Performance Baulk ring.
The standard sintered baulk (synchro) rings are not tough enough for the demands of performance usage, in many instances lasting only one race before failure or breakage. The main reason is the incompatibility of the material specification with the usage, basically, it is too brittle.
Our current competition baulk ring is cnc part machined then heat treated and then grooved for accuracy and concentricity in a certain grade of metal. This provides an exceptionally strong ring similar to those produced by Leyland in the 60s. Looks the same as standard apart from a corrected area of induction hardening around lugs and the 6 oil slots are rounded rather than square but performs better on moly coated gears such as all original Rover or Minispares evolution gears.
The old bronze type was for non moly coated gears which some gear makers were supplying but is now obsolete. These are also manufactured to sit at the correct height on gears unlike most others now available including genuine which can cause gearbox's locking up on assembly.
A new baulk ring should ideally sit at about 45 thou above gear with 40-60 being the usual range. anything below 30 thou and the gear should be examined for replacement.
Most of the racers using these baulk rings have found they last longer than any other available and because of the exact machining tolerances reduce the amount of sludge usually found in a gearbox as they wear.