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Thread: Quick bearing quality overview

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    Default Quick bearing quality overview

    Probably on VS somewhere(I might have posted similar at some point) but may be helpful to some.

    Annular Bearing Engineering Committee (ABEC)

    There are five classes from largest to smallest tolerances: 1, 3, 5, 7, 9. The higher ABEC classes provide better precision, efficiency, and the possibility of greater speed capabilities, but do not necessarily allow the components to spin faster. The ABEC rating does not specify many critical factors, such as load handling capabilities, ball precision, materials, material Rockwell hardness, degree of ball and raceway polishing, noise, vibration, and lubricant. Due to these factors, an ABEC 3 classified bearing could perform better than an ABEC 7
    Take care of yourself in this time of crisis and realize sadness, anger and grief are part of the process Brian Clare

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    Default Re: Quick bearing quality overview

    I think it is best to keep in mind that the efficiency of bearings account for very little once on the road as gravity and air resistance are the main resistance and in a drastically larger scale. You can ride back to back with a standard wheelset and one with ceramic bearings that seem to spin forever on a stand but out on the road this account to no measurable gain.
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    T h o m a s

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    Default Re: Quick bearing quality overview

    Quote Originally Posted by sk_tle View Post
    I think it is best to keep in mind that the efficiency of bearings account for very little once on the road as gravity and air resistance are the main resistance and in a drastically larger scale. You can ride back to back with a standard wheelset and one with ceramic bearings that seem to spin forever on a stand but out on the road this account to no measurable gain.
    yes and no. the free spin of a ceramic bearing on the stand doesn't carry over very much to a real world application because the races aren't under load. in that state the balls are more round and have less friction as a result. Once they are under load though you end up with slightly lower mechanical losses than a steel setup. at bicycle RPMs most of the frictional losses are more likely coming from lube and seal drag.

    I think you're right that compared to the work it takes to get your mass over a hill or drag losses from aero or tire rolling resistance, those losses are really small, but they're also real and measurable. They also sum into something slightly more significant if you're willing to go all in on your prep and throw a lot of money and trouble at it. Running ceramic bearings in your wheels, BB, and pulleys + using oversized pulleys and a prepped chain you're going to save about 5-10 watts vs a normal drivetrain. Toss in some aero BS and you can find yourself going faster without increasing your fitness or changing your position.

    but the biggest thing is just keeping your bike clean and well maintained. there's a small and real difference between a good ceramic BB and a good steel BB. there's a huge and real difference between a clean BB and a fouled one.

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    Default Re: Quick bearing quality overview

    Quote Originally Posted by zachateseverything View Post
    ... those losses are really small, but they're also real and measurable...
    I don't understand how this is measured, in theory yes, but on the road with a million variables....?
    Take care of yourself in this time of crisis and realize sadness, anger and grief are part of the process Brian Clare

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    Default Re: Quick bearing quality overview

    Quote Originally Posted by claritycycler View Post
    I don't understand how this is measured, in theory yes, but on the road with a million variables....?
    for frictional losses my expectation would be that lab measurements will translate to real life pretty easily. there aren't that many variables impacting the rotation of a shaft inside some kind of bearing for example.

    tiny individual losses are going to be tough to measure in the field, but what you can do with a power meter and a good test protocol is verify the aggregate of several improvements stacked together.

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