hi,

I have a 2005 MCS that I got about 3-4 weeks ago, it has about 1000 miles on it as of today.

I was having fun on the highway, and when I took the offramp, the rear en came out pretty fast . The best way I can describe it is how the 1980's porsche 911's handled. This was under moderate braking, so my porsche reflexes kicked in and I taped the throttle and just like a 911 everything came back in order. what's weird is while the car was sliding smoothly sideways, there was never even a little tire squeel .

Now, this was on a pretty hot day (90+), and I noticed that the tires had ALOT less grip when the temperatures are high. They seem to be at their best in the 65 - 75 degree range.

has anyone expericanced this with the stock runflats (Dunlop 5000's) ?

 

sorry for the typos, i'm at work and have to type really fast.

 

Were you braking when the rear end began to give?

 

I was starting to brake but very moderatly. When I entered the curve, I had to slow down about 15MPH so it wasn't hard braking.

Have you had this happen to you?

 

deleted

 

Wow...you must've been flyn Did you have the DSC turn off? Mine will rotate at will with throttle lift at those speeds

 

Must have been some special conditions to get a front-wheel drive car, un-modded (?), to get massive amounts of oversteer. I've thrown the back end out some but that was on a 90 degree turn I took at speed.

So how fast and such were you going?

 

So what is considered normal behavior for these cars. Say on a clover leaf getting onto a highway. If I take this at a good speed, should I expect to slide on all corners, or is the rear going to hang out. Maybe the front will plow?
I just couldn't get the total feel during my test drives....

 

For everyone's information, the car has no modifications.

Here is more detailed information:

going straight at about 70 and entering a clover leaf at about 60, it seems like the braking that is applied just by the fact that the car is turning will take enough weight off the rear wheels to break the rear end loose.

What is really interesting, is the fact that this will only happen when it's really hot out. When it's colder ~60-70) the car feels alot more neutral in handling.

anyone had this before?

 

why did someone post:



"deleted"

????

 

It might be a combination of odd onramp conditions mixed with the rigidity of the runflat tires (i think i read you have them...). I recomend you use your runflats up and then move on to some nice nonrunflat tires. They offer much better controll.

 

Hey, Brittish Kompressor--you're giving me too many ideas. Shame on you!

 

This was a post done in error. I can remove it altogether if you wish.

Back to the oversteer. Two thoughts-
One: the road conditions- maybe it was due to something affecting traction at that point in the road- some slick fluid on the road that could not easily be seen and avoided. OR

Lift-Throttle Oversteer A handling characteristic that causes the rear tires to lose some of their cornering grip when the throttle is released during hard cornering.

http://www.autozine.org/technical_sc...handling_5.htm
See Lift Off oversteer

http://www.rassoc.com/gregr/weblog/a....aspx?post=601
Last paragraph.

 

I've never come close to "massive oversteer" with stock suspension and runflats. It seems like this could happen if you had the power on pretty hard coming into the turn, then abruptly lifted off the throttle and applied some brake pressure at the same time. Never tried that myself, and don't think I ever will...

 

oversteer is much more fun than understeer in my book.

thankgoodness these babys can pull right out of just about anything

its not quite drifting style, but the all whell slide is in effect.

with a crazy suspension and weight reduction in the back, over and under steer are easily controlled or exploited; your choice.:smile:

 

What was your tire pressure?

 

Sounds like there was somehting on the road that caused it.

 

I have no idea what the tire pressure was, I got the car only 3 weeks ago so it's whatever they set it to.

Just so everyone is clear, I'm not complaining of this behaviour , I MUCH rather oversteer then understeer. The reason for my first post was that It was so unexpected that I thaught maybe somehting was wrong with the car.

Now that I think of it, with the MINI's weight balance, it's quite normal that the end comes loose under mild braking in a hard curve.

I went out to try it again today, and all I can say is WOW. I could "powerslide" almost all the way through a bend as if it was a 911... That's just amaizing!!!

I wish I never found that out, now the poor runflats are going to last all of 6 months

 

You might want to check those pressures. It's not uncommon for things to be off by quite a bit.

 

Mine was delivered with 27psi all round. You might want to check yours.

Luke

 

The stock all-season run flats, aren't the best tires for corners, but they should make a lot of noise before they let go. The only exception being if you break in a corner hard enought to lighten the rear end and have it start to come around on you. (Under this circumstance you'll probably also feel the anti-locks start to pulse on the rear wheels when the rear end gets loose.) Break before the corner, and then on the gas. The car should be pretty neutral with stock suspension.

Check out: http://www.se-r.net/car_info/suspens...cle%20Dynamics

BTW, be careful on the public roads. Entrance and exit ramps can have nasty surprises, like oil, gravel, debris, etc. If you really want to see what you car's limits are, do a day at the track, or check out a local performance driving school. You'll have a ball!

 

I would guess their was something on the road. Brgfan is right, the runflats make all kinds of noise when you take them to the limit. I have been autocrossing on mine and they are terrible. I haven't experienced much oversteer on them though. I want a rear sway bar to counter the understeer. I can't wait to replace runflats.