I have an '84 300SD with aftermarket 15 inch wheels in place of the stock 14 inchers. The documentation recommends 30 or 32 psi for those 14s. The new Goodyear Eagle LSs state 51 psi max on the sidewalls. Majority highway miles are traveled.

Today I filled up to 40 psi. My question is to maximize fuel efficiency and/or tire wear, what would be the best pressure for these tires on a car this large? I like to stiffer ride with harder tires but still efficiency remains my objective. Many thanks to all who respond!

The max pressure rating is not vehicle related but tire related as it shows the capability of the tire, in this case, the maximum pressure recommended. The vehicle recommendation is totally different from this as it is factored in by the engineers depending on body weight, payload, suspension etc. 40PSI is too high and you will not only get a choppy ride but you will damage your suspension as well, I suggest you go back to your manufacturer's recommendation.

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99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT

Goodyears are not known for having strong sidewalls. When they blow out a sidewall, good luck getting warranty. I would not try to exceed the low 30's on those tires.

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

LOL! Goodyears do make a ordinary amateur sound pro when taking corners, the squealing and the power slides are de facto even taking corners in a mildly aggressive fashion. The Wrangler ATs were a huge disappointment for me, they started cupping in under 5000 miles, extremely noisy with bad on road grip, they were OK off road though.

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99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT