suspension questions

[gert]

My series II has been modified in 1996 with a 1275 A+ engine, Sierra fivespeed gearbox, Dolomite rear axle, Marina discs and some other goodies.
Rear suspension was modified in an Owen Burton way with lowering blocks (which were shortened about 50% years later) and using his U-profile cross member to which telescopic shock absorbers were mounted on an angle.
This would also prevent axle tramp to a degree, which is correct, but the disadvantage is the shocks are not efficient enough because of their 45 degrees angle. I have heard reports of an improved and more comfortable ride if the shocks would be mounted upright. Can someone confirm this and is there a ready-to-fit system on the market nowadays which establishes this? And will it be necessary then to mount rear radius arms as well?

The front suspension was also modified with telescopic shocks and an anti roll bar, using Owen Burton parts, while ride height was lowered by unwinding the torsion bars one spline.
The result was that the bump stops were touched regularly, so I mounted 25% stronger torison bars. This cured the problem, but gave a bit of a harsh ride.
Now I wonder if I had better mounted new original torsions bars. Would that have cured the touching of the bump stops as well, with the advantage of a less harsh ride?
In the meantime I have mounted an adjustable system for the torsion bars, which makes various ride heights possible (at the front that is).

[Pyoor_Kate]

Jonathan! You're wanted!

Yes, there is an upright shock mounting system, it's done by JLH minors and involves some welding, but is considered a substantial improvement over the OB kit...

[minor_hickup]

The easiest way to stop the touching i believe is to raise the ride height. I also have to get round to this. If the car is riding too low you will mash up the inner wings, my passenger side inner wing got ruined

[Stig]

In the meantime I have mounted an adjustable system for the torsion bars, which makes various ride heights possible (at the front that is).

Er, how does this differ from the original adjustment system with the plate at the rear mounting or the torsion bars?

Is it really that bouncy at the back with the 45 degree telescopics? That's what mine has got and it seems fine, but then it's not lowered and it's a Traveller so has different springs (and probably different weight distribution).

[Willie]

GERT, although my Owen Burton rear shocker U section bar eventually
snapped in half I must say that they worked quite well although there is no
question that upright mounting of the dampers is far superior. This means
that the teles go up through the floor which means some welding is necessary. I wonder,since you have a lowered rear end, how much space
there is between the rebound rubber buffers and the plate they hit on the
body? On my standard Minor the gap is just under one and a half inches and, if your gap is much less due to the lowering blocks, and the rubbers have not been cut down to compensate then you would get premature contact
which would ruin the ride I would have thought?

[bmcecosse]

There is no need for uprated front torsion bars - no wonder the ride is harsh! Just fit standard ones and a sensible ride height - but how good are your tele-dampers ? And are they mounted out at the ends of the lower arm, or are they half way along? I also recommend filling the lever arm dampers with 20w50 oil - and this with my tele dampers gives me a wonderfully compliant ride but with absolutely no bounce or rebound - the car soaks up dips and rises no problem at all. Your anti-roll bar will be adding up to your bump rate too - I haven't bothered with one of these because they give more understeer - the very last thing a Minor needs ! I also recommend a little negative camber on the front - helps cornering no end.
At the rear - the suspension has no 'rebound' rubbers - it does have bump stops, and if these are constantly mashing the plate on the cahssis - they will crack the chassis! Tele dampers should always be mounted as near vertical as possible - they cannot do anything but 'damp' - they cannot aid/prevent axle tramp (except by good damping). Again - 20w50 in the rear lever arm dampers helps greatly. And a set of Traveller 7 leaf rear springs - possibly with lowering blocks - will help too.

[Innovator]

Dampers are displacement devices, ie they work best when they move, so they should be mounted so as much suspension travle as possible is translated into damper movement.

At the rear this means upright dampers as close to the wheel as possible. At the front again as upright as possible with the lower mount as close to the wheel as possible.

Generally suspension works best when it can work! So this means soft with travel. I would recommend soft springs and good dampers.

At the rear think soft and travel. Therefore 5 leaf springs.

I also agree that a front anti roll bar is not required. I have always suffered understeer in my Minors (except my latest!) when pushing hard.

John

[bmcecosse]

Agree completely - Colin Chapman was a fiend for soft suspension and good damping. My 7 leaf suggestion at the rear was to stop tramping - not really for the harder springing, although the 5 leaf spring is incredibly soft.

[gert]

“Er, how does this differ from the original adjustment system with the plate at the rear mounting or the torsion bars?”

It’s a bolt on kit that allows you to adjust the height of the front suspension to slightly raise or lower the front end (see pic below). MM Mania sells it.



”Is it really that bouncy at the back with the 45 degree telescopics? That's what mine has got and it seems fine, but then it's not lowered and it's a Traveller so has different springs (and probably different weight distribution).”

I would call it uncomfortable or harsh rather than bouncy. However this may be a matter of personal taste, but somehow I can’t get rid of the feeling that it must be possible to modifiy the setup into a more satisfying one.

I wonder,since you have a lowered rear end, how much space there is between the rebound rubber buffers and the plate they hit on the body?

