Michelin TRX

Michelin TRX
Company type	Product line
Industry	Automotive
Founded	1975
Founder	Michelin Group
Area served	Worldwide (notably Europe and North America)
Products	Radial tires (TRX and TDX variants)
Parent	Michelin Group

The Michelin TRX (along with its variant, the TDX) is a radial tire introduced by the Michelin Group in 1975. Recognized as one of the earliest widely produced low-profile tires, it featured advanced technology and achieved moderate market success. Nevertheless, its dependence on a unique rim design hindered widespread adoption, leading to its reputation as the "Betamax of the tire industry."

Background and development

During the 1970s, as passenger vehicles gained enhanced performance capabilities, there was an increasing demand for tires that offered superior handling. Reducing sidewall height was a potential method to improve road grip, but conventional rim profiles often sacrificed ride comfort.

Michelin addressed this challenge by engineering the tire and rim as a unified system.^[1] This innovation enabled lower sidewalls for enhanced handling while preserving comfort through optimized stress distribution facilitated by the redesigned wheel rim and tire bead.

The designation "TRX" originates from "tension répartie," highlighting even tire stress distribution; the "X" alludes to Michelin’s earlier radial tire models.

TRX tires necessitate custom-designed wheels since they are incompatible with conventional rims and tires. To avoid mix-ups, Michelin adopted metric sizing for TRX wheels rather than standard inch-based measurements.

Usage

Various European car manufacturers such as BMW, Audi, Mercedes-Benz, Citroën, Peugeot, Ford, Ferrari, Alfa Romeo, Renault, and SAAB offered TRX tires either as standard or optional equipment. In North America during the 1980s, select models including the Ford Mustang, Ford Thunderbird, Mercury Capri, Mercury Cougar, and Mercury Lynx were fitted with these tires.

While Michelin was the primary producer of TRX tires, certain sizes were also manufactured by Avon, Continental, Goodyear (mainly for the U.S. market), and Dunlop. Notably, Dunlop supplied TRX tires as original equipment on Austin Montegos and Austin Mini Metros.

TRX sizes

TRX wheels were produced in diameters ranging from 315 mm to 415 mm.

Typical TRX dimensions and their corresponding vehicles include:

Size Application

160/65 R 315 TRX Innocenti Turbo De Tomaso (1984-1989), Austin Metro
160/65 SR 340 TRX Citroën Visa GT
165/70 R 365 TRX Ford Escort GT, EXP, Mercury Lynx RS
170/65 R 365 TRX Citroën BX, Peugeot 305
180/65 HR 390 TRX SAAB 900 S and Turbo (1980/81)
190/65 HR 390 TRX Citroën CX, Ford Granada, Mercedes 200/220/240, Peugeot 504 Coupé, 505, 604, Renault 30TX
190/55 VR 340 TRX Alpine A310 V6 (front), Renault 5 Turbo (front), Alfasud Ti
210/65 VR 365 TRX Talbot Tagora SX
220/55 VR 365 TRX Alpine A310 V6 (rear), Renault 5 Turbo (rear)
200/60 VR 390 TRX BMW 518, 520, 525, 528, 728; Mercedes models;
210/55 VR 390 TRX Citroën CX 25 GTI Turbo
220/55 VR 390 TRX BMW 525, 528, M535i, 635 Csi, Ford LTD, Mustang, Thunderbird; Mercury Capri, Cougar; Ferrari 208, 308, Mondial (front)
240/55 VR 390 TRX Ferrari Mondial 8 & Cabriolet, Mondial (rear)
240/55 VR 415 TRX Ferrari 400 i, 512 B, 412 i
240/45 ZR 415 TRX BMW M635 CSi, Ferrari 512 BB (front), Testarossa (front)
280/45 VR 415 TRX Ferrari 512 BB (rear), Testarossa (rear)

Note: AV='front', AR='rear'. Vehicles from North America are not included.

Additional sizes such as the TDX variant of the 160/65 R315 were also produced.

Decline

Although the TRX tire was well-received and widely adopted by original equipment manufacturers, its unconventional sizing hindered its acceptance in the aftermarket sector. The bead-to-rim connection was particularly tight, complicating removal when using standard tools. Meanwhile, competitors such as Dunlop provided alternative wheel and tire options for popular vehicle models, focusing on both high-performance and winter conditions.

Over time, advancements in technology delivered comparable performance to TRX tires while offering increased ease of use and reduced expenses. Currently, TRX tires are manufactured exclusively as replacement parts for vehicles originally equipped with them. As of 2024, Michelin Classic still includes these tires in its product lineup.

References

Citations

External links

↑ For the first time, the tyre and its rim complemented one another perfectly, working as a single unit. The rim underwent a fundamental transformation, the essential characteristic of which was a flatter, lower flange. This new design of the rim and tyre bead resulted in a gradual curvature of the casing, without the "5" shaped flexing inherent in traditional designs.

[1] For the first time, the tyre and its rim complemented one another perfectly, working as a single unit. The rim underwent a fundamental transformation, the essential characteristic of which was a flatter, lower flange. This new design of the rim and tyre bead resulted in a gradual curvature of the casing, without the "5" shaped flexing inherent in traditional designs.

[1]