[proskills]

I was getting on the 405 in Irvine today, and there was a nice long swooping on ramp, so I took it relatively fast, but nothing different than I would usually do, and much slower than if I were on a track. Anyways, after I passed the apex of the turn, I noticed that I was sliding a bit. I caught it immediately and didn't even swerve into the other lane, but I was wondering what could have caused this. Is it possible that I hit a dip and didn't notice it, or was I just going too fast?

 

[Demonized]

Did you let off the throttle, upshift, or hit the brake right after the apex?

 

[ahofste]

I believe the favorite 'excuse' always is: Diesel on the road...

 

[...m...]

...drifting in an elise...

...my current set of rear AD07s are, to put it generously, slicks...over the past few months, it's become increasingly easy for me to break rear traction by adding power in a turn, which accelerating through a sweeping on-ramp provides an ideal opportunity to demonstrate...

...typically our cars handle so well that we can't really kick the tail out short of lifting to take weight off the rear wheels under very high lateral loads, but it's not too difficult to imagine drift-prone circumstances replicating the effects of my bald tires: colder temperatures, water or oil on the road, or any mixture thereof are the most likely culprits...

...how does traditional power oversteer differ from lift oversteer, in terms of controllability?..obviously our RMR layout is more likely to snap the tail around backwards than a typical FR layout, but can lift oversteer be throttle-modulated as easily as the power oversteer i've been playing with for the past few months?..personally, i'm really enjoying the practice of keeping things under control while going sideways, and in a way don't look forward to the new set of tires i'm putting on next week...

 

[mopho]

It's pretty cold this morning

 

[dwkoski]

I think previous poster's had it right. Do you have
ad07's? They're great when new and warm. When cold and worn you will get oversteer, especially if the rear's are worn significantly more than the fronts. Lifting at apex exacerbates problem. If your rears are heavily heat cycled and worn more than 2/3rds of tread depth, replace them and save yourself and accident. p.s. when worn, they are downright dangerous in heavy rain...Dave

 

[proskills]

Thanks guys, I think my tires are at first wear, but they definitely have some tread left. The tires were very hot at the time, I had just come up from San Diego. I assume that my rears broke traction when I accelerated off the apex. I think it just spooked me because I have never lost traction off the track. :/

From what I remember, I was low rpm in 4th, so maybe around 50 mph (never shifted or braked). I have done similar off/on ramps at this speed or faster without ever losing my tires...

 

[lotustype74]

but what about....

You say he tires were warm but what about the road? Don't worry about it if it happens again it might be something to think about. The highways are full of oil water coolant you name it, you just might have hitadamp spot and did not notice.

 

[Conan]

Thanks guys, I think my tires are at first wear, but they definitely have some tread left.

"Having tread left" on AD07's doesn't really mean anything. They heat cycle out quite quickly. I have > 1/8" tread depth left on mine and they have almost no grip left in anything but the best of conditions.

 

[Randy Chase]

Agreed. The tires are probably heat cycled out and are now dangerous. Replace them.

 

[proskills]

What type of tires would you suggest I replace them with? I might do one track day or AutoX every couple months, so I'm thinking R888's might be a bit overkill.

 

[Randy Chase]

I replaced mine for street with Yokohama A032s.

 

[Bleu Omdurman]

I enjoy these types of questions, so thank you for posting.

While there are probably too many things to consider for one of us that was not there to "answer" your question maybe I can suggest a few things that could have increased the chance of oversteer.

1) The "ruts" in the road, no matter how slight are there. If you were transitioning from the hump (both wheels on the crown of the ruts) down into the ruts, the wheels would lose weight briefly and thus lose traction. Once the oversteer carries the contact patch to the base of the rut, you would gain traction as the wheel is trying to move up hill.

2) Road grime is not equally distributed. You will find more in the crowns of these ruts than you will find in the ruts themselve as the constant tires running through them will push it out of the way.

3) Throttle changes mid turn, but I doubt it if you have "Proskills" and were in 4th at 50 mph.

4) Pavement shift, dip, or change in material. If there were a dip, or crack this could cause it. Also if there was a patch of new pavement holding you and then it changed to old pavement. Also, if there was a patch of concrete vs pavement, that would also reduce the traction.

Maybe one of those helps?

Cheers,

Thanks guys, I think my tires are at first wear, but they definitely have some tread left. The tires were very hot at the time, I had just come up from San Diego. I assume that my rears broke traction when I accelerated off the apex. I think it just spooked me because I have never lost traction off the track. :/

From what I remember, I was low rpm in 4th, so maybe around 50 mph (never shifted or braked). I have done similar off/on ramps at this speed or faster without ever losing my tires...

 

[proskills]

I replaced mine for street with Yokohama A032s.

A google search failed to return any reasonable results, are they these tires? Yokohama

 

[Randy Chase]

No, look up A-032

I ran A-048 front and A-032 rear after concluding that the A-048s heat cycled out too fast and became like someone spread crisco on them. This was only a problem on the rear which created massive oversteer.

 

[Randy Chase]

I also really like new Dunlop Direzzas. I am running these on the Noble for street and some misc autocross. Plus they are very cheap.

 

[milehitom]

"Having tread left" on AD07's doesn't really mean anything. They heat cycle out quite quickly. I have > 1/8" tread depth left on mine and they have almost no grip left in anything but the best of conditions.

Same here. I'm at 9k on my second set of AD07 rears and, particularly on cold days, I can break them free with a slight turn of the wheel and just a touch of throttle. Time for a new set.

I'm a big believer in buying tires way before you "need" them. They're the only thing connecting me to the road. The second they start to go, they're gone.

Bleu's comment about grime and sand is a good one to remember when street-driving. Around here, sand is the preferred method of dealing with snow, so we get quite an accumulation of pulverized sand late in the winter and into the spring. Any car will slide on these little tiny marbles. Ours are more likely to just because of the car's balance. Add wear, heat-cycling (even aggresive street-driving can heat up the tires considerably) and 40 degree weather and our sticky tires barely work at all.

Tom

 

[codymac]

The many causes of oversteer aside the simplest way to solve it is to drive slower.

 

[xtn]

The many causes of oversteer aside the simplest way to solve it is to drive slower.

:clap::clap::clap:

There is only one reason for oversteer: The vehicle has been asked to deliver more rear grip than it is capable of delivering in whatever circumstances or set of conditions you are in.

Perhaps you were near the limit, and you tightened the turning radius slightly, asking for more lateral force.

Perhaps you were near the limit, and although you held the radius constant, you increased speed slightly, asking for more lateral force.

Perhaps you held every input constant, but the road surface for whatever reason (insert everybody elses' possible explanations right here) caused a moment of reduced lateral force capability.

xtn

 

[proskills]

3) Throttle changes mid turn, but I doubt it if you have "Proskills" and were in 4th at 50 mph.

my 'proskills' have nothing to do with driving. but, I actually prefer to drive low in the rev range when on the street so I'm not wasting up a bunch of gas and have to fill up every 200 miles. On a track I probably would have been in second, but i wouldn't get offended if you accused me of driving on the road like a grandma.

4) Pavement shift, dip, or change in material. If there were a dip, or crack this could cause it. Also if there was a patch of new pavement holding you and then it changed to old pavement. Also, if there was a patch of concrete vs pavement, that would also reduce the traction.

Maybe one of those helps?

Cheers,

I am sort of thinking that it could be a slight dip, but I don't remember hitting one. New tires are probably also a good idea in this situation also.

thanks for all the suggestions.