Something really odd happened this morning.

[kwackers]

I was cycling along when the back of the bike started to weave exactly like I had a puncture.
Rolling to a stop I checked the tyres and they were fine, looked on the road surface - nothing there either.

Started going again - nope definitely something not right.

Stopped, checked the wheels were tight, checked for buckles, checked the tyres again (including tread/sidewalls), checked my panniers/rack were attached properly, checked the bars, head tube, forks - I even checked the frame for cracks.
Absolutely nothing.

Started riding again, still wasn't right so took it easy and over the next mile whatever it was went away...

[fausto copy]

Dehydrated (and not the bike)?

[kwackers]

Dehydrated (and not the bike)?

Nope.
Best thing I can think of is oil on the tyres - but I did check them.

Perhaps my brain is going. It can't have much longer left...

[landsurfer]

Frame cracked inside your front derailleur clamp ???
Had the very same symptoms with a Holdsworth 531 frame back in the day .... bike would wobble .... then stop wobbling ... weird ..

[kwackers]

Frame cracked inside your front derailleur clamp ???
Had the very same symptoms with a Holdsworth 531 frame back in the day .... bike would wobble .... then stop wobbling ... weird ..

Good call.
I'll have a look.

<edit>Oh wait! I don't have a front derailleur! I took it off...
I'll have another good look though.

[Vorpal]

The first thing I thought of whislt reading was rear hub or bearings, or the wheel mounting in the frame. But I have a hard time thinking of something that would feel that way for a bit, and then stop.

Do you have a rear rack? Something loose or broken on that? Rear triangle? I don't have any other ideas, just thinking where I'd look for the problem...

[NUKe]

Frame cracked inside your front derailleur clamp ???
Had the very same symptoms with a Holdsworth 531 frame back in the day .... bike would wobble .... then stop wobbling ... weird ..

my first thought was frame cracked too

[rjb]

It's upset by that 24" monitor strapped to your bars.

[foxyrider]

you sure its not the tyre? sounds like a possible carcass issue - the tread will look fine but the tyre will squirm and not consistently.

[Brucey]

it wasn't an incipient shimmy was it?

cheers

[kwackers]

OK mystery solved! (ish)

It's the road surface, exactly the same happened on the way home.
Just one section of road in either direction, once off it everything is fine.

So why "ish" - well, basically there's no obvious reason. The road has no real marks on it, I've ridden it hundreds of times without any issues and it does the same even if I change my angle slightly to move across it too.

So the only thing I can add to the mystery is that I put some air in my tyres this morning. That's probably the trigger but I can't explain it other than to say that bit of road and my tire (feels like the rear) don't like each other.

[kwackers]

It's upset by that 24" monitor strapped to your bars.

Don't be daft, if I was going to fit a monitor I'd get one of those 32" curved ones for a full on immersive experience.

[kwackers]

you sure its not the tyre? sounds like a possible carcass issue - the tread will look fine but the tyre will squirm and not consistently.

See my post above, but perhaps this could contribute?
That tyre isn't that old, probably only 1000 miles or so.

[londonbikerider]

Tyre carcass failing?

[kwackers]

Tyre carcass failing?

Externally it looks fine and why only one bit of road?

It's a mystery...
I might swap the tyre at the weekend and see.