Heat cycle procedure R spec tires – seeking real advice

difflock · Postby **difflock** » Sat Mar 01, 2014 5:00 pm

Good afternoon MX5 friends.

I can almost hear the sigh, mentioning this topic, since it is almost on every forum. Unfortunately most of the forums either end up into a tire comparison discussion or just copy information from places like Tire Rack and the sort; not that it is not true, good or interesting information.
The problem is that most info is based on real R spec racing tyres and does not give much information on tires like the Federal 595 RSR (140 wear rating) or equivalent road/track tires with regards to the need for heat cycling, before really giving it a hiding on the track.
The other issue is the procedure of heat cycling. The common advice is, to only go at a certain % of your normal race speed and then there is some sequence following that, and then letting the tires rest. Apart from the resting bit, this does not make sense to me, since we all drive at different levels of speed or skills around the track.
I would have thought that the tire will require a certain speed over a given time, to allow it to heat up to a certain temperature, allowing the rubber bonds at molecular level (as scientifically explained by a tire experts), but without overheating it, and then letting the tire rest for 24hrs to allow the rubber molecules to form new and stronger bonds, without harming the rubber keying affect to the road (grip), but making it last longer due to the new stronger bonds formed inside the rubber while resting. (A very watered down version of what I have read, but it should explain the point).

Now the real question to everybody, who have had racing or track day experience on Federal 595 RSR tires, considering the above points:
1) Do they need heat cycling? (Note: The local Federal bloke said – not really, just drive easily for a few laps – he was not really helpful and I am not sure what to believe).
2) If yes - Is there a recommended procedure based on true experience on these tires.
3) How long should I really let the tires rest – some say 24hrs (Note: The local Federal bloke said – no) It may be a case of him getting the tires for free.

If anybody can help to shed some more light on this subject, it would be greatly appreciated. I am running on 205/16/45 Federal 595rs-r tires. I am running a very limited budget, thus would like to stretch the track life of the tires, and thus would really appreciate help. It will only be used for track work.

Thanks
Regards

Difflock

Magpie · Postby **Magpie** » Sat Mar 01, 2014 7:36 pm

My federal 595 RSR's have not been heat cycled. I have been running them 26 cold and they go 31 hot. Possibly I'm running a little too much camber and the inner edge is heating up. At the moment I'm running -3.5 front and -3.0 rear camber and zero toe all round. I will more than likely removing -0.5 camber all round.

sailaholic · Postby **sailaholic** » Sat Mar 01, 2014 8:07 pm

I find 26 cold too cold for the street and run about 32. Lower resulted in wearing both shoulders and noticeable fuel efficiency loss. Can't help with the rest I'm afraid.

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Magpie · Postby **Magpie** » Sat Mar 01, 2014 8:39 pm

Sorry I was talking track pressure on the road I run them at about 31.

Guran · Postby **Guran** » Sun Mar 02, 2014 8:21 am

595RS-R are not really an R-spec tyre. The manufacturer describes them as "semi‑slick sport ultra high performance tyre". With 140 treadwear, that means they're in a similar space to Dunlop Star Specs, Yokohomo AD08s, Kumho KU36, etc. Noted, the MX-5 Club of Victoria & Tasmania has a different view and classify 595RS-R as an "R-spec". My advice would be to just drive them like a regular street tyre. Pay attention to the transverse temperature profile and wear pattern, and adjust pressures to get them as even as possible.

If tyre life is a critical factor for you, be aware that treadwear ratings are not a "wear rate". They combine wear rate and tread depth to give a rough indication of tyre life ... as specified by the manufacturer with no particular agreement on test methods. That is, they're very rough indication of tyre life and the figures apply to everyday driving, not on a track. Better than nothing.

I've had very good experiences with Dunlop Star Specs. They are 220 treadwear and reasonably cheap (around $190 each for 185/60R14). Worth about 1.3s per lap at Wakefield Park compared with Bridgestone Adrenalins and only 0.7s slower than proper R-specs. My first set survived 13 track days and about 900km on track, plus around 8,000-10,000km of normal street driving (hard to tell because I regularly swap over to R-specs for state supersprints). Once the outside shoulders are worn, you can spin them on the rims to even out the wear and maximise their life (symmetrical tread pattern). You do not need to temperature cycle them or worry about getting them up to operating temperature. They just work. Excellent in the wet too.

difflock · Postby **difflock** » Sun Mar 02, 2014 9:23 am

Thanks for the reply gents and information. Magpie thanks for the confirmation on the heat cycling, which agree then with the bloke from Federal. I am currently set up with a
-1.5 camber all round, Super pro bushes and std suspension. Tire pressure wise, I was thinking of 28psi - 30psi cold. My car is basically std and my speed is not that good yet (still learning). I am hoping the tires will give me that extra bit.

