while doing 140+ mph with huge loads from big sticky tires while turning, braking, and accelerating? You could make your argument about almost any part on a BMW...they are all WELL engineered, but that doesn't make them optimal for use in a track/race car. How many parts do you sell every day that are designed to be an upgrade to an already well engineered and manufactured part on these cars?

It may be silly to assume you can improve these bearings, and yet I and others have plenty of experience doing just what you say is silly. If you can provide some evidence that the bearings don't last as long or that repacking them is dangerous, please do. Come on Rob, you're arguing with theory, I'm arguing with actual results as seen on our car and others.

Does it make a huge improvement? I think so. Bearings were lasting us about 1 season or so in the past. IIRC, the RRT bearings lasted about 3 before we replaced them for a little play rather than a complete failure. Replacing the grease certainly didn't cause any huge problems. We probably put as much abuse on bearings as anyone.

In the end, I'd recommend replacing them every season, no matter what kind you use...but I think, based on my experience, that using the RRT bearings will decrease the chance of having a bearing go bad and ruin your weekend between your normal replacement intervals. Replacing bearings at the track sucks.

[vmwerks]

I would put stock wheel bearings in the car and be happy. Don't touch the grease. Bearing companies are very picky about the type and amount of grease that goes into a bearing.

Ever take one apart? Do you see how little grease there is? Barely enough to make the bearings look wet. This is not a street car it is a track car and is subject to different use. FWIW the recommendation I recieved was from an ex BMW team mechanic.

BTW: My major was electronics and computer science, not that it means anything.

[robweenerpi]

Grease expands and turns into liquid when insanely hot. This is due to thermal welding of the ball to the race. A tiny portion of the ball is 'welded' to the race then removed by the other balls as they move across each other. I am not aware of any grease that can prevent this no matter what quantity of it is in the bearing. The only way to eliminate this is to use a ceramic ball which is harder and has lower drag. If you are repacking bearings you are wasting your time.

[B.Watts]

If you are repacking bearings you are wasting your time.

Again...can you provide any actual evidence based on experience besides a text book answer? You know better than that Rob.

The oil BMW recommends for it's factory motors is based on a LOT of research, engineering, etc as well but surely you admit there are sometimes better options on the market for race use?

[vmwerks]

Insanely hot? Exactly how hot? If you want to replace your wheel bearings every 20 track days or so, be my guest. We pack EVERY wheel bearing that we have installed in all the SpecE30 cars, my personal E30 track car and my IP car. Since we started doing this we haven't had a bearing failure, need more proof? I sure don't, especially since it costs very little to do so. Prior to this my E30 track car ate 2 sets of bearings last year.

BTW if it is good enough for BMW team mechanics why isn't it good enough for you? The guy I spoke with has been wrenching on BMW race cars longer than you have probably been alive.

Ben, spend the extra 2 minutes and grease the bearings other wise I would be more than happy to be your wheel bearing dealer.

OK, let me ask you guys this: Is there a preferred brand of bearing? There is some price variation and several brands...SKF, Ruville, FAG, etc.
Also, it looks like the rear wheel bearings can be bought as just the bearing, whereas the fronts have to be bought with the hub. Is this the case?

True, the rears are a real bitch to get off. Typically you'll go through 2 fronts for every set of rears. We use either the SKF or FAG. Buy the RRT bearings.. lifetime warranty? Can't beat that!

[Cybertronic]

What type of grease should we use for repacking the bearings?
And how exactly do you disassemble a front bearing?

-jonathan

[vmwerks]

What type of grease should we use for repacking the bearings?
And how exactly do you disassemble a front bearing?

-jonathan

Any high temp / high pressure synthetic wheel bearing grease should do fine. Most packaging will say it is for cars with disc brakes. I think we use the Castrol synthetic. The bearing when new can be pulled apart to expose the balls and races.

[dak656]

Grease expands and turns into liquid when insanely hot. This is due to thermal welding of the ball to the race. A tiny portion of the ball is 'welded' to the race then removed by the other balls as they move across each other. I am not aware of any grease that can prevent this no matter what quantity of it is in the bearing. The only way to eliminate this is to use a ceramic ball which is harder and has lower drag. If you are repacking bearings you are wasting your time.

Grease does have a lower viscosity when it is hot, but I don't agree with the other portion of your statement (and I worked for a bearing company for a couple of years). If a bearing 'welded' itself to a race, it would immediately spall and die. Especially a tapered roller bearing.

Auto manufacturers want to save money in every way possible, shorting bearings of the proper amount of grease is one way they do it. Repacking a bearing with fresh grease (and a good quantity of it) WILL make the bearing last longer, end of story. Wheel bearings from factories come with cheap grease in small amounts, that's just the way it is...

As for what to use, if you really want 'no compromises,' you can try DuPont Krytox (but it's $$$ - around $140 per cartridge). Alternatively, Mobil SHC 220 is another good one that should last a while.

[JGood325]

Wow, RRT has a lifetime warranty on the bearings, and they are relatively cheap. Why would you go with anything but that?

[mtrsprt]

Just curious, as I read through this thread... We are all in agreement that the RRT/other repacked bearings are great items, due to the excellent choice of grease that they pack them with...
But, simply out of curiosity, is there any information on what kind of grease is in the OEM/OE replacement bearings? I only ask becuase there appears to be much info on the repacked bearings. But, there appear to only be assumptions being made about the original grease packing...
Just figured this would be useful to this thread and I don't know the answer.

[vmwerks]

Just curious, as I read through this thread... We are all in agreement that the RRT/other repacked bearings are great items, due to the excellent choice of grease that they pack them with...
But, simply out of curiosity, is there any information on what kind of grease is in the OEM/OE replacement bearings? I only ask becuase there appears to be much info on the repacked bearings. But, there appear to only be assumptions being made about the original grease packing...
Just figured this would be useful to this thread and I don't know the answer.

IMO there isn't ENOUGH grease, I don't think it is the quality of the grease.

[S.Lang]

Wow, RRT has a lifetime warranty on the bearings, and they are relatively cheap. Why would you go with anything but that?

If you race your car, that statement above is sort of a thread-ender.

DOES RRT in fact warrant these for lifetime on a race car? And does the bearing have to have failed in order for the warranty to be honored? Important questions. Everyone should be replacing bearings at short enough intervals so they'll never see a failed one, barring a manufacturing defect. How does this affect the "lifetime warranty"?

If not, a yearly replacement of the stock factory bearing might actually be the cheapest way to go.