the last cars to leave the factory with alloy wheels. Roadster The roadster was the first of the MGB range to be produced. The body was a pure two-seater; a small rear seat was a rare option at one point. By making better use of space the MGB was able to offer more passenger and luggage accommodation than the earlier MGA while being shorter overall. The suspension was also softer, giving a smoother ride, and the larger engine gave a slightly higher top speed. The four-speed gearbox was an uprated version of the one used in the MGA with an optional (electrically activated) overdrive transmission. Wheel diameter dropped from 15 to . In late 1967, sufficient changes were introduced for the factory to define a Mark II model for the 1968 model year. Changes included synchromesh on all four gears with revised ratios, an optional Borg-Warner 35 automatic gearbox (except in the US), a new rear axle, and an alternator in place of the dynamo with a change to a negative earth system. To accommodate the new gearboxes there were significant changes to the sheet metal in the floorpan, and a new flat-topped transmission tunnel. To meet US safety regulations for the 1968 model year, the MGB received a plastic and foam rubber covered "safety" dashboard, dubbed the "Abingdon pillow", and dual circuit brakes. Other markets continued with the steel dashboard. Rubery Owen RoStyle wheels were introduced to replace the previous pressed steel versions in 1969 and reclining seats were standardised. 1969 also saw three windscreen wipers instead of two to sweep the required percentage of the glass (US market only), high seat backs with head restraints and side marker lamps. The next year saw a new front grille, recessed, in black aluminium. The more traditional-looking polished grille returned in 1973 with a black "honeycomb" insert. In North America, 1970 saw split rear bumpers with the number-plate in between, 1971-1974 returned to the earlier single-piece full-length style chrome bumper. Further changes in 1972 were to the interior with a new fascia. To meet impact regulations, 1974 US models had the chrome bumper over-riders replaced with oversized rubber ones, nicknamed "Sabrinas" after the British actress Sabrina. In the second half of 1974 the chrome bumpers were replaced altogether. A new, steel-reinforced black rubber bumper at the front incorporated the grille area as well, giving a major restyling to the B's nose,