BB problem, I think!

[John]

Hi all, I'm new on here so be kind please. I've noticed I'm hearing a very slight clunking noise when left pedal goes down. Any ideas? Thought it might have been BB lockring but seems tight to me. Bike only 6 months old & don't want to go to shop as want to maintain bike myself.

[DaveM]

First check:
- pedals tight to crank arms
- crank arms tight to BB spindle
- crank arms not hitting anything

Then do the pedals spin smoothly? If you slide the chain off the chainrings and spin the cranks, does the BB feel smooth?