Michelin TRX: Difference between revisions

The '''Michelin TRX, '''(and the related TDX), is a [[Radial tire|radial]] [[tire]] introduced by the [[Michelin]] Group in 1975. It is one of the first volume-produced low-profile tires. Although technologically advanced, and reasonably successful, the tire's requirement for a non-standard [[Rim (wheel)|rim]] ultimately condemned it to a relatively short commercial life. It has thus been called the "[[Betamax]] of the tire industry.<ref name=":0">{{cite web |url=http://jpowell.tripod.com/saab-wheels/trx/ |title=SAAB TRX Wheels|last1= |first1= |last2= |first2= |date= |website= |publisher= |accessdate=27 February 2014 |archiveurl=httphttps://web.archive.org/web/20060530035844/http://jpowell.tripod.com/saab-wheels/trx/ |archivedate=2006-05-30}} </ref>"

As passenger car performance increased during the 1970s, the need arose for improved tire capability. One of the possibilities was to reduce sidewall height, low sidewalls being common at the time on crossply racing tires, but not usual for the better-performing radial tire.<ref>[[Pirelli]] 1975 Pirelli created a wide tyre with a reduced sidewall height like a slick, but with a radial structure.</ref> The problem was that reducing sidewall height compromised tire comfort, in part due to the roadwheel rim profile used.

Michelin therefore decided to introduce the world's first tire and roadwheel system, where the two were designed together.<ref>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 .</ref> This would enable both lower sidewall height, (for better roadholding) whilst retaining comfort due to better stress distribution within the tire, enabled by the redesigned wheel rim and tire bead.

TRX tires thus require the use of wheels that were specially designed for them; standard tires do not fit TRX wheels and vice- versa.

To avoid potentially dangerous confusion, Michelin used metric sizes for TRX roadwheels instead of the standard imperial wheel size, (normally stated in inches).

Although most TRX tires were produced by Michelin, a few sizes were made by Avon, Continental, Goodyear (mainly for the American market<ref name=reinventing>{{cite web |url=http://www.curbsideclassic.com/automotive-histories/automotive-history-michelins-trx-tire-reinventing-the-radial-tire-didnt-work-as-well-as-inventing-it/ |title=Automotive History: Michelin’sMichelin's TRX Tire–Reinventing The Radial Tire Didn’tDidn't Work Quite As Well As Inventing It |last1= |first1= |last2= |first2= |date= |website= |publisher= |accessdate=27 February 2014 |archiveurl=httphttps://web.archive.org/web/20131018232542/http://www.curbsideclassic.com/automotive-histories/automotive-history-michelins-trx-tire-reinventing-the-radial-tire-didnt-work-as-well-as-inventing-it/ |archivedate=2013-10-18}}</ref>) and possiblyDunlop. Dunlop fitted their version of the TRX tire as standard equipment on Austin Montegos and Austin Mini Metros.

* 185180/65 HR 390 TRX [[Saab 900|SAAB 900 S]] and [[Saab 900|Turbo]] (1980/81)<ref name=":0" />

* 220/55 VR 390 TRX BMW 525, 528, 728, 535, M535I 635 Csi, 735i. [[Ford Fairlane (Australia)#ZK / FD (1982–1984)|Ford LTD]]<ref>{{cite web|url=http://www.boostedfalcon.net/falconfacts/fairlaneltd/zkfd.html|title=Falcon Facts: ZK Fairlane / FD LTD|accessdate=29 August 2018|archiveurl=https://web.archive.org/web/20160806223659/http://www.boostedfalcon.net/falconfacts/fairlaneltd/zkfd.html|archivedate=6 August 2016}}</ref> Ford Mustang, Thunderbird. Mercury Capri, Cougar. Ferrari 208, 308, [[Ferrari Mondial|Mondial 3, 2]] (AV)

* 240/55 VR 415 TRX [[Ferrari 400|Ferrari 400 Gtii]], 512 B, [[Ferrari 400|412 Gtii]]

* 240/45 ZR 415 TRX [[BMW 635CSiM635CSi|BMW 635M635 CSi]], Ferrari 512 BB (AV), [[Ferrari Testarossa|Testarossa]] (AV)

In due course advances in tire technology caught up with the TRX line, enabling similar performance and greater convenience at lower cost. TRX tires are now produced only as special-order replacements for vehicles which were originally fitted with them. As of 2024, Michelin Classic stillis hasproducing these tires in its catalogue.<ref>{{cite web |url=httphttps://wwwclassic.michelinclassicmichelin.com/en/Classic-Tyre-range/TRX |title=TRX {{!}} Michelin Classic |last1website= |first1=Michelin |last2= |first2= |date= |website= |publisher=Classic |accessdate=274 February 2014 |archiveurl=http://web.archive.org/web/20140227115451/http://www.michelinclassic.com/en/Classic-Tyre-range/TRX |archivedate=2014-02-272022}}</ref>

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*[https://web.archive.org/web/20070430085728/http://www.michelin-passion.com/passion/front/templates/affich.jsp?codeRubrique=43&lang=EN TRX page from Michelin Group website].

* [http://www.curbsideclassic.com/automotive-histories/automotive-history-michelins-trx-tire-reinventing-the-radial-tire-didnt-work-as-well-as-inventing-it/ IndependantIndependent history and review of the TRX tire.]