Frequently Asked Questions at Simply Bearings

Frequently Asked Questions

1. When I search I get a lot of results which do not look like the products I searched for?
2. Can you give me some guidelines when measuring bearings?
3. Is there a method of measuring the clearance in a bearing after fitting and what should it be?
4. My bearing has 2 rubber seals but the number depicts only one, how do I get the correct number of seals?
5. What are C2, C3, C4 and C5 bearings?
6. Can you explain double sealed bearings?
7. LFS Sealed Bearings ~ What you need to know
8. What temperature will oil seals work at?
9. What inside diameter should my oil seal have?
10. What are the different characteristics between deep groove ball bearings?
11. What clearance is necessary between roller and crankshaft components?
12. Do you really carry 2 million bearings in stock?
13. Do you supply automotive bearings?
14. Do you supply shoulder bearings?
15. Do you supply gearbox oil seals?
16. Do you supply washing machine/drum bearing kits?
17. Taxes & Duties. Do I have to Pay them?

Question

“When I search I get a lot of results which do not look like the products I searched for?”

Answer

Different manufacturers use lots of different names for their products. e.g. search for returns a bearing , in the equivalents listing for this bearing is the search term listed as VBF , because this part number contains "" the search result for this is also returned.
At the top of each search result page are a set of filters that can be used to fine-tune the search results.

Beijing SKF Product Page

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Question

“Can you give me some guidelines when measuring bearings?”

Answer

The biggest and most common mistake when taking bearing measurements is to measure metric bearings in inches and likewise inch sized bearings in mm, no amount of searching will produce results for this scenario. Some simple guidelines are:

Generally, metric bearings will have full mm dimensions. Thus 20mm bore x 47mm outside diameter x 14mm width = series metric bearing.

Imperial bearings measured in metric will not have full mm sizes. Thus 12.7mm bore x 28.57mm x 7.87mm is in reality 1/2 inch x 1-1/8 inch x 5/16 inch = KLNJ1/2 series imperial bearing.

There are lots of unit converters available to go from metric to imperial and vice versa. You can also search in Google for "simple unit converter" https://www.google.co.uk there are many free to use online converters. We can of course measure your bearings for you. Please make sure your items are clean and post them to us stating how many of each you require and in what brand.

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Question

“Is there a method of measuring the clearance in a bearing after fitting and what should it be?”

Answer

Feeler gauges need to be used in the bearing to determine what clearance remains between the bearing outer and the rolling elements. This will be stated generally in the manual for the equipment and not by the bearing manufacturers.

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Question

“My bearing has 2 rubber seals but the number depicts only one, how do I get the correct number of seals?”

Answer

Bearing manufacturers generally stamp the bearing number on the bearing and not on the seals, historically numbers on the seals refer to the bearing number and the seal on that side of the bearing only hence the reference of single RS refers to one seal on that side only, for 2 seals 2RS would be the number but its rarely stamped on the seals. The same applies to metal shielded bearings, Z is a single shield reference for one side of the bearing becomes ZZ for 2 seals (Z becomes 2Z in some manufactures numbering schemes).

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Question

“What are C2, C3, C4 and C5 bearings?”

Answer

C3, C4 and C5 bearings are bearings that have an additional internal radial clearance to cope with high-speed environments where excess heat is generated. They are not suited to environments where critical alignment is required from the onset e.g. Where blades and cutters are set up to each other. Applications like motorcycle wheels or bicycle wheels do not require C3 rated 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 at the quality of the bearing being poor and having more movement than the one they are replacing. C4 and C5 are even looser still than C3 clearance bearings. This is the characteristic of these higher than normal clearance bearings marked C3, C4 and C5.
C2 marked bearings have less clearance internally than standard bearings and should only be used in applications that specify C2 clearance.

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Question

“Can you explain double sealed bearings?”

Answer

Some manufacturers put the bearing number on the seals, which is fine if you know that a bearing with 2 seals is referred to as 2RS or a ZZ or 2Z.
Customers often refer to these numbers and order a bearing with a number like xxxxRS which, when in the past, we have supplied as a single sealed unit. The customer then complains as they clearly required a 2 sealed bearing. To stop this problem we supply a double-sealed item. The customer can remove the surplus seal if it is not required. This can be done by applying light pressure at the edge of one of the seals with a blunt instrument. A large amount of pressure would need to be applied to a bearing to damage it.

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Question

LFS Sealed Bearings ~ What you need to know

Answer

We sell a lot of LFS bearings, in fact, a great deal more than we sell over the trade counter. It's the misconception that you are getting something better than a standard rubber sealed bearing. It's the opposite way round, LFS seals whilst offering lower friction than RS seals don't offer the same dust or water resistance.

The LFS seal is a none contact seal thus being a lower friction option, the RS is a contact seal and as such offers far better resistance to moisture and dust ingress or foreign matter than the LFS types. Consider your choice carefully, replace LFS with LFS but don't replace RS with LFS as it will undoubtedly lead to premature failure.

