Hey gang,
I have noticed that my MCS is becomes very unstable when I brake at a high speed (100+). I've only gone that fast twice but I think that my brakes might be messed up. Going in a straight, at about 110mph, I hit the brakes, not hard just medium, (just testing MINI) and the car pulled hard to the right and the back in starting swinging around to the left. I let of the brakes and then gently slowed down to a reasonable speed. There isn't much pull going slower. I have test it going 50 and 60 and I can really notice anything drastic. Have any of you experienced this in your car. I am not saying go 100+ and slam on the brakes, but if you just "happen" to be going that fast and a "deer" runs in front of you tell me your story. Thanks

 

Did the road have any ruts from tractor trailer use? Or any other rutting? If so that could be the cause.

 

no, it has happened both times, on different roads.

 

Try it at 120 mph or faster next time and see what happens.
Let us know
Buzz

 

I don't think the MINI is exactly the best shape from an aerodynamic point of view at 100+ so that is probably part of the problem. That blocky rear end is making lots of turblence that is probably doing strange things to the car when you decelarate into the turblence.

 

>>Did the road have any ruts from tractor trailer use? Or any other rutting? If so that could be the cause.

Well..........I have been known to go that fast and faster, also in all types of cars that were designed and those not designed to do the speed.............seeing people in wheelchairs after "accidents" has slowed me down quite a bit, not to mention tickets.................but if you must, as I have, go to track events where you can test that kind of stuff...........sorry to be harsh to your ears, but maybe you are getting a wake-up call.........to kick back a bit ......Mini, even a S is not really a sportscar, it is a nimble sub-compact....unless super modified as a racer.......................there are tons of cars that are faster both top and low-end.............nothing to prove or test going that fast really in a Cooper, except windnoise................

 

>>Hey gang,
>> I have noticed that my MCS is becomes very unstable when I brake at a high speed (100+). I've only gone that fast twice but I think that my brakes might be messed up. Going in a straight, at about 110mph, I hit the brakes, not hard just medium, (just testing MINI) and the car pulled hard to the right and the back in starting swinging around to the left. I let of the brakes and then gently slowed down to a reasonable speed. There isn't much pull going slower. I have test it going 50 and 60 and I can really notice anything drastic. Have any of you experienced this in your car. I am not saying go 100+ and slam on the brakes, but if you just "happen" to be going that fast and a "deer" runs in front of you tell me your story. Thanks

That should NOT happen. Sounds like you have a problem with your left front braking system. Maybe somewhere along the line you got oil or something on left brake pads or rotor? I'd get it checked out if I were you. That's an unsafe condition, especially if you like to rev it up occasionally!

 

Run-flats are notorious for sudden pulls towards other lanes, especially on uneven pavement. I've experienced it at 70ish. Do some research on run-flats. You may find them to be the problem.

_________________

Vince

[img]null[/img]VinceAndJessica.com

 

The MC and MCS were designed to be Autobahn cars. They should be stable at 100+++. There were designed to go that fast. It may not be a 911, but it is not civic either. It is a well balanced traditional British sports car: light weight, slightly underpowered (compared to it's competition), and it eats up the turns.

 

I've definitely found that the run flats will hunt around on uneven pavement (rain grooves and the like.) This extends to braking. I've learned to make sure I have a good hold on the wheel when braking, as I've had it pull one direction or the other after hitting ruts.

Is this not common?

Jeff

 

I can see the the service writer now :smile:

 

It may be your brakes, I have did brake tests at 80. 100, 115 mph and the anti lock always performed perfectly for me.

 

NPARTIST

I have found the same prob in my MCS........the road was not un even......i dont really want to go back to my dealer and tell them m car is unstable at 205km....imagine there face

 

I'd get those brakes checked. I don't have runflats so I can't speak
for them but the Cooper S shouldn't be pulling on hard braking. I
was on an open road today and braked hard at 120 and the car was
stable with no pull. If it is pulling to one side I'd have alignment and
brakes checked. IMHO.

 

Thanks, I think something is wrong so I am going to call my dealer and ask him what he thinks. I just won't tell him that I going 110, only "highway speed". I will update ya'll later.

