I read Tony Hart's article, "The Founder Member's Point Of View" with great interest. Before you read my response, you may like to read it again. Whilst most of his article makes a lot of sense, naturally I do not concur with everything he writes.

BRAKES
The Stag's brakes may have been adequate for the 70's, but on today's roads more powerful brakes with no fade and less pedal pressure must be desirable and even essential for those of you with enhanced performance. Tony says that "when they design any car a great deal of R&D goes into providing systems that are more than adequate for the job in hand." True, a great deal of R&D should go into providing systems that should be more than adequate for the job in hand....but in the case of the Stag?...I have my doubts about this. I think it is likely that to save money, Triumph used some parts from other (sometimes obsolete) models that they had in stock in order to come in with a price well under the Mercedes SL sports car which was the market Triumph were after. It is accepted by most people that the demise of the Stag was as a result of inadequate development. Some of the things Triumph did and did not do beggar belief. One small example, the use of UNF (fine) threads in aluminium instead of UNC. This causes so much inconvenience with stripped threads, especially on the rear hub fixing studs on the trailing arms and diff cover plate which pull out even if the very low torque figure is adhered to. And how Triumph could supply the car with drive shafts which have to be thrown away as they cannot have new U/J bearings fitted? I guess they reconsidered this as they put it right on the MK2. Was it to save money? Surely it would have cost only a couple of pence more to have studs made with a different thread each end and recess machined into the drive shaft yokes so that circlips could be fitted. Or was it that they had bins full of surplus incorrect parts and didn't care if they were not fit for the purpose so long as they were cheap enough? There are countless other examples...no drain plug on the diff etc etc... more on this later. Back to brakes...
Tony's racing Stag is 1000lbs lighter than the standard car which weighs in at approx 3000lbs kerb weight (including petrol, extras etc). This means that his brakes have much less work to do and he in effect with his standard brakes (except for the racing pads) has a 30% uprate which is the only reason he can get away with the standard set-up. Even so, with solid discs I am surprised that he doesn't suffer fade while racing, even with cooling ducts. For those of us with standard weight cars it is a different story. Front/rear brake balance also is most important and can be adjusted to suit weight distribution which is affected by engine weight. On the Monarch Stag, because of the all-aluminium Rover engine saving 100lbs weight and the battery being relocated into the hood recess behind the rear seat, this is 53/47 which is much closer to the 50/50 ideal and a huge improvement over Stag-engined cars with cast iron engines and the battery overhanging the right front wheel.
Only a fool would leave the front of the car sticking up in the air like Concorde taking-off at Heathrow after fitting a Rover engine. Shorter tailor-made progressive-rate springs take care of the lighter engine on the front so that the correct height and body rake can easily and cheaply be set. I can also supply adjustable-height struts, not so much for setting corner weights (although if you can improve this as I have on the Monarch Stag it makes a huge difference to grip) but more for setting the correct height due to chassis tolerances differing from car to car. By the way, since the Stag has the battery, driver and petrol tank all on the right-hand side of the car, there is NO chance of getting corner weights equal without moving the battery and petrol tank as I was forced to on the Monarch Stag. (What makes you think the Stag was made for the American market? It annoys me that home market customers counted for nothing in the 60's and 70's, although I guess it was export or die in those days).
It is a matter of opinion whether the rear brakes should lock up first. As this is more likely to precipitate a spin, I think it is not a good idea. In fact, my performance car tyre specialist (not a Quick-Fit establishment) recommends that when fitting only 2 new tyres these should go on the back wheels to give more grip and reduce the likelihood of the rear wheels locking first. Incidentally this is also the view of the Police. If deemed necessary, the power of the rear discs on my kits can easily and cheaply be adjusted by fitting my pressure proportioning valve in the circuit when the rear kit is installed. It is important to have the balance right on the Stag, which, with its heavy cast-iron Stag engine, is prone to be tail happy anyway.