Thanks again for the comments.

Difflock

sailaholic · Postby **sailaholic** » Sun Mar 02, 2014 10:46 am

Guran wrote:as specified by the manufacturer with no particular agreement on test methods

That's not quite accurate. The tread wear ratings are based on us government standardised tire test on a set test track for a set amount of miles vs a control tire (tread wear 100)

http://www.tirerack.com/tires/tiretech/ ... ?techid=48

The variance comes from how companies extrapolate the data as the test doesn't go the complete tire life.

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Guran · Postby **Guran** » Sun Mar 02, 2014 1:05 pm

Thanks Nick. I had read somewhere that there was "wiggle room" in the testing, and you've highlighted exactly where it is.

corners · Postby **corners** » Fri Oct 24, 2014 12:10 pm

I'm interested to hear what pressure people use in their RS-R tyres.

I have read and heard differing reports.

Trackphotos · Postby **Trackphotos** » Fri Oct 24, 2014 12:50 pm

corners wrote:I'm interested to hear what pressure people use in their RS-R tyres.

I have read and heard differing reports.

Back when I was still running RSRs on the track, I was aiming for 34psi hot at Lakeside and QR. Felt good, but unfortunately really too low pressure to get any long life out of them. I had 5 half-day track days out of the set before both my left side tyres were showing canvas through the outside shoulders. They were slower when I ran them higher, but if you could get more longevity out of them it's probably worth it. If I were running RSRs on track still, I'd prefer to run them at ~38psi and get more life out of them. All track days were run with 1.5deg camber all 4 corners.

MattR · Postby **MattR** » Fri Oct 24, 2014 4:55 pm

Problem you have Jaron is that what pressures the guys with MX5's run at will be different to what you need to run your tyres at with the S15 as it is a bit heavier and also the suspension behaves a bit differently.

If you are getting even wear across the tyre now for your alignment and you aren't wearing them out too quickly then you probably have the pressures about right.

As the RSR is an in between tyre I would run it at a pressure between what I would run a street tyre at, around 38psi hot for a car like yours, or 42psi hot for my ute and what I would run a R spec tyre at, 30 hot for the MX5 and abut 32 hot for a car of your size, depending on the actual tyre. A good compromise would be around 34, that is without looking at the spec sheet from Federal regarding where they say the tyre shoudl be run at.

corners · Postby **corners** » Fri Oct 24, 2014 4:57 pm

MattR wrote:Problem you have Jaron is that what pressures the guys with MX5's run at will be different to what you need to run your tyres at with the S15 as it is a bit heavier and also the suspension behaves a bit differently.

If you are getting even wear across the tyre now for your alignment and you aren't wearing them out too quickly then you probably have the pressures about right.

As the RSR is an in between tyre I would run it at a pressure between what I would run a street tyre at, around 38psi hot for a car like yours, or 42psi hot for my ute and what I would run a R spec tyre at, 30 hot for the MX5 and abut 32 hot for a car of your size, depending on the actual tyre. A good compromise would be around 34, that is without looking at the spec sheet from Federal regarding where they say the tyre shoudl be run at.

Yeah thats what I figured as I had previously been wearing the shoulders slightly.

I couldn't find a spec sheet for the tyre but did find a few threads.

ljs18 · Postby **ljs18** » Fri Oct 24, 2014 5:18 pm

corners wrote:I'm interested to hear what pressure people use in their RS-R tyres.

I have read and heard differing reports.

40 to 42 hot depending on track temp worked best for me. Any lower and they start sliding. I think their sidewalls are not that strong.

Snowmotion · Postby **Snowmotion** » Fri Oct 24, 2014 9:37 pm

ljs18 wrote:
corners wrote:I'm interested to hear what pressure people use in their RS-R tyres.

I have read and heard differing reports.

40 to 42 hot depending on track temp worked best for me. Any lower and they start sliding. I think their sidewalls are not that strong.

Interesting... last track day a few weeks back... 32psi at the end of the session was good but in the afternoon when it was warmer was lots of slides with this pressure. Will have to try increasing pressures with the increase temperature.