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I knocked the lower bearing off the stem by just beating the crap out of it and destroying it. Since I wasn't reusing it, it didn't matter. How am I supposed to press the new one on though? Do I just need a really long piece of pipe that is the size of the inner part of the bearing or will just tapping around with a punch on the inner part of the bearing work ok?

It should be pressed on. Most shops will do it for not much money if you have no press. In fact, many will do it even if you do have one.

Well even if I had a press, i guess I would need a long pipe or something to slide down over the long steerer tube and press on top of the bearing right?

It depends, if you can get the movable supports on the table of the press to support the bearing properly, you could invert the triple clamp and press it into the bearing. I would press the steering tube though, not the clamp.

Ok, that makes sense.

I try to save the inner part of the bearings so that I can use them with a press so that it only presses on the inner part and not load the outer part of the bearing.

I put a KX65 bearing on a stem the other day and used a punch and a hammer. I took my time and went very slowly by hitting alternate sides of the bearing (inner part only).

Inch and 1/8 pipe? Something like that.

The same size pipe you use to beat the hell out of your quad axle when the bearings are stuck in the carrier........

Get a piece with a threaded end so you can put a cap on it.

One good whack..couple pound sledge...you're done.

Worked fine for me!

..support the stem! Do not put pressure on the bearing using the bottom triple as the base. Put the bearing in the freezer (protected by something...wrapped with a paper towel and in an evacuated ziploc bag).


Don't support the properly sized socket you use on the bottom of the clamp with your foot.



Gee...what's the fun in having someone with the correct tool do it for 'ya?

I don't understand freezing the bearing in this case. Wouldn't it just make the bearing smaller and fit tighter on the stem?

So you are saying to put something under where the stem presses in to the bottom triple (like a socket ) to support the stem as opposed just putting the triple on the floor. Is that so you don't accidentally push the stem through the triple, or so you don't damage the triple?

canyncarvr wrote: ..support the stem! Do not put pressure on the bearing using the bottom triple as the base. Put the bearing in the freezer (protected by something...wrapped with a paper towel and in an evacuated ziploc bag).

Ummm, how about you put the STEM (and lower tc) in the freezer overnight instead. Put a wee bit of anti-sieze on the lower bearing area of the stem first. And use the plastic bag cc reccommended. New bearing should be at room temp. Using the old bearing inner race as a driver, it usually doesn't take much to seat the new using this method. Oh, yeah and before you get this far, do a little shoe-shine routine with a strip of emory cloth on the lower part of the stem to be sure it is clean and smooth and no marks from your old bearing removal surgery.

The new bearing outer races can go in the freezer to help installation in the frame.

Freezing makes things smaller..they contract. The METAL contracts...not the space.

Exaggerated for effect...but consider that the inner race diameter would be 25mm. Freeze it and the metal shrinks, the diameter (the space...the hole) would be 25.5mm.

Hell yeah. If you got the room, put the stem in the deep freeze, too.

Anti-seize. Most excellent point!!!

Absolutely. Put anti-seize on everything 'bearing' where it's crammed against another metal. Put it on everying NOT a bearing that fits WITH a bearing..like a pivot pin that fits inside collars/sleeve. It will save your bacon some day.

lemmy wrote:So you are saying to put something under where the stem presses in to the bottom triple (like a socket ) to support the stem as opposed just putting the triple on the floor.'

That is what I am saying.

lemmy wrote:Is that so you don't accidentally push the stem through the triple, or so you don't damage the triple?'

I'm saying those sayings, too.

The stem being pressed into the clamp, why would you want to put stress on the press-fit..in the opposite direction from which it went IN?

I'm sure that's in The General Rule Handbook. You always block against what you're pushing on...NOT a secondary/associated piece.

If that's possible.......



There is a video on PivotWorks site regarding steering stem bearing replacement. What do they say to do with the bearings?


...and you thought I was nutz-o.. C'mon...admit it! Yes you did!

