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On my way to Düsseldorf airport conditions were very wet. In a tight curve my GT86 unexpectedly wagged its tail. I wonder if this could be caused bij the limited slip differential or the moderate size of the tires?

Now I'm enjoying a holiday in the sun at the isle of Gran Canaria. 😁 Two weeks without my car. 😭 

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Primacies have limited grip? Indeed. Not shining too much in wet? Yes. But even with stock primacies twins have more grip and can go on average faster in eg. roundabouts then many generic family cars. While MPS4 is better tire both dry & wet grip wise, but not sure that upping tire grip a lot is right way to situations as in opening post. Simply one shouldn't push car too much due overconfidence and underestimation of available grip. Grippier tires often mask mistakes and are not the best way for learning car limits/car control.

At very same situation/same speed/same turn better tires will keep gripping .. and rise overconfidence and reduce need to learn something even more .. until something bad happens :), for example same grip loss, but now at 1.5x the speed and in more abrupt manner and less time to react/correct. It shouldn't be "unexpectedly". It should be rather expected (or intentional :)) with learnt reflexes/skills how to correct, or one should know car/grip/road pavement specifics/limits and go at that specific turn slightly slower, with steadier driver inputs to stay within grip limits. Car control and car limits is better learnt in controlled environment though, such as on track, then public roads.

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Of course it all boils down to too much throttle, BUT for the available grip, which to my opinion was less than expected. 

Don't be too concerned about me, as I've never wrecked a car in 40 years. I only crashed one go kart into the wall, which was mainly due to cold tyres.

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Too much throttle in mid turn might be one of many ways of loosing grip and getting tail sideways. One can also get rear to rotate with inertia (scandinavian flick alike in turns transition), or one can get rear sideways due grip & mass transfer mid turn with throttle off or braking. Even non-revmatched downshift midturn may make one loose rear grip. If car is turbo-ed, one can loose grip when turbo spools up. Sudden/non steady driver inputs on pedals/steering may make one loose grip when car is driven near available limit (though not all of them do that to rear, some may cause understeer or all wheels loosing grip).

One should learn what/how/when to do for it to not happen or what/how/when to do after it has happened. Though if one drives with safety nannies on (which i strongly suggest to not switch off (at least leaving vsc sport on always, never going for TRC off for DD) when driving on public roads, especially when it's wet and in winter, no matter what own overconfidence (and devil on one shoulder with face of Richard Hammond shouting "I'm driving God!" :D) may say), i find in most cases enough slack to correct car even with low to moderate skill (with eg. slight countersteering), and if i happened to spin or alike even with nannies on, that usually was only in rare cases where i intentially/deliberately tried to overcome them.

In that particular case imho it's not fault of car nor fault of tires. And very possibly other (RWD) cars at that turn at that speed and with giving beans at that point may loose rear traction aswell (if not sooner). Just wrong estimation of available grip by driver and pushing more then at that particular situation it was possible without overcoming grip. Hmm .. i wonder if it's not because twins seemingly allow to do much more in eg. dry, and subjectively signal less in some ways of nearing limits (for example, twins roll less then generic family cars that are sprung softer for more comfort, so if one is used to rely on extent of roll to estimate how fast going is "safe" and when to ease up, it may result in mistake. Or relying on tire audial squaling of when they loose grip - again can make one mistaken in estimating grip, when it's wet) and thus maybe may cause some growing of overconfidence of getting through everywhere.

If your type of driving is just to have car ride like on rails no matter what you do, one can of course just fit grippier tires. But imho it will make car loose some fun character, not chirping tires here and there, not slightly swinging rear in some turns :), at least with stock NA power, even at low/legal speeds. So if one goal is to keep fun, better tires might be not the right answer. (though i always advocate for getting all possible traction/grip via best tire choice in winter). Learning car (and tires) limits and car control, on the other hand, will help no matter what tires are fitted on.

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I have to say the gt86 is the most tail happy car I have ever owned in nearly three decades of driving. Our Yaris can take the mini roundabout in our local estate quicker than I can and I am am not talking exceeding the 30mph speed limit here lol. Put it this way unless I am pretty much dead straight facing the exit ANY more than a light throttle increase in wet weather will make the back twitch. 

My others car is a 300bhp rotrexed Celica so I am used to balancing a throttle and not the issue here lol.

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Wait. You compare with FWD cars, and with similar throttle use in FWD as in RWD? Of course giving accel past available grip in FWD car mid turn will make it understeer, not oversteer with tail. Slightly not getting why yaris or celica were brought up for comparison at all. Normally in rwd one mid turn one should balance throttle for neutral grip bias at position at which car won't engine brake and won't accelerate, at least if car weight & grip balance is close to neutral, and one should increase throttle gradually only as going out of turn, proportionally to reducing steering angle. Try rather braking mid turn in FWD car, for mass (and grip) transfer/extra tail rotation.

The less available grip or closer to grip limit one is (such as on primacies, and wet), the more careful one need to manage grip. Imho what helps well to illustrate proper grip management is drawing of available traction circle, that can be used for different things, turning, braking, accelerating. The more you use grip for turning, less for braking/accelerating, and vice versa (which is for trail braking into turn, and for accelerating out of turn).

