Circuit Semi Slicks

[V28VX37]

ideally, you want to do one smooth session on the track - no sliding, no understeering, but get them nice and hot. Then you take them off and leave them at least overnight. No-one does that though - just use them and don't worry about breaking them in. If you're fussy, be nice and smooth on them for the first track day.

Cheers Harry.

I've been reading up stacks of break-in/scrubbing instructions and unfortunately doing it properly on the track is not really an option for me, as most of them recommend 24-48 hours of cooling and sitting afterwards to cure.

Here's what I read on another forum: http://honda-tech.com/acura-integra-type-r-8/toyo-r888-break-heat-cycling-scrubbing-etc-2330967/

Actually, the ideal break-in (for any track tires) is to run them for about 20 minutes at highway speeds, then take them off the car for 24-48 hours. That's the same thing accomplished by the Tire Rack's heat cycling service, as described here. It sounds like that's not possible in your case.

Obviously running on the street won't bring the tyres up to track operating temps but I wonder if that or the rest time is more important?

Alternatively, I wonder if there's anyone who offers an electronic scrubbing service in Melbourne?

[Duncan]

I'll bet there is....but you won't wont to hear what it costs on top the tyre's cost.

I like Gordon Leven's style....lots of claims, no guarantee about actual outcomes for the money you spend. http://www.gordonleven.com/zapped4racing/about/

[gtr jet]

Do a couple of quick heli's in the closest intersection and then park it back in the garage overnight.

[hrd-hr30]

Cheers Harry.

I've been reading up stacks of break-in/scrubbing instructions and unfortunately doing it properly on the track is not really an option for me, as most of them recommend 24-48 hours of cooling and sitting afterwards to cure.

That's why I said no-one bothers with it. Just use them and don't worry about it like every race series in the world does with new tyres. No-one roads or scrubs tyres - except for wets, and that's for an entirely different reason.

I accidentally did it with my Nittos, only because a problem stopped me running after 3 laps. Let me tell you, it didn't make them any better!

Edited November 24, 2015 by hrd-hr30

[blackrex]

The difference being that most race series that use tyres like that, use them for a session, and then either bin them, or they use them for practice/setup work, where the ultimate pace is not available out of the tyres.

[hrd-hr30]

point was, if there were a performance advantage by scrubbing them in, they'd be doing it. There isn't.

[warps]

Just read some of the Gordon leven heat zap propaganda. Sounds like pseudoscience and bullshit physics to me

Anyone know what temp to heat the tyres to? I can throw them into a curing oven at anything up to 110 deg c for as long as necessary. Wonder if that would achieve anything

[V28VX37]

Cheers guys.

Toyo Australia seems to promote the electronic scrubbing service so I doubt it's complete voodoo: http://toyotires.com.au/toyo-blog/497-using-semi-slicks-part-1-scrubbing-in

Tire Rack offer a mechanical (non heated) version of the service: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=66

With regards to temps, from this Toyo UK page - http://www.toyo.co.uk/page/index/identifier/set-up-advice :

The optimum tread temperature range is between 71C and 105C measured using a probe type pyrometer, and ideally a maximum difference across the tread of 15C.

So I'm guessing an electronic or mechanical scrubbing service would slowly bring it up to that range?

Here's the scuffing procedure from the Hankook Handbook - http://www.competitiontyres.net.au/wp-content/uploads/2013/04/Hankook-Handbook.pdf :

To scuff a set of tyres, start by taking one or two moderately paced laps to gradually bring the tyres up to operating temperature, and then run one hard lap followed by a cool down lap. The ideal situation would be to stop and remove the tyres from the car and allow them to cool down to ambient temperature before running them again.

And here's the same from Hoosier - http://www.hoosierdirect.com/Tire_Heat_Cycle.html :

The first laps for the track 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.

Anyway the TL;DR is:

• Most tyre manufacturers seem to recommend scrubbing in a new set of competition tyres
• This consists of slowly (not suddenly) heating the tyres up to track temps, and then letting them cool down for 24h+
• In practice most people probably don't bother

All I'm saying is that if there's a sufficiently easy way to scrub em in and that gives me a little bit of extra performance and/or longevity, I'm happy to do it

Edited November 25, 2015 by V28VX37

[billywhiz]

I've no doubt heating/curing them in a controlled manner(ie off car) has some effect, we do it to loads of different materials to alter properties but:

- on car isn't controlled, different areas would be brought up to different temps at different rates and each tyre would be different again.

- even in a controlled manner, how big a difference? like adding nitrogen instead of air? I bet one clumsy lead foot session would negate any life expectancy gains from your controlled scrub.

So, worth the effort/cost, I doubt it. Your driving style/skill will have a bigger difference and the money you save in not paying for the scrub service you can put aside to lessen next purchase cost.