 

Any slight turn while braking at high speed causes this rear end swing. The only fix that I can think of is a heavy duty rear sway bar.

I have gone around (spun out) once due to this effect on an empty road. A slight shift in the steering wheel and woosh, the back end wants to overtake the front end.

I don't think it's your brakes, I think it's the design of the Cooper.

Just my thoughts

 

As stated above, have your brakes and alignment checked out and do a little research on the run-flats.

"It may not be a 911, but it is not civic either."
On a calm day (little or no wind) my '97 Civic was quite stable at 105 with plenty of pedal left in it. At about 115, I still had pedal left but I could feel the front end wanting to lift ever so slightly, so I did not push it any faster.
Have you ever been on an autobahn? Most folks in passenger cars do about 140-150 Km/h (85-90 mph). Occasionally you will see a big Benz, Bimmer or Porsche blast by at 200+km/h (125+), but it is rare. Those types of speeds should not be undertaken without functioning air dams, significant driver training and an appreciation of the risk involved.

"Any slight turn while braking at high speed causes this rear end swing. The only fix that I can think of is a heavy duty rear sway bar."
A thicker rear sway bar will reduce body roll in the rear, effectively giving the driver less indication before "snap oversteer" occurs. It is definitely not a fix. When a driver hits the brakes, especially at higher speeds, the weight is transferred forward, and therefore the rear tires have less traction and will be more likely to step out, causing the car to spin.
speed safely!

 

Ok, who is correct in these postings?

andrew said:
........to kick back a bit ......Mini, even a S is not really a sportscar, it is a nimble sub-compact....unless super modified as a racer................

sidbreen said:

The MC and MCS were designed to be Autobahn cars. They should be stable at 100+++. There were designed to go that fast. It may not be a 911, but it is not civic either. It is a well balanced traditional British sports car

I think sidbreen is 100% correct in saying that a mini is a sports car.. You couldn't
have said it better...thanks sidbreen. Also it handels better than a crown vic interceptor at those speeds (gave myself a verbal warning).

 

>>Ok, who is correct in these postings?
>>
>>andrew said:
>> ........to kick back a bit ......Mini, even a S is not really a sportscar, it is a nimble sub-compact....unless super modified as a racer................
>>
>>sidbreen said:
>>
>>The MC and MCS were designed to be Autobahn cars. They should be stable at 100+++. There were designed to go that fast. It may not be a 911, but it is not civic either. It is a well balanced traditional British sports car
>>
>>I think sidbreen is 100% correct in saying that a mini is a sports car.. You couldn't
>>have said it better...thanks sidbreen. Also it handels better than a crown vic interceptor at those speeds (gave myself a verbal warning).


Thanks for comparing, but check sales of MINIs in Germany, majority primarily sold in 2 large car markets for premium priced small cars, the UK and USA, not really designed for the Autobahn, if so, focus on selling more there would targeted more intensely by the Germans........While the mini has many attributes of a sportscar, just like an X5, it is not a sportscar in the purest sense, I will concede that it is sporty though !!!
>>
>>

 

I have driven three cars at over a 100 mph and I can tell you which one felt the most stable.

Go ahead and guess from this list.

1990 Jeep Cherokee with 30X9.50 BFG long trail TAs

1995 Nissan Maxima with normal BFG Grand Touring tires

1989 Pontiac Bonneville with grand Goodyear Touring tires again


The answer will surprise you.













The bonneville felt the most stable at about 115-120 and I think i know the reason why. The bonneville has a real front air dam and its front end/windshield are not as blocky as the Maxima. The Maxima could got faster simply because it has more HP but it felt much more unstable. I topped out at about 135 in the maxima before I felt the front end lifting/drifting too much and backed off. The bonne could only get up to about 120 and then it was done.

I was follwing a friend in the jeep and his speedo read 108 when reason came calling and I backed off. My jeeps speedo only went to 90 mph so this is an estimate. The jeep just felt strange. Those solid axels and big boxy body were just not designed to turn at those speeds.


I am not saying there is not anything wrong his car, there could be, I am just saying that I would not expect the MINI to handle normaly at 100+. At least not with out some kind of body kit to fight all the lift its blocky front end will generate.