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Thread: wrong sized ABEC-5?

  1. #1
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    wrong sized ABEC-5?

    I have a stroller with "ABEC-5" bearings in it. It recently became loose, and I planned on replacing it. Long story short, the bearings that came out of the stroller, and the replacement "ABEC-5" bearings I looked at , were a different size. My "ABEC-5" bearing is bigger than all the others I looked at. I was told by 3 different bike shops that that was the first time they had ever saw that. They said "ABEC-5/7/9 etc., were standard. Two guys even hinted at the possibility of it being a "black market" part.

    I am not happy to have a stroller company distributing ineffective parts. They also told me they no longer have the "part" I need...something doesn't seem right.

    I have pictures and the original bearing that I needed to replace, and the "TTN" replacement bearings they sent me. I hope this interests you or you have any insight on this matter. Thank you.

  2. #2
    ABEC-5 is a mechanical tolerance grade - not size. If the bearing became loose, there was probably a condition where the materials chafed away on either the bearing or the feature (or both) where the bearing fit into.

    Keep in mind that the bearing could be a custom or metric size. Do you have mechanical dimensional measurements you can post with your picture?

  3. #3
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    The bearing was not damaged in any other way besides losing the bearing shield.

    Is there a way to post pictures to this thread, or do I have to start a new one?

    Thank you!

  4. #4
    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by ImBearingConfusion View Post
    The bearing was not damaged in any other way besides losing the bearing shield.

    Is there a way to post pictures to this thread, or do I have to start a new one?

    Thank you!
    Bottom right "Go Advanced" then select "Manage Attachments".

    Upload and attach.. and follow instructions.
    Attached Images Attached Images

  5. #5
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    pics

    I have no Idea wy they sent a bigger bearing, I'm sure that an "ABEC-5" bearing is smaller than both.

    Hope this helps.
    Attached Images Attached Images

  6. #6
    Lead Engineer RWOLFEJR's Avatar
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    All you need to do is get the dimensions of the bearing (accurate) and order one from from one of literally thousands of places. Typically there will be numbers on the side of the bearing races to identify the things as well. As was mentioned the ABEC numbers are a tolerance or precision level. You don't need ANY "declared" precision for a stroller bearing. You need Inside diameter... Outside diameter... and Width. Then you need to determine if the bearing was shielded or sealed. I'm certain your bearing isn't a freak one of a kind bearing.

    In some / many instances the fit and style of the bearing is critical.... This wouldn't be one of them. In all likelihood there will be bearings from several different bearing manufacturers made to the same exact specifications. Your original was probably a run of the mill deep groove ball bearing sheilded both sides. Maybe an angular contact ball but I doubt it.

    Knowing and understanding the variety and purpose of different styles and classes of bearings and their variations of each is a very deep subject. The nomenclature for the bearing world... Prefixes and suffixes applied to bearings for different fits or assembly arrangements is a field in itself. But the unit you're looking for is probably a 3 - 5 dollar bearing at most.

    Couple of places right off that you could take your original bearing and show them and they could get dimensions and replacement... Applied Industrial Technologies (Used to be called Bearings Incorporated) Motion Industries (used to be Berry Bearings) Or any machine shop in your neighborhood that would own a pair of calipers to measure yours and then you could look it up in McMaster Carr and have one in your hand in a day.

    Side note... the bike shops are mystified by the ABEC 5,7,9 designations. What happened there was more of a marketing scheme that they got caught up in. Some companies selling skateboard wheels etc. decided using higher precision bearings would offer them a selling advantage. Something to pitch that sounds high tech... Smoke and mirrors is most of what that is. In reality... many if not most ABEC 5 bearings are ABEC 9. All bearings are made to high precision levels but the ABEC 9 are pulled aside and measured to be "proven" of their accuracy. The 5's are run on the same line and most, in all likelihood, are the same precision. When a critical piece of equipment running at high rpm's is involved it's nice to know that the bearing you're installing is exact in every aspect. The reverse can also be true. Example beaing a coal conveyor roll. Those bearings are purposely loose as a goose and one of the balls is removed from the assembly. They do this so the bearing can tolerate and chew up a little crud when the seal fail and to also reduce line start up friction.

    All that to say... loose isn't always a bad thing and sometimes better for a specific application. Your stroller will run wonderfully with ANY bearing of any type that fits your envelope. If the bearing is 1" x 1/2" x 1/4" ... Any bearing that size will work.

  7. #7
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    Thanks for your reply. I will try the closest fitting sized bearing. I was just told if it isn't the exact size, I would most likley need to replace it again and again. Still seems funny that the company has no past history of this sized bearing.

