1951 Ford Consul / Car & Classic
Engineer Earle MacPherson devised an early version of his now-famous strut suspension for an abortive GM small car project, the Chevrolet Cadet, but it wasn’t until he went to Ford Motor Company that he penned — and patented — the definitive version of what we now call the MacPherson strut, which first saw the light of day in the Ford Consul and Zephyr in late 1950. Here’s how it came about.
1951 Ford Consul / Car & Classic
The 1950–1955 Ford Consul, Zephyr, and Zodiac (sometimes collectively known by their chassis designations, “EOTA” and “EOTTA”) were very popular British family cars that probably won’t ring many bells for American readers. They were sold in the U.S. at the time, but in very limited numbers: U.S. sales never topped 4,000 units a year in the early 1950s. On this side of the pond, the Consul and Zephyr were far more significant as the first production application of MacPherson strut front suspension.
As explained in this article, Earle Steele MacPherson was a veteran auto engineer who worked at Chevrolet from 1935 to 1947, and before that at Hupp and several other automakers you probably haven’t heard of. Over the course of his career, he accumulated dozens of patents in engine and suspension design. MacPherson’s most ambitious project at GM was his last, a subcompact “light car” called the Chevrolet Cadet, with many advanced features, including fully independent suspension.
Artist’s impression of the 1947 Chevrolet Cadet
This last feature was achieved in a then-unusual way: using reinforced tubular shock absorbers as suspension struts, which were fixed to the wheel spindles. In the front suspension, the struts were also integral with the steering knuckles, and were pivoted on ball joints so they could turn as the wheels were steered. Here’s an illustration from MacPherson’s 1947 patent (US2624592), showing the left front wheel suspension of the Cadet. (I’ve removed some extraneous details for clarity.)
Here’s how the Cadet front suspension looked in plan view:
(Incidentally, while the MacPherson strut is now most strongly associated with front suspensions, the Cadet used them in the rear as well.)
The Cadet never got past the prototype stage: It was too expensive for its original price target, and with raw materials in short supply and demand for new cars strong, GM decided they didn’t need it. On May 15, 1947, the program was demoted to a pure R&D project, with production plans shelves indefinitely.
MacPherson, frustrated by the whole thing, then accepted a lucrative offer from Ford Motor Company engineering director Harold T. Youngren. In September 1947, MacPherson went to Dearborn as Ford executive engineer, with overall responsibility for design and development of Ford, Mercury, and Lincoln products; in August 1949, he was promoted to chief engineer.
1951 Ford Consul saloon / Car & Classic
Beginning in 1948, engineers in Dearborn started work on two all-new English Ford models, the four-cylinder Consul and six-cylinder Zephyr. By this point, Ford of England had some control over their products, but they still relied heavily on the U.S. parent company for design and engineering development work. The Consul and Zephyr were a big step up from previous English Ford cars in engineering sophistication, including the British subsidiary’s first unit bodies and first independent front suspensions. (To put this in perspective, Ford had only just adopted IFS for its U.S. cars with the 1949 models!)
Distinguished by its different grille, the Zephyr was a Consul with a longer nose to accommodate an inline six-cylinder engine — this Edinburgh Green saloon is a 1953 model / Bonhams
MacPherson decided to take advantage of the new models’ monocoque construction by adopting a refined version of the strut suspension he’d previously devised for the Chevrolet Cadet. Although the Consul/Zephyr suspension was similar in principle to the Cadet suspension, it was different enough that MacPherson was able to patent the new version separately (as US2660449, filed in January 1949 and issued in November 1953).
The diagonal braces at the back of the Consul engine bay triangulate the upper strut mounts / Car & Classic
Here are the patent illustrations showing the new suspension from several angles:
Although the Consul and Zephyr only had independent suspension in front, MacPherson’s patent again emphasized that the same basic layout could also be used for the rear suspension as well. Rear struts generally don’t need to be steerable, so they can be further simplified, but the principles are otherwise the same.
MacPherson explained the object of this suspension like this:
[An] object is to provide a suspension which is unusually light in weight and in which a considerable saving in cost is made by the elimination of many conventional suspension parts and assemblies. This is accomplished by combining a number of the functions of the suspension system [emphasis added]. For example, a stabilizer bar is provided which not only serves to effect transverse stability in the usual manner but also forms part of the wheel supporting and guiding structure, eliminating the need for separate assembles therefor. Likewise, a sturdy direct acting tubular shock absorber forms part of the wheel supporting and guiding structure, combining several functions into a single assembly. These and other advantageous features of the present invention result in a simplified, light weight and economical wheel suspension having very desirable ride and performance characteristics.
