Suspension & Braking

The car was a fairly good condition 2 when I bought it, but unfortunate family circumstances immediately after purchasing it meant that within 3 months I had racked up over 5 000 miles back and forth across the country – if nothing this is testament that a classic car can be used every day without drama!  This mileage however meant that things had started to wear out and it was becoming less fun to drive.  A local specialist undertook the following work for me:

• New rear suspension springs

• New front suspension except springs

• New complete rear brake assemblies

• New complete front brake assemblies including EBC pads and discs

The PO had already fitted new front springs and Koni rear ‘tube’ dampers about a year prior to purchase, so these were left on, but everything else was now standard.  The difference in the car before and after was immense.

Therefore this is my first piece of advice; 

when the car needs a complete overhaul like above, or you do not know the history of any components that you suspect are causing you to doubt the ability of the car, replace them all with standard new components before spending your hard-earned on aftermarket systems.  

The sellers of these will always tell you that their product is better than the old system – preying on the fact that you think it's the answer to all your troubles!  Many owners have been stung by this and it always ends in bad feelings - of course any new system would be better than it’s worn-out counter part!  Standard MG parts are typically cheap and plentiful and they worked excellently when new – bear in mind if you do not know when something was last changed on the car it could be the original therefore at least 26 years old now!  The standard B set up is fine and in fact is all some people need or want; but more importantly replacing these components with standard ones gives an excellent baseline with which to compare new improvements.  You should not compare new aftermarket components with worn out standard ones, only with new standard ones.  This careful pre-thought could save you some expensive mistakes (I have made a few!)

The photographs are of me and the BGT in action in 2003!

UPGRADES

Nonetheless, by the end of 2002 the GTK had racked up another 7,000miles on those new standard suspension components, including a track day and a trip to Le Mans.  By now I knew the car very well and knew what I wanted to improve on, having re-found the joy of British A and B roads.  I began researching as much as I could about handling upgrades and learnt to separate the wheat from the chaff.  Below I give you what is in my opinion the definitive list of MGB suspension upgrades and the order in which I think you should try them, given my experiences and the combined experiences of the many people I asked in the process.

Order of fitment;

• Poly-bushes

• Stiffer Anti-Roll Bar

• New Lever Arm Dampers with stiffer valves inserted on the front units.

Optional thereafter;

• Negative camber wishbone arms

• Stiffer front springs

It is important to remember that what you are trying to achieve is a suspension “system” – i.e. all components are matched and work together.  If one part is mismatched it can ruin the set up entirely.  Also the B works best on the theory of “hard front, soft rear” and that is how you should set the car up for best handling; which is what the factory racing teams did, way back when.

Polybushes

Some polyurethane bushes that can be bought for the B are , in my opinion, too hard – if you use hard bushes it transfers more of the loads unnecessarily to the rest of the suspension (springs and dampers) which were designed to use rubber bushes.  This means fundamentally that you may decrease comfort and increase wear.   

I would recommend only Superflex ‘classic blue’ bushes which use a compound that on average is only 10% stiffer than the standard rubber bushes.  What separates these from other makes of bushes is the individual bushes are manufactured to different ‘Shore’ ratings (essentially measuring their stiffness) for each location in an effort to maximise comfort.  Certain bushes such as the wishbone set, also come with stainless steel inserts which help keep their shape under load.  This feature is similar to the rubber bushes that were fitted to the BGT V8 models that are also commonly fitted as an upgrade to an 1800 B/BGT.  Polyurethane bushes offer a further advantage however and that is longevity.  The previous owner had fitted V8 bushes about a year before I bought the car but these were almost perished by the time I fitted the Superflex, not quite two years after the first replacements were fitted.  Since fitting the Superflex bushes, I have had the suspension apart a further two or three times and the Superflex bushes remain as new, even three years on!.

Anti-Roll Bar (ARB)

Once the bushes are replaced you may notice a slightly harsher ride, but with Superflex it should not be too bad – hopefully the suspension will simply feel more taut and more direct.  With the bushes transferring more of the load to the springs and dampers it means that any alterations done to these components will now have better effect, but not being too stiff means that you have not mismatched the components and they still work as intended.

To start improving the cornering ability of the B, a good place to start is the front ARB.  ARB upgrades are cheap, easy to fit and they do not affect the ride quality.  A ¾” or maximum 7/8” bar for fast-road BGTs are a good option; I chose the ¾” which gave better turn-in and a flatter stance through corners with almost no change in ride comfort – an ARB only works when it is being twisted by cornering forces.  For many people this is enough, but I found that the front end still wasn’t direct enough and set about thinking what else I could change…

Front dampers

When the dampers were replaced in 2002 the garage used reconditioned ones.  I have never liked these and replaced them subsequently with new ones – not cheap, but piece of mind is a funny thing!  To these I fitted new valve springs increasing the stiffness of the dampers to around 30%.  The suspension springs were still standard 480lb at this point so ride was relatively unaffected, but in tandem with the stiffer ARB the stiffer dampers really helped make the front end feel much more direct and the composure of the car in a bend to be more steady.  Accuracy of the turn-in was also much improved. 

For most people this may be as far as they need to go, because MGs are already relatively stiffly sprung anyway and they don’t necessarily want to make them any less comfortable.

