MGB to MGC: The Front Suspension Transformation

The MGB, a quintessential British sports car, was renowned for its nimble handling and light, responsive feel, largely attributed to its well-engineered coil spring front suspension. However, when the ambitious decision was made to transform this lithe roadster into the more powerful, six-cylinder MGC, its front suspension underwent a profound and, at the time, controversial metamorphosis. This wasn't merely an upgrade; it was a complete re-engineering, driven by the demands of a heavier engine and a new market positioning, leading to a legacy of misunderstanding and, eventually, appreciation.

The MGB's Original Front Suspension: A Benchmark of Agility

Before delving into the MGC's changes, it's crucial to understand the MGB's initial setup. The standard MGB featured a conventional, yet highly effective, independent front suspension system employing coil springs, wishbones, and lever-arm shock absorbers. This design contributed significantly to the car's balanced handling, its direct steering, and its reputation as a lively and enjoyable driver's car. It was designed around a relatively lightweight 1.8-litre four-cylinder engine, allowing for a near-ideal weight distribution and responsive cornering characteristics. The MGB was a sports car in the purest sense, offering an engaging ride that delighted enthusiasts worldwide.

The MGC's Genesis: A Search for Power and a Heavier Heart

The MGC was born out of a desire for a more powerful MG, capable of replacing the beloved Austin-Healey 3000. This ambition led British Motor Corporation (BMC) down a path that would significantly impact the MGB's existing architecture. The chosen powerplant was the substantial 3.0-litre BMC C-Series inline six-cylinder engine. This engine, while smooth and reliable, was considerably heavier than the MGB's four-cylinder unit – tipping the scales at 553 lb compared to the MGB's 390 lb. This significant increase in weight, coupled with the engine's greater physical length, presented immediate and formidable engineering challenges for the MGB's unibody structure.

Interestingly, an alternative engine, the Edward Turner-designed Daimler V8 (2.5-litre), was available within BMC's arsenal. This V8 was lighter than the C-Series six (419 lb) and physically shorter, which would have allowed for better weight distribution and fewer body modifications. Had this V8 been chosen, the MGC's front suspension story might have been entirely different, potentially retaining more of the MGB's original agility. However, for reasons of cost-effectiveness and utilising existing production lines, the decision was made to proceed with the inline six.

The Radical Overhaul: Out with Coils, In with Torsion Bars

To accommodate the larger, heavier six-cylinder engine, the MGB's lithe coil spring front suspension simply wouldn't suffice. It had to be completely re-engineered. The most significant change was the abandonment of the coil spring system in favour of a torsion bar setup. These new torsion bars extended longitudinally from the front suspension, anchoring to points in the floorpan beneath the seats. This innovative design was intended to distribute the suspension forces more effectively towards the centre of the car, coping with the increased load.

Beyond the torsion bars, other critical modifications were implemented:

• Increased Anti-Roll Bar: The front suspension was fitted with a significantly thicker anti-roll bar. This was a direct response to the heightened centre of gravity caused by the heavier engine and aimed to compensate for the additional weight, controlling body roll during cornering.
• Telescopic Shock Absorbers: The MGB's original lever-type shock absorbers were replaced with modern telescopic units, a definite improvement in damping technology for the era.
• Stiffer Ride: The new torsion bar front suspension inherently provided a harder, more firm ride compared to the MGB's softer coil spring setup.

These changes were not merely about accommodating the new engine's physical dimensions but also about managing its considerable weight and the resulting shift in the car's weight distribution. The MGC ended up with a front-to-rear weight distribution of 55.7% front and 44.3% rear, a noticeable shift from the MGB's 52.5% front and 47.5% rear. This front-heavy bias, exacerbated by the momentum of the heavier engine, would become a defining characteristic of the MGC's handling.

The Handling Conundrum: The Infamous Understeer

While the engineering team successfully shoehorned the large engine into the MGB's unibody, the changes to the front suspension had a profound impact on the car's handling dynamics. The increased load on the front outside tyre during cornering, a direct consequence of the new suspension and altered weight distribution, significantly increased the car's propensity to understeer. This meant the car tended to push wide in corners, rather than tucking in like its four-cylinder sibling.

Adding to this challenge were the original tyres. Early MGC models were fitted with 165R-15 Dunlop SP41 radials. These were Dunlop's first attempt at a performance radial and were, frankly, not entirely up to the task of compensating for the car's inherent understeer characteristics. While later models in 1969 received upgraded 165HR-15 radials, the initial impression was already set.

The MGC's rear suspension, by contrast, remained largely unchanged from the MGB, retaining the live axle with half-elliptic leaf springs and lever-type hydraulic shock absorbers. However, a stronger Salisbury rear axle was fitted to reliably cope with the additional engine power and torque.

