Scrubbing in tires/heat cycles

[leanittiluloseit]

Nice shiney new topic (to get kerm his muffins  )

Come across this, thought I`d share.

http://www.buellxb.com/Buell-XB-Forum/General-Motorcycle-Chat/Interesting-read-on-tire-scrubbing-release-agents--heat-cycles

[rotax81]

thats funny. i read that a couple of days ago and posted it on gbbikers to shut them up 

[Kermittheflyingbog]

Re-post it on here then tony then that'll be 2 new topics today

Seriously tho, tis a good topic, there are always loads of debates about heat ccles and scrubbing in and the manufacturers on that thread seem to say the same thing "Race tyres are totally different to road tyres" so I take it the even with a "Track Focussed" tyre such as the supercorsa then they are designed to go through many heat cycles as it is a road tyre, but race tyres/slicks only designed for 1-2 heat cycles 

[Kowalski]

Are we talking road or track here ?

[rotax81]

both mate.   i must be honest, everyone was talking about heat cycles ruining track based road tyres but i had my supercorsa pro on the front of mine for 4 years and never noticed any difference 

i ruined a few rears though 

Re-post it on here then tony then that'll be 2 new topics today

what, this one?   
http://www.gbbikers.co.uk/gbb/index.php/topic,52446.msg721455.html#msg721455

[Kowalski]

"Race tyres are totally different to road tyres" so I take it the even with a "Track Focussed" tyre such as the supercorsa then they are designed to go through many heat cycles as it is a road tyre

I'm not sure Pirelli recommends these for road use  Always thought this was just manufactures designing a tyre with enough tread to be road legal so they could be used in racing classes where slicks aren't allowed , therefore they'll lose there edge (not litterally) after a few heat cycles . Then again , racing and track days aren't the same , so regarding a loss of performance I don't think it matters much to the average track dayer . Sticking some cheap scrubs - whether supercorsas , racetec's , power one's or whatever on your road bike is one thing , but would anyone seriously go out and spend 300 quid on a new pair for the road ?

[Legzr1]

My personal 'rule of thumb':

If the tyres are 'compounded' (i.e K1,2 etc) then these are road-legal RACE tyres - they need care if used on the road/track if they've been raced with.

Any other tyres (including SuperCorsa SP's as fitted to the Duc 1198 as OE) are ROAD tyres - they don't seem to suffer from the heat-cycling that kills grip on race tyres.


You pay's your money,you take's your choice.




GB Bikers is a funny site - they'd argue black is white then some 'experienced' fella will jump in with "actually,you're off topic/off your head/talking shìt/I have a certificate/it's pink anyway'.

A pointless site imho...





 

[leanittiluloseit]

I`ll just add my experience of race scrubs (compound) and new (bsb/street compound apparently) supercorsa`s to what legz and kerm already covered.

Kerm
" "Race tyres are totally different to road tyres" so I take it the even with a "Track Focussed" tyre such as the supercorsa then they are designed to go through many heat cycles as it is a road tyre, but race tyres/slicks only designed for 1-2 heat cycles"

A point I think is relevant though, is that the main difference between a road and race version, is the optimum operating temp they are designed to work at. Agreed? Obviously tires temp is expected to get much higher on a track compound tire...
When it reaches that temp, the rubber is of the consistency that gives optimum grip, being allowed to cool again would then be 1heat cycle.
So from that we could say on the road the compounded tires are never operating at peak... but the flipside could be, that if they arent getting to or even near the temp they are designed for, then perhaps they are also not being subjected to "full" heat cycles....???

Legz
 "If the tyres are 'compounded' (i.e K1,2 etc) then these are road-legal RACE tyres - they need care if used on the road/track if they've been raced with"

This is so true. I`v found that as I was saying above, the compund of the tire is desgined (were are talking compounds again) to be the right...softness, at high temp, where as a road version would be at the right....softness, at a lower temp, meaning at colder temps they would still be within an acceptable level of grip.
Not the case with the compound tires! My rsv still has the 80quid SC scrubs on it that I had left after the R6, thing is the guy sent me softer compounds than I`d asked for or usually use. sc1 front, and sc0 rear! Stuck em on anyway just to get it mobile as only use it for fun on nice days really.
 Been using it this week, and nearly dropped the front! no brakes almost up right, about 15mph after leaving a friends house! Felt the tires today when it had been parked, and you would swear they were made of plastic. I could "tap" them with my nail, and couldnt leave a dent. Compined with such a steep profile they are deadly when really cold.
Obviously this is an extreme example, 5miles down the road and they aren`t great but turn back to rubber at least.
Word of warning 

