abec 9 bearings
abec 9 bearings
Author :Admin | Publish Date:2013-04-18 10:28:22
The most noticeable result is that you will end up with less money in your
wallet and the people that sold you the bearings will be eating out at restaurants at your expense for a few days. Under the
following conditions, you may notice an improved performance.
You spend a lot of money (i.e. thousands of dollars) to have your equipment
(wheels and board) redesigned and manufactured to suit these high precision
bearings. You will need to use some type of shock absorber that allows for
absolutely no vibration. You will have to be prepared to skate on a perfectly
smooth surface and make no attempts to use your feet to propel yourself. (Doing
so would cause shock loads to the nsk bearings and
any extra precision would be lost very quickly).After you work out how you are
going to achieve the above two criteria, you may (and that is only "may")
experience a better result than using ABEC 1 bearings after you attain a speed
of about 390 KPH (240 MPH) with 65mm wheels and grease lubrication.
OK, but don't forget that you really do not need to waste money on anything
higher than ABEC 1 or ABEC 3 for skating applications. It should also be pointed
out that the precision grade only tells us how close the bearings dimensional
tolerances are (that is, how close the bearing is to the stated size). There are
many other factors relating to the quality of a bearing, and many of these
factors will have much more of an impact on your skating experience than the
ABEC Grade of the bearing.
There are a number of factors covered by the ABEC grades, but to give you
an idea we will just examine one of these factors - the eccentricity (out of
roundness) of the track in the inner ring. For an ABEC 1 (lowest grade) bearing,
the maximum eccentricity allowable is 0.0075 mm (0.000295"). This is quite
precise - more than precise enough for skates and skateboards. The figures for
the other ABEC grades are 0.005 mm (0.000197") for ABEC 3, 0.0035 mm (0.000138")
for ABEC 5, 0.0025 mm (0.000098") for ABEC 7, and 0.0012 mm (0.000047") for [ABEC 9 bearings]
. If used in high precision, high speed machinery (see above), these minute
variations can make a difference. The fact is that no matter which of these
bearings you use in skates or skate boards, after 5 - 10 minutes of use the
tracks won't just be eccentric, they will become irregular (albeit minutely)
enough to be practically indistinguishable from one another. Your high priced
ABEC 9 bearing might as well be a 50 cent ABEC 1 cheapie.
We have to believe that they are until it is proven otherwise. If the
bearings are labelled as ABEC 7 then in most countries the manufacturers of the
bearings are compelled by law to provide ABEC 7 bearings. Some of the low prices
offered for high precision bearings in Supermarkets does look a little strange
though. Manufacture of high precision bearings is not cheap, although the costs
can be kept lower if other quality controls are not in place. Our Swiss quality
supplier RMB has recently checked the tolerances of a set of bearings that was
purchased at the Supermarket, and labelled as "ABEC 5". The bearings did indeed
meet the standard of ABEC 5, but more costly tests would be needed to check all
of the other important quality factors relating to the bearings (and many of
these other factors are more relevant to skating). See point 11 also.
"Z" is a designation which means a steel shield covering the side of the
bearing (for most brands). "ZZ" simply means that the bearing has a shield on
both sides. Normally, the shield itself will be branded as "608 Z" even though
there is a shield on both sides of the bearing. This is for practicality in
manufacturing. It is much more economical to produce all of the shields stamped
as "608 Z" than it would be to manufacture the exact same component with two
different stampings on them. Some manufacturers supply bearings with removable
shields, whilst others have shields that are crimped in place. Neither is
usually better than the other unless you intend replacing the lubricant or
cleaning the ntn bearing from time to
time.
B25-163AZNXC3
B25-164AZNXC3
B8-85T12DDNCXMC3E
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