Hankook RS3 Tyre pressures

DJ · Postby DJ » Wed Apr 08, 2015 11:24 am

Hi,

Was just wondering if anyone could help with suggested track day tyre pressures for a set of Hankook RS3's on a standard NB.

I have only previously run track days on average road tyres and I ran them at approximately 35-36 psi cold to get to 40 psi hot.

After doing a bit of reading these levels would seem too high for the RS3's. Any help with ideal cold/hot pressures to run with them would be greatly appreciated.

Cheers
DJ

Apu · Postby **Apu** » Wed Apr 08, 2015 12:01 pm

I ran 30psi cold last track day, but didn't monitor it through the day as it worked fine and I ran more laps that usual (open track day). JDMYard recommendeds starting at 29psi cold.

plohl · Postby **plohl** » Wed Apr 08, 2015 12:07 pm

I would start at 28psi cold, depending on track temp they would get around 31-33psi, would equalize to 31psi hot, do this for the first few sessions as the day gets hotter, than leave them. They would stay constant through put the day

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DJ · Postby DJ » Wed Apr 08, 2015 1:16 pm

Thanks for the advice

Dan · Postby **Dan** » Wed Apr 08, 2015 3:26 pm

Plohl, do you run RS3's? I ran them on my Evo for a while on the track and used to run them around 37psi hot.

I know it's not the same car but the RS3 is a high performance street tyre which needs more pressure than a semi and I run my Hankook Z221 Semi's at 32psi hot which is higher than you are suggesting for the RS3.

plohl · Postby **plohl** » Wed Apr 08, 2015 3:53 pm

Yeah, I ran them at 31. Lap times were ok (for my slow ass driving) and they lasted a fair while. The tyre wear always looked good after a day at the track. No evidence of something being a miss. The grip loss was noticeable above 34psi.

I have a mate with an sti....

...

...Wrx sti - he runs rs3's also. I know he's been having issues siding the pressures so I'll see what he has been doing. More comparable to the evo. Both are fat and fast.

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Postby **beavis** » Wed Apr 08, 2015 5:45 pm

Cold pressure is useless.
Hot pressure is what matters.

When cold, set them to 5psi lower than the targeted hot pressure.
After each session, check tyre pressures and let out air until they are at the desired hot pressure.

You probably want around 32psi hot

Dan · Postby **Dan** » Wed Apr 08, 2015 7:44 pm

plohl wrote:Yeah, I ran them at 31. Lap times were ok (for my slow ass driving) and they lasted a fair while. The tyre wear always looked good after a day at the track. No evidence of something being a miss. The grip loss was noticeable above 34psi.

I have a mate with an sti....

...

...Wrx sti - he runs rs3's also. I know he's been having issues siding the pressures so I'll see what he has been doing. More comparable to the evo. Both are fat and fast.

Sent from my SM-N9005 using Tapatalk

hmmm, it still sounds low to me even on an MX5.

I don't run these tyres so I don't really have a direct interest other than curiosity but if anyone running these wants a definitive answer from an expert, email Hankook Australia (sales@hankooktyre.com.au) and Dean Evans (FAST driver) will probably get back to you directly with an answer as he runs their Motorsport PR and has been helpful to me in the past answering questions about things like this.

Magpie · Postby **Magpie** » Wed Apr 08, 2015 8:51 pm

The only way to get the pressures right is to use a pyrometer.

http://www.longacreracing.com/technical-articles.aspx?item=46317&article=Tire%20Temps%20Tell%20a%20Story
If the middle of the tread face is hotter than both shoulders, you will want to consider lowering the air pressure. You will want to think about increasing the pressure if the center reading is cooler than both shoulders.

If the inside area of the right front tire is cooler than the outside area, you should look at increasing negative camber. Conversely, you would want to decrease negative camber if the inside area of the tread face is hotter than the outside area.

If the inside area of the left front tire is running cooler than the outside area, you should look at decreasing the positive camber. Conversely, you would increase positive camber if the inside area of the tire is running hotter than the outside tread area.

madjak · Postby **madjak** » Wed Apr 08, 2015 9:16 pm

Optimal tyre pressures vary depending on tyre construction (like side wall strength and compound), weight of the car and driving style. I run my Advans at less than 24 psi hot which is where I get the best performance and tyre wear. If I asked on here, as I did a while back the response will always be around 32 psi. Running a lower pressure feels squirmy on long sweeping corners but I find it results in more grip and exit speed and so lower lap times.

