Know When to Replace Drive Train Bits!

While the act of replacing your cogs and chainrings is simple, knowing when to do so isn't. What constitutes a worn sprocket is measured in mere 100ths of an inch - not easy to see at a glance. Even worse, the consequences of doing the wrong thing in the drivetrain department can be very hazardous indeed. Luckily, all potential ugliness can be avoided with a little preventive maintenance.

Very, very worn 32/22 chain rings. Combined with an equally worn cassette, the middle ring seen here was pretty much unridable (it would skip/slip at inopportune moments when applying peddling power).

What is the Best Regular Maintenance Schedule?

Riders who spend 8 to 15 hours per week on the same bike need to replace their chains a minimum of three times a year, and should consider replacing their chains up to six times per year if the terrain is muddy or extra dusty. The elements are very hard on drivetrain components especially the chain. There are 116 separate bearings between the cogs and the chainrings. Recreational riders who ride 5 to 8 hours a week should replace their chains twice a year. Casual riders (less than 5 hours a week) can simply replace their chains at the start of every year.

Why Change the Chain Instead of the Sprockets?

By keeping your chain fresh, wear on the cogs is greatly reduced. When a chain wears, it grinds away at the cogs and wears them out. If you replace your chain at regular intervals, the sprockets will last five times longer than the chain. If you continue to ride on a worn-out chain, you can expect to wear out both the chainrings and rear cogs.

Why Does my Middle Chain Ring Have Chain Suck?

The middle chain ring is the most commonly used chainring, so it wears out first. Chain suck occurs when the teeth of the sprocket refuse to release the chain drawing it up and over. The solution to chain suck is almost always new chainrings.

What Causes Chain Skip?

Worn out parts. When a chain rides up on a worn rear cog, it fails to get a firm grip on the angled teeth. The chain inches its way up each tooth as the cogset spins until the chain eventually skips off, causing the cranks to jerk forward on hard pedalling efforts (very dangerous to your knees).

What should you do if you suffer chain skip? Immediately stop riding the bike until you replace your cogset and maybe your small and middle chainrings as well.

Which Chainrings Wear Out First?

The ones you use the most. If you have a bike with aluminium chainrings, expect the granny and middle chainrings to wear out first. If your bike has a steel granny, it will last longer and the middle chainring will show signs of abuse sooner. If you have a steel granny and steel middle ring, they will still wear out before the big ring. The big ring takes the least abuse because you aren't in it as much.

Hope this is of help.