Marketers toss the word sustainable around with gusto, and for many people it means everything and nothing. We were therefore interested to see exactly what auto motor und sport had in mind when it announced that sustainability would feature prominently in its 2025 test of six tyre brands in size 215/55 R 17, a dimension found on both electric and combustion-powered cars and crossovers as well as compact SUVs.
For the test, the motoring publication chose the sustainably produced Continental UltraContact NXT, the Bridgestone Turanza 6, Falken e.Ziex, Goodyear EfficientGrip Performance, and the Michelin e.Primacy, which is optimised specifically for EVs. As the focus is on sustainable, energy-efficient tyres, it selected products with at least an EU tyre label ‘B’ rating for rolling resistance. Additionally, ams explored whether retreaded tyres might be a more sustainable and cost-effective alternative, including the only available retreaded tyre in this size and quantity at the time of testing – the Insa Turbo EcoEvolution.
What makes a tyre sustainable?
So, what is ams actually referring to when examining a tyre’s sustainability? That depends on the product. For instance, ams explains that the Continental tyre achieves sustainability in production through an intelligent combination of recycled materials and renewable resources. The NXT is primarily made from natural rubber, bio-based silica from rice husk ash, recycled PET bottles, and reused steel. Ams awarded extra points in its sustainability rating for innovations such as these. It also gave points for short routes from factory to market, the market in this instance being Germany, where the publication is based. As the Continental tyre is produced in Portugal instead of in a local factory, it lost three points due to higher CO2 emissions from logistics.
In contrast, Bridgestone derives the sustainability of its Turanza 6 mainly from higher mileage and improved fuel and energy efficiency. Various innovations in the tread, rubber compound, and construction aim to enhance the tyre’s performance and sustainability.
The Falken e.Ziex claims up to 29 per cent sustainable and recycled materials. The tyre pairs good wet traction with extremely low rolling resistance to lower energy and reduce CO2 emissions. Transport distances are relatively short for this Japanese tyre brand too, as Falken produces the e.Ziex in Turkey.
Goodyear, like Bridgestone, defines the sustainability of the EfficientGrip Performance 2 through a Longlife technology: Since EVs are typically heavier than conventional vehicles, they usually experience higher wear. The Mileage-Plus technology aims to give the new Goodyear tyre 50 per cent more mileage than its predecessor. Additionally, Goodyear has significantly optimised its efficiency through optimisations in its structure, compound technology, and sidewall aerodynamics, contributing to sustainability.
Michelin produces the e.Primacy in Germany using a manufacturing process the tyre maker says is CO2-neutral, giving the tyre a zero-carbon footprint at the point of purchase (when sold locally). On the road, the Michelin tyre’s very low rolling resistance, long lifespan, and minimal abrasion positively impact its sustainability.
And the Insa Turbo EcoEvolution? The Spanish retreader selects casings from used tyres and buffs these before inspection. Then it uses the mould cure or hot retreading process to give the casing a new tread and sidewall. As a final step before the tyre leaves the retreading plant, the company employs additional X-ray and visual inspections. Retreading is commonplace in the truck tyre sector and considered very sustainable; the focus for ams was therefore to explore just how environmentally friendly, dynamic, and safe retreaded car tyres are compared to their newly manufactured competitors.
Sustainability good, safety better
The aim for ams during the test was to save CO2 and ideally emit none at all. Since driving less and slower was not an option, the publication fuelled its diesel logistics and test vehicles with HVO 100 and petrol vehicles with e-fuels for petrol engines. But safety remained the priority, not least the ability for tyres to bring the car to a stop in the shortest distance possible on both wet and dry asphalt.
The test team conducted wet braking from 80 km/h, and the three best results – from Continental, Falken and Goodyear – were all within half a metre of each other. The Bridgestone tyre came to a stop 1.2 metres after the leading Continental tyre’s impressive 31.5 metre result while the Michelin, optimised for low rolling resistance and wear, required a further 3.5 metres than the Conti. Ams considers this result a “necessary compromise.” And the budget-friendly retreaded tyre? A car fitted with Insa tyres would still be sliding at 41 km/h at the point where a Conti or Falken-equipped car has already stopped, coming to a halt 11.1 metres later. The ams test team considers this result “unacceptable.”
