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KRAIBURG CONFERENCE
Kraiburg Testing Backs up Retread Performance
how retreads manufactured with its for traction on uphill and downhill
treads compare with new tyres. Firstly the company compared its own K729 pattern with Bridgestone’s equivalent M729 pattern in size 315/80 R 22.5. Both tyres rated C in wet grip but the tyres made with the Kraiburg pattern scored D in rolling resistance compared with E for Bridgestone, and was also quieter at 74 dB compared to the Bridgestone’s 78 dB.
Meanwhile, Kraiburg’s KDE2 tread came out absolutely identical in performance compared with Michelin’s XDE2+ pattern. Both tyres scored D for rolling resistance, C for wet grip and 75 dB for noise.
In order to illustrate that there was no bias in their choice of patterns, Kraiburg also compared their K30 design with Michelin’s XTE3. This showed identical rolling resistance ratings of C but slightly better wet grip for the new tyre (B compared to C). The XTE3 was also better on noise (69dB compared to 72 dB for the Kraiburg design).
Overall, though, the message from Kraiburg was that retreads are comparable in performance to new tyres. The final message was that, from a technical point of view, nothing distinguishes new tyres from retreads other than sustainability. Priewasser also reported some 3PMSF tests carried out last year in the Snow Dome in Bispingen, Germany, in which 5 sets of truck tyres were tested
gradients of up to 23per cent.
To achieve 3PMSF grading tyres need to be 25 per cent better than the reference tyre. Some of Kraiburg’s patterns showed themselves to be significantly better (the K213 was 66 per cent better than the reference tyres). As a result of these tests the K74, K213, K204, K225, K700 and K801 treads will all be marked with the 3PMSF snowflake symbol in the future.
Kraiburg tread showing 3PMSF snowflake symbol
Kraiburg Product manager Christoph Priewasser explains the testing programme that the company has carried out
In recent times Kraiburg has been heavily involved in in-depth testing programmes to validate the performance of its pre-cured treads against new tyres, in order to demonstrate the retreads can and do perform as well as new tyres across a whole range of applications. Product Manager Christoph Priewasser spent some time during the Kraiburg Retreading Summit outlining some of the tyre testing the company has done as part of its customer support work. Priewasser in particular emphasised
the importance of reducing rolling resistance, quoting Michelin – “a third of a tank of fuel is used on tyres.” Kraiburg has been testing tyres since 1999 and the company says that tyres are becoming much more comparable than they used to be. Overall, Kraiburg’s testing showed that retreads can show less, equal or more rolling resistance than new tyres due to the fact that 40 per cent of rolling resistance is caused by the tread pattern.
Kraiburg provided three examples of