Bridgestone Adrenalin RE001 vs PP2 vs rest?

[KRM]

Just to add to CB's point. My car is NA6 with suspension mods only running P6000 tyres (Class 3). I use to have a great comp with another car that was very similar in setup. We would trade fastest times by about 0.2 seconds. The evenness was the best part of the fun. It was down to driver's skill not modifications.

He has upgraded to an NC and is trying to catch CB.

Also in class 3 the majority of the cars have engine and exhaust mods but I am still catching some of these cars.

If I put on RT615's and only got 0.5 sec improvement I would have thought I was ripped off.

[Moto]

I've just done another track day on my Adrenalin's (3rd one) and they are starting to get a bit shitty, not as much grip on the front and starting to understeer more.

Dropping the pressures down to 36 hot made a decent difference.

It's also possible i'm just out driving the tyres now, considering I shaved almost 5 seconds off my laptime...

[tank]

Bridgestone RE001 feel good up to around 8 to 9/10s. Thats why they are a great street tyre. Lots of grip and response in the dry. Decent enough in the wet. But late braking in the wet is not recommended at all.

Start pushing to 10/10s or overdriving the tyre, like on Oran Park GP circuit and its a different story. There's decent amount of grip for sure, but not enough feedback to the driver. I really need to take a brave pill before going through the 'dog-leg' section of the track flat out (a high speed right then left). The on-the-limit window is very small or non-existent. So you are either gripping or sliding rather than dancing the car on-the-limit (riding the wave). The only positive I can say about the RE001 is they are awesome under brakes in the dry. The car is just so stable especially the rear-end. And you can really use this to your advantage.

[Old Dude]

Hi guys
Just bought 4 PP2 205/45x16 for the NB, Originally I had Bridgestone ER30 with 48000Km,

Now the PP2 are only a couple of hours old and they seem to grip OK but I have to turn the steering wheel more with these tyres to get the same directional responce that I had with the Other tyres.

I know that they need to settle themselves in but is that normal with these tyres I have pushed them a bit and they held on well, but just needed more turn in.
Thanks

Old Dude

[JBT]

I know that they need to settle themselves in but is that normal with these tyres

Yep, normal with all new tyres. Give them a few hundred kilometres to scrub in. Make sure your wheel alignment is OK too.

[Old Dude]

Thanks JBT
I had to sell the kids to buy these tyres, and thought maybe I had made the wrong decision .There was about $40.00 a corner more than the RE001's
I will give them a bit of time and see what happens, now I have to get the roll bar next...!!! just have to convince the better half

[SPy vs. SPy]

Thanks JBT
I had to sell the kids to buy these tyres, and thought maybe I had made the wrong decision .There was about $40.00 a corner more than the RE001's
I will give them a bit of time and see what happens, now I have to get the roll bar next...!!! just have to convince the better half

Per what JBT said . . .

Put some proper air in them, give em a good 500km or more to scrub off the mould lube, get a good alignment, see CT's specs in here somewhere.

They should murder the ER30's then.

SPy

[NMX516]

And when SPy says "some decent air", he means start at 36 psi cold. Increase from there if you still find them a little squirmy at 36.

[JBT]

Where do these tyre pressure recommendations come from 36psi is more than 20% higher than that recommended by Mazda for the MX-5.

Tyre manufacturers all seem to recommend using the vehicle manufacturer's placard settings and adding up to 4psi for consistent high speed driving or towing. Typical example: http://www.bridgestone.com.au/tyres/passenger/care/pressure.aspx

I find our car becomes quite skittish at 36psi as opposed to 30-32 psi. Mazda recommends 29 psi for the NC. All pressures referred to are cold settings.

[Old Dude]

I used to run the ER30 on 36psi they were run a lot lower than that when I bought the car, and it showed on the tyres,it also used to wallow around a bit when pushed hard until I upped the air pressure.
I checked one or the PP2 and it was at 36, I will check the rest over the weekend. As far as a good alignment I got one done so will have to wait and see if its any good

Old Dude

[Nark]

Where do these tyre pressure recommendations come from 36psi is more than 20% higher than that recommended by Mazda for the MX-5.

Tyre manufacturers all seem to recommend using the vehicle manufacturer's placard settings and adding up to 4psi for consistent high speed driving or towing. Typical example: http://www.bridgestone.com.au/tyres/passenger/care/pressure.aspx

I find our car becomes quite skittish at 36psi as opposed to 30-32 psi. Mazda recommends 29 psi for the NC. All pressures referred to are cold settings.

I've always found the manufacturers recommendations way too low.

