rear wheel woes

[jrt]

What dimensions are we talking here? Ratchet or Dave, do one of you have the measurements for the spacer? I can make a few phone calls and see what I can do.

[gh67]

http://www.ebatmus.com

do a search there for 6204-2rsh and 6205-2rsh

They have C2 and non-C2

The price is a lot less than I paid NAPA for the inferior 6204/5-2rsj that are SKF 6204-2rs1 and 6205-2rs1.

I was not prepared and needed them same day, otherwise I would have gone mail order through ebatmus.

Let us know if their service is any good if you go with them.

Who knows, they may not like selling small orders.

EDIT having just said that the -2rs1 is inferior to the -2rsh, I noticed the -2rs1 costs more money!

56239[/snapback]

 

I called E.B. Atmus, I gave them all the info and they are researching it and will call me back. They deal in a lot of bearings, though didn't know enough about the "H" or "L" designation to give a specific recommendation for our application....so they are going to get back to me on any 6204 or 6205-2RSH/2RSL C3's.

[dlaing]

What dimensions are we talking here?  Ratchet or Dave, do one of you have the measurements for the spacer? I can make a few phone calls and see what I can do.

56380[/snapback]

You are the man!

The stock spacer measured 112.55 mm and the space itself between 112.6 and 112.7 mm so I replaced the spacer with a new one which measured exactly 113.2 mm (as reported by Baldini).

 

So in conclusion, my spacer was 0.65mm short.

 

Gio

I vote for 113.1mm. I think 113.00000 would be perfect, but better to err a little long.

Or maybe the 113.2 is better as the torque may compress the spacer

Heck, I don't know!?! But I don't like the idea of it being too loose.

The inner diameter should be greater than 20mm, I vote for 21mm. Any other votes, opinions, etc.?

The outer diameter is not too critical. I say one inch or 25-26mm.

And then there is the spacer that more or less centers the spacer when the axle is removed. Mine are inside my wheel, so I don't know their measurement.

FWIW the 6204 is 20x47x14 (which is why the ID of the spacer must be atleast 20mm, but too tight and getting the axle through will be a real big pain, too loose and you won't get even pressure on the bearings)

The OD can go right up, but not past the rubber seal.

It might be a good idea to maximize that number. If someone could measure???

Here is the stock spacer, without spacer spacers...

[Baldini]

I made a spacer out of steel tube on a lathe to fit the space betweeen bearing housings. I made it still a little too loose a fit, but as it was better than std I used it anyhow. L side brng (not C3) lasted about 8k miles before getting notchy. I had a replacement spacer supplied on warranty (113.4mm). I trial fitted this with old brng & it locked up brngs solid. So I machined this down. At 113mm it was still slightly proud of bearing housing. I reckon 112.8mmm would be bang on (I guess how long you make it depends also on how compressable the material is you use, personally I am happier using steel than Alu) but unfortunately my old lathe doesn't give me a depth of cut reading & being too lazy to keep taking it out to measure I still managed to make it slightly too short (112.55mm). It's a loose interference fit now. We'll see how it goes, but I'll prob prepare another spacer .... I think C3 bearings are key to longevity whatever.

 

Re: locating plates - these are a press fit on std spacer & can easily be removed/fitted. I left them off as it makes bearing removal much easier ! . Fitting axle is slightly more fiddly (you have to centre spacer from opposite side with a rod) but no great problem.

 

ID of spacer I made was 20.75mm, OD 25.5mm.

 

The only sure way you're gonna get a spacer to fit your bike is by measuring - dunno how much variation there is.

 

If you're making spacers up - don't neglect to bevel the edges for location of axle, esp if you leave off locating plates.

 

KB

[dlaing]

At 113mm it was still slightly proud of bearing housing. I reckon 112.8mmm would be bang on (I guess how long you make it depends also on how compressable the material is you use, personally I am happier using steel than Alu)

56390[/snapback]

In my layman's opinion, bang on is good, but a fraction of a millimeter short of bang on will cause bearing failure. So, I believe it is better to error with too long a spacer. Gio measured 112.6 to 112.7 which is pretty close the 112.8 that you measured.

I suppose if we are to make a bulk batch, we should error a little high with atleast a 112.9. The 113.4 seems to be a bit of over kill, and a little too much room for slop.

If we go with steel, maybe 112.8 or a tiny bit more would be fine????

With T6 Aluminum Alloy, I think a higher number like 113 point zero or point one would be fine.

Any other opinions?

Great info!

I was worried the spacer might get lost without a spacer's spacer, but upon removal of bearings, you are correct that it would have an advantage!!!

[Baldini]

...In my layman's opinion...etc

 

I also am no engineer.....

It may be too long is better than too short. If spacer is way too short & inner races arn't clamped up then inner races spin on axle causing heat. (Brian R's inside brng welded itself to the axle didn't it?). But inner race is going to be out of line w/outer either way. Are you suggesting some compression of spacer when axle nut is tightened? This would surely be negligable w/ a heavy steel tube?

