When to Replace Crankset?

After 5,400 miles it is reasonable to replace the rear cassette and chain. The front chainrings may need replacing if they have been ridden with a wornout chain. The rest of the crank: the spindle cranks and spider should be fine. Sometimes it is cheaper to replace the whole crankset.

When should you replace a crankset?

My rule of thumb is to replace it at 75 per cent wear (as measured with a chain-wear indicator). If you stick with this guideline, your cassette and chainrings will last a lot longer. A cassette, in most cases, can last for approximately two to three chain replacements if they are done at the right time.

How long should a crankset last?

As long as crank arms are checked regularly for tightness they should last for years and years. I have vintage Sugino Aero Tour (AT) crank arms that I have used for over twenty-five years without any wear to the square tapers. I've installed and worn out four or five chain ring sets using the same crank arms.