This layout had many advantages. Here are some of the most important specific benefits of MacPherson’s strut suspension:
- There’s no need for a separate upper wishbone or control arm.
- The lower control arm (which Ford called a track control arm) doesn’t have to handle spring loads, so it can be very light.
- The coil spring can be longer (and thus softer) than on a conventional double wishbone suspension.
- The strut’s upper thrust bearing is very high, so the effective swing arm length (the radius of the arc the wheel traces as it rises and falls) is quite long, minimizing camber changes.
- There’s no need for a tension joint or compression joint, since vehicle weight is carried directly on the upper ball joint.
- Suspension loads are taken directly by the body structure (through the inner fender and cowl) rather than through the suspension arms.
- Assembly is simplified, saving labor cost per unit.
Although the shock/strut tube and the fender structure have to be reinforced to withstand the necessary loads, there’s still a significant net savings in both total suspension weight. That also reduces unsprung weight, giving better ride quality, especially with small, lightweight vehicles. (The 1951 Consul and Zephyr were heavier than the Cadet, but the four-cylinder Consul had a curb weight of only 2,435 lb, while the six-cylinder Zephyr was 2,591 lb.)
The way the Ford suspension used the front anti-roll bar was new and very clever. Each of the anti-roll bar’s thrust arms was carried on a short swing arm (highlighted in red in the illustration above), which was carried on a bracket bolted to the body structure. The swing arm allowed the anti-roll bar to pivot to accommodate the vertical motion of the wheels, but the thrust arm would act like a radius rod to limit the fore-aft movement of the wheel and the track control arm. This was a more elegant (and probably cheaper) solution than the Cadet approach: The Cadet had no anti-roll bars, so its front struts were each located by a track rod and a radius rod, which had rubber joints that controlled front wheel alignment.
Here’s an exploded view of the actual Consul/Zephyr front suspension, from a Ford parts book:
An additional advantage of the Consul/Zephyr suspension was that it put the steering linkage behind the front axle line. This meant that a front collision was less likely to push the steering box and steering column into the cabin — a worthwhile safety advantage in the days before collapsible steering columns.
Ford of England had adopted MacPherson struts line-wide by the late ’50s, and they were adopted for the new German Ford 17M in 1957. However, because these strut suspension layouts were heavily patent-encumbered, they didn’t see widespread outside use until the original patents expired in the early ’70s. I think the first major outside user was Peugeot, with the 1961 Peugeot 404, followed a year later by the BMW Neue Klasse sedan.
1961 Peugeot 404 / Classic Car Auctions
Unlike Ford, the Peugeot strut design (below) didn’t use an anti-roll bar, substituting a two-piece lower wishbone instead. Later, Ford also deleted the front anti-roll bar for some applications, instead using an articulated radius rod. This worked in mostly the same way as the original layout except that the left and right thrust arms weren’t connected, so they didn’t add to roll stiffness. Most modern applications now use a lower wishbone, usually with a separate anti-roll bar, which is a little more expensive, but allows more flexibility in front roll stiffness and bushing settings.
Once the original patent terms expired, MacPherson struts were very widely adopted throughout the industry. Today, they’re ubiquitous. There have been many variations on the original themes, but most of the basic principles still apply, and MacPherson struts still have enough advantages in cost, weight, and packaging that they have crowded out most competing designs.
Related Reading
1947 Chevrolet Cadet: The Revolutionary Postwar “Light Car” Chevrolet Never Actually Built (by me)
I always assumed MacPherson patented this while at GM and the patent “travelled” with him to Ford, so thanks for the research. I think back then the patent was truly held by the creator and not the employer. I’m not sure how corporations changed that besides the waiver engineers sign these days saying that anything created while employed is the property of the employer.
I’m also somewhat surprised that GM patent attorneys didn’t swarm over any design project looking for ripe fruit.
All of MacPherson’s patents were assigned to his employer at the time, which was the usual practice even then. (There were a few exceptions — Packard Torsion-Level was one — but GM and Ford were usually strict about it.)
ok that’s good info. So now I’m really surprised GM didn’t challenge the patent based on the drawings of the Cadet they had in the vault. I realize he changed it somewhat but a good attorney could have claimed prior art etc. etc. They must have assumed it wasn’t worth the bother??