SUSPENSION
Further to my statement earlier about bits being used from the parts bins of older models, take the front hub bearings and spindles for example. Unless I am mistaken, I believe I have seen front hubs and spindles identical to the Stag's on a Standard Vanguard Phase 3. I'm sure somebody will correct me if I am wrong, but I would bet my bottom dollar that they are the same. These may have been OK for the Vanguard in the 50's with drum brakes, but not for a modern high performance touring car with four times the performance and disc brakes. What I think happens is that the hub spindle bends under load causing the hub, and hence disc, to move out of true and knock the pads back. If you have ever driven fast enough through an S-bend you must have noticed a long brake pedal the next time you use the brakes. Also that very small outer wheel bearing doesn't help matters either. Most Stags suffer from this bearing working loose on the spindle due to the load on it being excessive as there is too little surface area in contact with the spindle.... "More than adequate for the job in hand"...?...Hmmm! I don't think so. Here's a tip. Assemble the inner race on the spindle with LOCTITE STUD'N BEARING FIT. Marvelous stuff. Only snag is they are harder to get off! However, for those of you who are serious about improving your Stag's handling and do not believe that two wrongs make a right, I can supply you with aluminium hubs (reduce unsprung weight) and bigger spindles made from EN24T high tensile steel that take a larger outer bearing (the same bearing as the inner one), all of which helps to reduce bending under load. This is the same steel as is used to make high-performance crankshafts (See price list).

LOW-PROFILE TYRES
Yes, wheels and tyres are an extremely important part of the set-up. I agree with Tony that the camber change of the Stag's rear suspension is a problem when considering "Inching up" to 15" wheels with wider rims. Slightly lower profile tyres can be fitted to the standard suspension, say 185/65 (621mm o/d) or even 195/60 (615mm o/d, which is the same as the standard car). These wheels and tyres are certainly a temptation as they look great and I believe the Stag's rear suspension can tolerate them. They increase the contact patch area and therefore offer a huge improvement in grip under braking without altering the rolling radius and hence gearing. I am not a fan of tyres that look like balloons on the Stag as they date it so. They have a place on 4 wheel drive vehicles, not on high performance touring cars! If your car suffers from the extreme wheel movement and hence camber change on the road then maybe some modifications to your suspension should be considered. I can help here. On the road there is normally very little suspension movement and the advantage that such tyres give in improved braking and appearance in my opinion far outway any disadvantage. As in most things, there are pros as well as cons. Originally I had very good results by lowering the suspension on the Monarch Stag (and hence c of g which in turn reduces roll), fitting 15" wheels and 205/55 tyres using standard suspension. Of course this was using adjustable camber inner trailing arm brackets to keep the camber correct when lowering the car, Koni Classic shocks, progressive-rate springs, adjustable Track Control Arms and up-rated front anti-roll bar to keep roll under control. (All available from Monarch). The standard Stag McPherson struts are ideally suited to the use of lower profile tyres. But for optimum grip the Stag's rear semi-trailing arms need to be modified to trailing arms (thus reducing unwanted excessive camber change as the wheel goes up and down) by fitting my new BMW rear suspension transplant which would enable you to fit 15" or 16" wheels and sticky wider Bridgestone Protenza 50 section tyres. A truly amazing increase in grip and traction for more powerful engines can be achieved by this modification.

