Squared off tyre spinning up
 

As my daily commute is all motorways and dual carriageways, my rear tyres get squared off pretty quickly.

I've noticed in the current weather that, despite in theory creating a larger contact patch, straight-line grip seems to have really gone downhill as a result, though the tyre is easily still legal and has plenty of life left in it.

The rear keeps spinning up for fun, even from a rolling start (think people thought I was attempting a burnout at the lights last night) and it's really easy to lock it up on the back brake.

Tyre is a previously excellent Metzeler Z6 but I had the same issue with the Continental I had on before it - that even spun at 80ish on the motorway, which seems absurd for a 70bhp bike.

Just wondering if anyone knows why? Guessing the rubber left in the squared-off section is maybe a harder compound than the stuff which has worn away?

Apologies if this has been asked before but I couldn't find anything via the search facility.

Re: Squared off tyre spinning up
 

Just putting this out there for the experts. Could it be that squaring-off may have an effect on suspension geometry? Or rather, you may need to adjust the suspension to account for the behaviour of the tyre?

Re: Squared off tyre spinning up
 

That's a possibility. I also wondered whether the flatter profile leads to less water displacement but it doesn't need standing water to do it - just a bit of damp seems to be enough!

Plus I'm 16 stone so it's not like there's not enough weight pressing down...

Re: Squared off tyre spinning up
 

Doesn't squared off = less tread and therefore a slicker tyre?

Re: Squared off tyre spinning up
 

Often does but on there's no tread down the centre of the Metzelers anyway, just on the shoulders.

Wondering whether it's worth buying a new rear or holding off until after the winter so it doesn't go to waste pootling about in crap weather....

Re: Squared off tyre spinning up
 

Can't answer for Chesire but down South we've had a dry spell then a wet spell so roads are slippy as hell. Even my car with absolutely mahooosive expensive tyres is like Bambi on ice at the moment.

Also it's got colder. Cold tyres on a cold road = less grip. Cold rider with cold brain = more ham-fisted throttle.

Re: Squared off tyre spinning up
 

Point contact curved new hoop cuts through surface contaminate
Squared flat profile less force per Nmm2.

Re: Squared off tyre spinning up
 

Replace it if it needs replacing. Winters on its way and personally speaking I'd rather have good tyres for the winter season so I have the maximum grip available to me to deal with the poor weather and corresponding road conditions.

Re: Squared off tyre spinning up
 

Some really good points there - know cold hands can be very clumsy, particularly when I'm wearing my slippery waterproof over-trousers which means I have to put more weight on the hands and they go a bit numb.

Also wondered weather a more contact patch isn't necessarily a good thing if it means the downforce is less concentrated and yeah it's been particularly bad up here too Mark with leaves, mud etc on the roads.

Might invest in a new rear - seen reasonable ones for 90 squid on M&P.

Re: Squared off tyre spinning up
 

what pressures are you running?