Negative camber arm, adjustable tue rods and all that..

[gs.davies]

I need to do some maintenance on my car's suspension in the coming weeks and get another couple of front tyres as they're 'worn to excess' on the outer edges. At the moment, it's at standard ride height on the front (and that is intended to remain so), using the early Mini lower arms with the top hat type bushes and standard tie rods. The top hat bushes were modern replacements are are now in a sorry state. Tracking was set when the car was freshly on the road with new rubber cones all round with a very high ride height, I've never had it done since.

The steering is quite heavy, even on the move, needing a bit of effort to get it to turn in, and the self centring effect is there but not particularly strong. There are no issues with tight balljoints, fouling on any parts of the rack, alignment of column etc. Wheels in the air, it's as light as a feather.

At my disposal I have:

- Some NOS lower arm bushes
- A pair of 1.5 Neg camber bottom arms with excellent bushes, barely used
- Adjustable tie rods
- Combination poly/normal tie rod bushes (presumably this is supposed to counteract the car's tendency to squirm about under whatever heavy braking the 998 brakes can inflict)
- Longer track rod ends

The car is on 998 brakes at the front, so standard 850/998 Cooper track width, and standard width Minifin drums at the rear (I also have available some 3/8 inch spacers)

At some point I do plan to move to S brakes when I build the 1300 engine.

Would it be worth fitting the Neg Camber/Adjustable Tie Rods now and getting it tracked up, or is there some reason that this doesn't work with the narrow track width of the 850? Do I need to fit the longer track rods? I seem to recall that adding neg camber lower arms requires quite a bit of adjustment on the front?

Looking for the usual wisdom of this fine forum...

Gary

[timmy201]

I fitted all adjustable suspension parts when I had the front drums and narrow track & no issues from that perspective

Minispares adjustable lower arms
Minispares adjustable front tie bars - std rubber bushes
Extended track rod ends
I did black poly lower arm bushes a few weeks later after the rubber ones shredded. They’ve been on 5+ years and still good

[Peter Laidler]

It reads as though you have identiified your own problem Gary. Worn/feathered outside edges of the tyres indicates, without any doubt, excess toe-in. The worn out replacement top-hat bushes are a little bit of a red herring here too.

The heavy steering on the road and lack of positive self centring also point to defective tracking also indicates to me, of poor tracking again. Yep, up in the air, all is well........! It SHOULD be because there's no load/weight to offer any of the usual road and rolling rsistance.

So. New lower arm bushes. A must. Neg camber bottom arms. To achieve what exactly? Adjustable tie rods? As per neg arms in your case. A set of poly bushes. I'd say a good idea if you've got the suspension apart. But as often said on this very forum, they're good, JUST SO LONG AS YOU KEEP AN EYE ON THEM as Tim says.

I'd respectfully suggest checking for looseness/sloppiness, if necessary using a long stout piece of wood as a lever, replacing the bushes and nuts, and then getting the track-in properly re-set. That's next sunny weekend taken up for you.

See other threads about how to DIY as many garages can't cater for 10" wheels. But they CAN check and adjust if you have a couple of slave 12" wheels handy

[timmy201]

Worn outside edges of the tyres also can indicate too much positive camber, and the factory set them up with positive camber front and back

My experience is that my mini drove OK, but had bad outer edge tyre wear. I installed all the adjustable parts and had it set up for road driving and good tyre wear and it felt much better to drive than before, and the tyre wear was more even

Adding caster can help with the self centering on the steering too

The fixed arms that add 1.5 degrees have the benefit of being simpler, but they won’t necessarily get the alignment correct and even on both sides like the adjustable ones

[MiNiKiN]

If you fancy sorting your suspension, consider the folowing:

Fit the said 1.5°neg. camber arms, with minispares bushes C-STR631
Adjustable tie-rods with uprated bushes C-STR627
You should at least also get yourself some adjustable rear neg. camber brackets to compliment the front neg. camer arms.
Don't forget to fit a 3mm plate below the front lower bump stop. This limits negative suspension travel and prevents your lower knuckle joints binding, caused by the increase in swivel angle from the neg. camber arms.