In general, if there were conflicts like that, the domestic automakers would try to work them out through the Automobile Manufacturers Association (which was also how they handled model names). Figuring out how certain conflicts may have been resolved is difficult because the AMA-mediated negotiations were not public, and the automakers were generally not keen to talk about them. (For instance, the GM Unitized Power Package used in the Toronado and Eldorado trod on some Ford patents related to the abortive FWD Thunderbird project; this was kind of an open secret at the time, but what arrangement Ford and GM may have reached wasn’t publicly acknowledged.) I assume there was a lot of quid pro quo — as much as GM and Ford were hammer and tongs commercially, I don’t think either was very keen to get into messy public legal battles if it could be avoided.
thanks for filling in my knowledge gaps. I guess the auto companies figured out there is plenty of grist for the mill so let’s work this out.
I also follow the Ag Equipment industry and they do things differently. John Deere especially has always been very adamant about going after patent infringement whether it be the little companies or large. I know of one case in particular where they went after a little guy brutally and ended up losing. But then they went after IH and won a lot of money.
I don’t follow ag stuff, but I know that about John Deere, which has given me a pretty negative view of them as a company. Since I’m not in the ag business, they have no reason to care what people like me think about them, but there can be negative publicity consequences even if you win, which may have been a factor for the domestic industry.
There may also be some other nuances that we can only guess at now. For instance, in the ’40s, U.S. courts were inclined to construe infringement claims very narrowly if the patent-holder wasn’t using the invention commercially (which I wish was still true today, as it might cut down on the plague of patent trolls); GM was well aware of that, as it had worked in their favor when an inventor sued them over Hydra-Matic. Since GM wasn’t using or planning to use the Cadet strut suspension for anything in particular, that would likely have limited what they could claim as infringement (and what they would stand to gain in terms of damages).
Also, it may or may not be suggestive that neither Ford nor GM used this kind of strut suspension on their domestic products until the patent terms had all expired. Ford of course used MacPherson struts extensively in the UK and later in Germany, but that only implicated the U.S. patents to the extent Ford imported English and German Ford cars, which was never very much. So, I think their potential exposure was probably fairly limited, which also probably reduced the likelihood of getting into it with GM about it. (Ford did contemplate using MacPherson struts for the Thunderbird, but decided not to, ostensibly because it would be too expensive compared to the coil-on-upper-wishbone approach, which I always thought was a peculiar argument.)
A more recent and “minor” example:
Honda has had a line of motorcycles called “Hornet” since the late 1990s. It’s owned by Hudson/AMC/Chrysler so Honda couldn’t use it in the US.
However for 2025 American Honda proudly introduced CB750 Hornet and CB1000SP Hornet, because RAM now has a pickup truck model called Rebel, which Honda has had since the 1980s.
Quid pro quo.
Kinze is a relatively small privately held company that makes corn planters among other things. Their folding toolbar was the big innovation and they were purchasing the planter units from John Deere. Deere noticed Kinze selling more and more units so they forbid any dealer from selling the planting units to him. Kinze just copied the planting units and Deere sued. After a long court battle Kinze won because they proved that Oliver had a very similar planting unit back in the ’60s and Deere was actually copying them. Too many lawyers at Deere I suspect. Lately they are in the news for other negative reasons. They were no. 2 until the 60s and then became a bully.
CC effect: just saw an old Alfred Hitchcock Presents episode (‘Crackpot’) where a main character came driving up in a Ford Consul Mk1. Since it first aired in 1957, I’m going to guess it was an early 1956 car.
I couldn’t believe it. At first, I thought it was one of those independent compacts and had to come back to CC to verify what it actually was. I really wonder how that car came to be used and am guessing that, due to the nature of the shot, they were looking for something rather small to fit. Not to mention that the guy driving was rather rotund.
One of the truly groundbreaking automotive inventions of the 20th century. Quite brilliant.
I’ve always had a bit of a thing for the Consul of this vintage. It’s what the Cadet could have been as a production car.
Peugeot really took it to the next level with their struts on the front of the new 404, giving them exceptionally long travel yet with good control thanks to their own very effective shock absorbers.
Great piece, thanks. Interesting that the Cadet had struts on the rear, I had assumed strut-type rear suspension was more or less invented by Colin Chapman.
Nope, but Chapman — who was a crook — liked to make people think that, and since rear struts weren’t widely adopted until years later, he mostly got away with it.