Slippery tyres.

[DarrenSV650S]

No oil dripping off the chain from the wet weather? Never trust a garage pump. Always take your own gauge

http://www.ebay.co.uk/itm/like/261409705511

Pr3's on my sprint felt squishy if I didn't have at least 39psi in the rear, but I think you'll find you've had some contamination of some kind on that tyre to cause a slide, whether that was from the tyre or from the road, we'll never know.

After a winter of occasional use I got the cb1r out and checked the pressures. They where low so I returned them to standard settings which is 42 rear 38 front (yes this is with or without passenger!!). I found that the rear would spin up really easily and it did lock up on heavy down shifts and braking. Weather was dry but no more than 10 degrees. I started to adjust the pressure to suit and now have 38 rear and 35 front. Suits my riding style.
Second for not believing the garage pumps either. Get a good pressure gauge

I would guess at something you rode over, diesel, oil, coolant etc
The pr3 are the closest road legal tire you will get to wets, a picture says more than a thousand words, or so they say, so I'll post 2

If you think the pr3's are good, give the pr4's a crack. They're awesome.