captainmarko
Member
Just curious.
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What is the life expectancy of our wheel bearings?
- Thread starter captainmarko
- Start date
stooie
Member
What an interesting question! (Yup, I'm a nerd.)
The short answer is "probably longer than that of the bike's owner."
Most bearings have two things that contribute to limiting their life, metal fatigue and contamination.
Bearing analysis indicates that bearings will always suffer surface fatigue failures eventually. Fortunately, they can be designed for the probability of when the failure will occur to be WAY out there. Think in terms of many hundreds of thousands of miles, if not more.
The vast majority of bearing failures are caused by contaminants getting past the bearing seals and into the bearings. Then the contaminant becomes a stress concentration problem as it passes between the rolling element and the bearing race. This causes local high local stresses which eventually lead to surface fatigue and eventual bearing failure.
How long do the seals last? That's a function of the environment the bike is exposed to (I bet I won't surprise anyone to say that more dirt and moisture is a higher risk for bearing contamination.) I don't have data to back this up, but I would assume that a GS ridden extensively off road would have a higher risk of a bearing failure than an RT ridden exclusively on the street.
In any event, bearing seal technology has matured a lot in the last 40+ years that I've been around this sort of stuff. Modern seals aren't bullet proof, but they're awfully darn good. For folks riding on the street (and again subject to revision based on service data from the field) I wouldn't worry about it. I'd focus on the more cosmic conundrums of crunchy vs. creamy peanut butter and great taste vs less filling beer.
Ride long and prosper,
Bob Stewart
The short answer is "probably longer than that of the bike's owner."
Most bearings have two things that contribute to limiting their life, metal fatigue and contamination.
Bearing analysis indicates that bearings will always suffer surface fatigue failures eventually. Fortunately, they can be designed for the probability of when the failure will occur to be WAY out there. Think in terms of many hundreds of thousands of miles, if not more.
The vast majority of bearing failures are caused by contaminants getting past the bearing seals and into the bearings. Then the contaminant becomes a stress concentration problem as it passes between the rolling element and the bearing race. This causes local high local stresses which eventually lead to surface fatigue and eventual bearing failure.
How long do the seals last? That's a function of the environment the bike is exposed to (I bet I won't surprise anyone to say that more dirt and moisture is a higher risk for bearing contamination.) I don't have data to back this up, but I would assume that a GS ridden extensively off road would have a higher risk of a bearing failure than an RT ridden exclusively on the street.
In any event, bearing seal technology has matured a lot in the last 40+ years that I've been around this sort of stuff. Modern seals aren't bullet proof, but they're awfully darn good. For folks riding on the street (and again subject to revision based on service data from the field) I wouldn't worry about it. I'd focus on the more cosmic conundrums of crunchy vs. creamy peanut butter and great taste vs less filling beer.
Ride long and prosper,
Bob Stewart
captainmarko
Member
Now THAT is an answer! Thanks, Bob.
And Trader Joe's Creamy Salted Almond Butter for conundrum #1. Anything brewed by Founders Brewing for #2, particularly the Backwoods Bastard.
Here is a thread from F-Twins on the subject-
https://forums.bmwmoa.org/showthread.php?73076-Rear-wheel-bearings-on-a-F800GS
OM
https://forums.bmwmoa.org/showthread.php?73076-Rear-wheel-bearings-on-a-F800GS
OM
pappy35
New member
...just remember: it's all RELATIVE!
taran1900
Member
A long time for modern wheel bearings. The last time I thought about wheel bearings was 1994 I think. This is when I sold my 1984 R100RS, the last bike I owned that required routine maintenance on the wheel bearings. Since then I've never touched them. Two of the bikes owned after that R100 I've put well over 100 thousand miles on them. As far as I know, the wheel bearings are a lifetime item.
No such thing as lifetime bearings, though modern sealed have made them out of sight out of mind for many. Some just keep rolling. Some will fail.
The thread linked by Omega Man shows some damage.Different model, but they do fail. Nasty pictures included.
I have replaced several sets on front wheels of Wedge K and RT's with a range of 22K to 140K. Have pulled bearing seals( covers) to check amount of factory supplied grease and it has been all over the place. I now remove them prior to install and add grease if it looks iffy. BMW sources different brands, some SKF, some from Taiwan and both have had minimal grease out of the box.
I do a finger check when changing tires, except for the one time I did not as I got distracted with our BS banter, and an hour later we were back at my house after lunch changing a wheel on a K13GT with a backup so the bud could head out on a trip. Thinking 30K on that bike. You can feel a suspect bearing , but it can spoil plans as well.
No rhyme or reason, maybe not enough lube, maybe too close with a pressure washer blowing past the rims seal and have found a few over-torqued front axles from folks guessing torque values during a tire change. One K12GT had just had a tire change at a dealer and the axle was close to 100nm when he came by with odd handling.The wheel would barely roll!
My 09 GSA at 135K has seen water a few times and finally got notchy and replaced last June. Just riding through water shouldn't cause issues, however high pressure could...which I never do.
The thread linked by Omega Man shows some damage.Different model, but they do fail. Nasty pictures included.
I have replaced several sets on front wheels of Wedge K and RT's with a range of 22K to 140K. Have pulled bearing seals( covers) to check amount of factory supplied grease and it has been all over the place. I now remove them prior to install and add grease if it looks iffy. BMW sources different brands, some SKF, some from Taiwan and both have had minimal grease out of the box.
