Bearings - How do you pull yours?

[Yellow Saddle]

So this is the scenario I have, the picture below is of my SRAM XD freehub from my gravel bike. The outer cartridge bearing clearly visible in the photo below needs replacing. Now the pre load tube behind this is completely immovable and preventing any access to the reverse face of the bearing. No tool is going to move this tube without damaging it.

View attachment 753155

Now for the avoidance of all doubt, I'm not being argumentative here, just trying to illustrate that I believe this scenario is more common these days. I also have a similar scenario on the mountain bike.

Now for me this is no problem, my cheap and cheerful €35 blind bearing puller will easily remove this and the inner bearing behind the preload tube. It's for this precise scenario though that I bought the blind bearing puller.

I'm just curious though to add to the already interesting and informative discussion taking place. So is there a tool or a way to drift this cartridge bearing out without any risk of damage to the preload tube or freehub body?

Chris, if your puller works, it works. I'm a big fan of stuff that works.

The scenario you present is typical nowadays, as you say. I firmly believe that the spacere in the photo (I assume it sits between two bearings?) can be shifted just ever so slightly to the side if you lever it.

Yes? No? If no, why not? It sits in a void constricted only in the front and the back. Yes?

I would tackle that problem by clamping the unit upright, lever the spacer to the side, then putting the unit flat (photo side down) on an anvil/vice flatbed, and tapping the bearing out towards the end shown in the photo.

 

[chriswoody]

Yes? No? If no, why not? It sits in a void constricted only in the front and the back. Yes?

I'm curious as well, I'm ordered some new bearings and I've been waiting for them to arrive before pulling the old ones out. Once the preload tube is out I'll pop a photo up once I've had a look because I'm always interested in learning something new.

This is a screenshot from the earlier video of the preload tube in the Hunt wheels and you can see how it's dumbbell shaped with O rings on the end. I've a feeling this one will be similar, but like I said I'll pop a photo up when I've done it.

 

[Yellow Saddle]

This is a screenshot from the earlier video of the preload tube in the Hunt wheels and you can see how it's dumbbell shaped with O rings on the end. I've a feeling this one will be similar, but like I said I'll pop a photo up when I've done it.

The O-rings intrigue me. You've worked on the hub, do they seal the spacer tube hermetically against the beaings? If so, it is a very bad idea and poor engineering.
Should they seal against the bearings, it means that when you move the bike from a warm to cold temperature such as in today's cold weather, the warm air cools inside the hub assembly and draws in external air through the bearing seals, bringing in water with it. This water would be any water sitting against the seal on the outside of the bearing.

I've seen this problem on designs where the bearing didn't even have an O-ring but sat tight enough against the bearing so that the path of least resistance is via the bearing itself.

This obvservation came in very handy when an electrical engineer friend of mine shared a problem he was having with an electronic processor housing placed in a very hostile environment i.e. a damp dusty mine. His company manufactures process control equipment. The housing is hermetically sealed in the way some tupperware tubs are sealed - with a silicone gasket and lock-down lid. Nevertheless, moisture got in and spoilt the electronics inside. I examined the unit and saw traces of dirty water passing the very tight seal. The combination of capilary action and negative pressure sucked water into the unit.

We then fitted a breather onto the box and the problem was solved.

Hopefully your spacer has O-rings to lock the end caps in place. If not, drill a small transverse hole in the tube.

Things are sometimes, paradoxically, more waterproof when they have a hole in. Guess what's in the bottom of all my bikes' BB shells.

 

[ColinJ]

Things are sometimes, paradoxically, more waterproof when they have a hole in. Guess what's in the bottom of all my bikes' BB shells.

Er... Water?

 

[ColinJ]

Er... Water?

Rust?

 

[ColinJ]

Rust?

Polo mints!!

 

[classic33]

Polo mints!!

Rusty Polo mints?

 

[chriswoody]

The O-rings intrigue me. You've worked on the hub, do they seal the spacer tube hermetically against the beaings? If so, it is a very bad idea and poor engineering.

The picture is actually screen grab from a youtube video, so it's not my preload tube it's from a Hunt wheel. The wheel from my gravel bike doesn't have these seals in their preload tube and the mountain bike has a really cheap hub that doesn't have a preload tube, the bearing sits instead in a machined "cup" that makes it difficult to access the back of them.

You do raise some interesting points though and I'll look into this when I remove the bearings from my freehub body and see what I'm working with. The cartridge bearings in the freehub body have lasted over 8 years though and done over 15,000km, so I've got my fair use out of them! I've still not done it yet though due to waiting on my new bearings to arrive and a crazy busy week at work. I try to keep away from the tools when I'm knackered in case I do something silly!

As an interesting aside I was reading some SRAM tech docs earlier for stripping one of their own brand hubs. I do love the technical documents for SRAM stuff because they lay everything out in a clear concise manner with excellent photos. In those documents they recommend the use of a drift to remove the cartridge bearing.

 

[fossyant]

I like the generic hubs because, they are easy to service. I have some formula hubs and some Fulcrums, once you look at them they have standard bearings, and you can replace the lot it they have got a bit rough. Bought a second hand CX bike, was able to replace all the front and rear bearings on the wheels for less than £30 for six (four in the rear).

 

[BrumJim]

Try with an intelligent but witty chat-up line, then complement them on their balls and cages. Smile, and laugh at their jokes, and try to find common ground.

Sadly, works as well on bearings as it did on women.

 

[Dogtrousers]

Try with an intelligent but witty chat-up line, then complement them on their balls and cages. Smile, and laugh at their jokes, and try to find common ground.

Sadly, works as well on bearings as it did on women.

Promise to smother them with grease?

 

[chriswoody]

Well I was wrong, turns out that the preload tube was free floating, it was just quite firm between the two bearings and once I started to draw out the front bearing it just fell down with no bother. So for anyone else with a SRAM XD freehub you could quite happily use a drift on these bearings to remove them. The preload tube is also pretty substantial so no need to worry too much about damaging it.