Front Sprocket for Aprilia RS125
MREV-P-000009Front Sprocket for Aprilia RS125: Heat-treated Chromoly 440 steel for the front sprocket that drives the chain. Select a tooth count, spline profile and chain size that match the bike. When the existing front sprocket teeth are worn, inspect the chain and rear sprocket too.
Front Sprocket for Aprilia RS125 mounts on the gearbox output shaft to drive the chain and transfer power to the rear wheel. The front sprocket on RS125 engages directly with the chain and determines one side of the final drive ratio.
What is Chromoly 440 steel used for?
Chromoly 440 steel is used for the front sprocket, which is CNC-machined and heat-treated. Steel suits the small front sprocket, whose teeth drive the chain through repeated revolutions. When selecting a replacement front sprocket, the priorities remain correct chain-size engagement and a secure spline fit on the shaft. Regular chain cleaning and adjustment also affect sprocket wear.
Selecting tooth count for your riding needs
If you are happy with how the bike rides and are replacing only a worn front sprocket, retain its tooth count to preserve the gearing. To change the bike's response, a larger front sprocket reduces the final drive ratio when the rear sprocket remains unchanged. This model is available with 17 teeth.
Checks before installation
When replacing only a worn part, use the chain markings and the tooth count of the front sprocket currently fitted. For a worn front sprocket, inspect uneven tooth wear and the chain currently in use. Incorrect chainline on a new sprocket will impair drivetrain operation.
Compatible vehicle models for Front Sprocket for Aprilia RS125
Recorded gearing options
Only recorded pitch, position and tooth options are shown. Final-drive changes must be evaluated against the complete front/rear setup; tooth count alone is not treated as a performance claim.