When designing a full traction differential replacement for the TRX-4 we wanted to make something indestructible, simple and cost effective. We also wanted a reasonable weight that still uses 3 bearings and of course offering a very tight fit to your axle shafts to eliminate slop. Lastly, we wanted "In Phase" outputs which can help to minimize drive train harmonics in CVD applications.

Keeping in mind all of those things we have come up with our latest creation ... the "FI Spool - TRX4".

This hardened steel axle spool is great for and TRX-4 that needs 100% traction, 100% of the time. These 1.34 oz spools are sure to get you through the toughest trails and have stood up to our worst abuse. They are "F*****g Indestructible ... hence "FI".

Each spool includes a silicone plug so you can completely remove your shift cable (and servo).

Thanks for reading!