P.S. If you say that car is too willing to rotate even at slight throttle unless it's almost straight .. i'd check car alignment. Sometimes issue might be zero or insufficient toe-in in rear. My stock alignment which i did first track days with and first year of winter driving was rather off, close to zero and uneven to sides. Properly dialing slight toe-in rear helped me much with making car more stable accelerating out of corners, reduced twichiness and fighting to keep it straight, eased driving straight on lack of grip eg. ice/snow. Truth be told, OE alignment also has toe-in, but also has allowed +/- range wide enough for it to be way off, so even if car is only daily driven and on public roads, worth after purchase at least once to check actual alignment and dial it more precise & even, even on car bought new.

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I do balance throttle for neutral grip for roundabout. However I can go around the roundabout quicker in both the other cars as the balance of grip is much lower in the gt86. Pushing too early in the fwd Yaris at the same speed I can do in the gt86 does not break traction and induce understeer. Equally, the Celica with alot more torque at low rpm than the gt86 doesn't either but that's probably a bad example in hindsight as it is running coilovers with fully adjustable top plates setup by a Motorsport company so I concede on that one lol. I should be able to negotiate the roundabout better in the gt86 as the front wheels aren't trying to power and steer at the same time but I can't and it would seem others find the same with the stock tyres and suspension setup. I am pretty certain Toyota set these cars up to be fun (read drift able) at a lot lower speeds lol

Will get alignment checked as the stock tyres still have 5mm all round (tyres rotated on mine to equalise wear) with 35k miles on the clock so not ready to be changed yet. No idea if the previous owner changed them but they have only gone down 1mm in the last 5k miles of driving I've done so not like I am drifting around corners scrubbing rubber off these primacy tyres at every opportunity. Maybe I should and get some different tyres on there on e geometry checked 🙂

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If it's damp/greasy, this car plus Primacy tyres loves to snap oversteer. I don't enjoy driving it on these tyres in winter at all, so I change tyre. Greasy roundabouts can surprise, and even slight uphill pull aways can be challenging if you are impatient. In a traction limited scenario, the car with the most weight on its driven tyre contact patch wins, so the FWD cars feel a lot safer. You should come to expect a bit of twitch anyway especially at low speeds, but if you're triggering VSC all the time then something is off.

Perhaps check the production date of the tyres? They definitely lose plasticity after 5 years.

 

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Out of curiosity I've just checked mine and three of them are 5214 (the 4th is 0115 indicating replacement early in it's life) suggesting that they are the original tyres on my MY15 and have lasted 35k miles. Definitely not trying hard enough then am I lol. Also they have 4mm left not 5mm but even so that's half worn in 35k miles.

I can wear out a set of continental sport 5s on the Celica in well under 10k miles so the primacys are alot a harder compound in comparison lol

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It is possible to get stiffed by tyre retailers who fit old stock, but the primacy is largely indestructible. I swap tyres in winter so mine miss a third of the year,  but I reckon mine have gone 20k miles and are down to 4mm. I wasn't nice to them, but it would take more special events to kill them. I think your tyres are past their best and that is amplifying the cornering issue for you. Continuous burnout to the tyre fitter for you sir?

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On the Lexus GS430 it usually took about 30k miles to wear down a set of Continentals. The Prius used up the front tyres in about 20k miles, the ones on the rear lasted for 60k with ease. I bought my 2.5 year old GT86 with almost new tyres. Let's see how long those will last.

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I've got just under 27k miles on my BRZs Primacies and shockingly ... they have plenty of tread left :( No I don't drive the car hard and it is an auto but please, please, please wear out soon so I can put better tyres on ;)

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12 hours ago, NJay said:

Out of curiosity I've just checked mine and three of them are 5214 (the 4th is 0115 indicating replacement early in it's life) suggesting that they are the original tyres on my MY15 and have lasted 35k miles. Definitely not trying hard enough then am I lol. Also they have 4mm left not 5mm but even so that's half worn in 35k miles.

I can wear out a set of continental sport 5s on the Celica in well under 10k miles so the primacys are alot a harder compound in comparison lol

Tyres are only good for two years. By the third year they harden up. This is a lot why you are having the issues you are. I ran winters for three years. By the last year they were bordering on dangerous. Change the tyres, they are well over due. That is your problem. 

@Jay just checked your first post on the forum. If your car is on it's original tyres that will be the issue. As I have explained above. 

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6 hours ago, Lauren said:

@Jay just checked your first post on the forum. If your car is on it's original tyres that will be the issue. As I have explained above. 

I guess the car is on its second set of tyres. They look way too good for tyres with 30k miles on. I'll have a look at the production date, as soon as I return from holiday.

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But you evaluate "good" only via depth of thread left or evenness of wear. State of rubber compound is not exactly what to "look" at. Though imho tire rubber doesn't suddenly go uber bad after 3 years, it's just that coincidentally by 3 years also it's worn accordingly, and together with that resulting net grip is noticeably less vs grip of new tires.

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You can get a specific tool to measure tyre hardness, it's called a durometer. It'll help you get an idea of how hard your tyres are, ideally you need to have a baseline to begin with when the tyres are new. 

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On 10/20/2019 at 11:13 PM, NJay said:

I have to say the gt86 is the most tail happy car I have ever owned in nearly three decades of driving.

I have been mildly disappointed at the LACK of tail happiness of the 86. Perhaps I need to get an old 911?

My Triumph Spitfire, with its 80 odd bhp and dodgy tranverse leaf spring rear suspension was far more tail happy.

I find you really have to be trying to break traction to actually get the back out. I drive in 'VSC Sport' mode all the time and even then I have to really try to get the back out (even when I had the Primacy HPs on). And I don't hang around.

I am bemused by the many posts I see from people 'complaining' that they're caught unawares by the back end suddenly snapping out? How people? How?

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