Why do my rear bearings keep coming apart?

[andrewclaycomb]

When I first got the bike, after maybe 2 months of riding I noticed strange noises coming from the rear wheel. Send it off with a mechanic and he shows me all three bearings were about to come apart. In fact just the process of taking them out caused them to fall apart. So I'm thinking Whew glad I wasn't riding when they fell apart.

Well today I'm cruising about 55mph on a country road and the real wheel gradually starts to wobble more and more, and I start hearing screeching noises. For some reason I think it's the chain because the wheel doesn't spin very well for a bit, and then starts spinning freely again. I get the bike home gritting my teeth the whole way.

I take the rear wheel off and notice some grease is dripping out of where the axle goes into the wheel on the sprocket side. Take the wheel apart and low and behold, a bearing has exploded. I haven't taken the other side apart, but went ahead and ordered a new rear bearing set from Z1.

What do you guys think is causing this? That bearing only lasted a little over a year.

I'm ordering some new hardware for the wheel and added new rear cushions as well. The bike has always seemed to kick hard when putting it into first gear for the first time in the morning, so I'm thinking maybe this jerk is causing the bearings undue stress because of old rubbers.

[Shin-Ken 1074]

Hi, very unusual to get suss bearings these days, but never say never. I don't think its a case of stress on the rear bearings via the drive train issue as the bearing is a free floating part its not directly connected to something eg. a mechanical link. I would replace the bearing with another brand, I use Timmken and have not had a failure so far, I replace each set every 50,000km as part of my own home service. Overkill maybe however, its easier to do in my shed with tools than beside the road in the middle of nowhere at night in the rain. The place to buy bearings is from a bearing supplier (here anyway) as they are about 1/3 the price of a bike shop/dealer for the same thing, take the old bearing in or give them the number stamped on the bearing to get a match, Cheers.

P.S. Some bikes list the sprocket side rear bearing to have a steel shield for the outer race, some owners here may have a view on that issue, I replace them without the shield model bearing as specified with a rubber seal bearing and todate have not had a problem.

[paco13]

couple pssibilities;
1. flawed bearing

2 some one didn't install them properly (beat them in with hammer or pressed on the inner race)

3 accidently ommited the steal spacer sleave between bearings in hub when installing.

4 too much pressure washing aiming at the hub area to get the chain lube grime off.

5 bent axle

[Scotts]

How tight is your chain with you sitting on the bike? It may be too tight with you on it or you may not have the wheel straight.

Mine currently has about as much as an old dirt bike I had. I did a search on here to check out the opinions on this board. There are a wide variety of choices.

Search chain tension. Lots of cam chains come up the drive chain is in there.

Record the numbers off the bearings and you will be able to get locally. Check out the above suggestions first. I have not changed mine yet.

PM me anytime. My youngest daughter is moving out this weekend and maybe after that my schedule will come more in line with some things I want to do.
Should not be much of an issue for us to get together and meet.

If you get over to mid continent air port You are very close to me. when I am at work.

Scott

[bwringer]

2 some one didn't install them properly (beat them in with hammer or pressed on the inner race)

3 accidently ommited the steal spacer sleave between bearings in hub when installing.

Or one of the bearings didn't get seated all the way due to a clueless or inattentive installer.

In other words, installer error.


Do it yourself. Being responsible for one's own life has a way of focusing one's attention properly, usually leading to far better results than with almost any "perfeshunol" mechanic.

[andrewclaycomb]

How tight is your chain with you sitting on the bike? It may be too tight with you on it or you may not have the wheel straight.

Mine currently has about as much as an old dirt bike I had. I did a search on here to check out the opinions on this board. There are a wide variety of choices.

Search chain tension. Lots of cam chains come up the drive chain is in there.

Record the numbers off the bearings and you will be able to get locally. Check out the above suggestions first. I have not changed mine yet.

PM me anytime. My youngest daughter is moving out this weekend and maybe after that my schedule will come more in line with some things I want to do.
Should not be much of an issue for us to get together and meet.

If you get over to mid continent air port You are very close to me. when I am at work.

Scott

I never thought about this. I make sure the wheel is strait by aligning the marks on the tension adjuster doohickys, but when I adjust the tension, it's always with the bike up on it's center stand. I never thought about the added weight of the bike and my 265 lb self sitting on top of it.