[warps]

Yep I've no doubt that heat cycling can affect a tyres properties. I can't see how sitting a Tyre in an oven at 100 deg for an hour would be any less effective than the expensive services offered by the suppliers. The other thing is how much difference does the process make? Is it even measurable?

[Duncan]

Yep I've no doubt that heat cycling can affect a tyres properties. I can't see how sitting a Tyre in an oven at 100 deg for an hour would be any less effective than the expensive services offered by the suppliers. The other thing is how much difference does the process make? Is it even measurable?

That's exactly the problem for me. If I could see proof that the tyre life/degradation will be x% slower or y% better grip for example, I could decide how much it is worth paying for the service. At the moment all the claims are unsubstantiated by any specific figures, let alone proven in some sort of study

[hrd-hr30]

R888s last forever anyway.

If scrubbing made them last longer, you can bet F1 guys would be scrubbing in every set they planned on using in the races. But they prefer to save new rubber for the races wherever possible, because its faster and lasts longer. Those guys should know.

[fatz]

I think f1 don't quite heat cycle as much as us good looking fellas

[hrd-hr30]

must be some good snake oil if it only makes them last longer and perform better if you use them a certain way afterwards...

imo it will make them last exactly 1 track day longer. The one where you scrubbed them in and basically did nothing with them.

As for how a heat cycle can make them faster, I have NFI. All a heat cycle can do is make them harder and slower. Every tyre is at its fastest when they are brand new.

Edited November 27, 2015 by hrd-hr30

[V28VX37]

I did a quick run up and down the freeway on the R888R's over the weekend.

Not much to report except that they were quieter than I expected, only started getting a little noisy around the 100km/h mark, a mild jet-like whine but not bad.

Anyway traffic's not the place for a proper run in so I'll save that for the track day on the 20th

[hrd-hr30]

I love them! Heaps of grip and the Z221 C70 compound is wearing well. After Lakeside and a hillclimb they still had the Hankook written on the outer tread block surface. That's gone now after the two day supersprint at Morgan Park, but the wear isn't bad at all. This is on a 1530kg Soarer (without driver) and temps in the low 30s. The tyres don't even feel like going off after the 3 laps we were running.

update on these. The rears are now toast after just a handful of track days:

1 at Lakeside - did 3 x 5lap sessions. Skipped the last one.

1 at Mt Cotton hill climb. I only did the Saturday afternoon part of the event. 3 runs of a sub 50 sec track. No burnouts. Did not cmpete on Sunday due to a wheel bearing and engine fan hub both being stuffed.

2 day event at Morgan Park in very hot conditions, but only 6 x 3lap sessions for the weekend.

1 at Philip Island. It was a 2 day event, but the first day I only did 2 sessions, and one of those was wet. I left before the last session on day 2 because I was out of fuel and brake pads, so I'm only counting it as 1 day's worth.

The next day at Lakeside they were loose as all hell from the start - fronts were still working OK, but the rears had no grip. Best lap of the day was the first lap and they just got looser and slower as the day went on.

I always wear rears out first. There's still some tread there, but the tyres have given up the ghost after barely 5 days worth of use! So maybe the C70 compound is not the best for heavy cars if you want any sort of life out of your semis. I'm glad I got them on special! $1056 for the set including delivery but even so, that's not exactly great value...

I'm not buying any more semis for a while. I might fit my old nittos back up, or maybe nittos on the front and the front pair of hankooks on the rear until I fry them as well lol got to get your money's worth!

[ssxRicho]

Phillip Island is very harsh on tyres.

The C70 got Chris's GTR 4-5 track days.

[SimonR32]

Yeah I've had my C70s and I reckon they lasted half the time if not less than A050 Medium and I'm not convinced they are that much faster, they are also cheaper but not half the price.

[ssxRicho]

Yeah I've had my C70s and I reckon they lasted half the time if not less than A050 Medium and I'm not convinced they are that much faster, they are also cheaper but not half the price.

You think it's half, we've been playing with 1/3 less life and 1/4 less cost. I find the ao50 is a more progressive tyre under foot.

Life through the tyre seems similar, if anything the ao50 still works until all the tread is gone, while the Z221 falls of a cliff before it looses it's last tread patches.

The GTR has C50 Z221 on it for this year, interested to see the lap pace comparison.

[SimonR32]

You think it's half, we've been playing with 1/3 less life and 1/4 less cost. I find the ao50 is a more progressive tyre under foot.

Life through the tyre seems similar, if anything the ao50 still works until all the tread is gone, while the Z221 falls of a cliff before it looses it's last tread patches.

The GTR has C50 Z221 on it for this year, interested to see the lap pace comparison.

My wear seems to be exaggerated a little to be honest. Too much pressure and they wear very quickly in the middle, any less and the side walls don't seem to be stiff enough and they roll onto the sidewall heavily causing very high wear on the outer edges.

I'm up for a new set of something at the moment but the motor finally died last week so will be a while before I get back to the track.