{{Infobox automobile | image = BMW 503 Coupé (5746741521).jpg | name = BMW 503 | manufacturer = [[BMW|Bayerische Motoren Werke AG (BMW)]] | production = May 1956 – March 1959<ref name="Norbye115">[[#Norbye|Norbye, Jan P., ''BMW - Bavaria's Driving Machines'']], p.115</ref> <br /> 413 built<ref name="Norbye115" /> | predecessor = [[BMW 327]] | successor = [[BMW 3200 CS]] | class = [[Grand tourer]] ([[S-segment|S]]) | body_style = [[coupé|2-door 2+2 seater coupe]]<br /> [[Cabriolet (automobile)|2-door 2+2 seater cabriolet]]<ref name="Norbye96">[[#Norbye|Norbye]], p.96</ref> | engine = {{Convert|3168|cc|cuin|abbr=on|0}} [[BMW OHV V8 engine|BMW OHV V8]]<ref name="Norbye113">[[#Norbye|Norbye]], p.113</ref> | layout = [[FR layout]] | transmission = 4-speed manual | length = {{Convert|4750|mm|in|abbr=on}}<ref name="CBD503">[[#CBD|''Car Body Design'': BMW 507 and 503 (1955-1960)]]</ref> | width = {{Convert|1710|mm|in|abbr=on}}<ref name="CBD503" /> | height = {{Convert|1440|mm|in|abbr=on}}<ref name="CBD503" /> | weight = {{Convert|1500|kg|lb|abbr=on}} approximately<ref name="CBD503" /><ref name="Norbye116">[[#Norbye|Norbye]], p.116</ref> | wheelbase = {{Convert|2835|mm|in|abbr=on}}<ref name="Norbye96" /><ref name="CBD503" /> | related = [[BMW 507]]<br />[[BMW 501|BMW 502]] | designer = [[Albrecht von Goertz]] }}

The '''BMW 503''' is a two-door [[2+2 (car body style)|2+2]] [[grand tourer|gran turismo]] manufactured by German automaker [[BMW]] from 1956 until 1959. The company developed the 503, built in [[coupé]] and [[cabriolet]] body styles, alongside the [[BMW 507|507]] [[Roadster (automobile)|roadster]]. The 503 and 507 cost about twice their projected price and did not recover their development costs. During production from May 1956 to March 1959, 413 units of the 503 were built, 139 of which were Cabriolets.

==Concept and design== Hanns Grewenig, sales manager of BMW, repeatedly requested the development of a sports car based on their [[BMW 501|501 and 502]] luxury cars, and which could take advantage of their new 3.2&nbsp;L V8 all-aluminium engine. He vetoed a proposal by chief engineer [[Fritz Feidler]] to develop a small car called the 331 on the basis that what BMW needed was a new [[luxury car]] more in keeping with its upmarket image.<ref name="Norbye95">[[#Norbye|Norbye]], p. 95</ref> He also felt that BMW did not have the capacity then to manufacture in quantity, but could make a smaller number of luxury cars with a higher profit margin per unit.

In early 1954, influenced by the public reaction to the [[Mercedes-Benz 300 SL]] and [[Mercedes-Benz W180|220 S Coupé/Cabriolet]] show cars in New York in February 1954, the management of BMW approved the project.<ref name="Norbye95_96">[[#Norbye|Norbye]], pp. 95-96</ref>

The initial designs for the 503 were the work of Kurt Bredschneider, head of the body department, and he produced the preliminary drawings which showed the bodywork that went through to the final design mostly unchanged.{{cn|date=March 2024}} [[Max Hoffman]], an influential automobile importer in the United States, saw early design sketches by BMW's [[Ernst Loof]] for the subsequent 507 and suggested to industrial designer [[Albrecht von Goertz]] that he should submit design proposals to BMW for both cars.<ref name="Norbye113_14">[[#Norbye|Norbye]], pp. 113-114</ref><ref name="Buckley40">[[#Buckley|Buckley, Martin, ''BMW Cars'']], p. 40</ref> Based on these proposals, BMW contracted Goertz to consider the existing design of the 503 and to design the 507 in November 1954.<ref name="Norbye114_15">[[#Norbye|Norbye]], pp. 114-115</ref>

The 503 was noted for having a cleaner and more modern design than the "Baroque Angel" 501-based sedans.<ref name="Noakes49_50">[[#Noakes|Noakes, Andrew, ''The Ultimate History of BMW'']], pp. 49-50</ref> The cabriolet version of the 503 was the first European convertible with an electro hydraulic hood and windows.<ref name="Lewin28_29" /> Only 3 RHD cabriolets were hand made for the British market.

