Have a question
I have heard that slicks and TVR tyres go ‘off’ normaly due to a number of heat cycles.
Do 48s go ‘off’ like this too? And if they don’t why?
They do, because due to the heat cycles, the rubber gets hard.
But has anyone had that issue with 48s?
I’ve got several small cracks in the sidewall and one 3 inch crack in the main tread area. Possibly caused by heat cycling?
But has anyone had that issue with 48s?
Loads of us!
At Anglesey for example, you’ll be lucky to get 10 quick laps in, before the tyres start to “go off”. Not really a problem on a trackday, you just drive accordingly.
Once the 48s have been through a “hot heat” cycle, they take longer (than when new) to get to their optimum temp. Hence, in the Mid Engined Series, the wealthier lads use a new set for each meeting (or in some cases, a different set for qualifying & the race itself!).
Bloody hell. Next year I was thinking one set for the whole season!!!
Then you better get some heat blankets in to keep them warm!
I hear they may be banning them in F1, so there could be some knocking about.
I’d see how your engine comes along Sean, before seeing how much extra help you need.
Ian
Sean
Don’t worry, quite a few of the guys make do with one or two sets (plus a set of wets) for the whole season. But for some, every 1/2 sec per lap is important, so they are prepared to spend the necessary dosh!!!
Who said motor racing was inexpensive???
Then if your feeling really rich you can send your tyres away for cnc pre-scrubbing and shaving…Apparently by heat cycling a new set of tyres 24-48 hrs before they are needed it is suppose to optimise the rubber to it’s best condition against the effects you get with heat cycling on your lap times. I have heard of 48R’s going off after only 4-5 cycles under race conditions.
I think I have heard of that being done on slicks (heat treating).
So the main issue is the tyre taking longer (needing more temp) to give its best grip? Good to know
I think I have heard of that being done on slicks (heat treating).
They bring the new tyres upto a set temperature over a certain time frame on a cnc rig. This is suppose to allow the molecular bonds within the rubber to be broken in a certain way providing taht the tyres are not given excessive heat (hence the use of cnc machines to control them). As the the tyre cools and is left to cure over night (24hrs they say) the molecular bonds in the rubber are reformed but are supposedly stonger than they orginally were which in theory gives more consistancy across a tyres life as it cycles.
Once a tyre has had its life sucked out of it, it dont matter how hot you get them they still wont grip even thought ey may appear to have loads of tread left…
Bloody hell. Next year I was thinking one set for the whole season!!!
Don’t worry about it Sean, I’ve been on the same set for the last two seasons!! I, and most others in the series sort of resent the fact that Yokohama (as the series sponsor) don’t help at all with the price or aquisition of tyres which is a little mean considering the rules say that we have to run on them in the dry.
That, and the fact that I’m a tight northerner…
I did a season and a bit on one set as well. I just treated it to a new set for Oulton and did not get to use them!
At Anglesey for example, you’ll be lucky to get 10 quick laps in, before the tyres start to “go off”. Not really a problem on a trackday, you just drive accordingly.
Pesky, I think you’re mixing two things here.
You may have seen that I like to do 1 hr stints out there, and no, they don’t go off if the tyre pressures are right.
What you’re experiencing after 10 hard laps is only the tyre ballooning as the pressures get too high.
You need two things for a tyre to operate corectly, the correct profile (so that the whole tread is touching) and the correct temperature (so that the rubber gets adequately sticky.
First laps on cold tyres they will start to heat. If you had them say at 24-26psi to start with , they will have the correct profile and most of the tyre will touch the asphalt, but as laps pass, theywill get hotter and the pressure inside is going to make them balloon, effectively decreasing the area touching the asphalt.
This is what you’re feeling, as there will be less traction then. I have measured the pressure after they “go” in a situation like this and it was 36 psi!
If you start with lower pressures, it takes the same 10 laps to get them ballooning, but then the profile is just right, most of the rubber is in contact and they don’t “go”. It feels like they’re already “gone” for the first five laps or so, though.
So there you go, it all depends on how you drive, this is whay the pressure should be measured hot and should be around 24psi.
Now, that still leaves us with the heat cycles and UV/Ozone effects, yes, tyres do get hard with time. But in normal road/track use they’ll get worn anyway so you change them at the right time.
I agree with Uldis - a good bit of analysis.
Since I started using lower cold pressures I have found more consistency after the first few laps, and the tyres don’t melt and slag off like they used too either…
Maddog will have seen me running wide on the old hairpin and on Macleans when we went out together after a cool down break, and I would put that down to low initial tyre pressures…
(Mind you, the Macleans wide was helped by mud on the outside tyres as well, I imagine)
I never felt my A048’s ‘go off’ as long as the pressure was kept in the low 20psi region.
I never felt my A048’s ‘go off’ as long as the pressure was kept in the low 20psi region.
Cold pressures?
BatW
Well ideally keep them at that temp all the time… but I meant hot really. Depending on how hot and sunny it is ambient, i’ve seen my cold (and i mean stone cold) pressures down at 15psi when I check them the morning after a track-day in my garage. Not very often tho’ when your local track is KH
The LOWS have it, I think