Choose the language.
TKART magazine Under Review | Tony Kart 401 RR Racer, the KZ world champion chassis
Exclusive Content


20 July 2022
CIK-FIA 2022-2023

The 401 RR Racer chassis is certified with homologation number 012-CH-30. The CIK-FIA regulation change provides that the new homologations last indefinitely as long as an annual fee is paid.


The only approval number that distinguishes the 401 RR Racer model includes two different chassis, with their technical peculiarities, their characteristics and their predispositions: one for the single-speed classes and one for the gear classes. we examine the Shifter version in this article.

30 mm

The chassis are generally made with 30 or 32 mm tubes. The Tony Kart 401 RR has a body made entirely with tubes of 30 mm in diameter and 2 mm thick.


There are two schools of thought that distinguish the welding of a chassis: by hand or robotic. The Tony Kart Racer 401 RR chassis is robot welded with a continuous arc technique with a fully automated process.


The standard accessories are in magnesium or ergal according to the type of use of the component: another factor that demonstrates the level of research and development that the Tony Kart chassis is based on. Choosing the right material for the specific component ensures maximum quality, performance and operational reliability.

A debut with a “bang”, at the end of 2021, also for the shifter version of the 401 RR Racer (on sale to the public from 2022), the top-of-the-range chassis of Tony Kart, the flagship brand of the OTK Kart Group manufacturer. In fact, in addition to the victory in the FIA ​​Karting World Championship in the OK class (to learn more about the single-speed model, "Under Examintion - 401 RR Racer, the latest evolution of the Tony Kart OK world champion") the 401 RR Racer also achieved success in the FIA ​​Karting World Championship KZ, the premier class of shifter karts. The common ingredient of these successes was certainly the underlying philosophy behind each product made by the company founded and still managed by Roberto Robazzi: "Designed, Engineered, Manufactured 100% made in OTK". This approach, added to the concepts of automation/standardisation of manufacturing and methods of quality control never seen before in the karting sector, has allowed them to develop, over the years and the various approvals, an increasingly refined and performing product.

Not surprisingly, already in 1997, the OTK Kart Group (well before the launch of the Racer), was the first to introduce, in a profitable and extensive way in karting, the robotic welding process for production. The use of highly automated state-of-the-art machinery is then flanked by a department dedicated to quality control and a state-of-the-art research and development centre to ensure maximum reliability and products that are always at the forefront for all kinds of customers.
alt alt
alt alt
alt alt
The collaboration between the Tony Kart Racing Team (Tony Kart's official racing department) and the OTK Kart Group R&D department has a double fundamental role: on the one hand it guides the design of new components and the refinement of those already being used, ensuring greater performance and constancy of operation, but not only, because it also affects the choice of the right materials based on the type of component use. For example, despite one of the historical characteristics of Tony Kart chassis is that of having accessories only made of magnesium. The company has recently chosen to switch to high quality forged aluminium for the production of some components, such as the pedal set and bearing housing shells. The reasons are, on the one hand, the environmental impact generated by some stages of magnesium production/treatment and, on the other, the excessive wear of specific components, such as the axle bearing flanges. The difference between magnesium and ergal is important: the former has certain physical qualities, such as a low specific weight and a higher thermal conductivity, which make it ideal for the production of those accessories that require good heat dissipation (disc housing, gear wheel housing, wheels and wheel hubs), while the second has better mechanical characteristics including greater resistance and less wear. Therefore it is preferable to make parts subjected to considerable mechanical stress. The new Tony Kart 401 RR Racer, approved for both direct-drive and shifter classes (the version discussed in this article), is a direct evolution of the Racer 401 R (model launched in 2019 which you can read about in the Dedicated “Under review" article. OTK technicians were faced with the difficult task of perfecting a chassis that overall had proved to be complete and, above all, a winner.
Continue reading the article by subscribing for only 0.96 € / week
Explore these and many other
premium contents
Go to Magazine