Heat Cycling Tyres

[handbrake]

hey guys,

will be going with new slicks this year after spending last year on second hand scrap, I will be running michelin slicks S8 compound up front and S9 rear.

interested to know if people do any heat cycling on their slicks or R comps prior to competition track use?

1. below is an article form Hoosier that is typical of most information posted on the internet. This is not very practical for amateurs like me
2. tire rack offer a service where they run the tyres under load on rolers to bring up to temp and also claim to help scrub off the mould release.
3. some others just heat cycle their tyres in an 'oven' or with tyre warmers- not sure how good this is, could be the 'easiest' way to do it but not sure if it has the same effect. of course you would hope to get the mould release etc off the tyre on your first few warmup laps.

here is the info from the hoosier site on their tyres

interested to hear peoples thoughts/experience

R6 Roadrace

The first laps for the tire are critical for setting up the durability and competitive life. The first session should consist of no more than 10-15 minutes of running. The early part of the session should be run at an easy pace, with the speed gradually increased until the end of the session. The final lap should be run at the fastest possible speed. The intent is to achieve maximum tire temp on the last lap. At this point the car should be brought in and the tires allowed to cool at a normal rate.

During the initial run-in process, the inflation pressure should be 3-5 psi higher than you would normally use. The best progression would have the driver taking 4-7 laps to accomplish this break-in. Each lap should be approximately 7-10 seconds a lap faster than the previous lap. The goal is to have the tire temp as high as pos- sible on the last lap without "shocking" the tire during the warm up laps. In essence, no wheelspin, late braking, or sliding. The last lap should be at, or very close, the maximum possible.

A6 Autocross

For autocrossing, the A6 does not need the same break in procedure as the R6. The A6 needs a minimal scuff-in session before the first autocross run. This "session" can comprise of simply driving around the event site at minimal speeds on the A6 set of tires. By scrubbing off the newness of the tread (no or minimal shininess remaining) prior to your first competitive run, the A6 tires will be more consistent in handling, grip and responsiveness on the first run. If this is not completed, running on un-scuffed A6 tires on your first run may result in the tires not gripping properly, or feeling like they "skate" over the course surface. You are welcome to run 3 - 5 psi higher when scuffing in a new set of A6's, but be sure to reset them to the correct operating pressures before your first autocross run. As you compile autocross runs on your new A6's, they should become more consistent in run times.

"Cure" Time

After completing the initial run phase, the length of time the tire is allowed to set is possibly more important. The barest minimum for this process to be beneficial is 24 hours. (Not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again.

Proper tire management is a difficult process. To accomplish this almost always requires a second set of wheels. The payoff is greatly increased competitive tire life.

Following the recommended break-in procedure will require a lot of planning to make it work. The benefits to doing it right include greatly increased tire life as well as consistent performance and durability under stress. Please make an effort to educate your team on the importance of this. It can save you a lot of money.

Hoosier tyre care guide.pdf

Edited February 7, 2011 by handbrake

[handbrake]

I should add, that I have enquired with Michelin but most of their info is on racing, not time attack use. very different heat cycling

[hrd-hr30]

leaving them to "cure" for 24hrs after the initial use is simply not practical.

Just follow their 1st session recomendations, then drive as you normally would after that.

[paulR32gtr]

First set of R comps here (A050) so I asked the question when buying them.

Was told to just warm up in the first session to around 8/10th's as most people do and it will be adequate. Also a quick 10-15 minute drive out on the street if road drivable would do the trick.

Idea is just to introduce heat into the tyre gradually.

Not sure if full slicks are a different story however.

[handbrake]

new slick tyre prep info on the internet is limited. I imagine it is either because

a) it is less comlex than I am trying to make it

or

b) people play secret squirel to gain advantage over competitors.

[Duncan]

I suspect there is something in it, the very serious guys do it. Generally run them once in a practice session the meet before you want to use them....then shove them under the house.

Most people in the real world don't bother or can't. A qualifying session is generally 15-20 min, and you can't go fast first lap due to the goop on the tyre.

However.....the 2nd and 3rd laps for some tyres are the best they will ever do. So if you were dead serious about time attack you might use new tyres in a morning session if you know the track, and give it a real shot on laps 2 and 3.

Finally....different tyres react to heat cycles very differently- some are hardly affected, some are absolute rubbish very quickly. Yoko A048 are an example of badly affected.

[handbrake]

thanks Duncan.

Might give it a go.

I have been told the michelins are faster but go off quicker with heat cycles.

Pirellis are marginally slower maybe but handle the heat cycles better.

the michelin guys confirm what you have said - that green tyres are the fastest they will ever be after 2 warm up laps to clean of the mould release stuff or whatever is on them and bring them to temp - biggest problem starting from cold is geting the pressures right

I take it tyre warmers are not allowed in CAMS sanctioned events.

Do time attack guys use them? eg superlap pro class? seems the format would really benefit from tyre warmers.

