Hand on heart: would you also rather buy a cheap new tire than an equally expensive retread car tire? Although the more sustainable? BAYERN 1 environmental commissioner clarifies how good and safe recycled tires really are.
By: alexander dallmus
Status: 12.10.2020 | archive
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Are retreaded tires worse?
The retreading of tires was common practice in the Federal Republic of Germany, especially in the post-war years. In the GDR, every second tire was retreaded, which was a result of the shortage of materials. Retreading of old tires was carried out primarily to meet the daily demand in the still young Federal Republic of Germany. At that time, however, materials and processes were used that are not comparable with today’s state of the art. But this is precisely the reason for the prejudices against retreaded tires that still exist today.
Also on the grid in Formula 1 racing: retreaded tires
In the commercial vehicle sector, in the earthmoving machinery sector, and even in motor racing, retreading is completely normal. In the aircraft sector, retreads are the order of the day. Aircraft tires are retreaded up to five or six times. Retreaded tires are also used in racing at speeds of over 300 kilometers per hour.
How retreaded tires are made?
Not only do they look like new: retreaded tires
The tread pattern of a tire must not be less than 1.6 millimeters deep, otherwise the tire may no longer be used. In principle, the retreader does nothing other than restore the tread rubberization and a thin cap layer in the sidewall area to ensure an optimum appearance and bring the rubberization back up to the level of a new tire. Rubber compounds of comparable quality are used for this purpose. Multi-layer processes are also used to optimize the rolling resistance of the tire. In the upper area of the tread, a useful compound is applied that is also used in the same or similar way in the new tire industry. So that no restrictions have to be accepted with regard to concentricity and driving behavior.
"When tires are retreaded, the tread, that is the area where the tread is, is abraded, ground down, and then what remains is very elaborately inspected for damage. And if the carcass is perfect, a new rubber is applied and then the tire goes into an oven, is vulcanized and gets its new profile."
Thomas schwarz from the vehicle technology department of ADAC southern Bavaria
A great deal of technology is now being used, which makes the process correspondingly cost-intensive for the company. For example, state-of-the-art technologies such as cherography, pressure testing, and in some cases X-ray processes or nail hole detectors are used to ensure the highest level of safety. This effort has consequences for business, says michael schwammlein of BVR, who is also technical secretary of the european retreading association BIPAVER:
"The financial costs of running a professional retreading operation have increased to such an extent that we are experiencing massive losses throughout europe. So that the market shares in the retread sector, as far as the tire replacement market in the passenger car sector is concerned, are certainly well below one percent."
Michael schwammlein of the Bundesverband reifenhandel/ BVR, and technical secretary of the european retreading association BIPAVER
In germany, passenger car tires are still stored in the factories of the company "rigdon gmbh" in gunzburg as well as from "reifen hinghaus" retreaded in dissen (lower saxony).
When is a tire new and when should winter tires be replaced?? read this and many more in our article "tips for storing your summer tires".
The carcass – the decisive tire framework
The basis of every retread, regardless of the tire segment and the type of tire, is always the worn tire, the so-called carcass. The carcass is, so to speak, the supporting structure in rubber tires.
The tire carcass is the heart of the process. The carcass contains the bead core, i.e. the area where the tire sits on the rim. It is therefore the direct link between the vehicle and the road surface. in addition to the sidewall and the fabric plies made of different materials, the carcass also includes the belt plies, which are installed at different angles. The aim is to guarantee the car maximum stability and safety, even at high speeds and during extraordinary driving maneuvers. Each tire manufacturer has its own "recipe" for its carcasses, of course and that’s why thomas schwarz from the ADAC also has certain concerns:
"As a customer, I can end up with carcasses from four different tire manufacturers that all look the same from the outside, but can have different handling characteristics."
Thomas schwarz from the vehicle technology department of ADAC Sudbayern
the problem could be solved, for example, by having the manufacturers chip their carcasses with the necessary information for the retreads. However, manufacturers are not likely to be very keen on disclosing the exact composition of their carcasses.
For michael schwammlein of the German tire trade association, on the other hand, it is much more important that the load-bearing structure of the tire is already designed for a multi-life strategy in the new tire concept:
"this means that if the carcass is already given a potential in terms of deformation and deflection cycles, i.e. it is designed for a second life, then the retread has a basis that is so good that one can say that a retread is absolutely comparable to a new tire product."