One of these days, I would just like to meet you and see your bike. If you could help me out with things, that would be a bonus.

[andrewclaycomb]

Also, when I'm putting the new bearings in, Do I need to apply grease on anything? I have the wheel completely apart and have been wiping up as much grease as I can.

And the large bearing was the one that came apart on the road, but the other two fell apart in the process of pulling them out. Their innards didn't look very good either.

[Scotts]

I can tell ya we are about the same size then. about 250 myself. I have not seen the bearings you have. Does anyone know the generic name? If it is just a single row ball bearing I know what they look like. Last thing I took apart like that the axle just slid through. Bearings are damaged by many things. If the axle slides through the bearings then they are usually presses into the housing they go in. In which case you should never press on the inner race in any way to install them. This would cause tiny flat spots on the balls and the grooves they roll in. Most standard ball bearings are not hard all the way through they are hard on the outside surfaces once the perfect shine is roughed up in the least the parts will begin fretting the hard parts off and you are now running valve lapping compound in the bearing itself. I have seen people use the axle bolt to install the bearings by stacking whatever on there to use the bolt and nut as a press. Which is ok as long as you are pressing on the correct race. If it is pressed into a housing you should not apply any pressure to the inner race to install and vise versa.

If this does not make any sense to you just ask and we can hash it out some more.

Scott

[andrewclaycomb]

Here's another question on this issue. I'm planning on installing the new bearings tomorrow. When I got the bike home after the bearings came apart, I was spinning the wheel and noticed it getting harder to spin and then looser. I also noticed the chain seemed to have a tight spot (near the master link). The chain has less than 3000 miles on it (same with the sprockets) and it is an O ring chain. Is it ok if I put everything back together with the new bearings and ride it with the current chain? I'm thinking the tight spot might have just been the bearing shrapnel in the wheel compressing against the axle and making it harder to spin.

If the chain is actually stretched is it ok to ride by adjusting the the tension at it's tightest spot?

[Scotts]

Well If you had the chain on the sprockets and the bad bearings in place, I would have to venture a guess that the rolling elements of the bearings were all ganging up and moving the axle closer and farther from the engine. This can happen.

Look at this cut away.

http://science.howstuffworks.com/bearing3.htm

The bearing at the top of this page is what is in the rear axle. As far as I could tell when I had mine somewhat apart last night.

If you look at the bearing it has an inner and outer race, rolling elements and a cage to hold the rolling elements at equal distances apart. This particular bearing does not have any shields or grease on it.

When bearings come apart the cage failure is very common. These can be damaged by the seal or shield being pushed into the cage. When the bearing turns these two pieces will rub on each other. The result is that the cage is ground away and one of the rolling elements gets loose It then goes to hell in a hurry. The rubbing action heats up the grease past its liquid point, the bearings begin to flake apart and grind themselves up. This all happens pretty quickly. As you may know.

I would put it together leave the chain off torque the axle down and give it a spin.

Check your chain without being on the sprockets. Does the tightness still exist around the master link area? If so the chain may be damaged.

Another thing to consider that was brought up in another reply.
The parts may not all be in their correct place. Check that the axle is straight. Place it on a flat surface with the head of the axle off the edge and roll it. If it is bent it will be very obvious. Look for burs on the axle especially on the areas where the bearings ride. If theses areas are lower than the rest of the axle it will damage the bearings. And if this is happening towards the ends of the axle it will also cause the tire wheel to not run true even though the marks on the adjusters are lined up. The bearings I linked to will not stand much side load.

Give the parts diagram at one of the parts suppliers a good looking over. Compare the parts you have to make sure you have all the parts, and they look like they are in the correct orientation even a small shim or washer in the wrong place can cause much misery.

When you install your bearings if you dent the seal or shield it won't last long. You will have a repeat performance. Get another bearing.

Scott

[Big T]

No, you can't ride with a bad chain

It sounds to me like you've been running the chain WAY too tight and that has ruined the bearings and the chain

get all new bearing for the rear wheel and sprocket. Get a new chain. Carefully install the new bearings using an old race as a driver. A bit of lube on the hub and freezing the bearing will aid it going in.

The only thing you need to lube is a light coat on the axle when reinstalling. Check your chain tension with you on the bike on the ground. Check the wheel alignment with a string. the swingarm marks are unreliable.

It's a big hassle, but be glad you weren't pulling out to pass someone when those bearings went.