 

In my case I'm hoping the extra clearance in C3 brngs will go some way to allow for est 0.25mm too short spacer. But I will make another spacer & this time measure it more accurately. It has to go in a four jaw chuck & it's a pain to centre it every time I take it out to measure.

 

I still don't understand why some bikes have this problem & some don't. It does seem there's a lot of L side brngs breaking. Are all the affected bikes same dimensions? Will one spacer fit all? Or is there a variation in housing widths? Do some wheels have smaller centres, pressing on steel inserts more?

 

There was plenty grease in my failed brngs. One failed after less than 1 mile. They slide into housings pretty easy. I do think it is lateral pressure that is the problem, suggesting spacer length.

 

I used some old steel tube I had for spacer. Measures 2.5mm wall thickness, 20.8mm ID, 25.4 OD, not sure what that is in inches but it may be available as stock size?

 

KB

[jrt]

I used some old steel tube I had for spacer.  Measures 2.5mm wall thickness, 20.8mm ID, 25.4 OD, not sure what that is in inches but it may be available as stock size?

KB

56429[/snapback]

 

 

25.4 mm is exactly one inch.

 

I'm not sure what part we're talking about here: is it part #6 on drawing 32 of the parts manual (from the V11 CD)? If so, does it need to have the two collars?

 

Dave, what are those notches cut in your spacer for?

 

What is the diameter of the axel?

 

So far, concensus is:

L: 112.9 mm

OD: 25.4

ID: 20.8

shape is plain sleeve, no collars, no detents

 

Material choices:

Alu, 36", enough for 8 pieces

7075 costs $35.34

7068 costs $51.53 (totally overkill for this application)

 

Steel, 01 drill rod sounds about right- mild steel (I don't know much about steel alloys)

36" is $30.71

cost of machining will be higher, because it will take longer, I presume.

 

Is that correct so far?

[dlaing]

snip

 

Is that correct so far?

56447[/snapback]

Hi Jason,

It is part 6. The collars on it are removeable and apparently unnecessary.

I like Baldini's comment on bevelling the edges to allow for easier axle insertion.

I called the collars, spacers for the spacer....

The notches on mine, I presume, are to aid in extraction of the bearings.

The notches are not necessary if we don't go with collars, as the spacer can be pushed to the side.

The 7075 from what I read is the better choice. The 7068 just increases tensile strength and machining costs. But Temper is key. I suppose the harder the better.

[Baldini]

...25.4 mm is exactly one inch. ...

 

... is it part #6 on drawing 32 ....... If so, does it need to have the two collars?.../quote]

 

(25.4mm=1") just testing you....

 

ID/wall thickness isn't critical if you can find available stock between axle diameter (20mm?) + clearance & OD of inner race.

 

Far as I know collars are only for locating spacer in centre of hub for easy axle install. They are a press fit. I didn't use them. Makes bearing removal a doddle, & axle install only slightly more fiddly.

 

DO NOT FORGET TO BEVEL EDGES OF SPACER for easy axle install.

 

KB

 

Edit: Just seen Dave's covered this....

[dlaing]

I also am no engineer.....

It may be too long is better than too short. If spacer is way too short & inner races arn't clamped up then inner races spin on axle causing heat. (Brian R's inside brng welded itself to the axle didn't it?). But inner race is going to be out of line w/outer either way. Are you suggesting some compression of spacer when axle nut is tightened? This would surely be negligable w/ a heavy steel tube?

56429[/snapback]

I don't know????

I just hate the idea of a heavy steel tube.

Yes, I am suggesting that there is some compression of spacer when axle nut is tightened.

I wish I knew how much the materials compressed under torque.

That is why I believe the spacer should be more than 112.8.

It may be a non-issue on tempered Aluminum Alloy and mild steel or chromoly steel?????

The races should only get catastrophically out of line if the spacer is too short or not square, but the C3 spec seems like good insurance for real world variations. A standard or C2 spec would last longer in an ideal world, that our bikes don't live in...

I still don't understand why some bikes have this problem & some don't. It does seem there's a lot of L side brngs breaking. Are all the affected bikes same dimensions? Will one spacer fit all? Or is there a variation in housing widths? Do some wheels have smaller centres, pressing on steel inserts more?

56429[/snapback]

The dimensions may be different, but so far all the posts indicate that the stock spacer is off by just a fraction of a millimeter. Or in the case of MG's newer 113.4 mm spacers, they may be too long...which is not all that bad. Much better than too short.

Variations in dimensions, is another reason why JRT's bulk run should be longer than the 112.8.

In my opinion, the outer race should not slop around too much, if the spacer is less than half a millimeter longer than flush.

I am only guessing, but I bet a C spec is one hundredth of a millimeter, so a C3 spec would have 0.03mm of freeplay?????

So I don't think the C3 spec will make up for your spacer being 0.25mm too short....Although it could be C3 might freeplay 0.30mm????And then you would be fine.

[Baldini]

...113.4 mm spacers, they may be too long...which is not all that bad. Much better than too short....In my opinion, the outer race should not slop around too much, if the spacer is less than half a millimeter longer than flush.....

