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MG MGF Technical - Advanced Suspension Settings
IŽve just ordered the Lowering Knuckle Joints from Mike Satur and iŽll fit them next week so i need the advanced suspension settings since Rover settings arenŽt good enought. From all the tested settings is there any one that might correct the understeer?
|Yes, change the front toe angle.|
As standard it is toe out- change this to either 0 deg or toe in to up to 0 deg 5 min- sould result in the improvement you are seeking.
I assume you'd also suggest the same now I have my S0-2's all round? I was thinking along the lines of getting the tracking set to bottom tolerance on the front and standard on the front? :-s
|>>I was thinking along the lines of getting the tracking set to bottom tolerance on the front and standard on the front? <<|
Erm, if you mean standard at the rear, and the minimum of toe-out at the front, then yes, absolutely.
|>Erm, if you mean standard at the rear, and the minimum of toe-out at the front, then yes, absolutely.|
Yeah, front wheels set as near as possible to the wheels being straight, but within the MG cars recommended settings. The rears just set to middle of the tolerance.
|So...it is just change the toe???|
what about the other suspension values???
You can only change the Tracking, Camber angles are fixed.
|Just thought i'd mention that i have just swapped the toe on the fron wheels, and its the nuts, i would recomend doing it. the garage that did it weren't sure, but when i go back i will let them know what i think. front end tends to want to go where you want to go now, if you know what i mean|
(rear is set to standard, what difference does it make reducing it to 5 min, instead of 10?)
|But you can change the tracking on the rear wheels as well as the front! If you do so you will find that can make a large difference to handling and feel. |
Currently my car is on 10 minutes toe in per wheel on the front (as opposed to Rovers 10 minutes toe out) and the rear wheels are set parallel (as opposed to Rovers 10 minutes toe in). The difference this makes to the handling and feel is night and day, especially on fast cornering, eg over 50 mph (80 kph), where you can actually feel the back helping the front. Do take care making these changes though and change only one thing at a time and evaluate the results carefully over an extended period of time before doing another change. Remember what one person likes may not be what you like.
Also do not forget that the tyres used and the tyre pressures run will also influence handling and feel immensely. All of this chassis setup is of necessity a compromise but part of the fun of MG owning is being able to play around with all of this. Try things out. There is no right or wrong way.
|Just to be a pain, the rover settings for the front are 5min, not 10 min toe out. atleast thats what the print out said.|
I think Rob made some comment a week or so ago about the rear settings, suggesting that going parralell could be risky without polly bushes, whats the reasons for that rob? and have you got polly bushes alan?
|> I think Rob made some comment a week or so ago about the rear settings, suggesting that going >parralell could be risky without polly bushes, whats the reasons for that rob? and have you got polly >bushes alan?|
I think Rob was talking about the tie bar spacers on the back as this helps prevent rear wheel stear under braking and acceleration.
I have I think front toe in 5mins and back parrallel and have the tie bar fitted and the handling is fantastic and so far no uneven tyre wear.
|Matt, Tom is spot on for reasons to avoid non-standard rear toe angles on unmodified cars. Without some kind of modification to the tie bar bush, its compliance is such that you may well get loads of rear wheel steer- very occasionally useful in some situations, but very bad in others.|
Tie bar spacers are cheap to buy (Brown & Gammons) and reasonably striaghtforward to fit. They cut down on the amount of compliance in the bush and cuts rear steer. I suspect, but have no actual evidence to support, that poly bushes will be even better in this respect. There are some pictures showing exactly how much compliance there is in each of these options on my web page in the suspension section (http://go.to/mgfgallery). I was amazed how obvious a difference a small piece of plastic makes.
Having got rear tie bar spacers, I now have parallel on the rear. I am pleased with the result: if you over cook it and slide the tail in the dry (that is going to make me sound like a real loon isn't it), the rear end remains remarkably composed and predictable: SNAP oversteer has gone!
Theoretically, rear toe OUT would be better (for steering responsiveness, agility, turn-in), but I don't think I 'd risk it with out fitting polyurethane rear bushes. I'd prefer to stay out of bushes (the sort with green leaves!!)
will setting the fronts to parallel help improve stability?
My F seems to be getting a bit twitchy, well it is in comparison to the Lancia. Not unstable just a bit twitchy. feels like I should increas from camber!!
|Think there should be a Ask Rob section set up in the BBS|
Rob, can you give more info on fitting the tie bar spacers, cheers
i don't like the idea of theback wheels wiggling around
This is a doddle
the spacers are about a tenner and are basically two big plastic washers
which go between the bush on the tie bar and the large steel washers ...dont worry you'll see the gap where they go
Just be careful about the front end of the tie bar which you will have to disconnect.
make sure that you reassemble the thing properly! a mistake here could be a bit of a bummer
|I have been trying to think of a way to succinctly describe the steering/ handling changes as one alters the toe angle from Rover's OE toe-out, through parallel into toe-in. I haven't enough experience yet, but I have tried examples of all three set-ups extremes so far.|
In my experience, toe-out reduces steering feel, and blunts steering resposiveness, but on centre feel is about as good as it gets.