Braking System Upgrades

With increased power and weight, the MGC also received a necessary upgrade to its braking system. The design team opted for servo-assisted Girling brakes, featuring larger 11-inch discs at the front and 9½-inch drums at the rear. This ensured adequate stopping power for the heavier, faster vehicle.

The Press Reaction and the MGC's Unfair Reputation

When the MGC was unveiled to the motoring press, the reception was largely negative. Journalists lambasted the car for its pronounced understeer and an engine that was perceived as reluctant to rev, a stark contrast to the MGB's lively and neutral handling. Donald Healey himself, who had envisioned an Austin-Healey Mk.IV from the project, was so unimpressed that he refused to associate his name with the car.

Part of this damning criticism, as later discovered by BMC, stemmed from an unfortunate oversight: the test cars provided to the press had their front tyre pressures set as low as 24 psi. This grossly incorrect pressure would have severely accentuated the car's understeer, painting an unfairly poor picture of its capabilities. Modern MGC owners, with the benefit of experience and better tyres, often recommend pressures around 36 psi front and 32 psi rear, which vastly improves handling.

MGB vs. MGC: A Suspension and Weight Comparison

Modern Solutions and the MGC's Redemption as a Grand Tourer

Despite the initial negative press and short production run, the MGC has found its champions among enthusiasts. Its perceived failings were by no means terminal, and with modern understanding and advancements, the car can be transformed into a very capable sports touring car. The key to unlocking its potential largely lies in addressing its suspension and tyre characteristics, precisely what the 1960s technology struggled with.

Contemporary MGC owners often implement several modifications to enhance handling and ride quality:

• Modern Radial Tyres: Replacing the original Dunlop SP41s with high-quality modern radial tyres (such as 185/70HR15 or similar) and ensuring correct pressures (around 36 psi front, 32 psi rear) is the single most effective improvement. This dramatically reduces the understeer and provides far superior grip.
• Upgraded Torsion Bars: Some owners choose to upgrade the front suspension torsion bars to stiffer aftermarket units, further refining the front end's response.
• Polyurethane Bushings: Replacing the old rubber suspension bushings with modern polyurethane alternatives reduces flex and play, leading to more precise handling.
• Rear Anti-Roll Bar: While the MGC's rear suspension was largely untouched, adding a rear anti-roll bar can help balance the car's cornering characteristics, working in harmony with the stiffened front.
• Improved Shock Absorbers: Upgrading to higher-quality modern telescopic shock absorbers, both front and rear, can significantly improve ride comfort and control.
• Panhard Rod or Watts Linkage: For the rear axle, some enthusiasts consider fitting a Panhard Rod or Watts Linkage to better control lateral axle movement, improving stability during spirited driving.

These post-production improvements allow the MGC to truly shine. Its smooth six-cylinder engine, combined with a fully synchromesh four-speed gearbox and optional Laycock de Normanville electric overdrive, makes it an excellent long-distance cruiser. It delivers a refined driving experience, ideal for extended journeys, fulfilling its destiny as a comfortable, stylish grand tourer.

Frequently Asked Questions about the MGC's Front Suspension

Why was the MGB's front suspension changed for the MGC?

The MGB's coil spring front suspension was replaced to accommodate the significantly heavier and physically longer 3.0-litre BMC C-Series inline six-cylinder engine. The new torsion bar system, along with a thicker anti-roll bar and telescopic shocks, was designed to manage the increased weight and higher centre of gravity.

What kind of front suspension did the MGC have?

The MGC featured an independent front suspension with upper and lower wishbones, longitudinal torsion bars, an anti-roll bar, and telescopic shock absorbers.

How did the new suspension affect the MGC's handling?

The heavier engine and redesigned suspension resulted in a more front-heavy weight distribution (55.7% front), which led to a pronounced tendency for understeer, especially with the original, less capable radial tyres and incorrect tyre pressures.

Was the MGC's suspension an improvement over the MGB's?

It was a necessary adaptation, not necessarily an improvement in terms of nimble sports car handling. The MGC's suspension provided a firmer ride and was designed for stability under the increased weight. With modern tyres and subtle upgrades, it can perform very well as a grand tourer.

Can the MGC's handling issues be fixed today?

Absolutely. With modern high-quality radial tyres (correctly inflated), upgraded suspension bushings, potentially stiffer torsion bars, and improved shock absorbers, the MGC's handling can be significantly enhanced, transforming it into a capable and enjoyable car.

In conclusion, the story of the MGC's front suspension is one of necessity and compromise, born from the ambition to create a more powerful MG. While the initial execution, compounded by external factors like tyre technology and press misjudgements, led to a challenging reputation, the underlying engineering was robust. Today, with the benefit of hindsight and modern components, the MGC's unique torsion bar front suspension contributes to its character as a smooth, comfortable, and increasingly appreciated British grand tourer. What happened to the MGB's front suspension for the MGC was a radical departure, but one that ultimately paved the way for a distinctive and rewarding classic car experience.

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