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A lot of bike riders would like to be able to do their own maintenance, but feel they lack the knowledge to be able to complete simple jobs correctly. Subsequently they would rather take their bike to a workshop, and pay handsomely for the pleasure of having someone else perform the tasks that they are perfectly capable of doing themselves.

Possibly one of the “Dark-Arts” most amateur mechanics get confused by, is the correct method of greasing wheel and steering head bearings. Nothings could be simpler….This post will show you how

The steps below shows the correct method for home mechanics to prepare a set of wheel bearings prior to installation. No doubt some of you will disagree with some of the content of this post, but after having spent 40+ years in engineering, I feel I have a reasonable amount of experience to back it up.

Some will argue that most new bearings come pre-greased and the manufacturers know best the correct grease and quantity to use…WRONG !!!!. Bearings can be used in many different applications, from simple wheel bearings to Ultra high speed applications. Motorcyle wheel bearings are a relatively low tech application. Provided we use the correct grease, (preferably waterproof) and the correct quantity, then finally install them correctly (a subject for a later post) your bearings will last as intended.


My method follows................

Items Required:

Good quality waterproof grease. My preference is to use Castrol APXT, others prefer Belray waterproof-grease. It is up to you.

A needle or pin

Kerosene

Small brush

Contact Cleaner or equivalent

Gloves

Clean rags (it is a messy job!!)



Find yourself a clean well ventilated area to work. Set out all the items you need



Gently prise out the seals from the bearing. I prefer to pick them out from the inner part of the race. (If you are using a variety of different brands of bearings, make sure you do not mix up the seals, as they may be slightly different sizes.)

Also be very careful when you insert the needle/pin that you do not damage the lip of the seal. Go in on an angle between the seal and the race before levering up

Place the seals in a safe place



The picture below shows the quantity and type of grease installed in this bearing. I wouldn't want that crap in my wheels, it looks like "petroleum jelly" to me..!! >



OK, lets get rid of that stuff by soaking the bearings in kerosene for 5 -10 minutes



Then gently brushing the remaining grease out using a small paint brush



It is advisable not to use petrol for this process due to the fire risk and potential health implications from breathing the fumes.

After making sure all of the grease has been removed, wipe off the excess kerosene and then completely flush the bearings by spraying liberally with "Contact Cleaner" or equivalent product.



Allow the bearings to then "air" dry for 10 minutes. Do not use compressed air to blow dry the bearings as it is possible to spin the bearings up to very high RPM and they have been known to self destruct with disasterous consequences.

NOTE: Avoid the temptation to "spin" the bearing when it is dry. This is the best way to destroy a new bearing...!!



To avoid possible contamination to your expensive pot of grease, trowel the amount of grease required into a paper cup and then immediatley reseal the grease container. This also stops you from potentially dunking a contaminated finger back into the grease pot..!! :



Now for the messy bit. Place a blob of grease into the palm of your left hand and then push the bearing into the grease, forcing it to fill the spaces between the inner and outer race. Slowly rotate the bearing till it is full, then flip it over and repeat the process. When you are sure that the bearing is fully packed. Now hold the inner race still, then slowly rotate the outer race through one or two full turns. This will displace some of the grease which you can now press back into the cage to thoroughly coat the balls. If you are happy with how it looks, use the tip of the index finger of your right hand to remove the excess grease so that you can see the cage. Repeat for the other side.



When you have finished your bearings should look something similar to the picture below.

Note: It is not advisable to pack the bearings 100% full. When the bearing spins up it needs some space for grease displaced by the rotation of the balls and cage. This may also result in the bearing running hot or even displacing the seals. :gerg:



Now all that is left to do is to replace the seals. Before doing that, I like to coat the metal on the back of the seal and smear some grease over the sealing edges. It is then just a matter of simply pressing the seals back in place



Time to sit back and admire your handy work



For the sake of half an hour of your time, you can be confident the bearings installed in your wheels are now going to be able to survive the worst you can throw at them.....