ROVER ENGINE CONVERSIONS
The complete opposite to what Tony wrote about the lower weight of the Rover engine is true!!! Tony's words should be corrected as follows: "The biggest advantage of a Rover conversion is that it's 100 lbs lighter than the Stag lump. (Appropriate term for it? Well, let's be honest, it is pretty heavy, isn't it? But at least the heads are aluminium). With the lighter all-aluminium Rover engine the weight distribution is better and brake bias, car height etc. can all be dealt with as already described. Car designers strive endlessly to reduce vehicle weight to improve performance, handling and economy, which is why even diesels are now being made out of aluminium. Like all modern engines, the all-aluminium Rover V8 is heaven sent to reduce unwanted performance-inhibiting weight.
I agree that there were some pretty dishonourable cowboys who did a disgraceful job in the past of putting Rover engines into Stags, but that's water under the bridge now. There are some really outstanding examples of installations that are better than the Triumph factory would have done, of which may I be conceited enough to say that the Monarch Stag is one. We have had over 30 years of technology advance in cars since the Stag designed, so lets benefit from this wealth of knowledge to increase the enjoyment to be gained from driving our Stags by transforming the performance, handling and economy.

I would also rewrite Tony's last paragraph as follows:
"To summarise regarding engine conversions, a 'Triumph' Stag can be vastly improved by using a 'Rover' engine." (Same manufacturer now in fact). Whilst the Stag engine is undoubtedly a superb engine and with its twin O/H cams is in many respects far more advanced than the Rover (apart from its weight) it nevertheless is not as robust as the Rover and cannot produce anything like the same power output reliably. The weight factor is a serious disadvantage. Triumph did indeed contemplate using the Rover engine and built a prototype Stag with one in but scrapped the idea for political reasons.

In my opinion our modern-day conversions which encompass appropriate re-engineering to compensate for less engine weight and altered weight distribution most definitely enhance the original safety margins designed in by Triumph engineers thirty years ago.

Pitch, Wallow and Twitch may sound like a firm of comic lawyers in a Christmas pantomime, but to owners of Triumph Stags and their similarly suspended brethren, they are three gremlins that have afflicted the handling of these cars since the day they were built.
Twenty five years ago, contemporary car design, road conditions and driver expectations were such that these short comings were not the bugbear that they are today.
Even ten years ago when I first got my hands on a Stag, I was prepared to accept that they were all part of the charm (or challenge) of driving a Classic Car, so I concentrated on enjoying its other attributes for the next five or six years. Eventually however, the gulf between the Stag's handling and that of the 90's cars on today's busy roads meant that just to keep pace on anything less than a motorway was 'bloody hard work'. I therefore decided that some serious improvements were needed if me and the Triumph Stag were not to go in different directions (literally).
Having an engineering background and a lifelong interest in cars and their technical development, I decided to investigate, identify, and modify the Stag suspension to provide safe and predictable handling, with no loss of comfort, at an affordable price.

My investigations began with a series of controlled (?) manoeuvres, (mainly slaloms) on private roads and car parks, backed up by static deflection tests and finally simulations on a home made 1/18th scale model of the rear suspension assembly. I clearly identified the three distinct characteristics and their likely causes, and then studied the rear suspensions of relevant modern cars in manuals and local breakers yards to see how their designers addressed the problems.

The pitch is predominantly in the diagonal mode (i.e.. corner to corner), and is mainly due to the trail angle of the rear subframes and trailing arms interacting with the strut type front suspension. Modern cars have a much reduced trail angle on the subframes and are invariably fitted with an anti-roll bar as standard.

The wallow is mainly caused by the inability of the standard shock absorbers to control and damp-out the combined effects of the primary and secondary spring modes ( i.e.. the coil springs and the tyres). More effective shock absorbers, correctly matched to the coil spring rates and lower profile tyres give today's cars their poised handling.

The twitch happens when one of the rear wheels suddenly changes track (normally 1/32" toe-in), usually just as you change gear coming out of a corner. This is caused by friction in the splined drive shaft temporarily holding the out of track wheel in this state until the load is reduced by de-clutching and changing gear, whereupon it promptly tries to re-align itself.
The track variation of one, or sometimes both wheels is due to the sideways deflection (during cornering) of the relatively long trailing arms being restrained only by their closely spaced pivot lugs and soft rubber bushes. Much wider spacing of the pivot lugs to reduce this sideways deflection is favoured by today's suspension designers, together with cleverly angled mounting points and bushes to give a measure of automatic track correction under load (i.e.. passive rear wheel steering).
A further refinement found on more sophisticated high performance cars is the use of dedicated track control arms or links to give precise and predictable behaviour under all conditions.

