chrisgixer Posted December 31, 2012 Report Share Posted December 31, 2012 I hate tram lining. I think Tony knows this, as a regular customer for set up with my omegas over the years. There's several "proverbs" on width and construction that are said to contribute to this hateful issue, but recently I have found a narrower and softer side wall tyre to tramline more than the wider firmer counterpart. I is confused. How can anyone tell if their new £520 worth of tyres will behave, and make my day knowing the next several thousand miles will be a delight? ...or reduce me to tears having spent a fortune and destroyed the handling of my car for the next year or so. HELP.... 245 40 18 sports contact 3 mo(Mercedes 93y) drives perfectly straight 234 40 18 sports contact 3 ao1(Audi, extra load) tram lines and pulls all over the place. (Both sizes are approved according to paperwork for factory fit sport wheels fitted. Although they quote a lower load rating of 91-93. Gm quote no lower than 94 in all sizes up to 17, 18 not listed.) Why do they behave so differently? Quote Link to comment Share on other sites More sharing options...
Tony Posted December 31, 2012 Report Share Posted December 31, 2012 Tyre communication is the key point here. Communication? A few factors allow the tyre contact patch to communicate back to the driver what's happening. As you say this communication is not always helpful, so here's my take on it.... 1: Starting at the contact patch the tread design has an influence toward tramlineing, these being... A: Symmetrical = lowest B: Directional = medium C: Asymmetrical = Highest C is actually the better tyre as far as performance is concerned but there's a problem obviously.... The Continental is class C so the best performing but the worst at belaying communication to the driver... Reason for this is the asymmetric tread runs a continuous solid band of tread designed to promote directional stability, well this is all well and good at testing on flat roads but we don't have nice smooth flat roads in the UK! The "continuer's " band here in the UK rides haphazardly the ruts and requires you the driver to compensate. In addition We have speed/ load and "approved" ratings? 1: The speed rating is beside the point unless the ring is your next trip? 2: The load rating is a safety issue and your insured at the OEM or above rating 3: Approved makings for type specific ( tyre-car ) are nothing more than that..... It's wise to use "approved" tyres/ compounds and i would suggest you do but in reality it's only the fact that particular tyre performed the best for that particular car and the tyre manufacture marked it "AO" Audi Only or "MO" Mercedes" Only, and so on....... Rigidity Communication between the tyres contact patch was in the past lost in the tyre's sidewall, as cars have evolved the wheels have become bigger and the tyre profile lower as a result the tyre sidewall smaller and more rigged, this "reggiet'y" if there is such a word transmits road irregularities directly to the driver. What to do? Well there's no real law here but i would suggest fitting the correct load rating/ symmetrical tyrer with a lower than suggested PSI - 2PSI. Quote Link to comment Share on other sites More sharing options...
chrisgixer Posted February 9, 2013 Author Report Share Posted February 9, 2013 Hi Tony, and thankyou. I will look into a symmetrical tread, in an attempt to lessen the odds to the problem re occurring. But in the cae of the sc3 mo/ao1 the tread pattern is exactly the same, so I had ruled that out as a cause in this particular case. Speed rating seems unlikely as the problem occurs at any speed, and these models have the same rating iirc. Approved ratings per manufacturer seem highly relevant to me too. Audi being front wheel drive, Merc rear. If only the generic sc3 had been available... Although, thinking back, I enquired about rim protection at a different tyre supplier, and was offered "another" model sc3 instead. Pure chance it worked on my car, and I was happy. Pehaps I should enquired somewhere, Audi perhaps, exactly which models the Ao1 is fitted to. If its smaller front wheel drive models there may be a clue. Ao1 might imply there is an Ao2.., or am I barking up the wrong tree? Quote Link to comment Share on other sites More sharing options...
Tony Posted February 9, 2013 Report Share Posted February 9, 2013 The load rating -V- compound -V- air pressure deviations also play a part over the marques.... A 235/40/18 A01 is specifically aimed at the Audi weight/ drive/ suspension and so on, work this tyre outside of that range than all manor of things can happen. Quote Link to comment Share on other sites More sharing options...
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