LKF 13 AND LKF 14, THE BRAKING SYSTEMS WITH THE "DOUBLE FACE" PUMP BY LENZOKART

Jacopo Colombo

31 March 2023 • 15 min. read

Intended respectively for the Shifter and Direct Drive classes, they have, both and simultaneously, two solutions for activating the pumping element: by direct traction and by compression, via a lever. Thus allowing kart drivers to pass, with the same system and in just a few steps, more modular or more incisive braking. How? Thanks to an innovative design solution

How many times have you said to yourself: “I can't find the right feeling when braking”. There are several variables to consider in order to solve this problem: the conditions of the track, perhaps too slippery or too rubbery; a too aggressive approach, or on the contrary being too delicate on the brake pedal, or, in relation to Shifter karts, an incorrect distribution of braking between the front and rear axles (but it could be a long list …). All braking systems have different setting modes in order to adjust and refine braking to your liking. However, up to now no system has ever allowed a complete reversal of the operating architecture of the system. Until the present day… Because, with the LKF 13 (Shifter) and LKF 14 (Direct Drive) braking systems, Lenzokart has for the first time marketed devices that have a brake pump with an innovative structure, which combines two types of activation of the pumping element, i.e. for direct traction and compression, via a lever. Two solutions that have a braking method that are quite different from each other. How is it possible? As mentioned, their structure is the fulcrum of everything. In fact, the Italian company has designed a brake master cylinder (single for the system intended for Direct Drive karts and double for the Shifter ones) which can be mounted in two different ways and which allows kart drivers to switch from modulable braking (braking with traction drive) to more aggressive braking (braking with compression drive) in a few quick steps. Both braking systems were CIK-FIA approved in 2022 (to find out how the approval process works in karting, read "Dossier | FIA Approvals: what they are, what they are for, how long they last... the definitive guide!"): LKF 13, with the number 033-B4-13, is the system configuration for Shifter karts (equipped with double brake master cylinder and front brakes); LFK 14, with the number 033-B2-14, is the system for Direct-Drive karts. In this article we find out how they work and what their main characteristics are.

The interactive animation allows you to see the double functioning of the brake master cylinder designed by Lenzokart. In the first part we can see the operation by traction: pumping element and brake pedal are connected directly by a linear tie rod (direct lever) and the braking power is directly proportional to the pressure exerted by the driver on the brake pedal. This setting ensures less powerful but more modulable braking, thus decreasing the risk of locking the tyres. In the second part of the animation, however, you can see the operation of the pumping element by compression. In this case, the brake pedal and pumping element are connected by means of a steel lever which, once activated, pushes the pumping element. In this setting, the lever acts as a multiplier of the force exerted on the pedal, which is why greater braking power and incisiveness are achieved.

Origin and production

The LKF 13 and LKF 14 braking systems are based on the precise aim of Lenzokart to develop a versatile product, capable of combining the benefits of the two types of pump action in a single brake master cylinder. A system capable of allowing all kart drivers to find the ideal braking feeling based on their driving style and the conditions of the circuits they find in their own country. In order to pursue this aim, the Italian company has been able to rely on the completely internal management of most of the manufacturing processes, from design to the final tests, which the products marketed under its brand are subjected to. Specifically, the creation of the new braking systems went through various evolutionary steps (about 15), which took the company about a year. Lenzokart focused on two aspects for their design: the analysis of the data collected through tests on the track, to identify the areas on which to intervene to improve the previously approved braking systems, and the development of 3D models, entrusted to the R&D team of the Racing Department which uses software such as AutoCAD and Solid Edge.
The use of these technologies has allowed the development of various prototypes and ensured simulations concerning deformations and torsions (aimed at checking the structural strength of each part of the braking system). Once the final project had been approved, the various components were manufactured using numerical control machinery, qualitatively evaluated and, finally, tested on the track to check that there were no modifications due to use that were not foreseen in the design phase. After the design and prototyping phase, the company was able to focus on mass production, which always takes place using numerical control machines and ensures each component is treated on the surface in a different way based on its intended use: the most "aesthetic" (such as the structure of the pump or the caliper, which are therefore visible) undergo an anodizing process, which in addition to protection also gives the colour. However, the black pieces are treated with oxidation. At the end of the entire manufacturing process, the products are tested again on a sample basis to assess their quality.

The system components (approved with code 033-B4-13) for Shifter karts: [A] oil pipes; [B] double master cylinder; [C] two front calipers and [D] one rear; [E] two front discs and [F] one rear; [G] the pads of various compounds; [H] the different supports necessary for the installation of discs and calipers.

The system components (approved with code 033-B2-14) for Direct Drive karts: [A] an oil pipe, [B] a pump, [C] a caliper, [D] a disc, [E] tablets of various compounds; [F] the disc holder and the caliper support.

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