Monitoring tyre wear characteristics can tell you if you're running outside the comfortable zone for your tyre, but if it's wearing evenly then it's whatever provides the best grip & feedback.

On the MX-5 (recommended 26psi), I ran the T1Rs at 36psi because anything below and the floppy sidewalls would make the driving experience horrid.
With the 595RSs, I'm running 32psi which provides me with good grip and plenty of feedback (thanks to awesome sidewalls). I find anything below 32psi and I'm sacrificing grip.

On the Liberty (recommended 32-36psi), I run 40psi in the RT615s.

[JBT]

So I gather from all this that:

a. the vehicle manfacturer's have no idea what they're doing, but spend considerable time and money doing it anyway; and
b. the tyre manufacturers are equally inept.

Does anyone have a science based answer (or empirical evidence) rather than opinion?

[Nark]

It would be that the car manufacturers have different goals for the tyres from those of the tyre manufacturers.

Comfort vs performance vs longevity

[rockitman]

So I gather from all this that:

a. the vehicle manfacturer's have no idea what they're doing, but spend considerable time and money doing it anyway; and
b. the tyre manufacturers are equally inept.

Does anyone have a science based answer (or empirical evidence) rather than opinion?

Don't have any science based evidence. (that would kill this thread anyway)

Can give you an observation.

I did a defensive driver training course last year and the instructor( Ian Luff) instructed all participants to inflate tyres to 36psi regardless of make. He seemed to think that it was quite normal to inflate above the manufacturer's recommendation.

[NMX516]

So I gather from all this that:

a. the vehicle manfacturer's have no idea what they're doing, but spend considerable time and money doing it anyway; and
b. the tyre manufacturers are equally inept.

Does anyone have a science based answer (or empirical evidence) rather than opinion?

JBT when we did our Roadcraft Advanced Driver Training course last year, the guys running that were all for higher pressures, for a number of reasons including tyre life, wet weather grip, braking efficiency, controllability and dry weather grip.

It's easier to explain with diagrams, but I'll try anyway. Firstly, if the pressures are too low, under hard braking, or when high load is placed on a tyre, such as during hard cornering, the tyre will "collapse" in the middle, reducing the contact patch and so too the grip. This is more noticeable in wet conditions when the tread blocks move in towards each other because the tyre is too pliable as a result of low pressures, thereby closing up the groves in the tread pattern which were designed for getting rid of water. If you ever have a look at a set of skid marks on the road, most of them have two narrow marks per wheel (the outer edges of the tyre), which illustrates that the pressures were too low, so the outside edges of the tyres are the only part in firm contact with the road. The more flex present in a tyre also creates more heat, and reduces tyre life. Higher pressures also keep the side walls stiffer, reducing "wallowing" during sudden direction changes. The idea of higher pressures is to maximise the stiffness of the tyre.

The Roadcraft boys have also done an experiment with tyre pressures to illustrate the correlation to tyre life. They use Camry's and Corolla's. They had always run 44psi in the tyres of those vehicles. They had a tyre rep come and try to sell them on running the manufacturers recommended pressure of 28 psi, because "they had recommended that for good reason, because manufacturers know best" Anyway, long story short, at 44 psi the tyres lasted approx 8,000kms of defensive driver training and skid pan type work. At 28 psi, the same make and model of tyre, on the same vehicles lasted barely more than 600 kms!!!

The reason 28 psi is "recommended" is because car makers don't want to upset customers with brittle bones who couldn't tolerate the ride provided at say 38 psi. And tyre manufacturers want to sell more tyres, so they recommend that they be run at a low pressure so that they don't last too long! If Roadcraft have their tyres lasting over ten times longer at higher than recommended pressures, imagine what would happen to tyre sales if everyone started doing that!! The other point to that is that tyres have a "best before" date, so if everyone even doubles their tyre life, then there will be a lot of cars on the road with rubber which has gone off and lost its grip - not a wise move. Remember kids, most people don't take too much notice/care of their cars or the tyres, so if the tread looks deep enough, they're not going to run out and get new tyres - even if they are 10 years old. Tyre manufacturers would also consider that point when recommending pressures, I would suggest.

My last set of PP2's were run at 36 psi cold. They completed 8 track days, 3 or 4 skid pan days, and over 28,000kms of road use - that got them down to just on the legal limit. My wheel aligner also recommended to me that I start at 36 psi in the tyres. I take his word for it too, as he has been in the wheel alignment (specialising in race cars) game for over 30 years.

If your tyres are sliding more at higher pressures, I would suggest that it is because they are now responding better to driver input. Drive more smoothly and those problems will disappear.