View source for Triumph TR4A

{{Use dmy dates|date=August 2017}}
{{Use British English|date=August 2017}}
{{Infobox automobile |sp=uk
|image=Triumph_TR4A_dutch_licence_registration_AL-47-75_pic1.JPG
|name=Triumph TR4A
|production=1965&ndash;1967
|manufacturer=[[Triumph Motor Company]]
|class=[[Sports car]]
|predecessor=[[Triumph TR4]]
|successor=[[Triumph TR5|Triumph TR5/TR250]]
|engine={{cvt|2138|cc|cuin|1}} [[Inline-four engine|I4]]
| layout           = [[Front-engine, rear-wheel-drive layout|Front engine, rear wheel drive]]
| transmission     = 4-speed [[manual transmission|manual]]<ref name="carfolio-specs"/>
| wheelbase        = {{cvt|2235|mm|in|1|}}<ref name="carfolio-specs"/>
| length           = {{cvt|3962|mm|in|1}}<ref name="carfolio-specs"/>
| width            = {{cvt|1473|mm|in|1}}<ref name="carfolio-specs"/>
| height           = {{cvt|1270|mm|in|1}}
| weight           = {{cvt|1016|kg|lb|0}}<ref name="carfolio-specs"/>
| body_style = 2-door [[Roadster (automobile)|open two-seater]]
}}
The '''Triumph TR4A''' is a [[sports car]] built by the [[Triumph Motor Company]] at its [[Coventry]] factory in the United Kingdom from 1965 to 1967.<ref name="piggottbook"/> It is an evolution of the [[Giovanni Michelotti]] styled [[Triumph TR4|TR4]], with the TR4's [[Hotchkiss drive]] replaced by an [[independent suspension|independent rear suspension]], indicated by an "IRS" badge attached to the car's rear.

==Changes from the TR4==
[[File:Triumph TR4 late US engine.jpeg|thumb|left|TR4A Engine]]
[[File:Triumph_TR4_late_US_interior.jpeg|thumb|left|TR4A Interior]]
The TR4A's rear suspension is a [[Trailing arm|semi-trailing arm]] system with coil springs and lever-arm shocks. It more closely resembles that of the [[Triumph 2000]] than the [[swing axle]] systems used in the [[Triumph Herald|Herald]] or [[Triumph Spitfire|Spitfire]]. The chassis was redesigned to accommodate the new suspension, with extensive changes to the side members and cross-bracing. After the redesign, reviewers noted the car's better ride comfort, although some felt that handling had not improved.<ref name="cm-may2011"/>

The chassis revisions resulted in a car roughly {{cvt|22|mm}} wider than the TR4, although length and height were unaffected. The wheelbase is {{cvt|3|mm}} shorter. The front track is unchanged, while the rear track grew by {{cvt|13|mm}} with the IRS. The car is heavier by {{cvt|50|kg}}.

Although consideration was given to both an enlarged 2.5&nbsp;litre four-cylinder or a six-cylinder engine, the TR4A used the same long-stroke, high-torque [[Standard wet liner inline-four engine|Standard four-cylinder]] [[Cylinder block#Cylinders integrated into one or several cylinder blocks|wet-sleeve]] engine as the TR4. While the bore, stroke, and displacement remained the same, changes to the cylinder head and manifolds raised net power to {{cvt|104|bhp}}, an increase of 4%, and torque to {{cvt|132|lbft}}, an increase of 10%.

Apart from the increase in width and the IRS badge on the rear of the car, other changes include a revised grille and new bonnet badge. There is also a new piece of chrome trim on the side, starting near the rear edge of the door and ending at the front of the car with integrated signal/marker lights, which were moved from their earlier position in the corners of the grille. New smaller front bumpers and a convertible top patterned after the one from the Herald complete the exterior differences. On the interior the fly-off handbrake lever is moved to the transmission tunnel between two revised seats, the gearshift lever is shortened, and fascias in all cars are covered with walnut, which had been optional in the TR4.

In 1965 the TR4A IRS sold in the UK for approximately [[Pound sterling|£]]968. Wire wheels added £36, [[overdrive (mechanics)|overdrive]] £51, heater £13 and seat belts £4 each;.<ref name="am-may1965"/>

== Surrey Top ==
The TR4A continued to offer the "Surrey Top" hard top system as an option. This weather protection system comprises a rigid rear back light, a removable rigid roof panel and a soft fabric panel that was the actual surrey-top. The back light is attached to the rear of the passenger area semi-permanently. Either the roof panel or the soft surrey top bridge the gap between the top of the windshield surround and the top of the back light. This aesthetically foreshadowed the silhouette of [[Targa top]] cars.

== Non-IRS ==
In response to requests from United States distributors Bud Forman and Les Genser,<ref name="sm-aug2011"/> Triumph developed a version of the TR4A fitted with a TR4-style rear [[beam axle|live axle]] and made IRS an extra-cost option for the US market.<ref name="auwm-oct2012"/> To accommodate the re-introduction of leaf springs, spring brackets were added to the revised chassis. Live axle cars received a commissioning number (Triumph did not use serial numbers) that starts with "CT" — the same prefix used for TR4s. IRS equipped cars' commissioning numbers begin with "CTC". The price in the United States was just under $2500.

