Mention tuning these days and most people involved in the tire retail and auto service business tend to think of aftermarket tuningor the practice of trying to modify a vehicle with different tires, wheels, shocks, steering and suspension kits, etc.to achieve a desired change in the way a vehicle performs or handles.
This often involves plus-sizing, that is, fitting larger-size tires and wheels.
But tuning to the qualified vehicle or tire engineer means something drastically different.
Tuning to most auto industry engineers means a more holistic, integrated tire/vehicle system engineering approach to vehicle engineering, one that takes into account a vehicle's complete range of operating characteristics, such as the road manners, rolling feel, sound, ride, handling, directional stability, traction, etc.
While this approach may seem like common sense today, it wasn't always so.
When I started working with Ford Motor Co. in the mid-1950s, the concept of tuning the car and tires was largely unknown. Tires were strictly the domain of the tire manufacturers.
It was at that time that I was able to implement the tire/vehicle system engineering approach to vehicle development, or tuning, that eventually became part of a comprehensive, previously non-existent Ford Engineering Product Acceptance Specification controlling tire and wheel precision and uniformity. This was based on the measurement of tire radial, lateral and tangential force variation, as well as conicity (conicity in view of the coming radial-ply tire era).
My views were based on observations that, for a given feel of vehicle sensitivity and tire/wheel assembly precision and uniformity, nothing could change or influence the road manners, rolling feel, sound, ride, handling, directional stability, traction and operating smoothness characteristics of a vehicle more than the tires fitted to that vehicle.
In other words, how well tires were developed and could, or should, be matched to the particular vehicle architecture involvedand vice-versaachieving the desired road/tire/vehicle system tuning.
It should be noted these views were developed at a time when bias-ply tires still dominated the U.S. auto industry and when Ford top management (including Robert McNamara, Ford Motor president, later U.S. Secretary of Defense) wanted to increase tire tread life to 50,000 miles from 15,000 miles or so.
To achieve this would have required a tire capable of lasting 75,000 miles to cover variations, an achievement not possible using the then-prevalent bias-ply tire architecture.
To get 50,000 to 75,000 miles out of bias-ply architecture, a tire/wheel assembly would have to be of a totally impractical size and weight and require a significantly higher structural integrity and more space in the vehicle to accommodate the resultant super-sized heavier and more expensive tires.
As a result, Ford was convinced that only radial-ply tires could fulfill their treadlife objective, and yet it took nearly a decadeuntil the 1970 Lincoln Continental MKIIIthat Ford brought to market a car in the U.S. mounted on radial tires.
At that time only Michelin Group was capable of meeting Ford's objectives. U.S. tire makers were outraged, but Ford's decision set into motion a tumultuous period that led to the radialization of the American tire industry.
Just fitting radial tires onto an existing car model did not, and could not, achieve Ford's desired ride characteristics, however.
Parallel to the radial decision, Ford had to consider fore and aft compliance in the suspension system as well as other vehicle engineering changes in order for radials to be compatible with Ford's car requirements.
These changes, which resulted in a smooth, low harshness ride and predictable steering, are what I called a radial-tuned suspension or radially tuned vehicle.
These events triggered gradual improvements in the operating smoothness and ride qualities of Ford carsand eventually of all American carsregardless if equipped with bias or radial tires.
Needless to say, this was not only a revolution but also a revelation.
Being able to implement at Ford the tire/vehicle system approach was due, I feel, to the considerable freedom, independence and support from Ford Motor. To be creative and develop significant technologically based systems you need time to think, research and correctly execute. One cannot be rushed, and above all, one must have scientific integrity.
I don't know if in today's rush-rush society and environment this would have been possible. The recent massive recalls of cars indicate clearly that the automotive culture, particularly in the U.S., must change. Engineering discipline and engineering also must improve drastically.
System engineering, or more specifically tire/vehicle system engineering, is just as important today as it was in the 1960s, if not more so, because of today's general adoption of unitized vehicle body construction rather than body-on-frame construction (which is easier to tune), stiffer bodies, stiffer tires and suspension systems, and the addition of all kinds of electronic controls, communications, etc.
At this point you might be asking yourself what exactly do I mean by system engineering?
System engineering is the design, development, validation and manufacturing of multi-component, interrelated or interdependent technologically based entities and functions. In our case, and simply speaking, tires and vehicles make up the system, since one cannot function without the other.
It is actually more complicated, since the vehicle has more than one sub-system. System engineering therefore requires understanding of what ramifications the failure of one sub-system can have on the other.