Toe-out is the other extreme. Techspeed desribes this set up as being 'pointy' and I think that this is an apt description! Turn in is shed loads better, off-centre steering feel magnitudes better, straight-line stability on motorway improved. The only slight downer is on centre steering feel is not as good. I don't understand why that is- can anyone tell me?
Parallel (effectively what I have now)- somewhere in between the above. Turn in isn't as ferocious, but striaght line stability is still very good. Nice compromise.
Like Alan, my preference is for cars that have sharp turn in and good steering feel- so I may be turning to a toe-in at the front- previously I had 5 minutes, so maybe next time I'll try 10 minutes to see how things shake out.
Neil, in answer to your question, given that you are happy that there is nothing else wrong with either the tyres or the suspension, then toe-in will certainly give your car something of a character transformation. Another approach is to cut front end lift... and I have a couple of thoughts as to how one might approach this problem without recourse to a front spoiler... ;o)
Matt, I didn't fit my own tie-bar spacers, but infact they are really simple to do- just as Neil describes in fact! My excuse? I didn't have the necessary torque ratings handy, and the car was due for a service with Mike and the crew anyway!
|Cut front end lift without use of a splitter Rob?|
tell us more...
|Rob is correct in his summation of how I like the feel of my car, but what he and I like may well not be what everyone else wants, or would like. Personally for anyone doing many Motorway miles each year I would think my settings would be much less than ideal. Certainly they are not relaxing. The car demands to be driven positively all the time. And just to answer Matt's question no I do not have the Polyurethane bushes fitted, YET. I do expect to change to them this year.|
But for anyone contemplating these changes please do take care and evaluate thoroughly single changes at a time. If you are used to the driving characteristics of a typical FWD hatchback moving from the standard Rover setup, which to me drives just like a typical FWD hatchback, to the settings I have described is a big difference. So big that the car could bite if you are not careful. It really does become sharp and responsive.
The other area to watch is the people operating these alignment machines. Matt mentioned that his printout said that the setting was 5 minutes toe out. Well on these machines what you see on the printouts is exactly what gets put in because according to my works manual the front settings are 10 minutes per wheel toe out with tolerances from 4 minutes to 16 minutes per wheel. In my case it took me at least 15 minutes patient explanation to the guy handling the Hunter alignment equipment to get him to set what I wanted. All he knew was to select MGF from the list and go with that. At the end my printout shows everything in the green (except for both left side wheels camber, but thats another story) because all wheels got set to what I made him put in the machine. If you just tell them you want something but don't watch what is done the chances are you won't end up with what you wanted.
Also its worth reiterating the essentials here.
1. Always get the ride height set first. If this is wrong nothing else really matters.
2. Make sure your tyres don't have marked uneven wear.
3. Before changing from the standard settings see if changes in tyre pressures can have the effect you want. Doing this costs nothing and may surprise you as to the results. Use the same pressure gauge each time to be consistent.
4. Only change one end at a time. Get the front right first.
I'm sorry this is a bit long but really you shouldn't start changing these settings without having a clear idea of what it is you are trying to do first, and go very carefully. It's taken me 4 years to get my car this way. Use what others have found out by all means but do be sure you are doing it because the likely effect is one that you do want.
|Anybody know which way the toe goes with the + and - signs on the printouts....|
I have one with standard (toe out?) Rover settings which says -5 and another with requested 5 mins toe in which says...............
Anybody know for sure??????
|As it happens I had my four wheel wlignment done today as a MG dealer. I've posted the before and after settings for my car...|
Before/After adjustment & MG Spec:
Before After Spec
Left 0 deg 7 min 0 deg 6 min 0 deg 0 min / -1 deg 0 min
Right -0 deg 59 min -1 deg 2 min -1 deg 0 min / 0 deg 0 min
Before After Spec
Left -0 deg 46 min -0 deg 39 min -0 deg 30 min / -1 deg 30 min
Right -1 deg 48 min -1 deg 46 min -1 deg 30 min / -0 deg 30 min
Before After Spec
Left -0 deg 18 min -0 deg 5 min -0 deg 16 min / -0 deg 4 min
Right -0 deg 19 min -0 deg 4 min -0 deg 4 min / -0 deg 16 min
Before After Spec
Left 0 deg 17 min 0 deg 5 min 0 deg 2 min / 0 deg 17 min
Right 0 deg 12 min 0 deg 6 min 0 deg 17 min / 0 deg 2 min
Well I hope that's clearer than it was to type in! :)
Home of the F'ers Gallery and MG Dealer Guide. :)
|Alan, i'm a bit confused, could there have been a change in the rover standard settings, because i confident that my print out said the standard settings were toe out 5 min, and i'm pretty sure thats what people have aid here before. i made sure he set it to toe in though, he wasn't sure about it but he did it anyway. the print out has, what it was, what it should be and what its set to printed on it.|
and its a marvelous difference, and 1000 miles down the road i managed to cream my front left into a kerb, nice one matt. but it still feels the same so i might have got away with it. next alignemnet when the tyres are replaced.
what do you advice for the next step. rear is still set to 10min toe in, as standard.
|Matt - I think many people have commented that at some points in time Rover have issued alignment changes. What I have quoted is what is in my works manual bought in mid 98 says. Also I have talked with my local mechanic yesterday and he confirms that the current practice is still the toe out at the front and toe in at the rear.|
Regarding the printout remember what I said. The settings ranges shown on the printouts are what is initially input. Whether that input is done manually or called up from a list.
