RPM Oversized Front Axle Carriers for the Traxxas X-Maxx were designed to solve two key issues reported by owners of these massive beasts. The first issue being durability. RPM designed these carriers to handle some serious abuse. RPM Oversized Axle Carriers are BEEFY with massive support ribs for the strongest possible carriers available.The other area of improvement comes in the form of larger inner bearings. How large? MASSIVE! The stock inner bearings are a mere 20x27x4mm. The oversized bearings used are gigantic 20x32x7mm bearings! That's 5mm larger on the diameter and 3mm on the width! The difference equates to a dynamic load rating that is nearly 300% higher than the stock bearings while the static load rating is over 300% higher! That's triple the strength of the stock inner bearings.If you've ever blown a stock inner bearing or broken a stock front axle carrier, you need to check these out! Tech Notes: RPM Oversized Front Axle Carriers replace stock Traxxas #7737. Each package is sold as a pair (one left and one right) and includes two inner oversized bearings (one for each side). Outer bearings are stock Traxxas bearings (#5106 or #5106A) and are not included in this kit.