I know many of us here put lots of miles on our bikes, which will result in wear of items. So the question may come up of when to put new chainrings, crankset, cassette, chain, pulleys on your bike.
Today, I’ll show you before and after worn chainrings and crankset.
Symptoms of crankset needing service: With chain off, front crankset doesn’t spin freely or makes grinding sound. This is a sign that bearings are worn, dirty or lacking grease. When crankset is off, spindle shows wear. This wear is due to crank grinding against the bearings.
Clean- brand new crankset:
Worn spindle due to seized bearings
Other symptoms: we had just put new chain and cassette on bike and chain would fall off front chainrings while applying force to crank. As you can see here, teeth are badly worn on force part of stroke. Inner chainring isn’t too bad- obviously the rider is a “masher”, not “spinner”
New vs old chainrings
New vs old cranks
By looking at above pics, you can see more wear on downstroke of right leg than left leg. ( my shameless plug to practice one legged pedaling drills - right @Coach_Theia ?).
I don’t have pics, but the outside of the crank arm was also worn from shoe rubbing crank arm.
I rebuilt this bike at the bike shop as special tools are needed to remove and press the new bearings into the bottom bracket.
This is my husbands trek checkpoint gravel bike with 2x11 Shimano Ultegra components.
Total cost: $320. Parts only
Crankset $199 from Jenson USA (shimano ultegra 50/34 175mm cranks)
Bearings from bike shop about $30 each= $60
Had also just changed out cassette. (Shimano 105 11-34) $47 from bike tires direct
And a Shimano ultegra/xt chain 11sp $33 from bike tires direct.
Since it’s a totally new drivetrain, we started waxing chains. That will be a different post.