Grating noise but don't know what's causing it

[pepecat]

I was out on the bike today for a 30 miler (the BHF Coventry Bike Ride) and pretty much from the start, something was grating slightly down by the front mech/chainrings. I wondered first if it was a brake rubbing on a rim from the bike being in the car to get to the event. But both wheels span freely with no rubbing, and with the back wheel off the ground and the pedals turning, everything seemed to run smoothly. However, the minute I put pressure on the pedal to cycle up the road, the grating was back. Is that then crank related? It was a pretty regular noise, as if it was only something happening when one pedal goes down. But I can't for the life of me work out what's causing it!

I noticed from looking at other riders today (as you do on these occasions I guess) that they all sit quite far forward on the saddle - that is, the end of their bums are about where the saddle ends. Is that the 'correct' or 'normal' seating position? I find I sit slightly further back than that, with my bum over the end of the saddle. I tried sitting further forward, but felt like I was falling forwards off the saddle and had to take much more weight on my arms. This position did seem to give more power to the legs, cos I guess the way to stop yourself falling off the front of the saddle is to pedal to keep yourself on it. Overall though, it was far too uncomfortable and I reverted back to my usual position, which is perfectly comfortable for me. I just wondered; is there a 'correct' seating position, and if so , what is it?

 

[Cheule]

It could be the crank arms, pedals, bottom bracket, chain rub on front derailleur....

EDIT: I would have loved to do this ride too, it's near me but my bike's under repair at the moment. Hope they do another one soon.

 

[Alembicbassman]

Check front mech alignment and cable tension.

Remove pedals and grease threads, check pedal spindle for play also.

If that doesn't work, unhook chain from small chainring and let it rest on the bottom bracket housing and rotate cranks. You may be able to hear if anything is up, press ear to nose of saddle to hear better.


Weight should be 50/50 when in normal riding, when climbing in the saddle weight should be moved backwards to aid traction.

 

[automatic_jon]

Sounds like the chain rubbing on the inside of the front mech to me. Perhaps because I've just had to sort out the alignment on mine for that reason. There are some good tutorials available online but I'm afraid I can't remember which one I used.

 

[Moodyman]

Could be all of the above or your cleats grinding against your pedals if you use SPD-type pedals.

Bit of light grease should sort out most bike noises.