But...considering the use of the bearing tool in the same video..who would ever believe a word they said about bearings? Holy Cow!! If I saw someone doing that to my machine..certainly if I was making a world-wide available video, I would be pissed to the point of having a stroke. My word!!! He'd be F'n FIRED on the spot!!

I don't believe it..........




Oh well. Yet another lesson, and example that says why I work on my own stuff.

Oh...re: 'Using the old bearing inner race as a driver..'

It's a given I'm sure...but that is used UPsideDOWN. Yeah...everyone knew that.

Boy, lot of talk about a simple bearing job......must be a lot of underemployment going on out there

"Do I just need a really long piece of pipe that is the size of the inner part of the bearing or will just tapping around with a punch on the inner part of the bearing work ok?"

Yes and yes

I don't follow this at all:
"Exaggerated for effect...but consider that the inner race diameter would be 25mm. Freeze it and the metal shrinks, the diameter (the space...the hole) would be 25.5mm. "

Warm = O, cold = o in my part of the country. Cool the stem if you want, warm the bearing if you want, I doubt you'll need to do either.

Sorry all, feeling kind of pissy today...

Well...let your pissy little fingers click on the whole lot of talk link provided to find that I didn't make it all up...and you will be able to follow it a liddle bit bedder.

Re: 'Warm = O, cold = o in my part of the country.'

...which is why so many words are used and the same thing is said over and over in slightly different ways. Cutting to the chase sometimes takes a whole lotta cutting..........


I haven't measured the ID of a bearing to know empirically that it gets larger with cold. Folks that I presume DO know, that SHOULD know that it does say to put the bearings in the freezer. As odd as it may be, it makes sense to me, I do it, it works.

Hope your day gets better...although this post isn't intended to help that idea along.

I agree with Karl, I think the hole gets smaller when you put it in the freezer. Which is why some folks freeze crank bearings and heat the case they go in to make it easier. That heat makes the hole bigger. it stands to reason cold is going to make the hole smaller. In the middle of the steering head bearing is a hole.

Re: 'In the middle of the steering head bearing is a hole.'

Dang! And I thought I'd lost it!! There it is. Right there!!!

...you can see right through it!!!


Re: 'I doubt you'll need to do either.'


Yah.

I guess I see what CC is saying. If you assume the "average diameter" or the diameter of the middle section stays the same but the metal shrinks around this "average diameter", then it would indeed have more space in the middle to go on the steerer. But if the entire thing shrinks (which is what I thought happened) then freezing would actually make it smaller.

I figured it shrank the whole thing. I heated engine cases and froze crank bearings to get the bearings into the case and they dropped right in. I then let everything come to room temp, and then heated case halves w/ bearings and froze the crank. Everything slid right together without needing any banging, cursing, prying, or persuading. Being that the cold crank slid right through the hot bearing It all made sense to me.


I would think the same would apply to the stem. Freeze the stem, heat the bearing. It should slide right on.

J.

canyncarvr wrote:
...and you thought I was nutz-o.. C'mon...admit it! Yes you did!

I just talked to a materials engineer in the office beside of me. He said if you tank a ring of metal, washer, bearing, whatever and freeze it, everything shrinks. So the hole or space in the middle would get smaller. IT makes sense if you think of what a rod would do and then visualize the rod being closed in on itself to make a ring.

CC is right the metal shrinks think of diameter of metal not the hole if you had a rod the rod would shrink when cold or expand with heat

Re: 'Warm = O, cold = o in my part of the country.'

Warm = O, cold = O 'round here.

...'round...ha ha ha...I kill myself!


Re: 'IT makes sense if you think of what a rod would do and then visualize the rod being closed in on itself to make a ring.;

I'm glad that makes sense to you.


Posit: The outside diameter of a tapered roller bearing is reduced in diameter when the temperature it is exposed to is significantly reduced.

Therefore: The inside diameter is likewise significantly reduced.


That may be true...but you cannot logically deduce the latter from the former. The outside and inside diameters could just as well react oppositely.

O and O.

I don't have a penchant one way or the other. Given the proof of either I'd think, 'That's nice.'

Can I say 'penchant' 'round here?