Over-steer on my mini
Turbo Mini Forums

I've been driving my mini on my hour commute to work and am starting to pick out all sorts of problems with it now.

My biggest worry at the moment is that it is over-steering (quite badly).
It seems worse when I take a right-hand bend rather than a left.

At the rear I'm running standard shocks, cones, arms and mounting brackets with alloy finned drums, 30mm extra spacer each side and 12x6 superlites with 165/60/12 A510 tyres and pressure 29 psi all round.

The car is fine on sweeping bends but if I want to turn tight it feels as if there is some elasticity in the rear, almost as if i have a flat tyre (which i don't) and the side wall of the wheel is giving me some spring back.

I'm off to combe on Sept 10th and then again for the mini day on 24th so would like to get it sorted so i can stay on the track

Any suggestions or anyone local got a tracking set they can come round with to help me check it all out?


Thanks
Dan

Edited by dan187 on 25th Aug, 2011.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

I had this same problem with my 12x6 wheels. This year i span out on a motorway slip road in France on the way to the imm and ended up facing oncoming traffic. Bit of a brown trouser moment!

With those wheels and those tyres there is some slight stretch on them, meaning the sidewalls have little give in them. When you push it round bends the tyre wont deform much to aid grip instead the back end will break free and it usually doesn't give much warning.

I have now gone back to 10" wheels and the larger tyre is definitely better for handling and grip.

My project Toyota powered mini: http://www.turbominis.co.uk/forums/index.p...tid=470448&fr=0

see now i get the opposite, I have lots of warning. It feels like there is loads of sidewall give and so i get a spongy back end feel that tells me when i'm pushing it too far.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

6x12s are by far the best handling combination I have ever had on a road mini. 30mm spacers seems a lot. I generally run 5mm more on the rear, which really helps with oversteer and stability.

anyway, I would try the following:

1) check that the front is not sat on the bumpstops, and is at least 5mm clear.
2) that the cornerweights are set evenly.
3) that the rear toe is equal and in.

Do you find that you need very little steering input?

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

i don't know then. maybe try a bit of negative camber on the back

My project Toyota powered mini: http://www.turbominis.co.uk/forums/index.p...tid=470448&fr=0

Edited by dan187 on 25th Aug, 2011.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Other than corner weights you can get a rough idea with string and a ruler.

Google ;home suspension setings' or some thing, lots of ways.

Low steering input could well be the front then.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

i had a similar issue... with the rear of the estate. Found to be toe-in on one side and toe-out the other.

probably a toe issue on the back - one side will be 'in', one side 'out'....

I assume you've checked there is no play in the radius arms? I've seen some horendously worn arms in the past that have caused this.

other than that, as already noted, get the geometry set. Keith T just has some similar issues with the mk1 and it was the toe settings

Thanks chaps.

Yeah checked for arm play, was pretty rigid.

I've forked out for minispares adjustable camber and toe brackets. So i'll get them fitted and find a good alignment centre

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

How rigid was it, was it moving through its arc as it should? A seized radius arm basically gives solid rear suspension which isn't good for handling.

Looking at previous posts i've opted for the following settings. It will be used as a road going track and hill climb car (currently my daily drive).

Front
-1 degree camber (I have the standard fixed lower arms I believe that is the camber offered?)
5 degree castor
1 mm toe out

Rear
-0.5 degree camber
2 mm toe in

Edited by dan187 on 26th Aug, 2011.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Much more front negative camber required.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

You will need other arms. 1 deg neg isn't enough in general for a hard driven Mini. Aim for 2 degrees or 2.5 deg

I disagree with Tom. -1 will be enough IMO, 1.5 a maximum.

Although I run crossplys, I run -0.5 on the front, radials will want more camber, but -2.5 will just ruin traction.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I run around -1.5 from my tracking report, and that's just from the car being lower, i find it about spot on :)

Thanks for all your inputs guys...

For now i'm going to stick with the standards arms due to the cost of new ones. I have lowered the front some so hopefully I will have between -1 and -1.5
I'll see how i get on with that and consider changing the arms in the future if needs be.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

On my race Mini running 6X12 or 7X12 with 48Rs I use approx 2 neg at the front and very little toe out. At the rear Approx 1,5deg neg and 5mm toe out. I'd guess if you set the rears parallel it'll make a very stable ride. Toe settings are MUCH more important than the camber.

5mm toe out at the rear, truly bonkers.

Not that I recommend it to anyone, I actually have 6mm toe in on the rear of the hillclimber. there are number of reasons for this but mainly it's because I like it and it suits my 'chuck it in style'.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I chucked mine in on saturday. Result? A spin

I wouldn't reccomend this on a roadcar, but it works well on a circuit racer.

All set up now and runs much better. Feels like a mini and sticks to the corners. Rather than making me crap myself because i can feel the back end coming round.

Thanks all

Edited by dan187 on 30th Aug, 2011.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Good news, and more proof that the 10", 12", 13" argument is not about the size, buit the way you use it.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.