I do a finger check when changing tires, except for the one time I did not as I got distracted with our BS banter, and an hour later we were back at my house after lunch changing a wheel on a K13GT with a backup so the bud could head out on a trip. Thinking 30K on that bike. You can feel a suspect bearing , but it can spoil plans as well.
No rhyme or reason, maybe not enough lube, maybe too close with a pressure washer blowing past the rims seal and have found a few over-torqued front axles from folks guessing torque values during a tire change. One K12GT had just had a tire change at a dealer and the axle was close to 100nm when he came by with odd handling.The wheel would barely roll!
My 09 GSA at 135K has seen water a few times and finally got notchy and replaced last June. Just riding through water shouldn't cause issues, however high pressure could...which I never do.
lirider
Member
I second the Founders recommendation ... go out find yourself a "Better Half" or "Blushing Monk" if you haven't already. The Better Half kicks up the Backwoods a tad. The Blushing Monk has a raspberry twang that's fairly unusual.
alegerlotz
Member
I can't speak specifically about bmw motorcycle bearings, but ...
I had a 1996 bmw 328is that I raced the crap out of and one of the front wheel bearings gave up at around 100K miles. That was extreme conditions, riding over rumble strips to eek about a bit more surface, etc... If I drove the car sanely on the street, I'm sure it would have been many hundreds of thousands of miles. I sold the car to a guy with about 120K (60K of which were race track miles) and he finally blew the engine with about 160K miles on the odometer. That car was bullet proof in almost every way.
I had a 1996 bmw 328is that I raced the crap out of and one of the front wheel bearings gave up at around 100K miles. That was extreme conditions, riding over rumble strips to eek about a bit more surface, etc... If I drove the car sanely on the street, I'm sure it would have been many hundreds of thousands of miles. I sold the car to a guy with about 120K (60K of which were race track miles) and he finally blew the engine with about 160K miles on the odometer. That car was bullet proof in almost every way.
bearing seal failure
A few years back I went to visit a friend in Topeka Ks. He was expecting me and was waiting in his driveway.When i applied my brakes I rolled past his driveway because my brake lever went to the handlebar.We couldn't find any leaking brake fluid and the master cylinders showed the correct level. I had the bike towed to a dealer who would be closed when the bike arrived. I gave the dealer my info and told him what happened over the phone.. I also told him that after they figured out why my brakes failed to see if they could see a reason for me to feel a slight click in my steering occasionally. They couldn't find anything wrong with my brakes and even started replacing parts in hopes of solving my problem and getting me home to not miss any work.I got a ride to the dealer from an moa member.When we got there two very experienced service techs were scratching their heads looking at my bike.We asked if the clicking I had felt in my steering could in any way effect my brakes.Hearing that they looked down at the wheel bearings and saw that the outer dust seal on one of my bearings was gone and so were the bearings.The front end of my 2008 K1200gt was so strong that I couldn't notice my wheel bearing had failed and that I was riding with bearings only on one side of the wheel. With the bearings gone there was just enough play that the wheel would shimmy enough to push the brake pads back.Then when I would apply the brakes I would only be pushing the pad closer to where it should have been and not putting any pressure on the disc. The service writer who took my info over the phone was so concerned with getting the big problem done ,my brakes,that he neglected to write down that I mentioned feeling a click in my steering. That bike had about 80k on it when that happened to the best of my memory.
A few years back I went to visit a friend in Topeka Ks. He was expecting me and was waiting in his driveway.When i applied my brakes I rolled past his driveway because my brake lever went to the handlebar.We couldn't find any leaking brake fluid and the master cylinders showed the correct level. I had the bike towed to a dealer who would be closed when the bike arrived. I gave the dealer my info and told him what happened over the phone.. I also told him that after they figured out why my brakes failed to see if they could see a reason for me to feel a slight click in my steering occasionally. They couldn't find anything wrong with my brakes and even started replacing parts in hopes of solving my problem and getting me home to not miss any work.I got a ride to the dealer from an moa member.When we got there two very experienced service techs were scratching their heads looking at my bike.We asked if the clicking I had felt in my steering could in any way effect my brakes.Hearing that they looked down at the wheel bearings and saw that the outer dust seal on one of my bearings was gone and so were the bearings.The front end of my 2008 K1200gt was so strong that I couldn't notice my wheel bearing had failed and that I was riding with bearings only on one side of the wheel. With the bearings gone there was just enough play that the wheel would shimmy enough to push the brake pads back.Then when I would apply the brakes I would only be pushing the pad closer to where it should have been and not putting any pressure on the disc. The service writer who took my info over the phone was so concerned with getting the big problem done ,my brakes,that he neglected to write down that I mentioned feeling a click in my steering. That bike had about 80k on it when that happened to the best of my memory.
mlytle
Member
105258
Old Rider - OK Mechanic
Wheel bearings
I change front wheel bearings every 80,000 kms for no other reason then I don't have worry on long trips. I also make sure the seals are well packed with waterproof grease when I change tires. So far no failures. Just one person's opinion. Great question.
I change front wheel bearings every 80,000 kms for no other reason then I don't have worry on long trips. I also make sure the seals are well packed with waterproof grease when I change tires. So far no failures. Just one person's opinion. Great question.
Rinty
New member
Once, with an early BMW 320i, I did a 2,000 km road trip with funny noise coming from the rear end. It turned out to be a shot rear wheel bearing, but there were two of them on each side, and I made it back on the other bearing, which was good.
Sometimes you get lucky.
