rear bearings and brake

[footgoose]

found this

 

[docc]

Wow, so great, footgoose. Thanks!  I am really struggling with my rearwheel bearings thinking it is something I am doing wrong. Perhaps it is that "silly millimeter?"

[footgoose]

this one popped up in the same search... maybe sumthin here. at least dlaing has some p/n's for bearings

 

[docc]

I have managed to source some high quality bearings, but keep suffering bearing failures like never before. Perhaps it is my installation technique. Perhaps my short spacer is finally telling on me. Seems my pinion bearing is also suspect . . .

[gstallons]

Hmmm. what brand n part #s did you find / come up with ?

[docc]

1 hour ago, gstallons said:

Hmmm. what brand n part #s did you find / come up with ?

SKF 6204 2RSJEM (Made in Argentina)

KOYO 6204 2RSC3GXM (Made in Romania)

After all this time/ miles, I keep destroying my rear wheel bearings. WTF? I've crushed my bearing spacer? It is definitely loose between the bearing inner races and not "captured" once the bearing outer races are seated . . .

[Lucky Phil]

3 hours ago, docc said:

What is the correct bearing spacer length for the early Sport 4.5 inch rim? (I found mine to be 112mm, but cannot be certain it is correct  . . . )

You need to fit one bearing docc then use a pair of vernier calipers and measure from the fitted bearing inner race face to the seat of the opposite side. A spacer equal to or few thou or even more longer than this measurement is ok but shorter is a no,no as it will pre load the bearing too much when you torque up the axle. I found my spacer too short and glued some shims onto it (only to hold them in place when the axle was removed).

You are aiming for a spacer that is the exact dimension between the bearing inner faces when both bearings are seated up against the bearing bores outer race shoulders. A fractionally longer spacer is acceptable but any dimension shorter is not.

This is the #1 reason for short wheel bearing life along with using high pressure washers foolishly. 

Ciao  

[docc]

Looks like the internal spacer is 0.045" undersize.  There are four spacers along the axle including one inside the bevel box. I ordered the other three, a couple more bearings and a new outside needle cage to see if I can tighten up the tolerance stack. It already has a new axle.

Internal space between bearings comes up 112.9 mm as best I can come up with. So, yeah, my spacer is short.

[Lucky Phil]

5 minutes ago, docc said:

Looks like the internal spacer is 0.045" undersize.  There are four spacers along the axle including one inside the bevel box. I ordered the other three, a couple more bearings and a new outside needle cage to see if I can tighten up the tolerance stack. It already has a new axle.

I'm not sure how to get that actual dimension between the bearings . . .

Thats a big issue docc, .045" is over 1 mm and that will place an large lateral squeeze on the wheel bearings inner races. You need to either machine up a new spacer of the correct length OR as I said use a shim or thin washer bonded to the spacer to get the length right.

Ciao

[Pressureangle]

On 4/21/2019 at 9:09 PM, gstallons said:

A lot of parts get reboxed when a Wholesaler changes suppliers .  It happens more than you want to know .

Probably counterfeit.

Even if Timken and FM actually have plants in China, I've crossed more than a couple websites for Chinese companies that make it their business model to print whatever brand name you want. My Cousin was U.S. Customs in Detroit, they captured TONS of counterfeit stuff crossing from Canada made in China, of every possible OEM from Ford to Harley to Caterpillar to Kraft foods. Bastages.

[docc]

There is a smaller spacer on the other side of the drive-side bearing that indexes to the inboard reardrive bearing. Not sure how it is supposed to be dimensioned, but mine shows visible wear, so I'm looking to replace it as well. Like I said, hoping to close up some of the tolerance stack.

Sheesh, our rear axle is a busy place!

[docc]

So, for certain, my internal wheel spacer is 112mm and (using LuckyPhil's method of removing a bearing and using a caliper for depth to the seating surface) the distance between the the bearings is definitely 113mm. No idea why this set-up worked pretty much all this time and now it toasts bearings almost immediately. I'm replacing two other spacers to try and tighten up the potential stacked tolerances.

Also, the SKF have a thinner inner race than the Chinese "National" and much thinner than the C3 Koyo.  Could this be a factor? And is the C3 the right thing for this application?

