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Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 4:48pm
by 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?

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 5:25pm
by Valbrona
Petrol/oil on road. Near a petrol station or HGV depot?

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 5:34pm
by 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.

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 5:50pm
by fastpedaller
Maybe Ice?

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 6:27pm
by 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? :?

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 6:52pm
by PDQ Mobile
Were you braking at all?
Contamination of the rim can cause "snatching".

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 7:09pm
by 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

Re: Back wheel jumping and sliding - cause?

Posted: 22 Jan 2017, 7:16pm
by Threevok
Sounds like the footprint of the rear tyre is minimal. I would definitely check the pressure.

Re: Back wheel jumping and sliding - cause?

Posted: 23 Jan 2017, 1:11pm
by Ruadh495
Sounds like black ice to me.