Folding Bikes - Clanking noise on my Birdy

My Birdy has developed an irritating and noisy clanking whenever I ride over anything but the smoothest surfaces. By comparison, even the cheapest budget bikes don't make any noise when they riding over the same roads, so it's doubly irritating.

I've had a very good look around the rear of the bike but can't find anything obvious. The cable tap and the chain can slap against the frame if I ride over a major hump, but I don't. All bolts seem to be tight.

My LBS have had a look and think it might be the SRAM Dual Drive, which would need to be sent away.

Before I do that, does anyone have any other suggestions?

Thanks

The source of a sound is not always obvious as it can set up a resonance in the frame.
My Birdy is pretty quiet but the Mini Evo U lock I have mounted can make quite a din where the lock section joins the U unless I reposition the rubber bumpers that are intended to stop it.

Check "Jurs" information on the birdie thread .It contains a comprehensive list of the chief suspects on a Birdie.

Thanks. Had a read but it's for creaks and this is for major and repetitive clanking. A creak I wouldn't be so bothered about, but this is so noisy and happens so often it's definitely something more than a creak. That said, I'll check some of those things anyway as routine maintenance.

Any other ideas?

Are your brakes firmly attached? Some Birdy models come/came with lower quality v-brakes with a lot of clearance even when tightened on the mounting stud. Result - annoying rattling all the time (at least on non-perfect surfaces) My solution was to wrap black thread in the gap, since shims don't appear to be available for this purpose. Doesn't seem to affect operation in any way, but it reduces the rattling to minimal.