SKF Bearing Assembly
Take your kart's rear bearings to the next level.
Failing rear bearings and worn out axles will occur to even the most savvy of karting mechanics. However, there's a product on the market that just may solve both of those problems for you. In this installment of Pro Tips, Justin at J3 Competition gives you the low-down on the technology behind the SKF rear bearings, the same bearings they use on their COMPKART chassis line.
There are three main parts to the bearing assembly: the bearing itself, then a two piece clamping device that includes a locking ring and collet (figure 1). The main advantage with this method over traditional methods is you leave no marks on your axle from set screws that eventually wear your axle and bearings out.
With the bearing inside the cassette, as you would any bearing, you then combine the two clamping pieces (figure 2) so the locking ring is up against the ridge on the inner device. With the clamping pieces combined, you simply push it into the bearing so the locking ring device is firmly up against the bearing. To remove, simply just pull it out with your hands.
Cleaning The Bearings
Both sides of the bearing have a removable plastic shield. To remove, use a pick or small screwdriver to get under an edge of the shield. While under the shield (figure 3), slide your pick all the way around the shield to pry it up. This reveals the bearings underneath, which you can now use some compressed air to clean out any debris and add some lubrication.
Installing an Axle
Assuming you've used our Axle Assembly Pro Tip, you already have the axle installed on your kart. With the inner locking ring loose around the clamping collet, it should spin freely around the axle. When you go to tighten the locking ring, it's going to clamp the collet around the axle to keep it from sliding. It's very important that when you go to tighten the locking ring that you have the set screws offset evenly around the collet slit (figure 4) and that the set screws have a flat end and not a knurled end.
First you need to loosen the set screws on your locking ring. You know it's loose when it freely spins around the collet and axle. Next, we need to get the collet to release from our axle completely, and to do that we need to give it a shock. Find an object with a blunt end, preferably steel like a T-handle wrench. Place that object on the bearing race (figure 6) and give it a sharp hit with a hammer, three times around the bearing.
At this point your axle is free to slide through the bearings, so grab a rubber mallet and hit your axle through the bearings as your normally would to remove your axle. You'll then find yourself rejoicing that your axle is still in perfect condition, thanks to the SKF technology.
SKF is a worldwide manufacturer and supplier of ball and roller bearings, among other products. Their bearings are used in motorsport of all varieties, including karting. J3 Competition is a dealer for SKF bearings, but SKF did not endorse this Pro Tip; Kart360 felt the technology was worthy of recognition in this feature.