Road Surface Effects

[ubrben]

Crucially Valencia was used a lot more than Austin was prior to a big international series going there and they seem to have avoided the other issue, which is oil coming up and contaminating the track surface.

This.

As for slick dry track vs. wet track... I think they're two entirely different things. If team 'X' is quite good in the wet it's part car control, but also part setup.

I think with the higher speeds in dry conditions it also emphasizes any downforce difference between teams as well. Little downforce goes a long way in masking handling issues.

I agree, I was being charitable in the context of the question that was posed. Obviously grip level in the wet is much lower again and then you have driver skill and the vast number of setup choices that could be made.

Having said that, very cold conditions and operation close to dew point with the occasional damp patch (think Nordschliefe) and full wet with no standing water are surprisingly similar in terms of what generates grip. The difference is that the full water film removes more energy and makes that compound durable enough to race on.

Ben

[Cam]

Crucially Valencia was used a lot more than Austin was prior to a big international series going there and they seem to have avoided the other issue, which is oil coming up and contaminating the track surface.

This.

As for slick dry track vs. wet track... I think they're two entirely different things. If team 'X' is quite good in the wet it's part car control, but also part setup.

I think with the higher speeds in dry conditions it also emphasizes any downforce difference between teams as well. Little downforce goes a long way in masking handling issues.

Thanks JT. So if a car is good in the wet, that would not necessarily transpose to being good on a slippery track? This is because a wet track needs more mechanical grip as opposed to a dry slippery track needing better aero? Would this be a good summation?

[Jersey Tom]

Thanks JT. So if a car is good in the wet, that would not necessarily transpose to being good on a slippery track? This is because a wet track needs more mechanical grip as opposed to a dry slippery track needing better aero? Would this be a good summation?

I prefer to be vague than to make quite all-encompassing statements like that

Suffice to say I agree with saying that just because Team X or Driver Y does well in wet conditions, doesn't mean they'll be so outstanding on a slick dry track.

How much of good wet driving is the driver making the most of poor visibility? How much is it the slower speed, wet-specific setup and knowledge of wet weather tires? In wet conditions, preventing hydroplaning is big. Not an issue on a dry track even if it's slick. How much does a downforce deficiency become neutralized in the wet at slower speeds?

Lot more to it than just a driver having good car control.

[Cam]

Cheers JT. I understand you not wanting to commit to that as yes, there's too many variables. The underlying principles though make sense. Thanks.

[godlameroso]

Here's something for us to chew on, what if certain exhaust configurations have advantages in certain temperature conditions, and that these advantages translate more into race pace than qualifying pace. For example we saw Lotus work their conventional exhaust to great benefit in tracks that had very hot ambient temperature. McLaren has tried so many iterations that they've been hit or miss during the season, so have Ferrari, as their design works best in hot and humid climates. The Sauber works in relatively cool conditions, but then they have problems getting heat into the tires so they require tracks with high speed sweeping corners so they can turn the tires on. The Red Bull has the most flexible design it seems but it seems to falter when there is some extreme condition, and I have a feeling their exhaust layout has something to do with this.

Could we see teams adopt different exhaust layouts next year depending on the predicted ambient temperature of each grand prix?

[Richard]

Don't forget the two posts from Ciro about adhesion, friction & interlocking .... viewtopic.php?p=217306#p217306

In my humble opinion and based on many long hours of designing, laying and testing highway & aviation pavements, the surface is smooth as a billiard table when first laid. The "grip" increases as the surface filler (sand) and binder (bitumen) are worn away to expose the coarse aggregates over a few weeks. Then the grip slowly decreases over years as the sharp arises (edges) of the aggregates are worn smooth.

By the way, many local authorities put out the temp signs warning of a slippery surface on fresh pavement, but that is largely due to them being slippery in the wet. This is because the surface is smooth and covered by a film of water. Once the binder and filler have worn away the water can sit between the exposed aggregates.

