A few teams have experienced a problem with the ring nut that holds the
main pinion bearing in place. In these cases the pinion bearing has
experienced enough thrust to force the pinion bearing housing aft, causing
the pinion bearing nut to jump threads. In all of the cases observed by Taylor Race Engineering, the ring nut is still staked in its staking grooves in the
pinion nut body, confirming that the nut did not come loose, but actually jumped
threads. If the nut jumps enough threads, massive damage to the gear
train, shift barrel, forks, dogs, hubs, and rear cover can occur.
As a rearward thrust of the pinion shaft is required to cause the jump, we at TRE believe that the problem has arisen from curb hopping, with a spinning wheel suddenly hitting the track, or a shift-without-lift switch not adjusted properly.
We at TRE strongly recommend that the ring nut be examined prior to each race meeting to verify its integrity. Hewland has advised us that a new nut has become available. This new nut has the washer included with the nut, providing both more threads and more radial strength. Both Star Mazda and Taylor Race Engineering will have these nuts shortly.
Craig Taylor
main pinion bearing in place. In these cases the pinion bearing has
experienced enough thrust to force the pinion bearing housing aft, causing
the pinion bearing nut to jump threads. In all of the cases observed by Taylor Race Engineering, the ring nut is still staked in its staking grooves in the
pinion nut body, confirming that the nut did not come loose, but actually jumped
threads. If the nut jumps enough threads, massive damage to the gear
train, shift barrel, forks, dogs, hubs, and rear cover can occur.
As a rearward thrust of the pinion shaft is required to cause the jump, we at TRE believe that the problem has arisen from curb hopping, with a spinning wheel suddenly hitting the track, or a shift-without-lift switch not adjusted properly.
We at TRE strongly recommend that the ring nut be examined prior to each race meeting to verify its integrity. Hewland has advised us that a new nut has become available. This new nut has the washer included with the nut, providing both more threads and more radial strength. Both Star Mazda and Taylor Race Engineering will have these nuts shortly.
Craig Taylor