I ran the car with this set up for many months, but as I got more confident and started to push the car harder, I learnt that in some instances there was still understeer in the system; particularly out of tight corners and hairpin bends, and also off of tight roundabouts, however delicate I was with the throttle but whilst still trying to ‘make progress’.  Ever the fiddler, I had another think and a chat to a few people…

Negative Camber

Without negative camber the full tyre section is flat on the road when the wheels are straight, but when you turn into a corner the weight transfer pivots the top of the tyre outwards lessening the contact patch and decreasing cornering ability.  When negative camber is used, the top of the wheels incline towards the engine block.  In a straight line this effectively means that less of the tyre’s cross section is in contact with the road, and has the same effect of fitting a smaller width tyre at the front of the car; but when cornering, the outward movement of the tyre forces the full-width contact patch of the tyre to touch the tarmac giving you increased cornering grip!   

The reason for fitting the negative camber arms was to try to eliminate the last little bit of understeer from my suspension system.  These arms were supposed to give about 1°-1.5° negative camber, however after the geometry was checked I found I had closer to 3°!  As a rule 1° is recommended for road, 2° for track.  3° is too much.  Fitting smaller width tyres is a tactic used by Lotus on the Elise and MG on the F & TF to give a bias towards understeer.  This was exactly the problem I had caused myself with 3° of camber.  In sweeping, flowing bends I had less front end grip and the steering felt vague and indirect with pronounced understeer – likely because there was less of the tyre contacting the tarmac and effectively acting like I had narrower front tyres on the car (incidentally I have run the GTK with narrower tyres on the front when I first had it and the suspension was otherwise standard, it isn’t something I would recommend).  That said, once the car got over on to that full contact width the difference was quite something; it cornered like it was stuck to the road and never ever let go for any speed I dared to try it at.  Fundamentally though, I had ruined the set-up of the car I had so far achieved for 90% of British roads, it simply couldn’t be driven with enough commitment on a public road to make use of the changes – maybe on a track it would be ok, but then again racers say don’t go more than 2°… 

Eventually I removed the arms and reset the geometry and curiously found I had just over 1° of negative camber with my replacement arms anyway (please note I had lowered springs fitted then, see the Spring section below for explanation)!  So now I can enjoy the benefits of slight negative camber without the hassles of the previous set-up.   In sweeping bends with 1° negative, there is little difference to having 0° camber but in the sort of tight bends we get on UK A & B roads it is much nicer; helping turn in to feel precise and direct and with great feedback and allowing you to really make use of the ‘slow in-fast out’ driving style; getting that cornering force sitting squarely on the outside tyre. 

Springs

Around the same time as replacing the wishbone arms to something a bit more tame,  I fitted 550lb front springs which  were lowered.  Lowering the spring height also gives a slight negative camber, approximately 0.5° per inch.  It is likely that the drop in spring height contributed to my overall geometry reading of just over 1° per side.

The reason I say leave fitting these springs until last however is because they really do affect the ride comfort levels and really are not necessary for most people.  I was in two minds whether to or not, but as I wasn’t entirely happy with the suspension without negative camber, I thought I might as well try them to see what we can achieve.  As a result I am probably 95% happy, but if I could have got around 1° negative camber with standard springs, I probably wouldn’t have fitted the stiffer springs. 

A further thing to note, is that if you fitted a 7/8” front ARB, you might find that the stiffer springs enhance understeer again.  A stiffer front ARB will probably need softer springs or possibly more negative camber to work more efficiently.  This is why I only went to a ¾” ARB.

Summary

So, after all of this fiddling, what have I ended up with?  Well of all the things I have done to the GTK, the suspension is probably that which I am most proud so far (the supercharging experiment is not yet finished). Practically anyone who has ever been in the car has always sung its praises and I have had racing drivers, MG specialists, enthusiasts, etc, all tell me that it is one of the best handling MGBs they have ever been in!  I feel quite chuffed at that!

Really I think it is down solely to putting everything back to standard and then working out from there what exactly needed altering and doing it one step at a time and  evaluating each step before the next. 

The engine upgrades came after I had finished the suspension, because I found that I had really showed up the limitations of the cars’ then bog-standard B series engine.  Its practical top speed on any straight was around 80-85mph and between my normal haunts of Bedfordshire, Chester, Bath and South Wales there are a number of very twisty roads that I drove regularly and which I was able to learn very well.  By the time I had finished with the suspension I found I was able to corner at this top speed on any of those roads.  It never felt dangerous, or uncomfortable; just one corner flowed into the next without having to lift the throttle hardly at all.

It’s hard to describe but the car is extremely sure footed and encouraging.  It can change directions mid-corner with just a mere flick of the wheel and if it does slide (which is rare with 185 section tyres on), it is easily controllable with full feedback given. 

I can remember on many occasions nestled into my bucket seats, late at night with the massive Cibie headlights on main beam, flowing through a set of bends; one after the other, never getting out of shape.  It always felt like there was far more to get out of the set up than the car had power to give!  On several occasions, having dealt with the corners I put my foot down on the straight thinking I’ll stretch it out a bit, only to look down at the dial and find the car won’t actually go any quicker!  This is pretty impressive for a 34 year old car!  I have many tales of little impromptu tussles on these roads with some impressive machinery and parting company with smiles, thumbs ups and even the odd chat at the lights/fuel station etc after a great little duel!  I guess that is what I was aiming for when setting the car up and largely I feel it is achieved. 

There is always room for improvement however and this set up is by no means perfect – particularly when more power is added to the mix!  But you’d have to spend a lot of money on suspension systems like Frontline’s or an Independent Rear Suspension (IRS) conversion to get it better in my opinion and really, unless you start getting beyond 160BHP (which is probably the limit of the gearbox anyway) these systems are probably not required.  

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(Photo from MG Enthusiast April 2006)

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