Testing on dry roads
When braking on dry asphalt, the Falken e.Ziex delivered the best stop from 100 km/h, requiring just 35.2 metres to do so. The Continental, Bridgestone and Goodyear candidates all pulled up somewhere between 36 and 37 metres, with Michelin close behind at 37.8 metres. The Insa tyre needed almost 42 metres to stop, its residual speed being around 40 km/h at the stopping point of the grippy Falken.
Whether in the wet or dry, quick reactions or a very generous safety margin are needed to prevent serious damage. Ams believes that the leading products’ close results show that these well-known brands have accepted the challenge to deliver more and have continued to develop products that offer not only sustainability, economy and comfort, but also safe traction.
Complex scoring system
Now to the final scores, and make sure you get a good night’s sleep before busying yourself with how ams awarded points during this test. Below is ams’ description of its scoring system:
The maximum achievable score in all test disciplines is ten points. In order to categorise the results according to their relevance to everyday use and safety, the individual disciplines in each category are weighted differently. Additionally, depending on the tyre specification (summer, winter or all-weather tyres), the test categories ‘wet’, ‘dry’, ‘environment’ and ‘sustainability’ are also evaluated in a second step according to a fixed key.
In this test, the auto motor und sport evaluation key applies to particularly sustainable summer tyres and standard summer tyres (information in brackets): Wet 40% (50%), dry 20% (40%), environment 20% (10%), sustainability 20% (0%). The overall score is calculated from the average of the sustainability and standard scores.
A score of 5 or fewer points in a safety-relevant discipline leads to a devaluation of one grade point in the overall score in the respective category. The grade ‘phenomenal’ can only be awarded once, in this case in the event of a tie for more innovative sustainability technologies.
Phenomenal
On the basis of this points wizardry, ams awarded test victory to the Continental UltraContact NXT – the only one of the six tyres to gain the aforementioned top rating of phenomenal. On dry roads, the Continental tyre (along with the Falken) showed the strongest safety reserves and safest cornering behaviour. Ams also praised it for delivering the shortest braking distance and balanced handling in the wet, safe understeer with high cornering stability in dry conditions, and low rolling resistance.
4 very good tyres
The Goodyear EfficientGrip Performance 2, just ahead of the Bridgestone Turanza 6, offered the best cornering grip, good aquaplaning protection, and high driving precision in the rain, despite minor weaknesses in wet braking. If comfort is what you seek, the quiet and particularly fuel-efficient Michelin comes to the fore. Apart from braking, e.Primacy impressed in corners and hazardous situations with safe, forgiving handling. In electric vehicles, it scores with maximum range, minimal rolling noise, and quiet running. Ams rated all four tyres as very good.
Swipe left – poor result for Insa
Did the affordable retreaded tyre prove its worth as a more sustainable alternative? Some factors, such as less resource-intensive production, suggest so. However, ams says the driving safety results “loudly oppose this” – its tester considers the tyre a risk.
“Neither in traction properties nor in manufacturing quality can we accept this,” states ams. “Unless you’re looking for an innovative tyre with built-in rough-road capability. Because that’s exactly how the Insa drives – rough, uneven, loud, and unpredictable. No wonder, given that each wheel position likely has a different tyre casing despite the same tyre appearance.”
But the motoring publication had not finished criticising this potential paramour: “Sustainable? It is not. Its immense rolling resistance not only causes over ten per cent higher fuel consumption but also affects acceleration and top speed. And what else? Yes, it also failed the high-speed test according to the VW standard we applied. The result: unsatisfactory! Not recommended!”
The test may have resulted in one jilted suitor, but ams shows ample love towards the tyres at the top of the table. “Like the Michelin e.Primacy, when it comes to maximum efficiency and optimal comfort. And the test winner, the Conti UltraContact NXT, when safety, dynamics, and the best possible sustainability matter. And not least, the Falken e.Ziex, which, with minimal compromises in sustainability, delivers outstanding safety results.”