Bloody longs post again 

[rotax81]

leanit. thats why i now use road based tyres (2ct's to be precise) and although it WAS fun on track tyres they were very unpredictable. for instance, if you were travelling a mile or two upright in the cold conditions the tyres cooled too much and bit you in the ass on corner entry.
by the way. the compounds are the same no matter the sc0/1/k1/2 numbers, its the tyre wall rigidity that is different.
be careful out there on them tyres this time of year dude 

[Kermittheflyingbog]

A point I think is relevant though, is that the main difference between a road and race version, is the optimum operating temp they are designed to work at. Agreed? Obviously tires temp is expected to get much higher on a track compound tire...
When it reaches that temp, the rubber is of the consistency that gives optimum grip, being allowed to cool again would then be 1heat cycle.
So from that we could say on the road the compounded tires are never operating at peak... but the flipside could be, that if they aren't getting to or even near the temp they are designed for, then perhaps they are also not being subjected to "full" heat cycles....???

I'm not a vulcanologist (Like Mr Spock  ) but a heat cycle in a rubber compound from my understanding is the rubber heats up then cools down, what temperature it reaches is not as relevent as you make out here, it has to do with the rubber compound changing state and then returning to previous state, this happens even with a rise/fall in temp of 10deg (even less how I understand it) each time the rubber heats and cools its performance becomes less whether it reaches a very high temp or not, a race tyre is designed to handle higher temps but can only handle this cycle once maybe twice
I don't chew gum these days but remember when I was a kid (yes I can remember that far back) whilst you kept chewing the gum its consistency remained the same, but stop chewing and take it out (at meal times) when returned to mouth it was never the same and to a point (and I know this is gross) but when you'd removed it a couple of times and sometimes over night it was like tissue paper after a few minutes chewing the next day and yes chewing gum is made from rubber

[RichieRotten]

leanit. thats why i now use road based tyres (2ct's to be precise) and although it WAS fun on track tyres they were very unpredictable. for instance, if you were travelling a mile or two upright in the cold conditions the tyres cooled too much and bit you in the ass on corner entry.
by the way. the compounds are the same no matter the sc0/1/k1/2 numbers, its the tyre wall rigidity that is different.
be careful out there on them tyres this time of year dude 

Good choice for the road I use Pilots for the Road bugger all this race rubber for the road - I also like BT 016
Some tires are described as 95% track and 5% road what the hell does that mean? What I think it means is this
a Race tire that is road legal so the commentators on Eurosport can say they are on road tires {I would never use say Power Ones or Racetecs on the road}- is that what it means ?

I agree with this point. Concerning Track Focused Tires.

I'm not sure Pirelli recommends these for road use  Always thought this was just manufactures designing a tyre with enough tread to be road legal so they could be used in racing classes where slicks aren't allowed , therefore they'll lose there edge (not litterally) after a few heat cycles .

Concerning Heat Cycles I did read recently in MCN that Tire Warmers can double the life of a Tire.

In conclusion this is my opinion regarding tires.

1 For the Track use Track Tires and Warmers.
2 For the Road use a good Sports Tourer - they do no worry about heat cycles, they have a high milage,  they are good in the wet and do not mind the cold i.e. they are reliable for the road. I like Road Pilots myself for the road.
3 And Scrub them in!

[shooey]

Wot he said 

[leanittiluloseit]

by the way. the compounds are the same no matter the sc0/1/k1/2 numbers, its the tyre wall rigidity that is different.
be careful out there on them tyres this time of year dude 

Is that so? Thats interesting. I was under the impression also the compound was different, different curing times and perhaps silica content etc. But this is not the case??

but a heat cycle in a rubber compound from my understanding is the rubber heats up then cools down, what temperature it reaches is not as relevent as you make out here, it has to do with the rubber compound changing state and then returning to previous state, this happens even with a rise/fall in temp of 10deg (even less how I understand it) each time the rubber heats and cools its performance becomes less whether it reaches a very high temp or not, a race tyre is designed to handle higher temps but can only handle this cycle once maybe twice

Surely it matters how hot to how cold they get to how much effect it has on the rubber though??
I mean I dont know, I`m just thinking out loud...
The first heat cycle the rubber is subjected to is when it is made..which is in an oven, which I am guessing is bloody hot. Then its cooled/allowed to cool, which leaves the rubber in the form we need it. Now if you halves the oven temp then you would not get the same result, which leaves me to assume that how hot the rubber gets has some effect on how the compound molecules are affected...
 Or not 

[rotax81]

 

a bit like baking a loaf of bread, great when its done but bake it a little more every day and its soon shìt 

 

[scooby]

by the way. the compounds are the same no matter the sc0/1/k1/2 numbers, its the tyre wall rigidity that is different.

thats a new 1 on me,where have you got that from? and i have to say i'm higher than highly sceptical on that,not that i'm calling you liar or owt