3 Things you must know before you buy a ball bearing

1. What do the suffixes C2, C3, C4, C5 mean?

The C in the designation stands for internal clearance which means the bearing has room for expansion if needed between the bearings, while holding the outer ring and moving the inner ring in a radial motion you will notice a small amount of play between the the two rings. All bearings have this movement, it may only be a small amount of movement but controlled by international standards. C3 and above means the bearing has more play than normal and C2 means the bearing has less play than normal.

C2 - Less bearing play than Normal (0-0.009mm)
CN - Normal Bearing Clearance (0.005-0.02mm)
C3 - Larger bearing clearance than Normal (0.011-0.025mm)
C4 - Greater bearing clearance than C3 ( 0.018-0.033 mm)
C5 - Greater bearing play than C4 (0.136-0.192mm)

But what bearing clearance (clearance) should you have?

C3, C4 and C5 bearings are bearings that have extra internal radial clearance to cope with high speed environments where excess heat is generated. They are not suitable for environments where critical customization is required from the start, e.g. Where knives and cuttings are aligned.

Applications such as motorcycle wheels or bicycle wheels do not require C3 marked bearings. Unless the bearing you are replacing specifically says C3 on it then you should not replace it with a C3 bearing, C3 bearings are loose to the feel from new and often people complain that the bearing is bad and has more movement than the one they are replacing . C4 and C5 are even looser than C3 bearings. This is characteristic of these higher than normal clearance bearings labeled C3, C4 and C5.

C2 rated bearings have less clearance internally than standard bearings and should only be used in applications specifying C2 clearance.

2. What does ABEC mean?

ABEC stands for Annular Bearing Engineering Council, which is a standard for defining the tolerance and precision of ball bearings. The tolerance of a ball bearing depends on how much the precision, based on an absolute measure, can vary during manufacture.

Ball bearings graded using the ABEC system are often referred to as "precision ball bearings" and are graded on a scale of numbers 1, 3, 5, 7 and 9. The higher the number, the greater the standard precision. There are no requirements for what material the ball bearing must be made of. The ball bearings only need to be made to a certain degree of precision.

How ABEC ratings work for skateboards and rollerblades

ABEC ratings are only odd numbers and start with ABEC 1

ABEC 1 is the crudest, least accurate, most durable and cheapest.
ABEC 3 is what most cheap complete skateboards come with, especially skateboards from China. ABEC 3 bearings work for most skateboards, but don't roll as smoothly or quickly.
ABEC 5 bearings are the norm for skateboards. You get a reasonable speed and at a reasonable cost.
ABEC 7 bearings would be very fast and smooth, but are expensive. In addition, you start to risk unnecessary damage to them if you ride hard or aggressively. Note that some cheap foreign made ABEC 7 bearings may not deserve this rating.
ABEC 9 and above would be ridiculous to use on a skateboard if you're going downhill or anything else where your goal is to go insanely fast. Unless you're spending a fortune on these bearings, don't trust that they're actually the ABEC 9 you got.

ABMA/ANSI Std. 20	ISO 492	DIN 620	JIS B 1514
ABEC 1	Normal	P0	Class 0 Class 6X
ABEC 3	Class 6	P6	Class 6
ABEC 5	Class 5	P5	Class 5
ABEC 7	Class 4	P4	Class 4
ABEC 9	Class 2	P2	Class 2

3. What does friction mean and how does it affect which bearing I should buy?

Friction is in physics a force that tends to counteract the relative motion between two surfaces that are in contact with each other.

If too much friction forms, the bearing runs hot and can break prematurely, and then you need a bearing that offers less friction. Bearings that offer less friction usually handle higher speeds because they don't get as hot.

Then it depends on the material the bearing is made of, if the outer track or the inner track is made of a material other than steel.

If you want a low-friction bearing or non-friction bearing, you should buy an open bearing or a metal cap as they offer just that. At the bottom of the page you will find guidelines for SKF's seal selection.

Advantages of non-contact bearings

Compared to standard bearings, low friction bearings reduce friction movement by 30% or more. This reduces surface degradation, which reduces the risk of machine failure

Guidelines for seal selection SKF Groove ball bearings

Symbols: +++ excellent, ++ very good, + Good, O acceptable, – not recommended (most common for SKF)

Claim	Z	RZ	RSL	RST	RSH	RS1
Low Friction	+++	+++	++	++	O	O
High RPM	+++	+++	+++	+	O	O
Retention of fat	O	+	+++	+++	+++	++
Protection against dust	O	+	++	++	+++	+++
Protection against water Static Dynamic High pressure	- - -	- - -	O O O	+++ + O	+++ +++ +++	++ + O

At Remlagret.se you will find most of what you need, should you not find what you need, do not hesitate to contact us via our e-mail address info@remlagret.se

We will subsequently update the information. If you have any comments where you think we have worded it wrong or tips on other important details we could write about, send an e-mail to info@remlagret.se