  8. #8
    Lead Engineer RWOLFEJR's Avatar
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    Yes close won't get it. It will either fit or not... no in betweens. The bearing number is written on the side of your "ABEC 5" bearing. I can't quite make it out in the picture but it looks like 690??S ???
    If you can make out the number on the thing I can tell you exactly what you had in there. Also it appears to be sealed both sides not shielded.

  9. #9
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    Confused

    I figured there was more to it.

    My "ABEC-5" says "6001RS" on it, and the "replacement" they sent me has the same code written on it. It does not say "ABEC" but rather "TTN" I think it is sealed, it looks like plastic??

    I am lost again...I cant see two custom bearings costing a few bucks, is it that easy to manufacture these? Every time I look up an "ABEC-5" bearing, they all look slimmer than the one I have...

    How do I find out if this bearing is legit? Is there a phone number? Like I said, If it was as easy as pie, why would the stroller company send me two complete wheels with the wrong bearing size, free of charge, twice? Are they hiding something? Seems to me if I could just pick up these bearings, I would have them already.

    Also, What is the difference between "ABEC_3/5/7/9"??

    The struggle continues...
    Last edited by ImBearingConfusion; 05-19-2011 at 09:52 AM.

  10. #10
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    I am reluctant to get involved here but ImBearing, you are not listening to the advice being given here.

    Some truths...
    Bearings fail regardless of manufacturer. The black material is a rubber/neoprene seal and maybe it was not fitted correctly at the factory and has let dirt in resulting in an early failure. Stuff happens in mass production and unless you want to pay $30 EACH a bearing for Class-7 bearings get over it. It is not bad or sub-standard. The people you are talking to are counter-jockeys and have no real idea about the engineering.

    Stop thinking that ABEC has anything to do with size and fit. Do some searching and educate yourself, start here...
    http://skateboard.about.com/od/gear/f/ABEC_Bearings.htm

    You need ONLY four things to buy replacement bearings for your application.
    1: Outside diameter in Decimal Inches or Decimal Millimeters
    2: Inside diameter in Decimal Inches or Decimal Millimeters
    3: Width in Decimal Inches or Decimal Millimeters
    4: Open, Shielded or Sealed. The pics you provided show SEALED bearings, so you need sealed.

    You can make this as easy or as hard as you like. You have tried "hard" now try "easy." Take the old bearing to a bearing supply place and ask for a new one just like it.

    Fini.

    Dave
    Generally, I will not give you the answer to your question, but I *will* guide you into discovering how to solve this yourself.

  11. #11
    Lead Engineer RWOLFEJR's Avatar
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    Well there you have it... 6001RS
    That's all you need to get the exact same bearing as was in it.
    It's a 12mm I.D. a 28mm O.D. x 8mm wide sealed both sides.
    McMaster Carr is selling them for $6.97 each
    http://www.mcmaster.com/#5972k82/=cdgpqg

    These will handle a radial load of 1,150 lbs. and a max. of 18,000 rpm. So unless your kid is really fat and you can run like the wind you'll be in good shape with this bearing.

    Like has been said... FORGET the ABEC numbers. This is a stroller, not a spaceship.

  12. #12
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    "you are not listening to the advice being given here."

    Which advice are you talking about??

    "If the bearing is 1" x 1/2" x 1/4" ... Any bearing that size will work." from rwolf

    or

    "Yes close won't get it. It will either fit or not... no in betweens." from rwolf??

    Sorry for being uneducated on this matter. Seems like if all I needed in the beginning was EXACT measurements, I should have been told that??? Again, sorry for my ignorance.

    Also what is the relevance to the "6001RS"??

  13. #13
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    Quote Originally Posted by RWOLFEJR View Post
    Well there you have it... 6001RS
    That's all you need to get the exact same bearing as was in it.
    It's a 12mm I.D. a 28mm O.D. x 8mm wide sealed both sides.
    McMaster Carr is selling them for $6.97 each
    http://www.mcmaster.com/#5972k82/=cdgpqg

    These will handle a radial load of 1,150 lbs. and a max. of 18,000 rpm. So unless your kid is really fat and you can run like the wind you'll be in good shape with this bearing.

    Like has been said... FORGET the ABEC numbers. This is a stroller, not a spaceship.
    soooo.....6001 RS is a specific size??? why then do I have two different bearings with the same number written on them?? The pictures I first posted show both "6001RS" bearings, both, different sizes.
    Last edited by ImBearingConfusion; 05-19-2011 at 01:54 PM.

  14. #14
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    Quote Originally Posted by ImBearingConfusion View Post
    "you are not listening to the advice being given here."