Regarding your setup you say you already have toe in at the front and its marvellous. I am glad you echo the normal findings. I am assuming that you also do have the correct ride height, decent tyres and standard tyre sizes. If so then you need to decide what it is you want to happen. From my experience that setup with the toe in at the rear gives fairly good steering response and feel but still with a lot of understeer, especially at low speeds. If you want still sharper responses and to kill some more understeer try first some judicious adjustment of tyre pressures, front and rear. Personally I think its safe to go anything up to 4 psi under and 8 psi over the recommended pressures. Others may not agree but I have definitely tried these extremes. This may give you what you want for no cost. If not then altering rear alignment is the only thing left from the toe in to parallel or even a smidgeon of toe out. But change them carefully, no more than 5 minutes per wheel at a time.
But do take heed of what I said before. Although my setup is great for country roads it most definitely would not be my choice for any serious amount of Motorway work. It is so responsive that it quickly becomes very tiring to drive in straight lines. In my case that doesn't matter as I avoid Motorways as much as possible and the car to me is a fun machine and a big toy. If I had to use it day in day out for backwards and forwards to work I think I would set it with both front and rear toe in. That way you get most of the responsiveness without the nervousness.
One last thing. Do not underestimate the importance of tyres here. In many ways they are probably the highest technology part of the whole car. Changing from the ubiquitous NCT3's (which are an ok compromise) to something better (however you define better), will make as much or more difference than the setup changes.
Hope this helps. Alan
|Very helpful , thanks alan. As i am changing to SO2s soon, next time the alignment is done i guess its a good idea to leave it as it is. I do want to reduce understeer but the 195s on the front should make a difference from what i've been hearing. So i shall take your advice, and make the changes slowly. |
I unfortunatly do a lot of motorway driving for one reason or another. As it is the car is much more settled on the motorway than it was, so i might well heed your warnings. i do a lot of country lane driving aswell, for no other reason than i want to, amazing how long a short journey can become!
reducing the toe in at the rear from 10 to 5, how do you reckon that will effect the motorway situation?
|Matt - When I did it I found 5 mins rear toe in didn't really change what the car did too much, but it did change the steering feel. Lighter and more direct. With M'way driving I would suspect that it would keep you alert. I should add here that I am not suggesting that the car loses stability or anything so disastrous as that with these rear tracking changes. Quite the contrary actually. But it does become very responsive to any movement of the steering wheel. This is what I mean when I say it isn't relaxing and demands to be driven positively all the time.|
In your case I would say why not try it out. What have you got to lose (except some money of course) provided you do it single step by single step and assess carefully whats happening each time. You never know it might be just what you want. For me right now with my combination of settings, ride height, tyres and tyre pressures I am happy. Just remember though I do not need to use my F each day so what I find great for me as an occasional user may well be totally unacceptable to others.
But if you don't experiment you will never find out.
|My car has 5 mins toe in each side at the front and 4 mins toe out each side at the back (both the reverse of the Rover specs). Steering feel and response are improved, the car does not feel unstable in fast corners, feels more chuckable and predictable to be honest. It also sits rock steady on the motorway, in fact only the other day i commented how relaxing it was to drive on the motorway since i had the new settings.|
By the way, Rover have never issued any revised tracking specs from day one. All non standard specs are just that, though there has been hints from dealers of other settings to reduce front tyre wear.
|I can only re-iterate what Alan's findings with tracking. He started experimenting much before me- and it was his alternative settings that first prompted me to alter the tracking settings on my car. I've been playing catch-up since then! ;o)|
It is interesting to read Alan's findings on how the tracking changes to front and rear ends alter feel. We haven't really discussed all this before, so independantly I can confirm that the changes to feel is exactly how Alan describes.
To restate the advice on changing tracking, then change the front toe-angles first. Personally I would not alter the rear toe angle without first [at least] having the tie bar bush spacers fitted for the reasons we have discussed before.
The ideal for quick turn-in is to have toe-in front and toe-out rear, thus explaining why the Mike Satur set up that Paul describes feels so good.
I hear from the grape vine that Techspeed advise against changing the rear toe-angle beyond parrallel. I presume that this is based on Track experience: a fast track car may not necessarily be the best 'feeling' road car...
How many cars are out there with modified tracking now? It'd be useful for us all to keep some form of database together (our tracking survey idea)...
This thread was discussed between 14/05/2000 and 19/05/2000
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