Settings to go for for road use:
Front:
neg. camber whatever you get from the fixed arms
castor: between 3-5° - the more castor the more return to central force you get
toe: 0 to 1/16 " (1.6mm) toe-out
Rear:
0 - 0.5° neg. camber
1/16" toe-in

Above are values and recommendations from own experience as well as reliable sources. These best work with 165 tyres, but surely not completely off with 145 tyres as well.

Whatever track width you have, make sure you have te correct offset on your rims. These sticking aut deep dished rims make for some very unpleasant driving experience, imho.

[gs.davies]

If you fancy sorting your suspension, consider the folowing:

Fit the said 1.5°neg. camber arms, with minispares bushes C-STR631
Adjustable tie-rods with uprated bushes C-STR627
You should at least also get yourself some adjustable rear neg. camber brackets to compliment the front neg. camer arms.
Don't forget to fit a 3mm plate below the front lower bump stop. This limits negative suspension travel and prevents your lower knuckle joints binding, caused by the increase in swivel angle from the neg. camber arms.

Settings to go for for road use:
Front:
neg. camber whatever you get from the fixed arms
castor: between 3-5° - the more castor the more return to central force you get
toe: 0 to 1/16 " (1.6mm) toe-out
Rear:
0 - 0.5° neg. camber
1/16" toe-in

Above are values and recommendations from own experience as well as reliable sources. These best work with 165 tyres, but surely not completely off with 145 tyres as well.

Whatever track width you have, make sure you have te correct offset on your rims. These sticking aut deep dished rims make for some very unpleasant driving experience, imho.

The bushes you've quoted here are the ones I have.

The rims are drum/7 inch Cooper offset, so I think that should work OK.

Are you referring to the little rubber wedge type bump stop that screws on with a single screw? Is there a modified bump stop available?

Do I need to fit the extended length track rod ends?

[MiNiKiN]

The bushes you've quoted here are the ones I have.
The rims are drum/7 inch Cooper offset, so I think that should work OK.

Are you referring to the little rubber wedge type bump stop that screws on with a single screw? Is there a modified bump stop available? Yes and no! You jsut need to make a little steel plate of 3 mm thickness with a tiny dimply for the locating thingy. If you look at the assembly you probably know what to do.

Do I need to fit the extended length track rod ends? I can only refer to what I read. People say you need them because of the neg. camber arms and also some say they are not good because the joint bolt has a different height, which leads to more bump steer. I hope someone else, an 8-legged forum member for example, can shed more light on this.

[Peter Laidler]

At the risk of simplifying things as opposed to complicating what is a simple mechanical problem, can I respectfully suggest that step one is to sort out what you've got - by correctly aligning the wheels - exactly as Tim's attachment kindly points out.

Remember K.I.S.S.

[MiNiKiN]

At the risk of simplifying things as opposed to complicating what is a simple mechanical problem, can I respectfully suggest that step one is to sort out what you've got - by correctly aligning the wheels - exactly as Tim's attachment kindly points out.

Remember K.I.S.S.

I 100% agree with Peter, I just got a bit side tracked after just skimming over Gary's first thread.
Because your car was high as kite when last adjusted it is now way out, as it has settled. So your toe-out may have become a toe-in and only the castor may be somewhere, but surely not where it is meant to be.

Following that you can think about tweaking the suspension

[Spider]

Particularly at standard or raised ride height, you need to take precautions not to break the lower ball joints. Special Tuning supplied the following information, but, they never spelt out why;-



At full suspension drop with standard suspension arms and the steering straight ahead, the lower ball joint pin almost contacts the outer cup. When putting in any steering angle, the pin does contact the cup. Adding in any negative camber makes this situation worse to the point were even in the straight ahead position, the pin makes hard contact and will lead to breaking of the Pin.