<gallery widths="200" heights="150"> File:BMW 503 2012-09-01 13-24-08.JPG|BMW 503 coupe File:BMW 503 2014-09-07 13-46-27.jpg|BMW 503 Cabriolet File:Schleswig-Holstein, Hohenlockstedt, Classic Motor Days (2016) NIK 1119.JPG|BMW 503 coupe interior </gallery>

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==Engineering and development== Tasked with designing [[rolling chassis]] for two cars while using as much as possible from the existing 502 sedan, engineer [[Fritz Fiedler]] designed two versions of a new [[Vehicle frame#Ladder frame|ladder frame]], one with the same wheelbase as the 502, and one with a shortened wheelbase. The long-wheelbase version was used in the 503.<ref name="Norbye96"/> Both cars used the steering system and a variant of the front suspension system from the 502; the 503 also used the 502's rear suspension.<ref name="Norbye113" /> As originally designed, the 503 used the 502's remote gearbox placement and shift linkage.<ref name="Norbye96" /> Both cars used the braking system developed for the 502, using [[drum brake]]s with vacuum assist.<ref name="Norbye113" /> From 1957 all 503s were fitted with discs on the front as a result of recommendations from John Surtees{{context inline|date=March 2024}} who had bought a 507. All 503s were configured for left hand drive except for three Coupés and three Cabriolets handbuilt for the UK market.<ref name="Buckley41" />

The perimeter chassis (so designed to keep driver and passengers safe in a collision) was constructed of sheet steel, as was the bulkhead, inner wings and some body bracing. The bodywork, bonnet, doors and bootlid were made of aluminium/magnesium alloy, the original aluminium having found to be too soft on the prototypes. The dashboard assembly was another hefty cast aluminium structure, with the cast glove box lid weighing as much as an ordinary dashboard on lesser cars. The side vents on the dashboard were discontinued in February 1957, the resulting hole being covered by a blanking plate being welded in which occasionally caused corrosion problems around the weld later on. It was intended that Baur should manufacture the bodies, and indeed they produced a prototype, but in the end they were hand built in house.{{cn|date=March 2024}} Despite some claims by owners and auction houses, no 503 bodies were either designed or built by Bertone.

The Mark 2 version from September 1957 resulted in few outward changes. The chrome trim strip along the side remained straight at the rear, rather than kicking up at an angle. The ashtray moved from beneath the dash to adjacent to the speaker grill above it.

Both cars used the 3.2&nbsp;L version of the [[BMW OHV V8 engine|V8 engine]] developed for the 502, but with two [[carburetor|carburettor]]s and with an improved lubrication system using a chain-driven oil pump. The 503's V8 had a [[compression ratio]] of 7.5:1 and yielded {{Convert|140|bhp|kW PS|abbr=on|0}} at 4800&nbsp;rpm.<ref name="Norbye113" /><ref name="Buckley40" /> Some UK 503s were delivered tuned to 507 specification, either by BMW or by AFN Ltd, the BMW Concessionaires for the UK; these engines developed 150 bhp.{{cn|date=March 2024}}

The 503 had sixteen-inch wheels and standard final drive ratio of 3.90:1,<ref name="Norbye96" /> A final drive ratio of 3.42:1 was optional.<ref name="Norbye113" /> Acceleration of the 503 in standard tune from standstill to 100&nbsp;km/h (62&nbsp;mph) has been estimated at 11–13 seconds since there are no reliable contemporary figures available; the top speed of the 503 is about {{Convert|120|mph|km/h|0}}.<ref name="Norbye116" /> Some cars were ordered with uprated engines with increased performance from standard.{{cn|date=March 2024}}

Also for the Mark 2 from September 1957, the 503's drivetrain was revised. The gearbox was bolted to the engine and the gear lever was moved from the [[steering column]] to the floor.<ref name="CBD503" /><ref name="Norbye116"/><ref name="Lewin28_29">[[#Lewin|Lewin, Tony, ''The Complete Book of BMW: Every Model since 1950'']], pp. 28-29</ref><ref name="Buckley41">[[#Buckley|Buckley]], p. 41</ref> All RHD cars had floor changes.

==Reception== Hoffman had wanted BMW's sports and GT cars to be positioned between [[Triumph TR|Triumph's sports cars]] and the [[Mercedes-Benz 190 SL]],<ref name="Norbye96" /> at a selling price close to US$5,000 (${{formatnum:{{Inflation|US|5000|1955}}}} in {{Inflation-year|US}} dollars {{inflation-fn|US}}).<ref name="Norbye115"/> He told BMW he would order thousands of their sports cars at a purchase price of DM12,000.<ref name="Noakes52">[[#Noakes|Noakes]], p. 52</ref> BMW, however, saw themselves as catering to the wealthy and aristocratic, and were not interested in cut price sports cars.

