rear bearings and brake

[FuelCooler]

I went ahead and installed one bearing so that I could measure the length that my spacer would need to be. Sure enough, it needs to be .014 inches longer to not bind. So my new bearings would have had a shortened life. I’ll get some .015 shim stock and make a shim. 
 

[Pressureangle]

15 hours ago, FuelCooler said:

I went ahead and installed one bearing so that I could measure the length that my spacer would need to be. Sure enough, it needs to be .014 inches longer to not bind. So my new bearings would have had a shortened life. I’ll get some .015 shim stock and make a shim. 
 

Check to see if some automotive valve spring shims won't get you there. I have a few, 15mm x 32mm and 22mm x 35mm. 

[Pressureangle]

10 hours ago, docc said:

Three weeks out - warding off the Waddington Effect  while seeing to necessary matters . . .

--> Decent Tune-up 

--> Motor oil/ gearbox oil/ neutral switch & shift linkage adjustments  

--> Fresh Pirelli tires/ brake inspection/ another new rear wheel bearing (again!)    

--> GPS routes laid in.  

Looking to roll some "ten flight hours " before embarking on this XXI SSR .

 

 

How many wheel bearings is that? How have you checked your spacers and hub for alignment?

[audiomick]

1 hour ago, Pressureangle said:

...How have you checked your spacers and hub for alignment?

Just what I was going to write. The spacer in mine was too short.

[docc]

10 hours ago, Pressureangle said:

How many wheel bearings is that? How have you checked your spacers and hub for alignment?

edit: Not sure how to check "alignment?"

        Records show front bearings changed twice at 60-65,000 miles (~100.000km).

        A ridiculous number of rear bearings: five left, four right with the 112mm spacer, yet this is the second left rear since going to the 113mm spacer, 16400 miles and this one: 10000 miles. In all honesty, it is barely gritty. I doubt anyone else would change it, but I got stranded once with a blown wheel bearing 310 miles from home. Right after installing new bearings (over the 112mm spacer).

 

9 hours ago, audiomick said:

Just what I was going to write. The spacer in mine was too short.

Exactly. I thought I had this solved . . .

[Pressureangle]

 

as long as you're in there, here's how I verify spacer fit-

Set both bearings tight to the hub shoulders, with no center spacer
Measure bearing depths from hub flange, both inner and outer races
Remove one side bearing, place spacer. Re-install bearing until it bottoms
Re-measure bearings; if you have *zero* change from no spacer measures, it's too short.
If driving the second bearing home changes the depth of the first bearing, note by how much. These small bearings have very little clearance, so I would say if your center (spacer) race moved by .001" to .003" you're in good shape. 
If you get more protrusion than a couple thousandths, your spacer is long- which can overload the bearings if the outer races are too tight to float in the hub, which they should be. 
I would rather shim up a short spacer than try to work with a long one, as it's important to have the ends perfectly square to the centerline of the bearings, hard to achieve with a file or stone. 
If your spacer is long, you *can* drive the bearings against the spacer with an appropriate driver that touches only the inner race- then when the driven bearing finds home, the direction of forces on both bearings will load the races equally and center themselves up. That does leave you with a couple or few thousandths between the hub and the outer race of one of the bearings; a few thousandths is ok, but if they aren't tight in the hub they can shift and chafe during use. 

Have I overclarified that to mud now?
 

[audiomick]

3 hours ago, Pressureangle said:

...
I would rather shim up a short spacer than try to work with a long one, as it's important to have the ends perfectly square to the centerline of the bearings, ...
 

That makes sense, as long as it isn't done the way it was in mine. The spacer was about 3mm too short, and was "shimmed up" with a slice off a bit of pipe that had obviously been cut free-hand with a hacksaw. Not even close to "square", so it was no wonder the bearings were shot. What sort of a gorilla does that sort of bullshit? 

[Pressureangle]

I should mention that it's critical to have the spacer perfectly aligned with the bearings when taking measurements. If it's tipped it will measure long. You can finger it out, or if it's a decent fit on the axle you can use the axle and a soft mallet as the bearing driver.  If the outer races are tight in the hub you can fit a piece of pipe to the outer race whilst the axle stays in place. 