(Left to right: Romanian Koyo C3 / Xhinese "National" bought as Federal Mogul / Argentinian SKF ):

 

[Lucky Phil]

41 minutes ago, docc said:

So, for certain, my internal wheel spacer is 112mm and (using LuckyPhil's method of removing a bearing and using a caliper for depth to the seating surface) the distance between the the bearings is definitely 113mm. No idea why this set-up worked pretty much all this time and now it toasts bearings almost immediately. I'm replacing two other spacers to try and tighten up the potential stacked tolerances.

Also, the SKF have a thinner inner race than the Chinese "National" and much thinner than the C3 Koyo.  Could this be a factor? And is the C3 the right thing for this application?

(Left to right: Romanian Koyo C3 / Xhinese "National" bought as Federal Mogul / Argentinian SKF ):

 

Docc all the other stack ups wont really affect or mitigate the short wheel bearing spacer. If I understand your post the spacer is 1mm too short. What are the actual differences between the bearing widths?

The place you usually find C3 bearings are fitted in engines. Ducati's always used C3's in their head bearings although I dont know its totally necessary as plenty have run std clearance bearings in them.

I've seen this issue of short spacer enough times for me to measure them whenever I have wheel bearing out. Its quite common, dont know why though. Maybe the bearing widths vary enough to make it an issue although I've seen plenty of original wheels and bearings with short spacers. If you look at the new bearings you will find they have a slight bit of lateral play so a tiny bit of lateral preload they can tolerate but you're aiming for zero. Maybe a combination of wider bearings and using all the lateral play reduced the issue of the short spacer on the original wheel bearings.I'd be surprised though if it mitigated 1mm too short.

In general I dont worry about where anything is made if its actually a "name" product. I am wary if its a product say its a Chinese product from a Chinese company. The known big brands like Timkin etc have their own quality management and monitoring structures so are generally high quality. I've bought a few Chinese engineering things from Chinese companies over the years and the simple stuff like Titanium bolts etc are generally fine but the more complex stuff is risky.

Ciao  

[docc]

The various bearings I have all show nearly identical width of the inner races using my dial caliper (not a micrometer, but probably good enough).

I don't think this application is a good place for extra lateral play, but if the spacer is correct it should be fine  . . . yes?

 

As I said, I am also replacing the spacer between the inboard wheel bearing and inboard reardrive bearing. The one that hangs on the axle when we take our wheel off. Also replacing the right side sleeve that seats inside the exposed needle cage.

 

[Lucky Phil]

47 minutes ago, docc said:

The various bearings I have all show nearly identical width of the inner races using my dial caliper (not a micrometer, but probably good enough).

I don't think this application is a good place for extra lateral play, but if the spacer is correct it should be fine  . . . yes?

 

As I said, I am also replacing the spacer between the inboard wheel bearing and inboard reardrive bearing. The one that hangs on the axle when we take our wheel off. Also replacing the right side sleeve that seats inside the exposed needle cage.

 

Yes docc all the bearing should have pretty much identical dimensions as they are made to a standard. I was a little perplexed when you mentioned they were different. The calipers are accurate enough for this type of measuring.

The mission is at the end of the day to minimize the lateral clamping force by the axle nut on the inner races as much as is possible. Ball bearings can tolerate some lateral load but its not their primary load path. Ducati main bearings on my engines for example are ball bearings BUT they are Angular contact type to cope with the lateral loads caused by the clamping effect of the crankcases when the engine is cold and the side thrust form those engines fitted with helical primary gears. 

My advise is to either machine up a new spacer which to someone like Chuck for instance would be a doddle or do as I did and add a shim to the spacer to bring it up to the correct dimension. I went the shim route because I could do it with a single shim I had on hand and I didnt have any raw stock that would be suitable at the time. I also rarely remove my wheel so the spacer falling out wouldnt be an issue. I bonded it to the spacer. When the bearings are fitted and the spacer is the correct length it also doesnt float around when the wheel is out like a short spacer.

The sleeve on the right side always tends to corrode anyway but any spacer in this application and the one on the other side of the rear drive thats made of steel ( which is all of them from  memory) shouldn't really suffer from any crush by whats produced from the axle being torqued up.

Ciao