Motorcycle wheel bearing installation
- Thread starter SZR48207
- Start date
While i have not done MC bearings, i have pressed sealed bearings in to hubs, so similar just bigger.
I have wiped the outer bearing surface with wd-40 or ballistol. I also put the bearing in the freezer at -4 overnight before pressing it in.
Just make sure you use something to press against the outer race of the new bearing, like an old bearing shell, or a socket. Don't press on the inner bearing race.
The bearing/hub will get warm in use and the alloy wheel will expand more than the bearing so it's important that they are a tight fit. That's the reason that you should have to heat the hub/freeze the bearing in order for it to fit easily. A bit of lube is not a concern for that sort of interference fit.
X2
Kestas
Staff member
Oiling is okay. My anal retentive nature would be to make sure there are no burrs or debris on the surfaces to hang up the installation.
The other thing that's going on when a bearing is an interference fit into a wheel is that the bearing running clearance reduces due to the outer bearing ring being compressed on installation. This will have been allowed for in the original bearing selection but it's another reason for cleanliness and avoidance of burrs.
X3. Heat hub/freeze bearing.
I use a small wipe of Moly grease on the outside of the bearing.
Just be aware that some motorcycle wheels have a bearing installed full depth on one side and the other bearing installed to the depth that the inner race is up against the spacer. The outside of that bearing might not be full depth. In other words you can't always just hammer/press both bearings in until the outer race seats.
Just be aware that some motorcycle wheels have a bearing installed full depth on one side and the other bearing installed to the depth that the inner race is up against the spacer. The outside of that bearing might not be full depth. In other words you can't always just hammer/press both bearings in until the outer race seats.
And don't forget to install the spacer on wheels so equipped...
I use grease, but oil will be fine too. But I don’t find it makes the installation any smoother, it’s an interference fit after all. I add the lubricant to protect against corrosion.
No need for motorcycle wheel bearings. They go in easily with light taps from a hammer.
That’s a broad brush you’re painting with!
I’ve not done as many as some people I’m sure but I’ve done probably 50-70 motorcycle wheel bearings and I’ve seen some VERY tight interference fits that were way beyond “a few light taps”.
And saying “freeze it” without any other information isn’t? It actually makes the moisture condense and then freeze on the bearing. That water can get past the seals. So it’s not some universal solution either.
If you want to mess around with freezers, it’s your business. I never had to resort to that. If light taps didn’t make it seat, then I started tapping harder. It’s not a heart surgery. I would think people messing with this stuff should be able to figure it out.
Could there be a case where you need to freeze the bearing? Sure I can see that, but that would be an exception, not the norm.
With respect freezing the bearings and heating the hub is a time tested and no downside procedure.
That's the first time I've ever heard about condensation quite honestly, because I've never heard of it being an issue and I suspect most folks here would say the same.
There are more folks that have had tighter fits than what you've experienced. I've done many in a motorcycle and car, and a tight fit is the rule not the exception. That's why the procedure is done and no one has ever mentioned condensation being an issue. Unless you're running them underwater lol.
Of course it will be a tight fit, that’s what it’s supposed to be. That doesn’t mean freezing and heating needs to be used. Heating especially can lead to bad things if done by someone inexperienced.
Plus I don’t think any of the service manuals I’ve seen call for it either. They all mention driving the bearing in.
Talk about making a big deal out of this simple task
Plus I don’t think any of the service manuals I’ve seen call for it either. They all mention driving the bearing in.
Talk about making a big deal out of this simple task
I just checked the original BMW workshop manual for my motorcycle and it calls for heating the wheel hub to 80 Deg C before driving in the bearing. Freezing the bearing isn't mentioned.
Again, with respect, saying heating leads to bad things and yet some manufacturers recommended it, I don't know where that knowledge is coming from. BMW bearings or Kawasaki bearings or Jeep bearings and hub tolerances across the board are similar, there's no rocket science in them.
Freezing is self evident, there is nothing in or about a sealed bearing that introduces any moisture worth mentioning in the negative sense. If the moisture gets in there in the first place as water (as you said) when the bike is run the first time moisture will evaporate off as a gas. In case that science is not evident here, gas will fit through a much smaller space than water. Help me understand how moisture gets into a bearing and causes an issue?
Freezing is self evident, there is nothing in or about a sealed bearing that introduces any moisture worth mentioning in the negative sense. If the moisture gets in there in the first place as water (as you said) when the bike is run the first time moisture will evaporate off as a gas. In case that science is not evident here, gas will fit through a much smaller space than water. Help me understand how moisture gets into a bearing and causes an issue?
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