17 replies to this topic

[classicoop]

Normal? Dont have a mini to compare with.

It feels like chassis flex more than anything (not same feeling of lack of spring rate/damping in a modern car). It doesn't oversteer dramatically, but it does feel like the rears stepping out.

Under then over then under then oversteer... The understeer feels like any other, the rears just feel odd.

Tires are low miles.
No suspension clunk/play
Lowered on hilo with old hard cones, spax adjustable.
Everything else standard.


One thing i noticed is the rears have zero camber, never driven another car with zero rear camber.

Fronts have 1.5 i think, i forgot exact camber.

[robminibcy]

i would check your radius arms for wear/ play and confirm the tracking is ok. I think there's a thread about ideal tracking figures in faqs.

 

Might be wrong but i though minis were supposed to have zero camber on the back (or at least within tolerance).

 

and i would replace the cones as well, old ones won't have the proper springiness. Makes a huge differance in comfort and handling to have new ones. I couldn't belive it when i first drove mine after replacing them.

Edited by robminibcy, 24 April 2014 - 05:53 PM.

[classicoop]

Zero play in arms.

Thanks for the info. I was thinking cones as well. Maybe too stiff making it bounce?

It feels planted in the corners then after a certain point it just feels like there's suddenly much more body roll. Then the rear feels like it's stepping out.

This is a whole lot more evident with trail braking, both under and oversteer.

[Captain Mainwaring]

i'd check that the subframe is staying where nature intended.

[classicoop]

Front or rear? Rears solid as can be. Front ehhh not sure. Bushings plus thin metal its bolted on. But no cracks, all bolts tight.

Fwiw I dont have the cowl shudder noise convertibles have.

It feels like the outer rear suspension is stiff then suddenly compresses then uneasy rear happens.

Does the rear suspension geometry change effective spring rate after a certain point of compression? Will that point be reached with spax yellow (i dont think this is the lowered model) or will shocks bottom out first.

[dklawson]

Also check your tire pressures.  Set the fronts about 2 PSI lower than rears.

[tiger99]

The spring rate changes PROGRESSIVELY all the way from full droop to full bump, and indeed has to, because of the short available travel, which is why rubber cones are a must, despite the assertions of some users of coilovers.

 

If something is changing part way, suspect seriously worn knuckle joints, with the ball ends grinding their way into the arms, which is dangerous and needs to be fixed at once if that is the problem, or, less likely, bent damper rods.

 

Have you accurately checked the rear TOE? The camber is relatively unimportant, and can be fine tuned to get the handling as you prefer, but the toe is extremely critical, and needs to be very slightly toed IN at the rear. The slightest hint of toe out will cause the symptom you describe.

[minisilverbullet]

+ one on the toe settings! 

 

It is a tricky one to comment on, not really knowing how aggressive your trying to corner. DO you have cheap tyres? 

[smudger068]

Would have to agree on both above points especially tyre brand and quality and toe setting?

[classicoop]

I gather from what you said, its supposed to get stiffer?

Cause mine feels stiff-stiff-suddenly soft.

Will check rear toe. Can the rear toe be adjusted with the standard bits? I'm under the impression it can't. Curbed and bent maybe...

[cal844]

Not wanting to sound stupid, is there grease in the radius arm pins??

[carbon]

Bit more detail about the car would be helpful. Does it have a solid mounted front subframe?

 

Reason for asking is I had a loose steering rack few months back and this gave handling issues quite similar to those you described.

[classicoop]

Double post..

Edited by classicoop, 26 April 2014 - 02:39 AM.

[classicoop]

Cal - yes it is greased by the grease nipples

Carbon - standard bushings, around 6k miles old, new from minispares.

Everything else apart from wheels (13x7), spax standard length adjustables, hilos are standard, suspension wise.

Rack bolts are locktighted, because it has loosened before. Will check as well. But steering wheel center doesn't change after turning like it did when bolts loosened before.

[tiger99]

Stiff, suddenly going soft, if it is real, is a symptom of a disintegrating rubber cone (quite unlikely), bent and jamming damper (not all that likely on a Mini),  siezed radius arm pivot pin (not uncommon, and will need a rebuilt arm unless you can get hold of the reamer) or, as I said, a jamming knuckle joint, which is downright dangerous and WILL result in a suspension collapse when it goes right through the arm, snaps or tears out of the end of the trumpet.

 

Before driving the car again (and yes, this IS urgent in case it is the knuckle), you need to disconnect the damper (undo at the top, or persuade it to come off at the bottom, which is sometimes possible). Work the damper up and down over its full stroke, and check that it is not jamming. Disconnect the knuckle and trumpet from the cone, and work the arm up and down over its full travel. Does it move freely, without sticking or jamming anywhere? While you have it partly apart, fit new knuckles anyway, they are very cheap, and ruined arms or the more serious consequences that can follow, are never cheap. Check that the knuckle ball has not gone through the cup and damaged the seating in the arm. It has on probably 90% of Minis.

 

If it is none of that, the sudden stiffening is most likely your imagination, which can happen, because things don't necessarily feel as they are, and the senses may be confused by sudden oversteer seeming to be an effect of spring rate, when it is something subtly different. And that does not mean that you are stupid, or have less "feel" than anyone else, it only means that all of us humans do not have the capability to diagnose every single mechanical malady by feel alone. Even professional road testers frequently disagree on how various cars feel and handle, so don't be dismayed in the slightest if it turns out to not be spring rate at all.

 

As to adjusting the toe, under no account waste money on a set of adjustable toe and camber brackets. Certain of those on the market have a solid track record of fatigue failure, because they are very badly made, and worse, are plated, without following the correct process, because it adds cost, causing hydrogen embrittlement. Yes, there are spivs and scumbags who will turn a quick profit at the expense of public safety, indeed there always have been and will be (think contaminated meat a few years back, and more recently, but relatively harmless, the horsemeat fiasco) and the Mini aftermarket has always attracted a lot of that type, unfortunately.

 

The camber and track may be adjusted by filing out the hole in the radius arm bracket, and welding on a thick washer afterwards to provide positive location. You could make a small adjustment towards toe out or positive camber by adding shims between bracket and subframe, but can't go the other way except by filing the hole. You could instead file the inner hole in the subframe web, if it was easier.

 

One unfortunate side effect of ride height adjusters (HiLos etc) is that they completely mask the initial effects of worn out knuckle joints (the first indication is low ride height), and so, while not in themselves usually unsatisfactory (there are some poor quality items around), they unintentionally can indirectly contribute to a serious problem.

 

Because of the rising spring rate, the matching of wheel loads left to right is rather sensitive to uneven height adjustment, and although no-one here seems to use the corner weight method of setting their HiLos, it may be worth considering, as it is possible that the suspension is set up incorrectly. The car, being adequately torsionally stiff (unlike some more recent and expensive models we could name!), will sit level, front and back, if mis-adjusted, with maybe 70:30 weight distribution across the rear wheels and a smaller error in the reverse direction (the front dead weight being higher, as you will know) at the front, but I don't imagine that it would handle well like that.

 

Actually, I see a need for a new aftermarket accessory here, a wheel load matching system that measures the loads as you adjust the HiLos. Fortunately it is beyond the capabilities of the most unsavoury parts of the aftermarket business to make such a thing. The other way, widely used on race cars, Sevens and such like, involves simple weighing devives which lift all the wheels equally off the floor to make a measurement, but you really do need a truly flat surface to use them.

 

https://www.merlinmo...er-weight-gauge

 

But a real-time measuring system would be of more use to you right now......