Intermittent Click from Left Pedal

twoodley

I appreciate that clicking noises from pedals has been covered many times, and I have read most to see if any are similar to mine, which is really annoying.
Bike is Cannondale Six Carbon. Everything great for first 100 miles or so, then a click starts when the left pedal is at 11 o'clock (start of down stroke). Nothing too unfamiliar here except I work out it is only when I am on the large tront chain wheel (no sound on small crank), and only when under load does not click if I lift the rear wheel off the ground).
After a few weeks I went over a particularly rough patch of road, which almost loosened my teeth fillings, but hey presto the click vanished. Next time out I was enjoying a nice quiet ride, and had to use the small crank to get up a long incline, which in itself is not a problem until I changed back to the large crank, where you guessed it "Click" each rev at 11 o'clock on left pedal.
I have had a look and nothing appears to be rubbing or hitting, and as said I does not click if I am off the bike.

Any ideas (apart from riding over very rough roads when it comes back)?

keef66

whip the pedals off, apply grease to the threads and pop them back on. Also a spot of light oil on the cleat mechanism.

I have double sided SPD's and my left pedal has developed a click but only on one side, so I'm starting so suspect a dodgy cleat mech.

Also check that the end of the front mech cable isn't catching on some part of a crank or chainring (had that on several occasions / bikes)

Twostage

I had a similar thing - clicking from left pedal intermittently. I noticed it was sometimes a double-click which gave away the problem. I have two sensors on the back wheel - one for the cateye and one for a garmin gsc-10. When I was pushing down on the left pedal the rear wheel was flexing just enough for the magnet to touch the sensors. Simply adjusted the sensors and the clicking went away.

ride_whenever

Either mech cable catching when in larger ring, or the chainrings moving slightly. Remove outer chainring and refit with liberal application of grease and check for contact.

Pop in your lbs and ask to borrow a set of cheapo plastic pedals for 5 mins, see if click is still there.

lucca

check chainring bolts also

twoodley

Thanks everyone for your suggestions.
Apparently it is a common problem on this particular bike and caused by the BB30. It has just been serviced by Evans, who know about the problem, so hopefully the problem has now been resolved, but will not know until I take her out.

Terry