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Question

“What temperature will oil seals work at?”

Answer

Nitrile rubber oils seals, the most commonly found seals in engines, gearboxes and general industrial applications have a working temperature range of -22 deg C to +100 deg C (-22 deg Fahrenheit to 212 deg Fahrenheit)

More information on temperature ranges for each material can be found here [Click Here]

Viton oil seals are available in a selection of sizes and can tolerate far higher extremes of temperature between -20 deg C to +200 deg C (-4 deg Fahrenheit to 400 deg Fahrenheit)

The temperature should only be one consideration when selecting an oil seal, the medium in which it must run is also of prime importance and can be checked by clicking Chemical Resistance Table: [Click Here].

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Question

“What inside diameter should my oil seal have?”

Answer

The required inside diameter of an oil seal is the same as the shaft size it will be running on (the seal manufacturers make allowance for the seal to be the correct fit on a shaft).

If you can supply us with the shaft size, outside diameter and width you require we can locate the seal for you and send you a link to it.
If the seal is missing or damaged beyond measuring then simply measure the shaft diameter and the diameter of the bore in the housing into which it fits and as best you can the width of the seal, these will be your inside, outside and width dimensions.

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Question

“What are the different characteristics between deep groove ball bearings?”

Answer

The standards of internal clearance that bearings are manufactured to are quoted by a C then a number or for standard clearance bearings are denoted to be CN clearance which is never stated and places the bearing between C2 and C3 Clearance.
The answer is that as the number gets higher the internal clearance between all the moving parts gets larger to cope with hot and high-speed environments better than standard or C3 bearings (C3 having slightly more clearance than standard) bearings would.
In principle as a bearing gets hot with speed or its environment then the parts expand, whilst expanding the distances between all the moving parts gets smaller.
Standard bearings are what are known as CN clearance but this is never stated in the bearing number thus CN would normally be stated as just .
C2 is less than normal so the bearing is tighter (designed for slower-moving more precise applications that require little or no play in the bearings where the temperature remains fairly constant.
C3 is designed for hot running environments; engines etc. where the bearing temp could reach 100deg or more.
C4 more extreme temperature applications and higher speed environments.
C5 the highest clearance bearing available, are extremely loose to start and can knock until at operating speeds and temperature.
For these reasons the materials and designs vary to accommodate these characteristics.

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Question

“What clearance is necessary between roller and crankshaft components?”

Answer

As the diameter of the crankshaft increases the clearance will stay proportional to the diameter. It comes under ISO standards of limits and fits. It will be in the back of a Zeus book or similar, Google will show some limits and fits tables. Our limits and fits tables can be found here [Click Here].

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Question

“Do you really carry 2 million bearings in stock?”

Answer

In reality, we probably have more! We now have a purpose-built 20,000 square feet UK stock holdings in the North West of England based in Leigh at the heart of Lancashire and receive deliveries daily from the US and Europe. Additionally, we have a large storage unit in Bolton where we store bulk stocks should we need them. We supply SKF, NSK, RHP, FAG, INA, IKO, NTN, SNR and many other major brands and have access to a huge network of National and International bearing distributors should we need them.

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Question

“Do you supply automotive bearings?”

Answer

The bearings we supply are suitable for most applications however we do not supply manufacturers specific bearings. E.g. if you have a bearing with a Renault part number on it then it’s not likely we can cross-reference it to anything standard. By the same token if you measure the bearing it will most likely be a standard bearing. Manufacturers do this and sell spares as OEM parts at a premium. (Original Equipment Manufacturer). Because there is such a phenomenal variety of bearings for cars we do not have access to cross-reference databases for these bearings. We do however sell wheel bearing kits for a very wide range of cars from stock. [Click Here]

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Want more information on Deep Groove Ball Bearings manufacturer? Feel free to contact us.

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Question

“Do you supply shoulder bearings?”

Answer

If you meant "flanged bearings" then yes we do, they can be found [here] other than that we do not have a database that provides the necessary information, however, if you can provide the bearing number, I am sure we will be able to obtain the bearing required.

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Question

“Do you supply gearbox oil seals?”

Answer

Yes, we do, our oil seals are used in many types of gearbox, unfortunately, we do not have a database that provides this information, however, you can easily identify an oil seal from the shaft diameter it runs on, the outside diameter of the seal or the diameter of the housing it fits into and its's width.

As you can imagine there are thousands of makes and models of vehicles, fortunately, they all generally, with the exception of a few manufacturers, fit standard oil seals which can be identified by their sizes. If you can provide the dimensions of the seal, i.e. bore, diameter and width, I am sure I will be able to obtain the seal required.

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 There are many different types of bearings available today with very little information on the differences between them. Maybe you’ve asked yourself “which bearing will be best for your application?” Or “how do I choose a bearing?” This bearing selection guide will help you answer those questions.

First off, you need to know that most bearings with a rolling element fall into two broad groups:

1. Ball bearings
2. Roller bearings

Within these groups, there are sub-categories of bearings that have unique features or optimized designs to enhance performance.