== Motorsports ==
Even though the SCCA declined to homologate the TR4A in 1965, [[Kas Kastner]], Triumph's US Competition Manager, and his modified "Super Stock" TR4A won the D-modified National Championship in 1965 at Daytona with driver Charlie Gates.<ref name="CDfeb66"/>

[[Bob Tullius]]' Group 44 and others successfully campaigned these cars during the 1965 to 1973 seasons, accumulating a respectable collection of finishes.<ref name="rsc-tr4a"/>

The high point of the TR4A's racing history is the team win by three TR4A IRS models at the [[12 Hours of Sebring|Sebring]] 12-hour race of 1966, finishing 1st, 2nd and 3rd in their class.<ref name="rsc-sebring1966"/>

== Successor ==
{{Main article|Triumph TR5}}
In 1968 the TR4A was replaced by a new model powered by Triumph's [[Triumph I6|2.5-litre straight-6]]. In the UK and most other markets this car was equipped with [[Lucas Industries|Lucas]] [[fuel injection]] and called the [[Triumph TR5|TR5]]. In the United States, price pressure and tighter emissions standards resulted in a less powerful but otherwise identical car fitted with twin Zenith-Stromberg [[Carburetor|carburetters]], called the [[Triumph TR5#TR250|TR250]].

== Survivors ==
In Q1 2011 there were approximately 789 licensed and 153 [[SORN]] TR4As registered with the [[DVLA]].<ref name="hml-tr4a"/><ref name="dft-vls"/>

As of Q1 2023, this had risen to 1,028 licensed and 209 SORN.<ref name="hml-tr4a"/>

{{clear}}

== Technical data ==
{{Table alignment}}
{| class="wikitable defaultcenter col1left"
|-
! width="240"|Triumph TR4A
! width="600"|Detail:<ref name="carfolio-specs"/><ref name="us-specs"/><ref name="mm-specs"/>  
|-
|Engine: || [[Standard wet liner inline-four engine]]
|-
|Bore × Stroke: || {{cvt|86| × |92|mm|in|3}}
|-
|Displacement: || {{cvt|2138|cc|cuin|1}}
|-
|Maximum power: || {{cvt|104|bhp|kW|1}} at 4,700 rpm
|-
|Maximum torque: || {{cvt|132.5|ftlb|Nm|1}} at 3,000 rpm
|-
|Compression ratio: || 9.0:1 (optional 7.0:1)
|-
|Valvetrain:&nbsp; || Single [[cam-in-block]], pushrods, rocker arms, 2 [[Overhead valve engine|overhead valves]] per cylinder
|-
|Induction:&nbsp; || Two [[Zenith Carburettor Company (British)|Stromberg]] 175CD [[Carburetor|carburetter]]s<br>or<br>Two SU HS6 carburetters
|-
|Cooling:&nbsp; || [[Radiator (engine cooling)#Automobiles and motorcycles|Water-cooled]]
|-
|Transmission:&nbsp; || 4-speed [[Manual transmission|manual]] with reverse (optional overdrive)
|-
|Steering:&nbsp; || [[Alford & Alder]] [[Rack and pinion#Steering|rack and pinion]]
|-
|Turns [[lock-to-lock]]:&nbsp; || 2.5
|-
|Turning circle:&nbsp; || {{cvt|33.0|ft|m|1}}
|-
|Brakes f/r: || Girling discs/drums
|-
|Suspension front: || Upper and lower wishbones, coil springs, telescopic dampers
|-
|Suspension rear: || Semi-trailing arms, coil springs, piston-type dampers
|-
|Body/Chassis: || Steel body on steel ladder chassis
|-
|Track f/r: || {{cvt|49| / |48.5|in|mm|0||abbr=on}} (disc wheels)<br>{{cvt|49.75| / |49.25|in|mm|0|}} (wire wheels)
|-
|[[Wheelbase]]: || {{cvt|2235|mm|in|1||order=flip}}
|-
|Tyres f/r: || 5.5/5.90x15
|-
|Length<br>Width<br>Height: || {{cvt|3962|mm|in|1|order=flip}}<br>{{cvt|1473|mm|in|1|order=flip}}<br>{{cvt|1270|mm|in|1|order=flip}}
|-
|Weight: || {{cvt|1016|kg|lbs|0|order=flip}}
|-
|Capacities:&nbsp;<br>&nbsp;&nbsp;&nbsp;Fuel:<br>&nbsp;&nbsp;&nbsp;Cooling:<br>&nbsp;&nbsp;&nbsp;Sump:<br>&nbsp;&nbsp;&nbsp;Transmission: || &nbsp;<br>{{cvt|14|usgal|1}}<br>{{cvt|16.8|uspt|1}}<br>{{cvt|13.2|uspt|1}}<br>{{cvt|1.8|uspt|1}} (non-overdrive)<br>{{cvt|4.2|uspt|1|abbr=on}} (overdrive)
|-
|Acceleration in top:&nbsp;<br>&nbsp;&nbsp;&nbsp;{{cvt|30|to|50|mph}}:<br>&nbsp;&nbsp;&nbsp;{{cvt|40|to|60|mph}}:<br>&nbsp;&nbsp;&nbsp;{{cvt|60|to|80|mph}}: || <br>8 seconds<br>8 seconds<br>11 seconds
|-
|Maximum speed: || {{cvt|175|kph|mph|0|order=flip}}
|}