[ubrben]

In my humble opinion and based on many long hours of designing, laying and testing highway & aviation pavements, the surface is smooth as a billiard table when first laid. The "grip" increases as the surface filler (sand) and binder (bitumen) are worn away to expose the coarse aggregates over a few weeks. Then the grip slowly decreases over years as the sharp arises (edges) of the aggregates are worn smooth.

That's a great summary.

I guess what we saw in Austin was the bitumen getting worn off as the weekend progressed. My experience has generally been arriving at a surface once that's happened and the new aggregate high micro-roughness generates high frequencies and grip, but with heavy abrasion.

Ben

[gixxer_drew]

Simple examples, the old qualifying tyres or purpose made Time Attack tyres that are arounf from Hankook and Yokohama.

The current Yokohama A050 comes in a super soft, soft and medium compounds across various sizes. The super soft is great (especially when pre-race heat cycled to properly) for the 4 laps it is required to work for when treated right for, however in trading ultimate grip through mechanical keying for energy dissipation it will not run over this expect operational window. Try and push it for 5 or 6 laps and its history and slippery as hell. The Medium will do 15 - 20 laps easily and last a few meets if

Again, it is a balancing act of durability over time against CoF. Time is what generally determines acceptable polymer degradation.

I have tested almost all the tires listed and what you were describing above sort of contradicts my test results so I am very curious about your heat cycling process details?

The Advan SS compound is something of a unicorn. It was never truly available. I was able to get one set of the A048 SS for testing and it took a miracle to get that set. It was used on the HKS EVO back when. Where did you get them? I put in an order for a set of four A050 SS even here in Japan, 2 years ago. It was more just to see if they ever produced them or just if they put it on a list to be legal so every once in a while they can make specials for people they want to win.

The Soft (GS) compound gets hot in less than a lap and goes for just a hair over one lap before becoming useless. One of my customers found they could shave some of the surface off and use them for one more single lap session at a loss of roughly 1/2 second at Tsukuba. The super soft was in use by the HKS Evo when they ran it in the US and I saw them come off the car, the fronts were severely blistered after a single lap session. I tested the tire myself on a 2WD car and experienced the same thing with the rear tires. Admittedly that car had issues with rear temperatures and had a heavy rearward weight bias.

Any details you would share on your process? What sort of car was that on? I have issues with keeping the normal GS compound cool enough through the duration of just one single hot lap.

[aussiegman]

I have tested almost all the tires listed and what you were describing above sort of contradicts my test results so I am very curious about your heat cycling process details?

The process the tyre/suspension guy I use is with 2 x electric ovens, each that that fit two (2) tyres and he cycles them over a period of a few days. I'll ask him for some more details, but I drop them off on Saturday and pick them up on the next Saturday so what happens in between I am not exactly sure.

The Advan SS compound is something of a unicorn. It was never truly available. I was able to get one set of the A048 SS for testing and it took a miracle to get that set. It was used on the HKS EVO back when. Where did you get them? I put in an order for a set of four A050 SS even here in Japan, 2 years ago. It was more just to see if they ever produced them or just if they put it on a list to be legal so every once in a while they can make specials for people they want to win.

I got a few that were left over from WTAC in Oz. Some used some not but all servicable. I did see some that were totally "cactus" from overheating and were going to try and shave them down and use them but they were well past their best.

IIRC, Yokohama made the SS and the 295/35/18 size in the A050 as the Australian and Japanese WTAC guys were screaming for something to compete against the Hankook Ventus TD which had a SS in the 295 size. Outside of the WTAC I have no idea of availability for either the 295 or the SS compound. I've only seen them in this size from WTAC.

The Soft (GS) compound gets hot in less than a lap and goes for just a hair over one lap before becoming useless.

I can absolutely see this happening if tyre isn't heat cycled, it is a car is heavy, is 4WD, has aggressive suspension settings for camber/toe, runs large brakes with poor ventilation, aggressive diff rates (Front/Rear or even a tight 2WD diff) and they are operating in medium to high ambient and track temps and the driver tries for flying laps every time out.