In this bearing selection guide, we’ll cover the four things you need to know about your application in order to choose the right type of bearing.

Find the Bearing Load & Load Capacity

Bearing loads are generally defined as the reaction force a component places on a bearing when in use.

When choosing the right bearing for your application, first you should find the bearing’s load capacity. The load capacity is the amount of load a bearing can handle and is one of the most important factors when choosing a bearing.

Bearing loads can either be axial (thrust), radial or a combination.

An axial (or thrust) bearing load is when force is parallel to the axis of the shaft.

A radial bearing load is when force is perpendicular to the shaft. Then a combination bearing load is when parallel and perpendicular forces produce an angular force relative to the shaft.

To learn more about axial and radial ball bearings, contact our team of engineers!

How Ball Bearings Distribute Loads

Ball bearings are designed with spherical balls and can distribute loads over a medium-sized surface area. They tend to work better for small-to-medium-sized loads, spreading loads via a single point of contact.

Below is a quick reference for the type of bearing load and the best ball bearing for the job:

• Radial (perpendicular to the shaft) and light loads: Choose radial ball bearings (also known as deep groove ball bearings). Radial bearings are some of the most common types of bearings on the market.
• Axial (thrust) (parallel to the shaft) loads: Choose thrust ball bearings
• Combined, both radial and axial, loads: Choose an angular contact bearing. The balls contact the raceway at an angle which better supports combination loads.

Roller Bearings & Bearing Load

Roller bearings are designed with cylindrical rollers that can distribute loads over a larger surface area than ball bearings. They tend to work better for heavy load applications.

Below is a quick reference for the type of bearing load and the best roller bearing for the job:

• Radial (perpendicular to the shaft) loads: Choose standard cylindrical roller bearings
• Axial (thrust) (parallel to the shaft) loads: Choose cylindrical thrust bearings
• Combined, both radial and axial, loads: Choose a taper roller bearing

Bearing Runout & Rigidity

Bearing runout is the amount a shaft orbits from its geometric center as it rotates. Some applications, like cutting tool spindles, will only allow a small deviation to occur on its rotating components.

If you are engineering an application like this, then choose a high precision bearing because it will produce smaller system runouts due to the tight tolerances the bearing was manufactured to.

Bearing rigidity is the resistance to the force that causes the shaft to deviate from its axis and plays a key role in minimizing shaft runout. Bearing rigidity comes from the interaction of the rolling element with the raceway. The more the rolling element is pressed into the raceway, causing elastic deformation, the higher the rigidity.

Bearing rigidity is usually categorized by:

• Axial rigidity
• Radial rigidity

The higher the bearing rigidity, the more force needed to move the shaft when in use.

Let’s look at how this works with precision angular contact bearings. These bearings typically come with a manufactured offset between the inner and outer raceway. When the angular contact bearings are installed, the offset is removed which causes the balls to press into the raceway without any outside application force. This is called preloading and the process increases bearing rigidity even before the bearing sees any application forces.

Bearing Lubrication

Knowing your bearing lubrication needs is important for choosing the right bearings and needs to be considered early in an application design. Improper lubrication is one of the most common causes for bearing failure.

Lubrication creates a film of oil between the rolling element and the bearing raceway that helps prevent friction and overheating.

The most common type of lubrication is grease, which consists of an oil with a thickening agent. The thickening agent keeps the oil in place, so it won’t leave the bearing. As the ball (ball bearing) or roller (roller bearing) rolls over the grease, the thickening agent separates leaving just the film of oil between the rolling element and the bearing raceway. After the rolling element passes by, the oil and thickening agent join back together.

For high-speed applications, knowing the speed at which the oil and thickener can separate and rejoin is important. This is called the application or bearing n*dm value.

Before you select a grease, you need to find your applications ndm value. To do this multiply your applications RPMs by the diameter of the center of the balls in the bearing (dm). Compare your ndm value to the grease’s max speed value, located on the datasheet.

If your n*dm value is higher than the grease max speed value on the datasheet, then the grease won’t be able to provide sufficient lubrication and premature failure will occur.

Another lubrication option for high-speed applications are oil mist systems which mix oil with compressed air and then inject it into the bearing raceway at metered intervals. This option is more costly than grease lubrication because it requires an external mixing and metering system and filtered compressed air. However, oil mist systems allow bearings to operate at higher speeds while generating a lower amount of heat than greased bearings.

For lower speed applications an oil bath is common. An oil bath is when a portion of the bearing is submerged in oil. For bearings that will operate in extreme environments, a dry lubricant can be used instead of a petroleum-based lubricant, but the lifespan of the bearing is typically shortened due to the nature of the lubricant’s film breaking down over time.

There are a couple of other factors that need to be considered when selecting a lubricant for your application, see our in-depth article “How to Choose the Correct Ball Bearing Lubricant".

For more Bearing Product Distributorsinformation, please contact us. We will provide professional answers.