Armed with all of this knowledge, I began to apply it systematically to the Stag as follows:

1) The pitch was easily tamed by fitting a readily available and proven anti-roll bar to the rear suspension, once I had figured out where and how to mount it.
There was no obvious or easily accessible chassis strong point to fix the bar to, so I opted to clamp it directly to the trailing arms in a position that gave the effect of a 'twist beam axle' (as used on the rear suspension of many front wheel drive cars). I did however contrive to leave enough compliance to retain the benefits of the independent suspension over small bumps and ridges.

2) The wallow was also easily taken care of by fitting new good quality shock absorbers all round, (adjustable on rear), combined with wider but lower profile tyres ( nothing drastic, just 195 X 65 on std. alloy wheels).

3) The twitch proved the most difficult to eradicate completely, although the two previous stages of improvement had reduced it noticeably under most driving conditions.
Determined to make the Stag handling completely vice-free I then carried out a series of trials with variously positioned tubes and links until I hit upon a simple but effective design of 'track control rods' that gave me just what I was looking for. As a bonus the Stag has also gained a new found precision in straight-line driving (even on bumpy 'B'roads), combined with improved steering response and turn-in on bends, together with the ability to hold a good line through the curves without 'sawing' at the steering wheel.

Well, thats my contribution to the Stag handling saga and the proof is demonstrable by arrangement to anyone who is seriously interested in comparisons with their own modifications and ideas. Maybe someone could even advise me as to the viability of making my modifications generally available, as I can only produce the occasional set for local club members.

Suspension can be tuned for ultimate performance or ultimate comfort. Somewhere between those two extremes lies a compromise that can tailor the car's handling so that it fits your style like a made-to-measure suit. As Eddie Evans explains, the key is in knowing where to modify and to what extent.

Essentially, handling improvements are about cornering ability and straight-line stability and these characteristics show themselves through the steering. We also steer partly with the accelerator - putting power down to nose the car into bends - so it follows that the engine's state of tune and responsiveness will also have an apparent effect on handling.

Before deciding how the car should handle and which defects to eliminate, we must have a true picture of the car's standard handling characteristics and this can only be seen if the suspension is in reasonable condition. Front and rear suspension checks have been covered in previous issues of Triumph World but as a minimum, brakes and dampers need to be serviceable for a true appraisal.

It is important to understand which suspension components produce which effects and what the likely outcome will be if they are modified, remembering of course, that modifying one aspect will affect the performance of the other components in the system. So we need to consider the whole of the front and rear suspension together when implementing changes.

STEERING
Most suspension changes will affect the steering characteristics by either promoting understeer (running wide on bends) or oversteer (where the car turns tighter than you expect). So modifications can, for example, reduce the understeer caused by the GT6's heavy engine, or the oversteer experienced when backing-off the throttle on an early Spitfire in a tight bend.

The chassis is designed with inherent, slight understeer for safety reasons and this should be retained, though the amount can be adjusted to preference; remembering that good throttle usage will also counter understeer.

Steering modifications will not affect these characteristics, but a high-geared competition-designed 'quick-rack' will increase responsiveness.

GEOMETRY
Front and rear wheel alignment, or toe-in, must be kept within tolerances. Aim for zero toe-in at the rear, but a rear-wheel drive car must have slight toe-in at the front to help stability.

Castor angle and king pin inclination are steering features and, in general, neither need to be modified unless ultra-wide wheels are being fitted for track work. Our particular interest is camber angle - the amount by which the wheels lean in or out at the top. A positive camber leans out at the top, negative angle leans in.

