Rubbing chainset/cranks

hey guys, need some help!!

for some reason my cranks have started rubbing up against the bottom bar of the frame on the back triangle. tried readjusting the angle of the wheel slightly but it didn't seem to have an effect. it's as if my wheel or bottom bracket has shifted over a couple of millimetres to one side, i don't know how or why. also tried getting an allen key in the bottom bracket but it's so tight on both sides that i can't move it, and i don't think it's that.

any help greatly appreciated!

here's a pic for reference. the bike is upside down so this is from the other side showing where it connects and rubs;

http://www.lfgss.com/picture.php?albumid=1353&pictureid=17646

just on the right there where the frame is blue

You need a bottom bracket with a longer axle, by the look of it

well the problem is like if that was the case, but it's only just happened, it's been fine for about 3 years already!

Did the BB develop a little play? Because that can cause the crank to move a bit. But yeah, the BB axle looks too short.

it doesn't feel loose at all but i guess may have moved over a mm or 2?
pretty sure it's not the axle width as it's never been a problem for a while, but thanks for your suggestions guys.
anyone else able to solve/fix this mystery?

Maybe hit the chainring on something and bent it?

Clearance looks non-existent, but I guess if it worked before ...

Incipient crack in the chainstay? I'd clean it up and have a damn good look round the edge of the lug.

If it has been running fine for three years and the problem has come on suddenly, then something is broken:

• either the frame has moved towards the cranks, ie it's bent or cracked;
  
• or the cranks have moved towards the frame, ie they're loose or bent, or the bottom bracket is loose or the bearings have gone.
  
  

Check the frame over for tell-tale cracks in the paint, particularly around the bottom bracket shell. Eye it up to see that it's straight and symmetrical.

It would help if you cleaned your bike.

The gap between the crank and the bottom bracket does look bigger on the non-drive side, so it's likely that this is where your problem is.

Check the crank arms and chainring are straight and all bolts are tight: if they only rub against the frame intermittently, then they are probably bent or loose.

Now hold the ends of the cranks at the pedal end and rock them from side-to-side across the bike: there shouldn't be any play.

My guess is that there will be play and that you will need a new bottom bracket.