Release time : 2015-06-10 12:26:40
By Bearing Manufacturer>Bearing News>How to measure needle bearing dimensions and choose the correct bearing type?
The first method: reference Numbers
The quickest way to determine which bearing you require is using the bearings reference number.Most bearings have their references numbers engraved on the bearings themselves, but these often rub off over time and so it may be necessary to measure the bearing yourself, as described below.
The second method: measure needle bearing dimensions
Sometimes you may need to identify a bearing due to general wear and tear. Most bearing references now are laser stamped but these wear and rub off more quickly than the previous method, which was engraved deep in the bearing's metal.
Once you have determined the dimensions of your bearing, you can use our bearing search tool to find the correct bearing.
It is sometimes necessary to measure bearings to determine the correct bearing type.
Each bearing has an inside diameter, outside diameter and width diameter in that order. Most bearings are metric in size, but can also be imperial. On our site, each bearing shows needle bearing dimensions.
d = Inside diameter
D = Outside diameter
B/T = Width diameter
There are three main types of bearing - roller bearings, ball bearings and needle bearings. The differences between these bearings are detailed below.
Once you measured your bearing, you can use our search to find the correct bearing size.
e.g. Inside Diameter: 25mm; Outside Diameter: 52mm; Width: 15mm - Bearing Type: 6205
Once you know the bearing you need based on size, you can then choose further options:
The bearing also has a seal either side of the bearing and this will be indicated by the suffix:
ZZ or 2Z = 2 Metal Shields
2RS1 or 2RSR or DDU= 2 Rubber Seals
Additionally, bearings also have a clearance value. This provides the bearing room for expansion between the bearing races and will add a small amount of play between the two rings.
An example of where a larger clearance is required is if a bearing is likely to get hot. The heat needs room to escape otherwise there is a risk of bearing failure.
C2 = clearance is less than international standard
C3 = international standard for bearing clearance
C4 = clearance is greater than international standards
Ball Miniature Bearings - A ball bearing uses loose balls to maintain separation between the two races.
Deep Groove Ball Bearings - The same as a ball bearing but instead of balls, a roller is used to maintain the separation,
Needle Roller Bearings - a small bearing which uses small rollers to reduce the friction between the races.
Above are the most simple method of measure needle bearing dimensions and choose the correct bearing type.