The anti-roll bar is one of the simplest and most effective handling upgrades available to a classic-MG owner. The bar connects the left and right sides of the suspension through a torsion spring, resisting body roll when the car corners and transferring some of the lateral cornering load between the two sides of the axle. The result is reduced understeer, more responsive turn-in, and a flatter cornering attitude that the standard suspension setup cannot match, particularly valuable on the front-heavy six-cylinder MGC where the original specification was already factory-fitted but a stiffer bar substantially reduces the characteristic understeer tendency.
Front Anti Roll Bars & Production History
The MGB went through several front anti-roll bar specifications during production, originally a 9/16-inch bar as an optional extra on roadsters, standardised in late 1966, with the heavier 5/8-inch bar fitted from 1965 on certain applications and standardised across all four-cylinder cars from the 1977 model year, while early rubber-bumper roadsters had the front bar deleted as a cost-reduction measure and reintroduced for the 1977 model year with stiffer bars. The MGC was fitted with a front anti-roll bar as standard from the factory across all cars from the start of production, while the Midget was supplied with 9/16-inch, 5/8-inch and 11/16-inch bars across its production run. Uprated front bars are stocked in 3/4-inch, 7/8-inch, and 1-inch diameters for owners running fast-road and competition specifications, with the 3/4-inch being a heavy-duty Special Tuning item, the most accessible step up from the original roadster specification, the 7/8-inch providing a more significant reduction in body roll, and the 1-inch being the competition-derived option for committed fast-road and circuit use. Kits are typically supplied complete with polyurethane bushes and all fixings.
Rear Anti Roll Bars
The standard car had no rear anti-roll bar through most of production, but a rear bar was fitted as standard equipment on certain later applications, the MGB picking it up from the 1977 model year on rubber-bumper cars using dedicated mounting points on the Salisbury tube axle casing, the bar never fitted to chrome-bumper cars whose standard axle does not carry the mounting points needed for a straightforward fitment. Rear anti-roll-bar service items for the cars that did have it factory-fitted, the bar itself, end joints, urethane and rubber centre bushes, and end-stop locator kit, are stocked for owners maintaining or refreshing the original installation. Rear bar conversion kits are stocked for cars where adding a rear bar is feasible, the kit including the bar, mounting brackets, drop links, and rubber-isolated bushes. A rear bar reduces rear body roll and shifts the handling balance, and the combination of a properly-specified front bar and a rear bar produces a balanced handling package that retains the intuitive driver feel while substantially improving the limits.
Bushings, Drop Links & Trade-Offs
The supporting hardware is as important as the bar itself. Polyurethane bushes covered in the dedicated Polyurethane Bush Kits section replace the original rubber bushes at the bar mounting points, providing more direct connection between the bar and the chassis and eliminating the slack that aged rubber bushes inevitably develop, particularly important on the clamp bushes which must match the bar diameter as the various sizes are not interchangeable. Drop links connect the ends of the bar to the suspension components, typically the lower wishbone at the front and the axle mounting points at the rear, and worn drop-link bushes cause clunking noises over uneven surfaces and reduced bar effectiveness. The trade-off with a larger or stiffer bar is a firmer ride over single-wheel inputs such as potholes or sharp bumps on one side of the car, because the stiffer bar transfers the input to the opposite wheel, and for most road-driven applications the mid-range bar provides the best compromise between handling improvement and ride comfort.
On installations with very large bars, engine clearance can be a concern on some specifications, particularly where wider engines reduce the available space for drop links, so the bar specification should be checked against the specific car. Care should be taken to fit the bar the correct way up, as the bar geometry is directional on most applications.