Back wheel jumping and sliding - cause?

[mnichols]

Had a fall today, quite nasty landed on my head. Back wheel just flipped out from under me on a bend. It was just like someone kicked the wheel out from under me.

This had happened a few times on the ride before, but to a lesser extent and I managed to recover the balance. The wheel just jumped or skipped sideways

I'm running Robino Pros at 100psi on Ultegra Wheels. I was probably doing about 20mph. The ride average was 18 and it was skipping on the long flats

Anyone know what might cause this?

[Valbrona]

Petrol/oil on road. Near a petrol station or HGV depot?

[Scunnered]

Happened to me today as well, although I didn't fall. If it's not diesel, then it's likely to be wet muck. I ride back roads where possible, but farm vehicles leave muck on the road. This afternoon I changed my tyres to ones with significant tread (was using Voyager Hypers), time will tell if this makes a difference.

[fastpedaller]

Maybe Ice?

[Cyril Haearn]

Maybe you were just going too fast, that could be why you slipped several times before. I would take that as a warning and go slower. Maybe you should use heavier tyres in the winter, they will slow you down a bit more.

Anything that reduces speed is welcome - or does that only apply to motors?

[PDQ Mobile]

Were you braking at all?
Contamination of the rim can cause "snatching".

[mnichols]

No I wasn't braking.

I'm wondering if my tyres were over inflated? I was feeling every bump which is unusual on that bike. Maybe the pressure gauge is wrong, or under-report the pressure in the cold.

A friend reminded me that my mountain bike was jumping a couple of weeks ago. Only two common factors: me and the track pump

Also I just remembered that I wasn't getting any traction on the climbs yesterday. I had to stay in the saddle. If I stood up I was will spinning

[Threevok]

Sounds like the footprint of the rear tyre is minimal. I would definitely check the pressure.

[Ruadh495]

Sounds like black ice to me.