NEGATIVE CAMBER
Negative camber is desirable so that as the car leans into a corner, the outside wheels, which take most of the weight, transmit their load directly through the tyres to the road rather than trying to drag the tyres sideways. On the minus side, when travelling straight ahead, some stability and braking efficiency may be sacrificed because the tyres will not be quite square to the road surface. For this reason most vehicles are set up with slight positive camber which, by way of suspension geometry, varies into negative camber as the wheel moves up under cornering load.

This tendency towards negative camber can be increased at the front by fitting extra shims between the bottom wishbone brackets and the chassis - or on cars with MacPherson struts, by inserting shims at the bottom of the strut. Increased negative camber at the front can produce oversteer, so although the car may corner better, it won't necessarily feel as if it does. A similar camber angle at the rear will tend towards understeer, somewhat neutralising the combined effect.

Rear camber variation is a well known problem on Herald derivatives, though the Rotoflex and pivoting spring systems fitted respectively to the Vitesse, GT6 and Spitfire cope admirably. Earlier models can easily be converted to a Spitfire swing-spring, though the spring will be rather weak if carrying four people in the Herald or Vitesse. Alternatively a conventional, but de-cambered, rear spring can be fitted.

LOWERING AND STIFFENING
Lowering the centre of gravity of a car reduces body roll, so there is less lift on the inside wheels when cornering. Adhesion is improved, making the car feel tighter and giving the driver a more accurate impression of what is happening at the vital interface between rubber and tarmac. Lowering invariably means shortening the springs. This stiffens the spring rate but also reduces the suspension travel and hence the amount of camber angle variation during cornering. For this reason, lowering may need to be balanced with camber modifications as described above.

Fitting short springs which retain the standard spring rate goes someway to help. Stiffer springs of standard length will also give a reduction in body roll, but any stiffening will reduce comfort. Another point to consider here is that the shorter suspension travel will reduce the wheels ability to follow undulations in the road surface, with a potential loss of tyre adhesion.

Lowering the front end will further increase understeer, but this time its a tyre problem. The energy that would otherwise make the car's body roll has to go somewhere and the tyres take the full rap. In extreme situations they will slip, allowing the front to run wide on bends. this calls for wider tyres (and preferably lower profile ones so that the sidewalls don't deflect as much) keeping the tread flat on the road. Alternatively, the increase in understeer can be countered by stiffening the rear suspension.

The transverse leaf spring cars can be lowered approximately half an inch (12mm) at the rear by fitting a de-cambered spring, otherwise a one inch (25mm) thick spacer block - machined for an exact fit - can be installed between the spring and the differential and this will produce a half degree of negative camber.

ANTI-ROLL BARS
For normal road use, adding a front anti-roll bar (or a stiffer one if already fitted), will produce a similar effect to the shortened, stiffened springs. It increases stability by reducing cornering body-roll and especially the rebound roll experienced when driving rapidly through a succession of bends. Even better, the anti-roll bar only comes into play when you need it - when cornering - leaving straight line performance and comfort uncompromised.

Stiffness of the anti-roll bar has to be chosen carefully because it will effectively increase the overall spring rate and also tends to induce understeer. But this can be countered by fitting another anti-roll bar, or harder springs, to the rear axle to give an opposing oversteer. This front/rear balance can be fine tuned by changing the anti-roll bar link bushes for harder or softer material to increase or decrease their effects.

Generally, it is advisable to install a rear anti-roll bar if the front one has been upgraded and/or the spring rate or height altered. A rear bar will produce a very marked improvement on the Vitesse, GT6 and Spitfire.

DAMPERS
Adjustable dampers provide a quick and easy way to tune the suspension. Dampers only control the spring's rebound movement and not its initial movement when going over a bump or leaning into a bend, so ride quality need not be reduced for the sake of improved control.

Damping rates can also be adjusted to counter the effects of understeer and oversteer in the same way as spring rates, but an excessively high setting can overload the suspension and restrict its movement.

