My bike has deveoped a knock

[200bhp]

Back at the end of 2010 I decided to buy myself a new bike, having had the same one for 10 years. I diddnt ride it much over the winter and have only recently started going out on it once or twice for a few hours at a time each weekend.

However, last weekend I noticed a knock which seems to be coming from the pedal area. It's a dull mechanical knock that sounds once per revolution of the pedals - Only when under reasonable heavy load (going up hills).

It's a £500 Carrera from Halfords.

Could something need tightening as it is now bedded-in ?

Any ideas?

[anonymous-user]

Could be where the crank arm joins the bottom spindle... on mine there are 2 x 5mm allen bolts attaching this & they do work a bit loose, causing the problem which you describe.

[BliarOut]

Make sure the crank arms are tight then try rocking them side to side. The bottom bracket could be worn out, they don't last that long these days. I assume you're stood up when going up hill so it's not the seat?

[200bhp]

Thanks for the help - I doubt it's worn that quickly as I've probably only done 20-25 hours on it since new.

Yes, it does it when standing up.

[voicey]

It sounds like it's less than a year old - get it back to the shop.

[chopper602]

Mine did something similar, but I found it was my shoe 'very' slightly catching on the chain stay protector . . . .

[Sheets Tabuer]

My bike is 8 weeks old and the crank arm has worn itself loose 3 times, I never leave home without tools now as walking home with a pedal arm in your hand is quite humiliating and it kills your feet.

So check bolts before you go out and carry a multi-tool.

[Mars]

Pedals. They take a lot of knocks and are first to get wet. I bet it's one of those. It is on mine.

[bleesh]

I had very similar this week - seemed to tie in with pedal rotation when under tension. Changed when I stood up and disappeared if I leant sideways trynig to find out where it was coming from.

Quick visit to LBS - they greased the stem and the handlebar assembly - and that sorted it :-D.
To my "expert" ears it was obviously a major issue with the frame or bottom bracket!!!!!