They need to be treated sensibly for the first laps, and there is little need to swerve around etc to warm them. Just get them slowly up to temp on formation and make sure the brakes are OK to go for the first corner.

The car I ran and will run mine on is light at approx. 1000kgs (2,200lbs) with driver, FWD and we have ran the SS tyres knowing that you bring them up slowly (1 lap) run them once for feel (1 lap), your timed lap (1 lap) then a proper cool off (1 lap and VERY important).

Its all been testing to get the car ready for proper TA racing ATM, but what we have seen so far is they will only give you the two laps of "work" if you push hard and you setup and a treat them right. The normal tyre for the car a 255/40/18 in a GS compound, however to run the 295 if we raise the car slightly and stiffen up the spring on it.

The 255/40/18 GS (Soft) is no problem after cycling as long as you are sensible in what you do with it. If you try 5 qualifying laps then yep, they are toast and you'll you'll burn them out easy.

But 12+ racing laps in traffic and an couple of good braking passing attempts they are OK but you need to manage them. Weight and suspension/diff settings seem to be the big killer. The guys that prepare my FWD do one of the WTAC cars and they saw a big change when they went to the A050 SS.

The A050 Medium is also the class tyre for one series In OZ, and there are some serious 600+hp RWD 1400+kg V8's running the Med A050's are loving them, especially when compared to the A048's which were terrible.

HUGE compound step from Med to Med-Hard, massive green tyre difference and around 60% remaining tread or a few heat cycles of use and they were totally gone and not recoverable!

For my race car its now moving to only TA, so everything is changing. Less weight, more tyre, more aero, more power and fewer expected laps.

One of my customers found they could shave some of the surface off and use them for one more single lap session at a loss of roughly 1/2 second at Tsukuba.

I think the biggest difference (in our experiences) maybe the weight of the Evo and your car (I have seen the pics of your Black car) and the Evo's higher weight (over 1250kgs or 2,750lbs), aggressive 4WD (diff ramp rates) and suspension setting the Japanese favor. My old Monster Sport suspension in my STi was quick, but it was VERY stiff and murder on the tyres (and the back). We eventually moved to a different setup to get a little more compliance from the car.

They DO NOT like aggressive shock, spring, camber and toe settings which the Japanese typically run for their billiard table smooth surfaces. You also need to manage pressures as they seem to be very pressure sensitive which can overheat them. 28-32psi hot is what we found as the "butter zone" depending on other factors.

For the current car, we have had to re-arrange the suspension a fair amount to get the tyres to work. We dialed out some static camber and went for more caster to increase dynamic camber as a trade off by moving the lower arm locations forward in an effort to manage tyre temps as an example. We also improved the rear torsion beam by using a new Mumford Link over the previous system. Its was mainly for tyre management but it also added to the overall suspension package.

The super soft was in use by the HKS Evo when they ran it in the US and I saw them come off the car, the fronts were severely blistered after a single lap session. I tested the tire myself on a 2WD car and experienced the same thing with the rear tires. Admittedly that car had issues with rear temperatures and had a heavy rearward weight bias.

The HKS Evo (if its the red CT230R car) was very tough on its tyres as the expectation was only 1 demonstration/flying lap so they traded ultimate grip for tyre degradation. HKS after taking the Tsukuba title were all about then showing how fast it was everywhere else in the demonstrations (Japanese pride et al) so they killed the tyres to get the 1 flying demonstration lap.

The CT230R had "relatively high downforce" (when compared to newer TA cars like the Australian Nemo Evo), aggressive diff settings, lots of static camber and lots of toe to help the car rotate if what I am told is correct. These were likely Tsukuba race settings where (as I am sure you know) its very cold most of the time (well every time I have been there it was!!). Also when oversea's they likely kept playing around to with it to get it fast at the different tracks and this could have seen them burn more than a few tyres quicker than normal

The run in the USA IIRC was at Button Willow in 2007 where average temps are usually higher than Japan and the surface is also pretty different. I also think the new SS compound is different from the original used when the A050 was released. But that's just the rumor and "marketing speak" I've heard. You might know some of the guys at Yokohama and the actual "story".

