The MGB uses a live rear axle located by semi-elliptic leaf springs throughout its entire production life, with hydraulic lever arm Armstrong shock absorbers. While this layout remained consistent from 1962 to 1980, there are important differences in spring specifications, leaf counts, and hardware between model years, body styles, and axle types that must be understood before ordering.
Axle Types
The MGB was produced with two distinct rear axle types, and several suspension components differ between them. The banjo axle was fitted to all roadsters from 1962 and continued in use on roadsters until approximately July 1967. The tube axle was introduced on GT models from September 1965 and became standard on all models from around 1967 onwards. U-bolts, spring locating plates, bump stop pedestals, spring fitting kits, and axle check straps all differ between axle types and must be matched correctly.
Spring History
The original roadster springs had six leaves without interleaving, but from car number 11313 in May 1963 interleaving was added and the springs were made slightly softer to lower the rear of the car. The GT model from 1965 was given stiffer seven-leaf springs to offset the car's increased weight at the rear. These specifications remained stable until September 1974, when the start of rubber bumper production brought significant changes to meet US bumper height legislation. The rear spring hangers were lowered, the springs were stiffened, and the roadster adopted the GT-type seven-leaf springs, though the roadster reverted to six-leaf springs in September 1975.
The handling of the early rubber bumper cars was widely criticised, which influenced the belated introduction of a rear anti-roll bar from the 1977 model year in June 1976. Replacement leaf springs are available individually for all four model variants, chrome bumper roadster, chrome bumper GT, rubber bumper roadster, and rubber bumper GT, along with an uprated Special Tuning specification spring that lowers the chrome bumper car by approximately one inch. Springs should always be replaced in pairs, as replacing one alone results in uneven ride height and a handling imbalance.
Spring Kits & Hardware
Complete spring kits supply matched pairs with all associated hardware for a full replacement, and are offered in standard rubber or uprated polyurethane bush specifications across banjo axle chrome bumper roadster, tube axle chrome bumper roadster, chrome bumper GT, rubber bumper roadster, and rubber bumper GT applications. Spring fitting kits provide all the mounting hardware separately for banjo and tube axle cars, again in standard or polyurethane bush options. Front spring eye bushes are available in standard rubber and polyurethane. Rear spring shackle kits supply the shackle with all hardware, with bushes available individually in standard rubber, fast road polyurethane, and race polyurethane specifications.
Spring locating plates, spring pads in rubber and polyurethane, bump rubbers, and bump rubber pedestals are all available for both axle types. The axle check strap, which limits downward axle travel and prevents spring overextension, differs between chrome bumper and rubber bumper cars and should always be checked when renewing springs or suspension hardware. The MGOC Spares range covers all rear suspension components including leaf springs, spring kits, spring fitting kits, shackles, shackle bushes, spring eye bushes, spring pads, U-bolts, bump stops, pedestals, axle check straps, and shock absorber mounting brackets for every MGB configuration across the full production run.