    Which advice are you talking about??
    Around an hour and fifteen minutes after your original post, RWolfJr had this to say as an OPENING paragraph.

    Quote Originally Posted by RWOLFEJR View Post
    All you need to do is get the dimensions of the bearing (accurate) and order one from from one of literally thousands of places. Typically there will be numbers on the side of the bearing races to identify the things as well. As was mentioned the ABEC numbers are a tolerance or precision level. You don't need ANY "declared" precision for a stroller bearing. You need Inside diameter... Outside diameter... and Width. Then you need to determine if the bearing was shielded or sealed. I'm certain your bearing isn't a freak one of a kind bearing.
    You then continued on with a rant about other irrelevant issues about the value and quality of the stroller all the while clinging to the why, the ABEC stuff and what you were told by others not from this site.

    NOTE the word in parens in TW's opening sentence. in Engineering a tape measure is NOT an "accurate" device for bearing measurement. Had you followed that advice you would be pushing the baby in the stroller by now.

    Dave
    Generally, I will not give you the answer to your question, but I *will* guide you into discovering how to solve this yourself.

  15. #15
    Administrator Kelly Bramble's Avatar
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    Oh, I see - you have a 6001 RS industry standard series deep groove probably ceramic bearings manufactured to the ABEC-5 Tolerance.

    How's you noodle doing now?

    As already stated, you need to measure the outside diameter, inside diameter and Google or Bing for "6001 RS". You will find that this series of bearings comes in a size range -I believe all metric sizes.

    You need to measure using a pair of calipers or equivalent, a tape measure does not count. When installing, consider using the thick thread locker or similar stuff since the bearing OD will likely fit loose (just my guess).

  16. #16
    Lead Engineer RWOLFEJR's Avatar
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    Yes... 6001 calls out a specific bearing size that is an industry standard. Any brand bearing you buy that is called "6001" will be the same BASIC dimensions. The other bearing does not have the same numbers on it otherwise it would indeed be the same size. You might need to get a magnifying glass and look again. It's probably a 6002 or 6200 or whatever. It's definitely not a 6001 iff (if and only if) the correct bearing is indeed numbered 6001. Period.

    Also... recall on my first response I said...
    "All you need to do is get the dimensions of the bearing (accurate) and order one from from one of literally thousands of places. Typically there will be numbers on the side of the bearing races to identify the things as well."

    Also... When you said something like... I'll pick something close... My reaction was close won't get it. Reason for that response is akin to the old adage... "Ten pounds in a five pound bag. You obviously can’t put a bearing into a bore that is a quarter inch smaller than the bearing… right? Even a couple thousandths difference of interference to the fit could bind the bearing up if it isn't DESIGNED for a press fit by being built with looser than normal running clearance in it to accomodate the shrink tha would occur with a press fit. If it were designed for a press fit on both the shaft and inside the bore the bearing would have a suffix of C3 or C4 or C5. But forget I said that... Again... IT'S A STROLLER... NOT A NUCLEAR POWER GENERATOR. (Caps to signify being said with enthusiasm...)

    So...
    What you can do is basically one of three things...
    1) Buy a new bearing. You can do this by calling a bearing house and tell them "I have a bearing with the number 6001RS on it and it's ABEC 5 for a kids stroller. Then they'll say... Sure we can get you one of those for 49.oo that is part number P5 6001 RS. Then they'll say ... but why would you feel the need for a precision bearing for that application? We can sell you an ABEC 1 bearing that will do the job for 7 bucks?

    2) Get ACCURATE measurements... Calipers, micrometers... not a tape measure... And call a bearing house and tell them you have a bearing that measures this by this by this and order one.

    3) Scrap the stroller and go buy a new one.

    Tah Dah!!
    That's all there is to it.

  17. #17
    Administrator Kelly Bramble's Avatar
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    Red face

    How many engineers does it take to... oh never mind.

  18. #18
    Senior Engineer Marky's Avatar
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    :bash:

    I would love to see this Stroller......it must be smooth riding.

  19. #19
    Project Engineer CCR5600Design's Avatar
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    Whew...

    I had less trouble finding bearings for my air-cooled VW engine that had the crank ground .060" and the case line bored .030".



    Ron

  20. #20
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    still dont get the "rocket ship" mention....bearings either fit or they dont.....right???? Too small and they'll be destroyed and too big....well, you're an engineer! And excuse me for not putting incorrect smaller bearings on my $600 stroller...what an ass I am eh???

    How many engineers does it take to screw in a light bulb?

    All of em. A few to actually help, and the rest to make fun with dry humor and poor sarcasm.

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