 

I still don't understand why too long is better than short? When I fitted long spacer brngs locked solid. Are you saying that outer race would move out from fully home to align with inner in use?

 

If C3 brng had 0.3mm freeplay I think you'd feel it, it's gotta be less than that. I really need to make a new longer spacer.

 

Who said ignorance is bliss?

 

KB

[jrt]

 

DO NOT FORGET TO BEVEL EDGES OF SPACER for easy axle install.

 

 

Fear not KB!

 

Both extremes- too long or too short are not optimal. I'd like to get the number right before asking anyone to make a couple of these. "Bulk run"??? that's pretty funny. I can't think of anything Guzzi as 'bulk' except the motorbike itself.

And I don't think the aluminum is going to compress any. Do the steering clamps compress when you tighten them down? How about the brake calipers? Those are alu, and probably a lot softer. 7075 will be fine. I can get rolled rods from McMaster Carr (prices given above) that are 1" +/- 0.002% (always under rather than over tolerance though).

[dlaing]

I still don't understand why too long is better than short? When I fitted long spacer brngs locked solid. Are you saying that outer race would move out from fully home to align with inner in use?

56467[/snapback]

Hmmm?

I am not sure, but it might.

The way I have been seeing it, is that if the spacer is just a tiny bit, too short, the inner races of the bearings will be drawn by the full force of the torqued axle nut out of alignment with the outer races.

If the spacer is oh, say a millimeter too long, the inner races will remain stationary, and the outer races will more or less stay inline with the inner races. Lateral wheel forces being the exception, but lateral wheel forces are not avoidable.

However, theoretically, if the spacer was spot on, the lateral wheel forces would be shared by the two bearings, simultaneously. But spot on may not exist in the real world.

But maybe it is worth a shot to aim for it!

If the spacer is say, a half inch too long, I could imagine the wheel shifting back and forth, unpredictably, rubbing against the brake pads, causing a hazard.

I suspect you may have had a problem with the long spacer, because when you drove the bearing home, you likely damaged the bearing by forcing the inner and outer races out of alignment. I am just guessing, but I'll bet you drove it in by hammering on the outer race, possibly with a large socket to match the outer race.

The inner and outer races should be driven in simultaneously.

(Something I did not know, until Mike Stewart instructed me)

[jrt]

What about this stuff? Sorry, I can't provide a direct link. Go to www.mcmaster.com and search the part #.

 

1968T39

 

Alloy 2024 Aluminum Tube 1.00" OD, .76" ID, .120" Wall Thickness

 

1" OD gives the right...uh...OD.

Wall thickness of the part should be 2.3 mm or 0.09 in. (that sounds thin to me, but I haven't looked at one)

The .12" tubing would be easier to drill out than a solid rod.

 

The 2024 alloy looks good on paper; here's what mcmaster says about it:

 

With superior strength and good machinability, 2024 is the most widely used aircraft alloy. The addition of copper improves strength, but decreases corrosion resistance. It can be spot or arc welded, however MIG/TIG welding is not recommended. Use for aircraft parts, screw machine parts, and wheels. Nonmagnetic. Temperature range to maintain properties is -320° to +300° F.

[gh67]

Back to the bearing topic for a moment so we can hopefully put this to rest. I contacted EB Atmus...if you don't see it on their website for sale....then they (at least the 2 people I spoke to) probably can't get it.

 

Second call went to "Bearing Kinetics" form Dallas

http://www.bearingkinetics.com

1-877-242-4469

 

I just lucked on to their website by chance when googling. FYI - their website is not that great...but I went ahead and called them and was very very happy I did.

 

I initially spoke to Erica in the sales side of things and asked her about the 6204/5 SKF bearings that I found earlier. She found the part numbers, they have both the RSL and RSH in a C3....about $5.00 to $6.00 each. So...now that I had to choose, I wanted more insight to which may be better for our application. She transferred me to the owner, Don. One of the nicer guys you could ever speak and obviously has years of bearing experience. I told him our scenerio and he said although the SKF bearing that we were looking at would work, he would recommend one that is more motorcycle specific....turns out he makes bearings for some of GP teams. What luck! If we really wanted performance and low friction, 7x more life, 1/2 weight, then ceramic (silicon nitrate) are the best...and what he does for the GP guys and other auto racing teams....though they're about $50.00 a piece (yes...50 bucks). But if we want a normal (ie..less expensive) person's street-use bearing, he would make the following:

 

6204-LLB C3 and 6205-LLB C3 ....for about $4.50 each. SKF ones were only about $5.00 each FYI

 

If you are that 1%er and want ceramic then put a "C" in front of the 620x for the part number. Regardless, he definitely said that we want C3’s.

 

I went ahead and ordered 6 each of the standard steel ones...that should serve me and other needy people for a while. Don was going to make them up in the next couple of days and get them out.

 

Can't express how helpful these folks were and volunteered an abundance of information for a "small fish" order.

 

Will let everyone know how it goes when I receive the bearings.

 

cheers.