[Lucky Phil]

6 hours ago, Pressureangle said:

 

as long as you're in there, here's how I verify spacer fit-

Set both bearings tight to the hub shoulders, with no center spacer
Measure bearing depths from hub flange, both inner and outer races
Remove one side bearing, place spacer. Re-install bearing until it bottoms
Re-measure bearings; if you have *zero* change from no spacer measures, it's too short.
If driving the second bearing home changes the depth of the first bearing, note by how much. These small bearings have very little clearance, so I would say if your center (spacer) race moved by .001" to .003" you're in good shape. 
If you get more protrusion than a couple thousandths, your spacer is long- which can overload the bearings if the outer races are too tight to float in the hub, which they should be. 
I would rather shim up a short spacer than try to work with a long one, as it's important to have the ends perfectly square to the centerline of the bearings, hard to achieve with a file or stone. 
If your spacer is long, you *can* drive the bearings against the spacer with an appropriate driver that touches only the inner race- then when the driven bearing finds home, the direction of forces on both bearings will load the races equally and center themselves up. That does leave you with a couple or few thousandths between the hub and the outer race of one of the bearings; a few thousandths is ok, but if they aren't tight in the hub they can shift and chafe during use. 

Have I overclarified that to mud now?
 

I'm not a big fan of fitting and removing bearings in the hub unless it's totally necessary to minimise wear and tear on the bearing bore. Once a bearing has been "driven" on the inner race which is the only way to remove them the bearing is junk. Throw it in the trash. Here's my way.

Fit one bearing to the hub bottomed out on the shoulder. Insert the spacer so it's seated on the fitted bearing and then a large flat washer into the other bearing shoulder and measure with a depth gauge on the end of a pair of callipers between the face of the washer and the end of the spacer. Subtract the thickness of the washer and add a thou or two to the calculated spacer length. Everyone has access to a decent set of 6 in verniers and a hardware store for a large flat washer. This way the fitted bearing stays in place and the other bearing only needs to be installed for the final assembly. 

Instead of a large flat washer you can use anything with accurate thickness and parallel of the right dia to insert in the bearing hole to measure down to the spacer face such as a piece of 6 in stainless steel rule cut to just under the the bearing bore OD that can rest on the bearing bore shoulder and measure down from the top edge when held vertically to the spacer end face then subtract the measured width of the piece of SS steel rule. Obviously better and easier to just machine a flat washer but not everyone has a lathe.

 

[Pressureangle]

11 minutes ago, Lucky Phil said:

I'm not a big fan of fitting and removing bearings in the hub unless it's totally necessary to minimise wear and tear on the bearing bore. Once a bearing has been "driven" on the inner race which is the only way to remove them the bearing is junk. Throw it in the trash. Here's my way.

Fit one bearing to the hub bottomed out on the shoulder. Insert the spacer so it's seated on the fitted bearing and then a large flat washer into the other bearing shoulder and measure with a depth gauge on the end of a pair of callipers between the face of the washer and the end of the spacer. Subtract the thickness of the washer and add a thou or two to the calculated spacer length. Everyone has access to a decent set of 6 in verniers and a hardware store for a large flat washer. This way the fitted bearing stays in place and the other bearing only needs to be installed for the final assembly. 

Instead of a large flat washer you can use anything with accurate thickness and parallel of the right dia to insert in the bearing hole to measure down to the spacer face such as a piece of 6 in stainless steel rule cut to just under the the bearing bore OD that can rest on the bearing bore shoulder and measure down from the top edge when held vertically to the spacer end face then subtract the measured width of the piece of SS steel rule. Obviously better and easier to just machine a flat washer but not everyone has a lathe.

 

Well, for those with complete machine shops and expensive measuring tools, sure. I could set it up on a surface plate and use a height gauge too and get it within  a  couple tenths. 
But for everyone else, this works with a cheap chinese caliper with depth tail.
And no, a bearing isn't junk just because you tapped  on the inner race. 

[Lucky Phil]

3 hours ago, Pressureangle said:

Well, for those with complete machine shops and expensive measuring tools, sure. I could set it up on a surface plate and use a height gauge too and get it within  a  couple tenths. 
But for everyone else, this works with a cheap chinese caliper with depth tail.
And no, a bearing isn't junk just because you tapped  on the inner race. 

I mentioned in my previous post the technique for those without machine shop equipment. If you haven't got the money for a $50 set of 6 inch verniers that will last you for life then you probably shouldn't be working on you bike to start with.

I've never had a wheel bearing that was a "tap fit" in a hub that wasn't damaged in some way. Thats why they are usually C3 bearings standard. Every one I've ever done on an undamaged hub required enough hammering on the inner race during removal to make it unusable again. Unusable in the sense that it will have reduced life by quite a margin. It is still of course "useable" in the sense you can fit it and ride around for a while but long after you've forgotten how you hammered it you'll be wondering why it's life was far shorter than you expected.

 

Phil