The rebound buffers were cut to restore the original space.

[Innovator]

The normal suggested set up for suspension is as soft as possible so the bump sopts are "kissed" only on the severest bumps. Then control the movement with arb`s and good dampers.

The skill comes in deciding how low to run, therefore requiring stiffer springs.

John

[gert]

There is no need for uprated front torsion bars - no wonder the ride is harsh!

I started with 50% uprated bars which I soon replaced by 25% uprated.
At least ten years ago this was popular believe by the then “specialists”...

Just fit standard ones and a sensible ride height - but how good are your tele-dampers ?

Spax adjustables.

And are they mounted out at the ends of the lower arm, or are they half way along?

Half way along (again the OB setup).

I also recommend filling the lever arm dampers with 20w50 oil.

Has been done.

“ - and this with my tele dampers gives me a wonderfully compliant ride but with absolutely no bounce or rebound - the car soaks up dips and rises no problem at all”

I wish I could agree...

[wanderinstar]

Would it be possible to fit upright dampers without the towers that go into the boot? My reason for asking this question is that I have an LPG tank in the boot, where the towers would go.
Ian.

[gert]

Would it be possible to fit upright dampers without the towers that go into the boot?

I can recall once having seen upright dampers mounted on the outside of the rear inner wings, but that was a long time ago. Don't know who supplied that system though. Possibly Charles Ware, but it might have been a DIY-attempt as well.

[jonathon]

C.S Autoclassics, now The Opus car compamy produced these kits .C.Ware also uses this design.

[KirstMin]

Your anti-roll bar will be adding up to your bump rate too - I haven't bothered with one of these because they give more understeer - the very last thing a Minor needs !

Hiya, you are talking about the most popular upgrade to handling amongst minor owners right? This is possibly the first (and most cost effective) way of dramatically improving the minor handling and you're telling everyone it's not necessary; implying it is in fact dangerous. I disagree and noticed enormous improvement when mine was fitted.

You may have adapted several other parts of your handling to negate the need for one but I don’t think it's fair to say it's a no-go area.

[Willie]

AGREED, next to fitting radial ply tyres the front anti- roll bar is probably the
most effective change you can make on a normal Minor. The fitting of a front
roll bar will increase the understeer on almost all cars but this does NOT apply to the Minor, a very worthwhile modification. It is possible that any poor
results from fitting one may be noticed on cars which have heavily modified
suspension systems but certainly not on a run of the mill car.

[Willie]

BMC "no such thing as rebound rubbers" look in your workshop manual,
where you will find 'rubbers-rebound'.

[Cam]

The anti-roll bar also dramatically reduces the 'wandering' caused by sidewinds on the motorway.

I'd say they are a good thing to have on a standard car. Mine does not need one as I have stiffened the suspension quite a bit anyway and adding one would be too stiff.

I know that soft suspension and large dampers is a good idea generally for handling but there are plenty of cars around with astounding handling and the opposite set-up. The Mini for example which is renound as being one of the best handling cars has hard suspension with tiny dampers. I must admit that I followed the Mini route for suspension and as such don't have any body roll when cornering (unlike the soft spring set-ups). Overall I'm pleased with the handling on my car BUT it is very harsh. If you want comfort too then I'd say go for the soft-springing hard damping route.

John's (Innovator's) car might have excellent handling but then again it's not a Minor. It's a custom handbuilt frame with custom suspension (and pretty much everything). Beautiful creation, but you can't compare it to the standard Minor as they are light years apart.

What I'm saying is that there are lots of different ways to go with suspension, but the way I looked at it was find the problem with the component and fix it. I lowered my car slightly at the front and so needed stronger springing. I also felt that I wanted a harder ride (being used to Minis) as the standard Minors suspension was way too sloppy, so that's the way I went as I wanted a Mini-like feel.

[Innovator]

It is a fact of physics that the softer the suspension the more the grip will be, all other things being equal.

Generally the reason why an infinitly soft suspension does not give the best grip is that you need more suspension travel so a higher ride hieght and a higher C of G, the body rolls more causing camber control problems.

On the other hand a very low suspension which is very stiff will slide a lot. The compromise (and this word comes up all the time with suspension design) is somewhere in between.

As a previous post of mine mentioned the skill is finding the mid way point.

What nobody can argue with is what each person prefers, that is a personal preference.

All my experience with standard Minors and modified Minor suspension show that when pushed hard a Minor will understeer. A front anti roll bar will make this worse.

However a gently driven Minor will probably feel a lot nicer to drive with a front ARB (I do not know as I have never driven) because it will roll less.

Body roll is also not a bad thing as long as the wheel camber is controlled. People associate body roll with poor handling but again the stiffer the roll the more the wieght transfer and the less the grip.

Suspension is a complicated business.

John

[Multiphonikks]

I'd agree with what John said in my own limited experience that is.

The K series Traveller had very tough springs and stuck to the road very well. However, I missed the roll that the normal minor gives because I was used to the roll telling me when the car was reaching its limit! (Though I never did quite get there in the Traveller I did have a few scary moments pushing the back end out!)

:O