The elements that make up our system are:
c A tire/wheel assembly;
cA vehicle to which said tire/ wheel assemblies are coupled;
cA road surface on which the tire/wheel/vehicle combination is operating; and
cA driver who controls the road/ tire/vehicle-system combination.
Actually, we really are talking about a road/tire/vehicle/driver system.
Many cars today still exhibit insufficient operating smoothness characteristics, as evidenced by their higher-than-desirable tire/vehicle ride harsh-ness, boom noise levels and insufficiently developed good vehicle-rolling feel. They are in dire need of tuning.
Some of you, no doubt, have experienced this, particularly this year with the ever-increasing number and size of pot-holes and general poor road-surface conditions, resulting in flat tires and broken wheels. Better tuning might have prevented some of this damage.
As I mentioned earlier, years ago well-developed cars in America were body-on-frame architecture, featuring soft body-to-frame mounts, and made use of compliant suspension and steering systems, which also included soft bushings and lower pressure, higher-section-height tires mounted on narrower rim width (51/2 to 6 inches) 14- and 15-inch diameter wheels.
The powertrains of these cars were isolated from the vehicle frame with very soft mounts. The overall results were that road-induced noise and vibrations, including from slightly out-of-balance tires or tire-force variations due to tire/wheel assembly non-uniformities were, for practical purposes, fully absorbed by such tire/vehicle system.
It's almost needless to say, but people for the most part take tires for granted.
Actually, tires are a critical part of the vehiclethey are the only thing that touches the ground. Without tires a vehicle can't move. Tires provide the vehicle with traction, directional control, stability, operating smoothness and ride and absorb all normally encountered road-surface irregularities, providing the tires are of sufficient section height and properly inflated.
All car, SUV and light-truck tires should be developed and produced at the same high levels of structural integrity as aircraft and medium/-heavy-duty truck tires, thus providing the consumer with good mileage and the potential for retreading.
Today, we are confronted with some unfinished tire/vehicle system engineering challenges:
1. More fully exploit the potential for the radial tire architecture and significantly improve road/tire/vehicle system tuning.
2. Significantly improve tire tread life and tire structural integrity retention, for one does not go without the other;
3. Continue to improve tire manufacturing precision and uniformity;
4. Reinstate passenger car and light truck tire retreading/remanufacturing, for these processes are the real measure of original tire quality, as is seen in medium/heavy truck, aircraft and earthmover tires;
5. Simplify the tire design and manufacturing process. This is, in my view, where most technological efforts should be concentrated. Simplification should apply to the whole vehicle.
6. Develop and produce tires specifically for hybrid and fully electric-propelled vehicles;
7. Improve relations between tire and vehicle manufacturers and their dealers, with the manufacturers providing more and better training to their dealers, including providing technicians with better service equipment; and
8. Educate consumers in tire/vehicle system technologiesgranted a costly and lengthy proposition, but in my view absolutely necessary.
In my view, the current automotive situation developed as a result of insufficient knowledge and understanding of the vehicle system and sub-system engineering and development approach, and insufficient knowledge of the radial-ply architecture capabilities and tire/vehicle system tuning possibilities.
Only through tenacity, perseverance, dedication and passion can the problems facing the vehicle system engineer and this industry today be solved.
To reach these desirable objectives will require hands-on engineering education in tire/vehicle system technologies through comprehensive and intensive apprenticeship programs staffed by experienced mentors, as well as a change in corporate thinking and culture.
This could be a win-win situationa happy consumer contributing to a happy (and profitable) automotive industry.
Jacques Bajer is founder and president of Tire Systems Engineering Inc. in Grosse Pointe, Mich., a consultancy dedicated to road/tire/vehicle systems technology
The French-born engineer was an active participant in the evolution of the automotive and tire industry. His work at Ford Motor Co. from 1955 to 1970 led to the development of the tire uniformity grading machine (1962) and the low-profile tire (1964). Mr. Bajer also was a key figure in the radialization of America.
Mr. Bajer has many patents on tire production and design. He realized that American automobiles would have to have both dramatic and subtle modifications to chassis, suspension, drive train and body panels to fully utilize and appreciate all of the advantages of radial construction. To this end, he helped develop the idea of power-train presence (power spectral density analysis), the acoustical tuning machine technique and the virtues of suspension compliance. His work earned him a spot in the Tire Industry Association's Hall of Fame, to which he was inducted in 2006.