THE TRICKS (AND CRAFTY MOVES) SEEN AT THE 2025 KZ WORLD CHAMPIONSHIP – PART 2

Giacomo Mantovani

21 December 2025 • 6 min. read

Second episode of the "Must Have" miniseries dedicated to the tricks implemented by professional mechanics during the most important event of the year for the Shifter FIA KZ categories: the FIA Karting World Championship (Missed the first? Here it is: "The tricks (and crafty moves) seen at the 2025 KZ World Championship – Part 1"). Over the weekend at the Franciacorta Karting Track (Italy), we observed, documented, and photographed 15 of the most ingenious tricks that emerged in the paddock: a wealth of information that allowed us to create a series of three articles, each dedicated to a different area of kart management. In this second installment, we collect the solutions adopted to refine the chassis setup and engine thermal management. Some of these can be replicated without any particular investment during your track days, such as the stiffening brackets on the bearing castles; others, however, such as a chain with a reduced pitch compared to the standard 428 for the Shifter categories, are among the measures within the reach of those who have...

Metal stiffening brackets on the bearing castles

what

In the paddock of the 2025 KZ World Championship, we observed an uncommon but very interesting solution applied by the LA Motorsport team to the rear of the kart. This intervention stemmed from the need to more precisely modulate the behavior of the axle in particularly high grip conditions, such as those encountered in Franciacorta during the race weekend. In these situations, the upper portion of the bearing housings can exhibit a slight and normal elastic compliance. This flex is sufficient to "absorb" a small amount of the deformation that would normally be entirely left to the axle. Some drivers and technicians prefer to reduce this elasticity to obtain a rear end that is more responsive to load transfers. To achieve this effect, the team used small metal brackets to selectively stiffen the upper portion of the housing. In practical terms, the brackets are made of steel, approximately 30–35 mm long and approximately 4 mm thick. They feature a transverse fold at mid-length that acts as a small elastic "hinge," designed to control how they react to loads. A total of four brackets are used, installed on the two outer bearing cages: one is attached to the front and one to the rear of the shell on each cage, using the cage's upper screw and the upper hole in the bearing flange. The result is that the cage and bearing flange, once the brackets are installed, behave as a single block, stiffer in the upper area, equivalent to a higher box section. The result is a more responsive kart, more precise in the initial phase of the curve, and more stable in high-speed sections, without altering the flexural characteristics of the chosen axle.