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General Category => General Discussion => Topic started by: bmc5733946 on January 11, 2022, 07:32:13 PM
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I'm probably overthinking this but ball bearing classification for Guzzi wheel bearings, C3 quality or should I be looking for tighter tolerances?
Brian
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C3 bearings have greater internal clearance to allow for heat expansion- like in a hot electric motor or an engine crankshaft. You don't want or need C3 bearings for motorsickle wheels.
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They came with the boggy 6000 series bearings Brian; can't see much advantage in going to C3. Cheap enough to change them out each year if you wanted to.
I got 16 years out of the front ones on the Breva, the back one still original.
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I'm probably overthinking this but ball bearing classification for Guzzi wheel bearings, C3 quality or should I be looking for tighter tolerances?
Brian
As others have indicated C3 is not an issue of quality but internal clearance and normally specified for bearings that run hot and/or at elevated speeds. Ducati 2 valve cam bearing were always C3's but I've seen std clearances used as well. C3's are often a special order from the bearing shop also. I've sometimes seen C3's used on wheel bearings because the bore ID on the wheels was undersize for some reason and a std bearing was rotationally tight when installed. The biggest thing to check when replacing wheel bearings is that the bearing spacer isn't too short. Many a wheel bearing has been sacrificed at low mileages because of this from the factory.
Ciao
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The biggest thing to check when replacing wheel bearings is that the bearing spacer isn't too short. Many a wheel bearing has been sacrificed at low mileages because of this from the factory.
Ciao
Indeed. It is much better to have the spacer a little long rather than a little short.
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Thanks fellas! C3 seem to be the ones most readily available.
Brian
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Thanks fellas! C3 seem to be the ones most readily available.
Brian
Which bike are you working on Brian? Greg Bender’s site has part number references for wheel bearings for Tontis and they are relatively easy to source for short money. I just bought several on Amazon. Maybe he has references for other bikes.
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I'm working on the alloy wheels for my Mille GT. I have the numbers 6004 & 6204. The C3 classification refers to internal tolerances of the bearing. C3 seems to be the most common and is greater tolerance than "normal" as mentioned above. I am sure normal tolerance bearings can be sourced from local bearing houses but if it is unnecessary or overkill why bother? I am going with the C3 class bearings.
Brian
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I'm working on the alloy wheels for my Mille GT. I have the numbers 6004 & 6204. The C3 classification refers to internal tolerances of the bearing. C3 seems to be the most common and is greater tolerance than "normal" as mentioned above. I am sure normal tolerance bearings can be sourced from local bearing houses but if it is unnecessary or overkill why bother? I am going with the C3 class bearings.
Brian
I've always found the opposite myself.
Ciao
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Another common use for the C3 clearance bearings were in many British motorcycle motors where the bearing would
frequently require tapping ( hammering) the inner race onto a shaft and then chilling that bearing afterwards and pressing
that assembly into a heated set of cases . So called normal clearance bearings would end up with very little running
clearances . As above , far from necessary on a wheel , but hey if that's what's available it's sure not going to be a problem .
Peter
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I ordered 2 sets of NSK bearings, they arrived today. 8 bearings in all, all from India, 4 x 6004 2rs all C3, 4 x 6204 2rs all C1. They will get used. I am somewhat amused at the mix but I think all will be fine. C3 is tighter clearance than C1.
Brian
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I ordered 2 sets of NSK bearings, they arrived today. 8 bearings in all, all from India, 4 x 6004 2rs all C3, 4 x 6204 2rs all C1. They will get used. I am somewhat amused at the mix but I think all will be fine. C3 is tighter clearance than C1.
Brian
Just for the sake of clarity and information here, not trying to win any points but this got me questioning my previous experience/knowledge and for those mechanically anal types I checked my Koyo bearing handbook that I've always used as reference for calculating bearing loads/speeds and applications when making and modifying things.
A Koyo deep groove ball bearing is rated for internal clearance as follows for a 18-24mm id bearing. C2.....0-10 microns, Standard (unmarked) 5-20microns. C3....13-28 micron. C4...20-36microns and C5....28-48 microns. These are for unloaded bearings on the bench and there is a calculation to determine the loaded clearance as well. Bearing standards are basically universal so as a rule of thumb with the "C" clearance rating system the higher the number the greater the clearance. As can be seen there is some overlap.
Ciao
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Phil, I think I might be misinterpreting the information I found here.
https://www.engineersedge.com/bearing/ball_bearings_tolerances.htm
I am also aware that there is more than one system using numbers to classify bearings, it is one of the reasons I asked in the first place. I think for my use these bearings will be "OK" but my knowledge is scant.
Brian
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If you have a question about any bearing, regardless of type, application, availability etc..... contact these folks, I am amazed as to the specialty bearings they can source.
https://www.123bearing.eu/
I have been purchasing all of the bearings I need from this supplier for the past 3 years, they are very helpful and will find any bearing you can think of. I have asked for advice on the two bacon slicer Guzzi motors I have recently rebuilt (250 and 500), a Ducati 860, Morini 350 and 500, Benelli 175 and 650, Aermacchi and many more. They also have supplied magneto and dynamo bearings and seals.
I measure the size, send pictures of the bearings I have extracted and they take it from there and get back to me in a day or two with cost options and reccomendations. They ship DHL express for a nominal fee and the bearings arrive in under a week from across the ocean.
