Bearing Race

1speed

1speed

Incredibly profound yet fantastically flawed
Just wondering if anyone else has encountered this ...

My front wheel was showing a lot of lateral play and shaking quite a bit lately so I figured it was time for new bearings. It's a DT Swiss 350 hub, and the bearing race is so flush to the axle that it seems almost impossible to get it out without going final solution and cutting through the steel race. It seems like once it's pressed in, it's permanent - like the whole bearing is spring loaded to snap into place and then never come out. So what happens when it needs to be replaced? Are you supposed to get a whole new hub and rebuild the wheel? There is literally no point where you can get any purchase to remove it.
 
Get a blind bearing puller set. Just had to do this on my hardtail. Just hope the inside of the bearing comes out with the outside of the bearing. One of mine didnt..lol. Soooooo much fun !
 
mtbiker87 said:
Get a blind bearing puller set. Just had to do this on my hardtail. Just hope the inside of the bearing comes out with the outside of the bearing. One of mine didnt..lol. Soooooo much fun !
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That's exactly what happened in this case - the inside (and the bearings themselves) all come out eventually but the race that's flushed up against the axle wall is not moving for anything. A bearing pull won't work though because it needs something to grab on to and there really is nothing- if you didn't know better, you'd think the entire internal axle is one piece including the bearings. I don't understand why they wouldn't have left a small notch in the internal axle - they could have even created a proprietary tool that would fit in the notch and pop the bearing out (and sold that separately!) But it's just completely flush to the axle. And even when the bearings and outside race come out, there isn't anything on the inside race to grab on to. It's incredibly frustrating. I guess perhaps they figure it's better to sell a new hub than a tool to extract the bearings??? I even considered using a slide hammer but the inside of the race is just too smooth for it to grab. It's an odd thing because, on the one hand, I totally get why they'd want it to be flush the way it is (both aesthetically and functionally) but on the other hand I just can't see how this design makes it possible to extract it.
 
1speed said:
That's exactly what happened in this case - the inside (and the bearings themselves) all come out eventually but the race that's flushed up against the axle wall is not moving for anything. A bearing pull won't work though because it needs something to grab on to and there really is nothing- if you didn't know better, you'd think the entire internal axle is one piece including the bearings. I don't understand why they wouldn't have left a small notch in the internal axle - they could have even created a proprietary tool that would fit in the notch and pop the bearing out (and sold that separately!) But it's just completely flush to the axle. And even when the bearings and outside race come out, there isn't anything on the inside race to grab on to. It's incredibly frustrating. I guess perhaps they figure it's better to sell a new hub than a tool to extract the bearings??? I even considered using a slide hammer but the inside of the race is just too smooth for it to grab. It's an odd thing because, on the one hand, I totally get why they'd want it to be flush the way it is (both aesthetically and functionally) but on the other hand I just can't see how this design makes it possible to extract it.
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Did you watch the video Magic posted? Looks simple, with the tools they have. I still say new bike tho.
 
MadisonDan said:
Did you watch the video Magic posted? Looks simple, with the tools they have. I still say new bike tho.
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I did watch it, and it does look easy. All I can say is that it wasn't. The bearings just wouldn't come out when we tried to knock them out by any means. They just wouldn't budge. I don't know - perhaps it's the wheel itself that's screwed up. The way he just popped them out with a few taps of a soft mallet - we tried that and it didn't move them at all.
 
Dingo said:
Can you go "in" from the other side with a long punch or drift and wack it?
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This. There is an aluminum spacer (#4) in between the two bearings that can be pushed aside from the inside. Get a drift or punch and work your way around to knock out one side. You can then easily do the same to the other bearing or use a press. Not sure if picture this is the same hub but should be pretty similar in design.

1594998262623.png
 
1speed said:
I did watch it, and it does look easy. All I can say is that it wasn't. The bearings just wouldn't come out when we tried to knock them out by any means. They just wouldn't budge. I don't know - perhaps it's the wheel itself that's screwed up. The way he just popped them out with a few taps of a soft mallet - we tried that and it didn't move them at all.
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FTR, I don't do any of this stuff myself. 😛
 
Gotta support the hub shell when you are punching it out. The force required goes from 11 to 1.

If there's rust, that's a different story.

I've "reassembled" cartridges that exploded just to remove them before. Food for thought.
 
Mr.Moto said:
This. There is an aluminum spacer (#4) in between the two bearings that can be pushed aside from the inside. Get a drift or punch and work your way around to knock out one side. You can then easily do the same to the other bearing or use a press. Not sure if picture this is the same hub but should be pretty similar in design.

View attachment 134525
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plus 2 #4 is pushed to the side.
 
So quick update ...

Turns out the bearings race bonded to the axle somehow. My shop just called and told me. I have no idea how that's even possible. I'd have imagined it would take an enormous amount of heat to melt them together, but apparently its possible through some kind of galvanic reaction of aluminum on steel. I don't know anything about chemistry so I have to take it on its face. But it's sure as hell bonded. Last ditch effort to save the hub is a chemical bath, but I'm not super excited by the prospects at this point. I think I'm going to be getting a new hub.

Sometimes I hate bikes ...
 
1speed said:
So quick update ...

Turns out the bearings race bonded to the axle somehow. My shop just called and told me. I have no idea how that's even possible. I'd have imagined it would take an enormous amount of heat to melt them together, but apparently its possible through some kind of galvanic reaction of aluminum on steel. I don't know anything about chemistry so I have to take it on its face. But it's sure as hell bonded. Last ditch effort to save the hub is a chemical bath, but I'm not super excited by the prospects at this point. I think I'm going to be getting a new hub.

Sometimes I hate bikes ...
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Galvanic corrosion might certainly be a candidate explanation for what you experienced.
 
Pictures please.

The axle should only be bonded to the inner race, not the outer. So just hammer it out along with the bearing it's seized to. Replace bearing and axle.

Unless it's bonded to both, if that's the case put one end in a vise and drill out the other side with a bit the ID of the bearing. New axle, two new bearings.

DT hub so new axle should be easy to get.
 
Santapez said:
Pictures please.

The axle should only be bonded to the inner race, not the outer. So just hammer it out along with the bearing it's seized to. Replace bearing and axle.

Unless it's bonded to both, if that's the case put one end in a vise and drill out the other side with a bit the ID of the bearing. New axle, two new bearings.

DT hub so new axle should be easy to get.
Click to expand...

I don't have it at home right now - it's in the shop. But it may be a quesdotn of terminology - when I say the "inner race", I mean the in the inner circumference of the bearing ring itself. The "outer race" is the outer circumference of the bearing ring.
 
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