New wheel bearings, worried about side loading

[MarkJ]

Hi, I've just fitted new front wheel hearings to the Gsxr. I drove the first bearing outer race down to the metal, then the second one I wanted to drive in so the inner race was just touching the hub spacer. I went a bit too far and to move the spacer inside the hub around you have to use your thumbs.

I have another wheel with some old (but good) bearings in and the spacer can be moved around by your little finger. Am I being paranoid about side loading the new bearings, or is it that the old ones will have worn a bit, hence more free movement for the hub spacer. I've put the new rim on the bike and it spins freely.

[misscrabstick]

In my experience of having done a few wheel bearings, you drive both bearings in (on the edge of the outer part) as far as they will go, this should be against a shoulder that is part of the hub, the spacer tube should be made such that it's touching the centre part of both bearings to support them when the axle nut is done up tight.

If your wheel is turning nicely with no binding I would think it's job done.

[MarkJ]

Cheers, I originally drove both down to the metal but they made the spacer impossible to move by hand, and when I test fitted the rim on the bike it was very hard to pull the spindle out again, like it was being pinched way too tight. So I knocked those out and fitted these new ones, which has made the spindle easy to slide in and out.

There's a few video instructions on YouTube with people saying only to drive the second bearing down so the spacer not outer bearing is touching which was why I was asking

[Acerman]

Do i understand this correct if i say you got pressure on the inner ring of the bearing not equal to the outside? then its not good at all, most importan is that the bearing itself can run as at did before you put it in.

[MarkJ]

Yeah there's pressure on the inner race as the hub spacer doesn't move as easily as it does on the other wheel, I just wasn't sure if it was too tight, or that the other wheel is too loose. Uploading a video now so you can see

[MarkJ]

linky

[Acerman]

Yes its not recomended having pressure in the inner race like that, difficult to know how much angle you got from this. When you first doing this i would take it out and get it in the correct position in there.

[MarkJ]

Right, I've figured out why it's so tight. The bearings are 15mm deep and the seals are 7mm deep. I popped the seals out of the other good wheel and measured the gap from the top of the bearing mounting hole to the top of the outer race - 7mm on both sides. I then went to this wheel and measured with no seals in - nearly 8mm one side, nearly 6mm the other!

So I knocked the bearings out again and measured the distance from the top edge of the bearing mounting hole to bottom where the outer race would hit the lip. If it's got a 15mm bearing and 7mm seal that's 22mm right? Well it was 22mm one the left and 23mm on the right! And the 23mm (right) side was the bearing I drove in first, essentially making the fit 1mm too tight!

Now in the Haynes it specifically says to drive the left bearing (22mm deep) in first, then the right (23mm) but doesn't actually say why, so I figure that some how the left side hole is made more accurately perhaps? Who knows. Either way it looks like I'll need some new bearings again, mount the left side down to the lip, then carefully mount the right so it is 7mm, not 8 deep.

Does that sound right? The wheel looks fine, no cracks, bumps, nothing. Manufacturing defect perhaps? It's part of my wheels I have my race wets on so I wonder if whoever originally bought it got it at a good price as it was a Friday afternoon job.

[Acerman]

Yes thats because you should have 1mm adjustmentgap on one side so you dont get pressure in the inner race.

[MarkJ]

So is only driving one outer race down to the metal lip normal then?

[Pete.]

On your GSXR you drive one bearing down the the seat, install the spacer then drive the other bearing in until it touches the spacer. Which one you fit first should be listed in the manual. They don't both get driven to the bearing seat.

It would help if you put the spindle through the assembly before pressing in the second bearing. This stops the tube spacer getting slightly cocked only to fall loose and rattle later.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[kramdra]

Bollocks I asked the same question last year with this pic:

https://i1133.photobucket.com/albums/m593/Kramdra/cbr600fwheelbeaing_zps096ef845.jpg

Also asked at mot and several garages... answer was that it doesn't matter, it will compress anyway when tighten spindle.

I assumed bearings should be driven fully into their seat.. why shouldn't they... Spacers should therefore be the correct length - the gap between the seats.

Service manual has a pic of bearing being fitted with a driver and hammer with the text "drive in left bearing squarely then distance collar, the left bearing with "special tool"". No idea what the special tool is??!?

