View Full Version : Squared off tyre spinning up
ChrisCurvyS
27-09-12, 01:24 PM
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.
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?
ChrisCurvyS
27-09-12, 02:08 PM
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...
Brettus
27-09-12, 02:26 PM
Doesn't squared off = less tread and therefore a slicker tyre?
ChrisCurvyS
27-09-12, 02:42 PM
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....
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.
Point contact curved new hoop cuts through surface contaminate
Squared flat profile less force per Nmm2.
fizzwheel
27-09-12, 07:46 PM
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....
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.
ChrisCurvyS
27-09-12, 08:40 PM
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.
chris8886
27-09-12, 08:50 PM
what pressures are you running?
ChrisCurvyS
27-09-12, 09:45 PM
36/38 - use a couple psi over standard due to my weight. Have had the rear as low as 30psi though and it doesn"t seem to make much difference.
I have a fairly new back tyre on (done around 2k on it atm) and am frequently locking the back wheel up if there is any moisture around at all.... really starting to wind me up. Even tried applying pressure gently and still ended up locking back wheel before I stopped.... Even had the rear end skip out on me the other day when coming to a stop from about 20mph, problem was I ended up skidding straight towards a car that had stopped infront of me... A*** hole resembled a rabbits nose at that point.
I have a fairly new back tyre on (done around 2k on it atm) and am frequently locking the back wheel up if there is any moisture around at all.... really starting to wind me up. Even tried applying pressure gently and still ended up locking back wheel before I stopped.... Even had the rear end skip out on me the other day when coming to a stop from about 20mph, problem was I ended up skidding straight towards a car that had stopped infront of me... A*** hole resembled a rabbits nose at that point.
You may want to look at how you use your brakes. Sounds like you need a tad more on the front.
If your standing it on it's nose..You can't use much rear when the back wheel is an inch of the road.
Too much rebound can have the same feeling when you brake hard and late into corners .
You may want to look at how you use your brakes. Sounds like you need a tad more on the front.
Yeah thought that was the case. Trying to use it but had a bit of a scare where I locked front wheel up in the rain a few weeks back, Felt bike start to go but thankfully let it go nearly instantly and since then I'm very concerned about locking it again. I can kind of control the rear lock where as the front I cannot lol.
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