12 replies to this topic

[Grilled]

I've only owned my Mini three days but this concerned me, When going around a long bend it felt like the back end was attempting to slide out, it's not just once it has done this so I know it's not something like a poor road or a lubricant spill.

 

Tyres have plenty of tread so unsure what might be the cause of it, although I thought rear buses may be a possibility? 

 

Any help would be awesome thanks :)

 

It's a 1991 Cooper if that helps at all!

[sonikk4]

Check for wear in your radius arms, this is a very common area and suffered this on my wife's Mayfair. Felt like the car was falling over in the bends.

[jaydee]

Other chances are rear tires toeing out, too high rear ride height or incorrect suspension stiffness, these have to be checked by a mini suspension specialist

[Cooperman]

Other chances are rear tires toeing out, too high rear ride height or incorrect suspension stiffness, these have to be checked by a mini suspension specialist

 

It's usually incorrect toe-in on the rear wheels. They must toe-I between 1 mm and 2 mm on the rear. Or it could be too much positive camber. A lot of after-market rear sub-frames giver positive camber and it's best to have between zero and -0.5 degrees negative camber. Ride height at the rear should be about 1 cm higher than the front measured from road level to top of wheel arch (as a rough guide).

[bluemini1979]

I had a friend who had this.. Every round about he would be completely sideways if it was wet for no rear end grip. His problem was suspension too hard, rear tyres were a cheap make ( replaced them with yokos) and softened the rear shocks and it was fine after that

[Grilled]

I am unsure how to check the wear in the radius arms but when it goes in for it's MOT after I get some work done I'll get some four wheel tracking done as after checking the rears they looked like they had a bit of positive camber. 

It may also be the rear tyres are too thin and too cheap to keep up with my spirited driving !! 

 

New tyres, wheels, suspension... so the second hole in my wallet opens  

Thanks for your advice, if I remember I'll update with the results.

[bluemini1979]

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Edited by bluemini1979, 15 July 2013 - 08:49 PM.

[sonikk4]

If the radius arm pins are worn you will fell this wear when you jack the car up and grab hold of the wheel at the 9 o'clock and 3 o'clock position. You should also see the arm move around the pin if badly worn.

The wear was so excessive in the radius arm pins on my wife's mini the bearing had failed completely and the pin was actually wearing into the arm itself. Scrapped.

[patto]

lol hang on a second guys, no one has asked the critical question here. how fast where you going? 

 

lol only joking, i had a bit of an incident a month or so back which involved a car on my side of the road and a blind corner which was closely followed by my near side wheels becoming closely antiquated with the curb, a full 360 spin a lot of squealing tires and me needing a new set of pants  . After checking it over i had bent the bracket on the radius arm and split the heal board around the subframe mount. i have to confess i still drove it the next day to work    but it handled like a pig. so just check the subframe is nice and secure with good metal around it (best to jack it up and give everything a good tug to check for play), and check the toe with something straight (should be pretty much parallel with the sills, possibly with a small amount of toe-in for straight line stability) along with the other bits people have suggested.

 

once i got the heel board welded up i put on some adjustable toe and camber brackets on which totally transformed the car. just cant get the back end out at all now (well without the help of the hand break  ), currently running 0.75 degree of camber and a small amount of toe-out (this reduces the under steer a bit but makes the steering VERY responsive in corners so you have to be on the ball)

[Cooperman]

 

 

once i got the heel board welded up i put on some adjustable toe and camber brackets on which totally transformed the car. just cant get the back end out at all now (well without the help of the hand break  ), currently running 0.75 degree of camber and a small amount of toe-out (this reduces the under steer a bit but makes the steering VERY responsive in corners so you have to be on the ball)

I hope you meant to say a small amount of TOE-IN. Toe-out on the rear is very unsafe and promotes an oversteer which must be immediately countered by full power. On race cars zero to about 1 mm toe-out is used, but the idea is to get the car to really turn-in under braking, then get back hard on the throttle right through the bent to get maximum exit speed. That is simply unacceptable on a public road.

[patto]

 

 

 

once i got the heel board welded up i put on some adjustable toe and camber brackets on which totally transformed the car. just cant get the back end out at all now (well without the help of the hand break  ), currently running 0.75 degree of camber and a small amount of toe-out (this reduces the under steer a bit but makes the steering VERY responsive in corners so you have to be on the ball)

I hope you meant to say a small amount of TOE-IN. Toe-out on the rear is very unsafe and promotes an oversteer which must be immediately countered by full power. On race cars zero to about 1 mm toe-out is used, but the idea is to get the car to really turn-in under braking, then get back hard on the throttle right through the bent to get maximum exit speed. That is simply unacceptable on a public road.

 

sorry when i say a small amount i mean tiny tiny Amount. Your right though, i did try it will about 0.75mm Toe-out and it was far too much for public roads. I'm probably running no more than 0.25mm at the most and even that as i said you have to be on the ball. For an every day car though i as i said Parallel or a slight amount of toe-in 

[Captain Mainwaring]

lol hang on a second guys, no one has asked the critical question here. how fast where you going? 

 

lol only joking, i had a bit of an incident a month or so back which involved a car on my side of the road and a blind corner which was closely followed by my near side wheels becoming closely antiquated with the curb, a full 360 spin a lot of squealing tires and me needing a new set of pants  . After checking it over i had bent the bracket on the radius arm and split the heal board around the subframe mount. i have to confess i still drove it the next day to work    but it handled like a pig. so just check the subframe is nice and secure with good metal around it (best to jack it up and give everything a good tug to check for play), and check the toe with something straight (should be pretty much parallel with the sills, possibly with a small amount of toe-in for straight line stability) along with the other bits people have suggested.

 

once i got the heel board welded up i put on some adjustable toe and camber brackets on which totally transformed the car. just cant get the back end out at all now (well without the help of the hand break  ), currently running 0.75 degree of camber and a small amount of toe-out (this reduces the under steer a bit but makes the steering VERY responsive in corners so you have to be on the ball)

 

 

Antiquated with the curb eh?

I think it has to be 50 years old or more for that.

[patto]

lol hang on a second guys, no one has asked the critical question here. how fast where you going? 
 
lol only joking, i had a bit of an incident a month or so back which involved a car on my side of the road and a blind corner which was closely followed by my near side wheels becoming closely antiquated with the curb, a full 360 spin a lot of squealing tires and me needing a new set of pants  . After checking it over i had bent the bracket on the radius arm and split the heal board around the subframe mount. i have to confess i still drove it the next day to work    but it handled like a pig. so just check the subframe is nice and secure with good metal around it (best to jack it up and give everything a good tug to check for play), and check the toe with something straight (should be pretty much parallel with the sills, possibly with a small amount of toe-in for straight line stability) along with the other bits people have suggested.
 
once i got the heel board welded up i put on some adjustable toe and camber brackets on which totally transformed the car. just cant get the back end out at all now (well without the help of the hand break  ), currently running 0.75 degree of camber and a small amount of toe-out (this reduces the under steer a bit but makes the steering VERY responsive in corners so you have to be on the ball)

 
 
Antiquated with the curb eh?
I think it has to be 50 years old or more for that.

acquainted