Uprated non-adjustable dampers should always be bought with matching springs.

BUSHES
Harder bushes reduce unwanted suspension movement during braking, acceleration and cornering, giving a tight feel and accurate feed-back to the driver. But the harder they are, the more road noise and shock they will transmit. Again the compromise is a personal choice.

Bushes are a particular problem on the rear suspension of the TR7 and Toledo/Dolomite range. Even new bushes can allow sudden, transverse movement of the rear-axle under hard cornering, so it is imperative to fit harder bushings to the rear radius arms.

Hard bushes will also help to eliminate rear axle torque-twist, which is prominent on Stags when changing gear under hard acceleration. This problem also occurs on the swing axle TRs and the 2000/2500 saloons and can also be reduced by fitting modified axle shafts such as those offered by Chris Witor, Monarch and others.

WHEELS AND TYRES
The large camber changes and castor characteristics of Triumph suspension systems were never designed to keep a wide, non-flexing tyre in contact with the road, so extensive modification is needed before fitting anything in excess of a 6J wheel width, and then, only for the race track.

Tyre pressures offer the last tweak in honing the handling. A lower pressure in the front tyres will give a slight increase in understeer, while in the rears it will promote oversteer - and vice versa. But keep tyre pressures within manufacturers limits.

STATE OF THE ART
Much of the Triumph's character is to be found in the way it handles. And whilst some serious modifications will change the car's personality, the elimination of vices can make driving more enjoyable - and even safer! The shortcomings have not gone unnoticed by the specialist suppliers who have put much effort into designing and testing new systems, components and modifications. The result is that all the parts are now available to make your Triumph handle exactly as you feel it should.


Article featured in August/September 1998 Triumph World magazine

In answer to the questions raised by Chris Spain and Matthew Taylor in recent issues of the Stag magazine concerning the Stag steering and handling problems, I can advise you as follows:

There is nothing basically wrong with the power steering system even though there is a bit of a dead band in the straight ahead position. It was typically light and unprogressive as was the fashion in luxury cars of the 1960/70 era, equipped with solid rear axle assemblies, which gave good track alignment at the expense of poor traction on anything but the best of roads.

The problem lies in the uncontrolled and contradictory steering inputs from the poorly located trailing arms of the rear suspension fitted to the Stag and it's predecessor, the Triumph 2000. As the suspension tries to cope with varying road conditions on the move, such as bumps, dips, cambers and side loads, each wheel independently deviates from the theoretically correct and stable toe-in setting that it has in a static condition. This subsequently degrades the natural self-centring and aligning effect of the strongly castored front suspension and is not easily countered by the feel-less steering. The uncontrolled variations of tracking from toe-in, through neutral, to toe-out under hard cornering, also produces the familiar understeer to oversteer switch and accentuates the spline lock/unlock twitch effect.

The solution to the problem is to introduce better track control to the basically correct suspension geometry, and there are to my knowledge only two effective ways to do it.
1) Replace all the suspension bushes with the stiffest, most unforgiving type you can find, a la competition cars. Okay if you can stand the noise, vibration and harshness - I couldn't!
2) Keep the standard rubber bushes and their refinement and add specially designed control links ('Traktoe Bars' I call them) to maintain consistent rear wheel tracking and alignment and 'hey presto' you have 'hands-off' straight-line steering and predictable handling - I like it!

I have developed and used such a system on my car for many years after studying the suspension designs of most modern rear wheel drive vehicles and I can fine-tune it to suit individual tastes by small adjustments to the basic settings.

A similar system based on my design was illustrated on page 16 of the August (2002) Stag magazine and was displayed at the SOC National Weekend.

I hope the foregoing helps clarify matters and look forward to seeing responses especially from any other experienced engineers.

I have also developed a simple add-on anti-roll bar system to further enhance the above improvements and reduce the bouncy nodding dog and diagonal pitching traits of this type of suspension.