All of our EVO 8 and 9 5-speed rebuilds include updated bronze synchronizer rings. The factory original rings were brass and though these rings were very well designed, the brass is too soft and wears too quickly in your EVO trans causing grinding into the gear and damage.
The triple synchro 1-2 gears and double synchro 3rd don’t allow for much wear, so these gears were problematic over the years as only the slightest amount of wear caused issues with grinding. 4th and 5th are just a single synchro unit and one missed shift could burn them up in a hurry causing grinding as well. We now include all bronze synchro rings in all of our EVO rebuilds.
Bronze consists of mainly copper and tin and brass consists of mainly copper and zinc. Bronze is much harder than brass which allows for the rings to last a lot longer and take a lot more abuse. Shifting hard into 2nd and 3rd gear? No longer a problem as the rings will no longer wear as quickly. Miss a shift into 4th or 5th? No big deal with the bronze rings as they can now take the abuse. In the pictures below are comparisons between the two types of rings. Brass is yellow in color and the bronze has more of a goldish look to it. In the first pic the rings on the bottom are brass and the rings on top are bronze. In the 2nd pic, the close-up shot shows a little more of the color change (bronze on left side, brass on right).
If your EVO tranny always seems to have issues with wearing out synchros, feel confident that our bronze synchro rings will take the abuse and no longer give you the short synchro life that many owners seem to experience.