[avi550m]

I recently changed my 7 year old XM2s on my A-Star for a set of MRF ZLX's of the same stock size (155/80 R13). Apart from the noticeable improvements like lower noise and better ride comfort that comes with a new set of tyres, one thing I noticed was that the cars acceleration seemed to be better. I have always filled the Michelins with 33 psi all around (just that morning in fact), and the MRF's with the same pressure seemed to deliver better acceleration with the same throttle input. In fact, it was very similar to when I originally replaced the OEM CEATs with the Michelins in the beginning. Any idea if tyres gather more rolling resistance with time? This phenomena is quite perplexing to me.

[driver52001]

If indeed what you felt is a fact and not a play of the mind on driving with new shoes, then it's a bit perplexing. Not sure about the science. But since tyres tend to harden with age, the only logical outcome would be lower rolling resistance, not to the contrary. Could be ZLX has a wee bit more harder compound than XM2?

[dhanushs]

Originally Posted by avi550m

I recently changed my 7 year old XM2s on my A-Star for a set of MRF ZLX's of the same stock size (155/80 R13). Apart from the noticeable improvements like lower noise and better ride comfort that comes with a new set of tyres, one thing I noticed was that the cars acceleration seemed to be better. I have always filled the Michelins with 33 psi all around (just that morning in fact), and the MRF's with the same pressure seemed to deliver better acceleration with the same throttle input. In fact, it was very similar to when I originally replaced the OEM CEATs with the Michelins in the beginning. Any idea if tyres gather more rolling resistance with time? This phenomena is quite perplexing to me.

Apart from new tires giving a placebo effect, the lowered road noise (Clear and smooth engine sound) adds to the experience of better acceleration. As such, IMO, old tyres vs new tyres dont differ much as far as rolling resistance is concerned.

[pradkumar]

The road transport ministry has come out with draft rules which say that the tyres of cars, buses and trucks should meet the requirement of rolling resistance, wet grip and rolling sound emissions – a move aimed at ensuring quality and reliability of tyres.

https://www.firstpost.com/tech/auto-...y-9650281.html

[rajathv8]

I too felt the same when I changed my A-Stars Apollo Aceleres to MRF ZLX but later realized the lower road noise meant the engine noise was clearer and felt smoother.