No one gave me a correct answer... that its supposed to have an adjustment gap on the second bearing? so last year I filed the spacer down to the correct size.

[Pete.]

Yep, the yellow spacer in your diagram is there specifically to stop the left bearing being pressed into the seat. They MUST be slightly longer than the seat-to-seat distance to prevent axial loading of the bearing.

As your manual says, left bearing first (for that wheel, on that bike) then spacer then right bearing. The 'special tool' is most likely just a threaded puller that pulls the inner races together.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[kramdra]

Please explain. My understanding is that the spacer is there, so when spindle is tightened, the inner races are supported. If the spacer was the correct length it would be perfect.

Its been like this a year, 10k miles, and I do have a space spacer. Would you suggest I do it properly with new bearings or leave as is?

[Pete.]

Well, there are two considerations - thermal expansion and manufacturing tolerances. You can all but discount manufacturing tolerances in this case but you can't ignore thermal expansion.

The wheel is ally which has a coefficient of expansion of 22m10¯⁶/°C, and the spindle is steel and it's expansion rate is half that of ally at 11m10¯⁶/°C. The only interface between them is the three bearings and their axial clearance, which is very small.

So if you take a wheel in winter at zero degrees then move it to summer at 30 degrees, assume the two bearings are 250mm apart, the wheel housing will have expanded 0.165mm in width but the spindle only increased 0.085mm in length. Now that might not sound like a huge amount but terms of bearing axial clearance it's like trying to force a sofa through the front door sideways.

To allow for this expansion and contraction, you have that little gap between the outer race of the second installed bearing and the 'seat' machined in the wheel hub.

The job of the tubular spacer is two-fold. It maintains that gap and provides a solid support between the inner races of the bearings so that when you tighten the spindle nut you're not loading the bearings axially (basically it stops you trying to pull the inner race out of the bearing by tightening the spindle).

Specifying which bearing gets fitted first is probably a combination of two things - it controls the alignment of the wheel and therefore the chain run (in Kramdra's case pressing in the wrong bearing first would set the wheel over by 2mm) but more likely the bearing seats are machined to different classes of fit. The first bearing is not expected to move so it can have a press fit. The second bearing might have a close sliding fit so the outer race can slide to relieve axial load.

References for the clever bits:

https://engineerstudent.co.uk/thermal_expansion.html

https://www.calculatoredge.com/calc/exp.htm
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[kramdra]

Ok this makes sense. I will order some new bearings

However both bearings are the same press fit, they are not going to move.

[kramdra]

An update! Also both bearings are equally tight bastards to get out. The fully seated right bearing was easier. The left is not any kind of sliding fit. Old bearings did 30k miles after incorrect fitting by me No play in them, still too tight. The outer dust seal spring failed, outer bearing face solid rust, but under the seal balls and races looked good, grease like new. Good time to fit new ones.

When fitting the second bearing, should I drive it all the way to the spacer, by the outer race? Seems to me the last half millimetre it should be driven by inner race to stop it going to far? (or this special honda tool) I was very careful putting it in with the old bearing as a drift, but it did go too far so I had to knock it back out a bit

TL:DR - cocked it up again.

[0l0dom0l0]

[Commuter_Tim]

Pete. is totally wrong.
Here's what you do...

Using the finest Punch tool you can find, whack the bearing on the seal with the Might of Thor using the largest rock you can find/lift.
Then throw the spacer away, it's for noobs.
Next you need to drive down the second bearing as tight as it goes using the aforementioned Punch Tool method.
After this you should consider welding both sprockets in plac...

...Sorry I thought this was BodySprockets thread, nevermind, as you were.
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The above post is most likely nonsensical.

I ride a Bandit 600... badly.

[barrkel]

I just want to add: heat and cold are your friends with bearing installation. Freeze the bearings for an hour, and use a heat gun on the hub, and your life should be much easier. Probably do less damage to the hub too.

I replaced 6 bearings (4 blind) when fixing my scooter's final drive last year. Temperature difference makes things so much easier.
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Bikes: S1000R, SH350; Exes: Vity 125, PS125, YBR125, ER6f, VFR800, Brutale 920, CB600F, SH300x4
Best road ever ridden: www.youtube.com/watch?v=s2MhNxUEYtQ