==References==
{{reflist|refs=

<ref name="carfolio-specs">{{Cite web|url=http://www.carfolio.com/specifications/models/car/?car=55693|title=1965 Triumph TR4A|access-date=2008-01-01|work=carfolio.com}}</ref>

<ref name="piggottbook">{{cite book |last=Piggott |first=Bill |title=Haynes Great Cars: Triumph TR |publisher=Haynes |date=2003 |page=104 |isbn=185960997X }}</ref>

<ref name="cm-may2011">{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Triumph TR4 |url=https://www.classiccars4sale.net/classic-car-review/c2c-triumph-tr4-a |magazine=Classic Motoring |location= |publisher= |date=10 May 2011 |access-date=}}</ref>

<ref name="am-may1965">{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Triumph TR4A IRS |url=https://www.facebook.com/TriumphTR4AIRS1965/photos/pcb.1651636301740442/1651635261740546/?type=3&theater |magazine=[[Autocar (magazine)|Autocar]] |pages=58–63 |location= |publisher= |date=28 May 1965 |access-date=}}</ref>

<ref name="sm-aug2011">{{cite web |url=https://stevemckelvie.wordpress.com/2011/08/13/the-triumph-trs-the-triumph-tr4a/ |title=The Triumph TRs – The Triumph TR4A |last=McKelvie |first=Steve |date=13 August 2011 |website=SteveMcKelvie.com |publisher= |access-date= }}</ref>

<ref name="auwm-oct2012">{{cite web |url=https://ateupwithmotor.com/model-histories/triumph-tr4-tr4a/3/ |title=Grandfather’s Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A |last=Severson |first=Aaron |date=22 October 2012 |website=Ate Up With Motor |page=3 |publisher= |access-date= }}</ref>

<ref name="CDfeb66">{{cite magazine |last=Jennings |first=Gordon H. |date=February 1966 |title=Kas Kastner and his Super Triumph: The car they couldn't keep from winning |url=http://www.kaskastner.com/feb66.pdf |magazine=Car and Driver |pages=48, 49, 92 }}</ref>

<ref name="rsc-tr4a">{{cite web |url=https://www.racingsportscars.com/suffix/Triumph/TR4/A.html |title=Triumph TR4 A |author=<!--Not stated--> |date= |website=Racing Sports Cars |publisher= |access-date= }}</ref>

<ref name="rsc-sebring1966">{{cite web |url=https://www.racingsportscars.com/race/Sebring-1966-03-26.html |title=Sebring 12 Hours |author=<!--Not stated--> |date= |website=Racing Sports Cars |publisher= |access-date= }}</ref>

<ref name="hml-tr4a">{{cite web |url=https://www.howmanyleft.co.uk/vehicle/triumph_tr4a |title= Triumph TR4A  |last=Smith |first=Olly |date= |website=www.howmanyleft.co.uk |publisher= |access-date= }}</ref>

<ref name="dft-vls">{{cite web |url=http://www2.dft.gov.uk/pgr/statistics/datatablespublications/vehicles/licensing/ |title=Vehicle licensing statistics |date=10 June 2011 |publisher=Department for Transport |access-date= |archive-url=https://web.archive.org/web/20110829152645/http://www2.dft.gov.uk/pgr/statistics/datatablespublications/vehicles/licensing/ |archive-date=29 August 2011 }}</ref>

<ref name="us-specs">{{cite web |url=https://ultimatespecs.com/car-specs/Triumph/19626/Triumph-TR4-A.html |title=Triumph TR4 A Specs |author=<!--Not stated--> |date= |website=ultimatespecs.com |publisher= |access-date= }}</ref>

<ref name="mm-specs">{{cite web |url=https://mossmotors.com/tr4a-i-r-s |title=Car Specifications - TR4A I.R.S. |author=<!--Not stated--> |date= |website=mossmotors.com |publisher= |access-date= }}</ref>

}}

==Further reading==
* {{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Road Research Report: Triumph TR-4A |url=https://autohistorypreservationsociety.org/wp-content/uploads/1965-05_CD_Triumph_TR-4_Test_1-8-1.pdf |magazine=[[Car and Driver]] |pages=39–45, 90 |location= |publisher= |date=May 1965 |access-date=}} 

==External links==
{{Commons category|Triumph TR4A}}

{{Triumph_Motor_Company_timeline}}

[[Category:Triumph Motor Company vehicles|TR4A]]
[[Category:Sports cars]]
[[Category:Cars introduced in 1965]]
[[Category:Cars discontinued in 1967]]
[[Category:Roadsters]]
[[Category:Rear-wheel-drive vehicles]]