Michael schwammlein federal association of tire dealers and european retreading association BIPAVER
In the passenger car sector, the volume of old tires is so high that the retreader has plenty of choice if there is the slightest doubt about the quality of the carcass.
Scrap tires are an increasing environmental problem
Around 60.000.000 tons of used tires are generated in germany each year.
In germany alone, almost 60 million old tires are discarded every year. That is the equivalent of a good 600.000 tons of material to be collected and also stored. Although the possibilities for recycling have multiplied in recent years, only about half of the used tires are actually processed into rubber granulate, for example. The old tires are shredded to such an extent that the rubber can be separated from the metal struts in the tire by a screening process. A large proportion of this granulate is later used on sports fields to make artificial turf or running tracks. But recycled old tire granulate can also be found as dampers in washing machines, in insulation mats or in electricity pylons.
There are already promising attempts to dismantle old tires back into their original components. In the so-called pyrolysis process, steel, soot, pitch and oil can be recovered as raw materials in the thermochemical decomposition process at up to 800 degrees Celsius. However, the process is still very time-consuming and cost-intensive and therefore not economical.
How to recognize retreaded tires?
Each tire may only be retreaded once.
Retreaded tires are not subject to the tire label obligation. According to the EU regulation on tire labeling, however, manufacturers of new passenger car and light and heavy commercial vehicle tires have been obliged since 2012 to indicate a fuel efficiency class for each of their products, as well as the wet grip class and external rolling noise class. But of course there are also strict legal requirements for retreaded tires and internationally valid minimum standards: each passenger car tire may only be retreaded once. Recycled tires can be identified by the (economic commission for europe) ECE numbers 108 for passenger car tires and 109 for truck tires on the side and – similar to the eggs – a code for the country that issued the approval. For germany this is "E1 . Furthermore, "retreads" must or "retread" be marked with the respective date of retreading. Tire size, speed class and load index are of course – as with conventional tires – also indicated.
Tests that motorists like to refer to before buying a set of new tires hardly exist for retreaded tires. thomas schwarz from ADAC sudbayern also admits this:
"ADAC has done very few tests with retreaded tires because the market does not accept retreaded tires."
Thomas schwarz from the vehicle technology department of ADAC Sudbayern
On the one hand, this is of course understandable, but on the other hand, it means that drivers have little or no chance to compare the driving performance in relation to the price with other suppliers. Michael schwammlein of the BVR can also only refer to internal tests of the retreader "reifen hinghaus" from dissen in lower saxony in the teutoburg forest: "and it achieves absolutely comparable values in these areas for both rolling resistance and wet grip, as is also achieved by a premium new tire."
Then it’s better to go for the cheap but new tires
A big problem in recent years has been the cheap tires from china that have flooded the european market. Retreaded tires are still a little cheaper, but the savings are not the decisive factor for many drivers, says thomas schwarz of the ADAC Sudbayern. "We have a lot of cheap new tires on the market, where the price advantage becomes relative again. Many people prefer to buy the new one before they buy something they don’t know the history of."
In the low inch size ranges, the retread is hardly worth it. That’s why retreaders tend to focus on the larger sizes, winter and all-season tires, or mixed on-road and off-road use, according to schwammlein "where new tire prices are in a range that makes retreads really competitive, with savings of 40 to 60 percent."
There is a future for retreads
The poor image of retreaded tires in large parts of the population is one problem, but the public sector could also position itself more clearly. For example, retreaded tires are generally excluded from police tenders, even though safety or quality standards are unlikely to play a role here.
The use of retreaded tires can still be expanded, especially in the commercial vehicle and transport sector.
"In the truck sector, a heavy truck tire saves about 50 kilos of scrap material and a considerable amount of CO2 in production. The old tire mountain grows. The question is, how long can we afford to keep working like this, when we have the opportunity to create a quick win?."
Michael schwammlein federal association of tire dealers and european retreading association BIPAVER
With the "de-minimis" program the federal government, for example, also uses public funds to promote environmental protection in companies that use heavy goods vehicles for road haulage. Here, it is also possible to apply for subsidies for investments in retreaded vehicle tires.