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Phil, I think I might be misinterpreting the information I found here.
https://www.engineersedge.com/bearing/ball_bearings_tolerances.htm
I am also aware that there is more than one system using numbers to classify bearings, it is one of the reasons I asked in the first place. I think for my use these bearings will be "OK" but my knowledge is scant.
Brian
That link Brian I believe is for the bearing dimensional tolerances as opposed to the internal clearance tolerances. I agree that at the end of the day what you have will work out fine.
Ciao
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This thread interested me in an academic sense, as I realized (for at least the third time today, not counting Kathi pointing out more deficiencies :wink:) how little I know about so many things. :cry:
But I then thought about the last time any of the bearings on my battle fleet had been replaced. Let's just say it's been awhile. :rolleyes:
So, to shift this thread's focus without hijacking it from its title, I would like to know what tools are needed to remove the old and install the new.
Do I have to remove the wheels to do this?
Just kidding to see who is reading this far. :evil:
Seriously, I have nary a clue about this. Figure that neither my Stornello nor V7 III (at 9K & 12K miles, respectively) are candidates.
But the EV at 106K -- tho it's had new bearings installed by dealers at least once -- the Norge at 85K (no known replacements) and Griso at 28K (ditto) are all on borrowed bearings, so to speak. :shocked:
Now, not that I intend to lose my moto-virginity in doing this myself, but I would like to have the right tool in the hands of a bunch of Guzzisti who will be attending Moto Grappa Tech Days next month.
With that in mind, is anything at this link the sort of item I should get (for the volunteers :grin:)?
https://tinyurl.com/Wheel-bearing-installer (https://tinyurl.com/Wheel-bearing-installer)
If so, please recommend which. If not, be kind. :wink:
Grazie in anticipo!
Bill
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This thread interested me in an academic sense, as I realized (for at least the third time today, not counting Kathi pointing out more deficiencies :wink:) how little I know about so many things. :cry:
Bill, you should check out my recent thread. Might be helpful:
https://wildguzzi.com/forum/index.php?topic=113741.0 (https://wildguzzi.com/forum/index.php?topic=113741.0)
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Bill, you should check out my recent thread. Might be helpful:
https://wildguzzi.com/forum/index.php?topic=113741.0 (https://wildguzzi.com/forum/index.php?topic=113741.0)
Doh.
Completely missed that.
Many thanks. :bow:
Bill
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If I don't have a socket whose od matches the od of the bearing pretty closely to use as an installation driver, I go to the big box store and find a piece of PVC pipe or a PVC fitting to use as a driver. As long as you don't drive on the inside of the bearing or seal surface you should be OK. For removal I use a standard long punch and reach through the internal spacer cocking it off to one side and drive on the inner race, I never reuse bearings removed in this fashion.
Brian
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If I don't have a socket whose od matches the od of the bearing pretty closely to use as an installation driver, I go to the big box store and find a piece of PVC pipe or a PVC fitting to use as a driver. As long as you don't drive on the inside of the bearing or seal surface you should be OK. For removal I use a standard long punch and reach through the internal spacer cocking it off to one side and drive on the inner race, I never reuse bearings removed in this fashion.
Brian
What Brian said. Spot on.
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Just be careful you don't gouge the hub and go side to side.
kk
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Just be careful you don't gouge the hub;
go side to side.
kk
Just to make sure the sentence structure is clear, aye?
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I could have worded it better. I figured the procedure would be obvious.
kk
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https://www.youtube.com/watch?v=mngsq-m43A4&ab_channel=Brock%27sPerformance
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Just to add to this subject belatedly, mainly with reference to bearing clearance specification: I'm just replacing the front wheel bearings in my 2012 V7, and the spec of the (almost certainly) original bearings is C3 clearance; ie. reasonably loose.
To be precise, they are (Italian made) SKF 6004-2RS1/C3. (20 x 42 x 12 deep groove roller bearing with rubber seals both sides, C3 clearance)
Too bad I'd pre-empted the work, and already ordered bearings with 'standard' clearance before I'd seen the originals, following the general consensus above that C3 are too loose for wheel bearings: However, I'm not going to worry too much - the tolerance overlap between 'standard' and C3 is quite large. Either way, it's well worth sourcing your own bearings.. the mark-up on original equipment replacements is crazy.
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I ordered 2 sets of NSK bearings, they arrived today. 8 bearings in all, all from India, 4 x 6004 2rs all C3, 4 x 6204 2rs all C1. They will get used. I am somewhat amused at the mix but I think all will be fine. C3 is tighter clearance than C1.
Brian
Quality name brand breading are readily and usually only a few percent more (especially for common bearings like 6004/6204) than no-name bearings produced in a 3rd world facility with dog only know what metallurgy was used.
Watch YT videos on manufacturing in India and Pakistan and you’ll see how nothing goes to waste and no 2 batches of metal are the same.
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C3 are fine for wheel bearings. Wheels are not that precision. C3 won't give you noticeable deflection at the rim.
Low clearance bearings end up in precision locations like machine spindles or work holders where the device is expected to hold tolerances measured within 0.0001" .
Motorcycle wheels don't need that and with the lack of precision in hub bore and spacer faces the extra clearance works on the side of longevity.