I believe that the middle chainring on my Ultegra 6603 triple road crank is due to be replaced. The mileage is about 12,000 miles. It will hang up and delay releasing to the granny ring at times causing slow shifting & chain slap.

I found a replacement 39 tooth ring for the “6604” that sounds like it would work.

But i’m also curious to know: what are some other symptoms that my chainrings are on there way out? Does noise increase when under climbing torque? I lubricate my chain and change it when it is stretched @ 1.0% which helps but I am getting “imprecise” type of noises that don’t sound healthy.

Thanks for any help you can give....