This situation exists regardless of ride height, but becomes worse at standard or raised height as when the suspension goes in to full droop, it will do so with some considerable force, even as much as jacking the car up with wheels in the air will do this.

Fitting the 1/8" plates as ST recommend prevent (and limit) the full drop position and so reduce this issue occurring. Going beyond adding -2degrees - that is adding -2, not setting to -2 - may warrant thicker plates.

[1071bob]

Like this, I fixed the plates to the droop limiter with some 3mm c/sunk screws. You have to slot the fixing hole to suit.

[Catmint]

If you fit the 1.5 bottom arms, don't forget about fitting the longer track rod ends. Vizzard has a section on how altering all this affects the car in "how to modify your mini" - The settings minikin gave are a good bet

[timmy201]

At the risk of simplifying things as opposed to complicating what is a simple mechanical problem, can I respectfully suggest that step one is to sort out what you've got - by correctly aligning the wheels - exactly as Tim's attachment kindly points out.

Remember K.I.S.S.

Thing is that you can’t align it as per those specs as it isn’t adjustable. And the factory specs are less suitable for today’s tyres and the intended driving. If you had 1 degree positive on one side and 3 degrees on the other then it’s within the factory spec but it might drive a bit wonky

[Ronnie]

Particularly at standard or raised ride height, you need to take precautions not to break the lower ball joints. Special Tuning supplied the following information, but, they never spelt out why;-



At full suspension drop with standard suspension arms and the steering straight ahead, the lower ball joint pin almost contacts the outer cup. When putting in any steering angle, the pin does contact the cup. Adding in any negative camber makes this situation worse to the point were even in the straight ahead position, the pin makes hard contact and will lead to breaking of the Pin.

This situation exists regardless of ride height, but becomes worse at standard or raised height as when the suspension goes in to full droop, it will do so with some considerable force, even as much as jacking the car up with wheels in the air will do this.

Fitting the 1/8" plates as ST recommend prevent (and limit) the full drop position and so reduce this issue occurring. Going beyond adding -2degrees - that is adding -2, not setting to -2 - may warrant thicker plates.

Interesting to note that the UK ST sheets do not mention the paragraph referring to the rear wheel to front wheel differential that is from page issue 1-8 (that is up to 1275 GT) despite paying good money at the time! Not a patch on the Ford or Vauxhall equivalent

[Exminiman]

…..presumabley the theory was or is that being a front wheen drive car, the front driven wheels need more camber than the back, as back are undriven and less likley to under steer on corners - so, in theory, the car is balanced on cornering….?

[timmy201]

The front wheels will have some camber change with suspension travel and when steering, I assume they’d also have a lot more load on them with the weight of the car and steering duties?

The rear suspension should maintain the same camber throughout the suspension travel?

The numbers above suggested by special tuning are pretty close to what’s still being suggested these days
https://www.med-engineering.co.uk/blogs ... etup-guide

[1071bob]

Forgot to mention, use the Minispares 'Poly option' rebound buffers 2A4267POLY instead of the standard version which are too soft.

[gs.davies]

Thanks all, some absolutely fantastic top-notch advice here.

For simplicity, I think I'll renew the failed lower arm bushes, renew the tie rod bushes with the black/ones from MiniSpares, renew the front tyres and have the tracking reset. I'll save the pain of negative camber and all that entails for another day. Now, to find a local place that can correctly track up 10 inch wheeled cars - a phone call to the local tyre shop revealed that their Hunter jig will only align from the tyre walls, which isn't ideal.

[Peter Laidler]

Mmmmmm....., that's an interesting observation about measuring tracking by using the tyre walls Gary. I can see why you say this, but are tyres so bad that it's unwise? But how can you tell whether the tyres are bowed or bulged slightly relative to the actual wheel?

If the other tyre shops can't cater for 10" wheels, then maybe the hunter jig tyre-wall method TAKEN AT 3 POINTS around the circumference might suffice. Just a thought