Edited February 8, 2011 by handbrake

[blackrex]

Ii have just recieved an email back from a friend of mine, who happens to be the Michelin tyre engineer for one of the ALMS teams ( he has asked me not to say which one, but they did win one of the championships last year ) his response to this queston is that if you want the tyres to last, such as for use in the actual race, then do the slow heat cycle build up, and store the tyres for at least 24 hours, if they do not have a compound or construction change for the following race, then they bed thetyres in the previous races practice sessions and then store the tyres to allow them to totally cure.

However, for outright quickest laps out of a set of tyres, then go for the green tyres, a lap or two too scrub them and then do your flyers. This will give you the quickest results out of that set, but the heat load put into them will cook the tyre too quickly and they will only come back to about 80% of a properly bedded set.

[warps]

I have a set of 048's. I work up to speed over the first few laps, then drive "flat out" (FWIW with my driving skill). So far they have been heat cycled at 3 events - once at lakeside and twice in the gravel at Willowbank (not allowed to use rally tyres there). This equates to about 16 sessions.

I'll keep doing this till they're bald, then I'll probably get another set and go again.

Then again, in a FWD shopping trolley, I can't see myself ever chasing trophies / pitbabes / glory etc so my needs are probably very different to yours.

Sounds like some good advice from others above - particularly if you're chasing the last few hundredths of a second.

[handbrake]

thanks again guys.

blackrex, appreciate the info. this sounds similar to the stuff I have read.

green tyres for the fastest ever lap in a single session - but potentially screwing the performance life, versus heat cylcing and allowing 24 hrs to 'cure' which hopefully results in slightly less ultimate performance but a longer consistent use through more cycles.

Edited February 8, 2011 by handbrake

[Neil]

Yea I have to agree with what the boys have posted mate. The trouble is what do you do when you only have limited supply of tyres and a limited amount of time.

In the Radical (on slicks) at supersprints I go out last and just trundle around for the 1st two sessions and then on the 3rd session I make sure I go out 1st and smash the shit out of them. The trouble with that though is the tyres will not be at their best ever again.

But it is very important to at least be nice to them on the 1st run.

Hillclimbs are much harder to do,,,as you should be on the softest tyre you can possibly get which just makes the whole process much harder.

I think it's also important to actually look after your tyres as well,,,I'll try and clean as much crap off the tyres as possible after every run and clean the crap out of them when I get home. You should also lower the pressures and keep them as cool as possible when not in use.

Well thats what I try and do,,,hope it helps.

Cheers

Neil.

[handbrake]

Thanks Neil,

I have noticed some guys wearing mits and scrubbing their tyres between runs. must admit, with the scrap tyres I have not paid them any attention to date.

plan to look after the new ones a bit better and maximise the performance I can get out of them

also will play around a bit more with pressures and temp monitoring this year now i have half a clue about how they impact on handling and times

[GTR32G]

Agree with a lot above info, if you are running supersprints - lap dashes best to bed them in for one run at 80% and leave them till them next round, or bed them in at a practice day but no more than 1 heat cycle that day. Let them sit for at least 24hours.

Have found on our turbo PRB Clubman not doing this tyres will go off after around 10-15 heat cycles which is 3 supersprint rounds. Loses around .8 sec a lap and gets worse the more heat cycles.

If bedded in correctly tyres hold their grip for around 30 heat cycles good 6 rounds but this is based on 550kg clubman so I understand skylines tyres won’t last that long

But for the ultimate best lap time go out on brand new tyres and be on 10/10^th for lap 3 and 4. But doing this found tyres will be drop around 1 sec if you run them the next day and never seem to come good again.

Comes down to how much money you can spend on new tyres every round or if you want them to last as long as possible.

[Nee-san]

Hi Handbrake, try a huge f**k off powerskid through the middle of west end.

[LSX-438]

I should add, that I have enquired with Michelin but most of their info is on racing, not time attack use. very different heat cycling

Michelin don't really know much about R35's, let alone three to four lap sprints.

Mark i reckon you need to get the N1's - if they are still around.

Michelin built the perfect tyre for the R35 right there (N1) they were by far the best combination of compound and sidewall construction i have ever used.

Iinteresting with the new S7's - we only got 5~8 heat cycles out of them only, and when they went off, they were worse (much worse) vs thrashed S9's which would have done 10~15 heat cycles.

As others say, the 2nd to 4th lap on a fresh set will yield the absolute best times. Absolutely phenomenal grip. Once you experience it, well let's just say it's crack for rev-heads!

[handbrake]

will be out on new slicks for first time next tuesday. keen to see what we can manage with them.

have used a secret ninja heat cycling method , no phat skidz in west end though sorry Nee San

[Nee-san]

We need someone to scare the weirdo's off

don't get caught doing what your doing in carparks hahaha.

[handbrake]

Lol, heat cycled the tyres didn't 'road' them

[260DET]

As far as road use goes, I've never got semis up to temp driving legally on the road, never. They just don't get the loads put through them that track work involves.

[handbrake]

just to be clear, the tyres have been heat cycled, not roaded in, ie: not driven on.