After its introduction at the [[Frankfurt Motor Show#1955|Frankfurt Motor Show]] in September 1955, the 503 began production in May 1956 with a selling price of DM29,500, while the 507 roadster sold for DM26,500 when it began production seven months later,<ref name="Norbye115" /> twice the price that Hoffman had hoped for.

[[Battista Farina|Battista "Pinin" Farina]], felt the 503 was superior in design to the 507,<ref name="Norbye115" /><ref name="Buckley40" /><ref name="Noakes49_50" /> However, while neither the 503 nor the 507 sold well enough to earn a profit,<ref name="Norbye130">[[#Norbye|Norbye]], p. 130</ref><ref name="Lewin29_31">[[#Lewin|Lewin]], pp. 29-31</ref> the larger, more luxurious, more elegant, and more expensive 503 sold 412 units to the 507 roadster's 253.<ref name="Lewin28_29" /><ref name="Norbye251">[[#Norbye|Norbye]], p. 251</ref> The problem with the 507 Roadster was that the performance did not match its looks or the price in the US market that was used to big V8 cars. Another difficulty for both cars was that Hoffman took fright at the very high price and cancelled his arrangement with BMW. Thus BMW had no dealership or servicing arrangements in the US which potential purchasers were wary about.

The 503 did better amongst the upper levels of society in Europe, (particularly Germany and Switzerland) with many going to film stars ([[Curd Jürgens]] and others) Heads of State (e.g. [[Tito]]) and the nobility (e.g. Count Faber-Castell) and it won numerous gold medals in International shows at the time.<ref name="CBD503" /> Production ended in March 1959.<ref name="Norbye115" />

==Legacy== The 503 was BMW's first postwar sports coupé.<ref name="Langworth49">[[#Bluechip|Langworth]], p. 49</ref> It was replaced by the [[Gruppo Bertone|Bertone]]-bodied [[BMW 3200 CS]] in 1962.<ref name="Noakes63_65">[[#Noakes|Noakes]], pp. 63, 65</ref><ref name="Norbye131_32">[[#Norbye|Norbye]], pp. 131-132</ref>

==References==

===Citations=== {{reflist}}

===Sources=== {{Commons category|BMW 503}} ;Books and journals *{{Cite book |last1= Buckley|first1= Martin|year= 2001|orig-year= 2001|title= BMW Cars|url= https://books.google.com/books?id=Mo1tyh2HM18C|location= St. Paul, MN USA|publisher= MotorBooks International|at= ''Coupe Elegance&ndash;The Forgotten 503'', pp. 40-41|isbn=0-7603-0921-3 |access-date= 2013-12-09|ref= Buckley}} *{{cite book |last= Langworth|first= Richard M.|year= 2000|title= Complete Book of Collectible Cars: 70 Years of Blue Chip Auto Investments 1930-2000|url= https://books.google.com/books?id=6jpVtX9Epi4C|page= 49|publisher= Publications International|isbn= 0-7853-4313-X|access-date= 2013-12-09|ref=Bluechip}} *{{cite book |last1= Lewin|first1= Tony|title= The Complete Book of BMW: Every Model since 1962|url= https://books.google.com/books?id=AZKFLcLybIMC|access-date= 2013-12-08|year= 2004|publisher= Motorbooks International|location= St. Paul, MN USA|isbn= 0-7603-1951-0|pages= 23–37|chapter= Faded glory|chapter-url= https://books.google.com/books?id=AZKFLcLybIMC&pg=PA23|ref=Lewin}} *{{cite book|last= Noakes|first= Andrew|author-link=Andrew Noakes|title= The Ultimate History of BMW|year= 2005|publisher= Parragon Publishing|location= Bath, UK|isbn=1-4054-5316-8|ref=Noakes}} *{{Cite book|last= Norbye|first= Jan P.|title= BMW - Bavaria's Driving Machines|year= 1984|publisher= Publications International|location= Skokie, IL, USA|isbn= 0-517-42464-9|lccn= 84060309|chapter= Postwar Panache: Baroque Angels, Timeless Sports Cars|ref= Norbye|url-access= registration|url= https://archive.org/details/bmwbavariasdrivi00norb}}

;Web sites *{{Cite web| url =http://www.carbodydesign.com/archive/2006/11/21-bmw-507-and-503/| title =BMW 507 and 503 (1955-1960)| author =Albrecht von Goertz| author-link =Albrecht von Goertz| date =21 November 2006| work =Car Body Design| publisher =FTM Studio| location =Rome, Italy| access-date =23 June 2010| ref = CBD}}

{{BMW cars: 1940s to 1960s}}

[[Category:BMW vehicles|503]] [[Category:Grand tourers]] [[Category:Rear-wheel-drive vehicles]] [[Category:Cars introduced in 1955]] [[Category:Cars discontinued in 1959]]