It's something you just have to trial yourself. Start at 32 PSI and drop pressures throughout the day on the same track to see where you feel most comfortable. You can get technical as Magpie suggest and use a pyrometer, but for me, times tell the story well enough.

DJ · Postby DJ » Thu Apr 09, 2015 10:16 am

Thanks for all the responses, I will let you know how I go after Sunday.

DJ · Postby DJ » Thu Apr 09, 2015 1:09 pm

For anyone who is interested please see response below from Dean Evans at Hankook:

"Hi Daniel,

We have tested those exact tyres on an MX-5 and found you have a big operating window between 32-38psi. It definitely ‘feels’ different (lower pressures walk around more, higher pressures work earlier), but in our tests, we found no difference in lap times or speed. If you are doing shorter distances/fewer laps, aim for around 36-38psi, but if you’re doing longer laps in hotter temps, aim for 34-36psi hot.

Hope that helps.

Regards,
Dean"

MattR · Postby **MattR** » Fri Apr 10, 2015 3:21 pm

I would go with what Dean Evans said rather than all us tyre "experts" here.

As has been said, the hot pressures are generally what to aim for, the cold pressure will vary depending on car, conditions, driving style and so on.

The pressures will be enough to get a feel for what you want.

Whilst Magpie is correct in that a pyrometer will also give you the temperatures across a tyre to fine tune the pressures, for a MX5 track day it is overkill as most of us aren't skilled or consistent enough to make use of the data, nor will our cars offer the adjustment needed to get the best from this information to tune at the track.

Also a decent tyre pyrometer is expensive and an IR temp gun will only give surface temp, not the temp of the rubber that the probe from the pyrometer gives you.

Dan · Postby **Dan** » Fri Apr 10, 2015 5:16 pm

^ Yep, I agree completely, you also need to have some more knowledge of car setup to use a pyrometer to make setup changes as it’s not simple and multiple things can affect tyre temperatures including the way the car is dríven. The way I think of it is a pyrometer is more of a fine tuning tool you can use once you are already fast.

There are even conflicting points of view on certain topics too, for instance Magpie quoted this from the Longacre website:

Magpie wrote:If the inside area of the right front tire is cooler than the outside area, you should look at increasing negative camber. Conversely, you would want to decrease negative camber if the inside area of the tread face is hotter than the outside area.

If the inside area of the left front tire is running cooler than the outside area, you should look at decreasing the positive camber. Conversely, you would increase positive camber if the inside area of the tire is running hotter than the outside tread area.

If you read Carroll Smith’s book Drive to Win (Page 2-16) he talks about camber and the fact that a well setup car's tyres should be hotter on the inside and if you take for example the tyres I use (Z221’s), Hankook themselves talk about the fact that there should a temperature spread across the tyre and "Normally the optimum temperature is within a spread of about 20°C between the inner and outer part of the tread. For example, inner 90°C, middle 80°C, outer 70°C” http://www.competitiontyres.net.au/wp-c ... ndbook.pdf (page 7).

So for me personally, if I was to use a pyrometer and change camber to get an even temperature spread I might go backwards and not get the most out of my tyres.

Magpie wrote:The only way to get the pressures right is to use a pyrometer.

The same book I wrote about in the last point (Drive to Win by Carroll Smith), he writes about how he doesn’t use a Pyrometer to set pressures, saying that temperature measured in the pits isn’t a good representation of what the tyre is actually doing under load and he only uses a pyrometer to determine if he is getting near the compound limit or if he has an oversteer/understeer imbalance (on a well balanced car the front and rear temperatures should be close to equal).

He does however go into a lot of depth though into ‘reading’ tyres by looking at the way the graining is on them to determine the right pressures to run, showing pictures and diagrams of what to look for and also talks about things like how to test pressures for different circuits.

I’m not trying to say I'm an expert on the subject or saying using a pyrometer is bad but it’s only a tool and people should understand the theory before they start making setup changes based on pyrometer readings (I don’t use one myself).

Magpie · Postby **Magpie** » Sat Apr 11, 2015 6:28 am

Dan, I agree with your whole post, it is very well balanced and points out it is not as simple as it appears. I have also read the same book. Like anything having a place to start (baseline) is better than nothing.

I use a notebook and keep track of tyre pressures, temps, suspension setting as well as personal comments. This way I can set the car up again at a known point.