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In order to choose the best sprocket kit, you must determine what parts you need to change the sprockets. Some sprocket kit packages include a pair of sprockets, a drive chain and mounting hardware, while others can include only a pair of sprockets. The best sprocket kit packages will commonly include both the sprocket hardware and chain as well as installation shims, thread locking compound and extra chain links. The extra chain links are helpful because they allow adjustments to be made to compensate a sprocket diameter change down to the half link. You must ask the retailer selling the kits about the parts included in the kit and choose the one that best fits your needs and application.
When changing a sprocket due to wear, damage or desired performance changes, it is mandatory to purchase a sprocket kit that includes both the drive and the driven sprocket. Sprockets wear in particular patterns, and simply changing one sprocket is bound to end in failure of the new sprocket or the other original sprocket. Both sprockets must be changed together, and it is often recommended that the chain be changed as well to avoid damage to the new sprocket kit.
There are two limiting factors when changing the size of a sprocket kit, clearance and drive shaft size. The sprockets must be able to be attached to the shaft driving the sprocket and there must be sufficient clearance to avoid contact between the chain, sprockets and other components in the system. Chain and sprockets are sized according to the size links and rollers used in the chain, therefore, sprocket kit components must contain all of the same-sized components. This is especially important if you are keeping the original chain and simply replacing the sprockets with a sprocket kit.
The best sprockets have welded centers at the shaft-mounting location of the small drive sprocket. Do not choose a kit that has sprockets that are only spot-welded to the center hub, because a fully-welded sprocket hub will be much stronger. Two-piece sprockets are also used in some high-performance kits for the makeup of the large sprocket. This type of sprocket kit makes it possible to change the large, typically rear, sprocket without removing the rear axle. These kits are especially popular among go-cart racers and other chain drive competition machines, and the kits commonly represent the best parts available where strength, quality and dependability are important.