Automotive OEMs across the world are diversifying their product ranges and producing a wider variety of cars from the same basic architecture. The evolution of the BMW 3 Series is an excellent example.
Originally launched in the late 1970s, the E21 3 Series was only available as a two-door sedan with two engine options. In the early 1980s, a convertible version became available. When it was revamped, the E30 generation added both four-door sedan and five-door wagon. A diesel engine was added along with an all-wheel-drive option and an M3 performance model. In the 1990s, a 3 Series hatchback joined the range, along with a wider engine choice and the Z3 sports car, which was built using the same platform.
This trend of diversifying the product has accelerated in recent years. Fast-forward to today and the current 3 Series platform supports multiple, entire model ranges. This means the same basic underlying chassis is available in four-door sedan, wagon, Gran Turismo (four-door coupe), two-door coupe, Gran Coupe (a somehow different four-door coupe), convertible, SUV, slightly larger SUV and a sports car! Across all those body types there are six petrol engines, three diesel engines and a hybrid. All are available in numerous combinations with a total of five different wheel sizes.
So why such a broad range? It all comes down to return on investment. The cost of developing a new platform is enormous, while the cost of modifying an existing platform for a new body type or engine is much cheaper but can still create what customers see as a very different car.
Using this approach, BMW created a platform for the core model 3 Series sedans, which appeals to customers in that market. However, by designing a convertible built off the same platform, BMW has a low-cost way of offering a different flavor of the same basic car, which then appeals to different customers. Continuing to do this divides the enormous cost of platform development across a wide range of cars that appeal to the broadest possible range of customer groups.
The problem is that while this is great for the car companies, it’s far from ideal for the tire suppliers. Most of these unique combinations of body style, engine, drive type and wheel size will require unique tires to be developed for each model. For example, the coupe will probably have a sportier feel than the sedan, so it’ll likely need a sportier tire. The problem is that while the sum total of vehicle sales across the entire platform will be higher, these sales are divided across a very wide range of different models, so the number of sales of each individual model will be lower. If each model requires a unique tire, this means fewer sales for each tire design. Tire companies still need to invest in designing tires for each of these fitments, only for them to sell in lower numbers, making it harder to recoup their development costs.
To address this, tire companies could increase their piece prices – unlikely given the cost-down pressures we see across the automotive industry. Alternatively they could lower their quality, but neither the OEMs nor the tire companies themselves will be happy with an inferior product. That just leaves a reduction in development costs. Should you have a solution of exactly how to do this, then myself and every other tire engineer would be interested to hear it!
Many approaches are being introduced to address the problem. For example, not all of these fitments necessarily have to be completely unique. When the various vehicle models are all adaptations of a common basic platform, the same philosophy can often be applied to the tire designs. A common core tire could be tweaked for different applications, rather than completely redesigned. Furthermore, modern mathematical simulation technology is being used to iterate tire designs without the use of expensive prototype tires and vehicles. This reduces the development costs not just for the tire companies, but for the OEMs as well. While this comes with a lot of challenges to overcome, it is undoubtedly the direction in which the industry is heading. Watch this space.