IF you could get the SS or even the Soft for a run, then you'd need to set the car up for them. You can't just throw them on the car and expect them to work.

They need very specific settings from suspension, diff rates, pressures etc even when compared to the old A048.

On an Evo they really need to try to get the weight down and loose the aggressive static camber, ease up on the rearward bias a lot of the Japanese 2-Way and "Tarmac Spec" centre diff's (like Cusco) use as this can burn the rears very quickly. They like a very finely balanced setup if they run on a medium weight car. A 1.5 way diff with moderate lock and more even front rear bias would help, less static camber and try to zero the toe in the rear.

Any details you would share on your process? What sort of car was that on? I have issues with keeping the normal GS compound cool enough through the duration of just one single hot lap.

As a recap:

Cycling: Oven curing (not sure on time horizon but can check)
Car: 1000kg with driver FWD, moderate aero, 550+hp
Comparatively "flat" static suspension settings in favor of dynamic settings (not ideal but it helped in our case)
Good brake ventilation (stops overheating the carcass through the rim as they were originally almost too hot to touch)
Careful lead in lap and importantly a cool down lap to ease tyres back down
As wide a tyre as you can fit under the guards as getting heat into them is no issue so you can use the extra footprint.

I now have a new set of A050's 225/45/17 in GS (Soft) compound tyres for the Christmas break to run around on on my road/track hack that usually runs either the Toyo R888 or NT-01's, so it will be interesting to see how they go with a more weight (1,200kgs with driver) and less tyre to spread the load over. It the same car as the TA car so FWD, but only around 200kw ATFW so nothing stupid, but it will be an interesting comparison none the less.

The TA car is now being re-built to use the 295/35/18's full time on the front (new wheels, guards, hubs) and maybe the rear too. Or we may just stick with a 255/40/18 on the back depending on other things, but I like the idea of having the same size all round.

[gixxer_drew]

Are you involved in the Tilton Interiors Honda? I can only think of two FWD cars in that event. Which car are you talking about is the "black car"?

[aussiegman]

Are you involved in the Tilton Interiors Honda? I can only think of two FWD cars in that event. Which car are you talking about is the "black car"?

No, not the Tilton Honda but it is the same guys prepping the car. The car hasn't run WTAC yet but will 2013 hopefully.

I thought I saw a black Mitsubishi Eclipse GST with your name on it. Then again, maybe it was white.

[gixxer_drew]

oh wow, thats bringing back some memories when the car was black. I built and drove that car in university days.

[FW17]

New track to make wets thing of past

(24-Nov-98) - A revolutionary new track surface could render wet-weather
tyres a thing of the past.

The track material, developed in conjunction with former Ferrari fuel
supplier Agip, absorbs rain to reduce standing water.

A section of the new surface being laid at Monza will be put to the test by
an undisclosed F1 car early next year. If the experiment proves successful,
the complete circuit could be resurfaced in time for September's Italian
Grand Prix.

The new surface is thought to give more grip and should be harder wearing
than conventional track materials.

Tests will take place on a section of Monza not used for racing since 1961.
A 650-metre long stretch of straight adjacent to the Rettifilio chicane is
being laid with the new material.

Does anyone have details about this? This is something called as double layer draining and sound-absorbing wearing course developed by ENI I guess but have not been able to get more details of it being used.

[FW17]

Also an interesting video on resurfacing of an oval

[youtube]http://www.youtube.com/watch?v=DshG_XG_fJY[/youtube]

[Blanchimont]

Have a look at page 13!

Google for porous asphalt or offenporiger asphalt, if you want to see some pictures.

[youtube]http://www.youtube.com/watch?v=I16WGau3jxE[/youtube]