grege Posted August 18, 2021 Report Share Posted August 18, 2021 2018 cmax and had a sidewall puncture in original michelins (~36,000 miles). Opted for 4 new tires and went with Goodyear Assurance max life. Horrible experience thus far. Vibrations readily obvious and horrible at highway speeds. Mileage after one day driving identical route to work yielded 10mpg drop already. WTH? Might need to have all replaced under the 30 day "guarantee". Don't know if it's a combination of bad tires and bad balancing or...??? Car was so smooth that I could do 80mph on original tires and not realize it; now, at 65mph and higher, it's unbearable. Something is not right. Greg Quote Link to comment Share on other sites More sharing options...
Billyk24 Posted August 18, 2021 Report Share Posted August 18, 2021 Hurry and return to retail location for refund, replacement or evaluation. fbov 1 Quote Link to comment Share on other sites More sharing options...
grege Posted August 20, 2021 Author Report Share Posted August 20, 2021 Car went back to dealer and they confirmed there was a problem with their balancing machine, so rebalanced all and huge improvement. Problem now is, driving the same routes, mileage is much reduced (9-10mpg lower with same tire pressure) after switching from Michelin Energy to Goodyear Assurance Maxlife. Will track mileage for two weeks and if mileage remains this bad, will seek another tire change. Anyone swap new tires due to performance problems??? Thanks, Greg Quote Link to comment Share on other sites More sharing options...
ptjones Posted August 20, 2021 Report Share Posted August 20, 2021 If you want the best mpg's use Michelins Energy Savers V93 Paul C-MaxA2 1 Quote Link to comment Share on other sites More sharing options...
fbov Posted August 20, 2021 Report Share Posted August 20, 2021 Glad to hear there was a root cause for the major issues. I use Tire Rack reviews for things like rolling resistance, but I find their latest on the MaxLife has no mention of rolling resistance. That's not good, even if the tire fairs quite well in the objective testing. https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=265 Looking at the specs, I see an 11/32" tread depth. Michelin Energy Savers tread is 9.5/32". This matters because a thicker tread is harder to bend, so has greater rolling resistance. However, as a newer tire, I'd expect the MaxLife is a LRR design. This test includes the Energy Savers... in 2009. Very interesting variation in results.... https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121 Finally, give them time. This data's from the new Escape, but the pattern is consistent. Mileage data is noisy, even if you control for things like speed and temperature. I will note that the car's rolling resistance is easy to measure. - find a paved surface that transitions from flat to hill - find the location on that surface where the car will just barely stay put, not roll - measure the angle of the surface. The Tangent of that angle is the rolling resistance. The easy way is to measure the angle in radians, which is ~= tangent for small angles like this. Put a bubble level on a meter stick, hold it level with one end on the ground. Measure the distance from the ground in millimeters. That's the RR. You want less than 0.010, I got 0.007 for my C-Max. I need to measure the Escape before the OEM tires die. ptjones 1 Quote Link to comment Share on other sites More sharing options...
grege Posted August 23, 2021 Author Report Share Posted August 23, 2021 On 8/20/2021 at 3:09 PM, fbov said: Glad to hear there was a root cause for the major issues. I use Tire Rack reviews for things like rolling resistance, but I find their latest on the MaxLife has no mention of rolling resistance. That's not good, even if the tire fairs quite well in the objective testing. https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=265 Looking at the specs, I see an 11/32" tread depth. Michelin Energy Savers tread is 9.5/32". This matters because a thicker tread is harder to bend, so has greater rolling resistance. However, as a newer tire, I'd expect the MaxLife is a LRR design. This test includes the Energy Savers... in 2009. Very interesting variation in results.... https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121 Finally, give them time. This data's from the new Escape, but the pattern is consistent. Mileage data is noisy, even if you control for things like speed and temperature. I will note that the car's rolling resistance is easy to measure. - find a paved surface that transitions from flat to hill - find the location on that surface where the car will just barely stay put, not roll - measure the angle of the surface. The Tangent of that angle is the rolling resistance. The easy way is to measure the angle in radians, which is ~= tangent for small angles like this. Put a bubble level on a meter stick, hold it level with one end on the ground. Measure the distance from the ground in millimeters. That's the RR. You want less than 0.010, I got 0.007 for my C-Max. I need to measure the Escape before the OEM tires die. Thanks for the response. Not surprised about the greater tread depth for the "max life" given they claim an 85,000 mile warranty. Tracking mileage daily, so... day 1: 50 mpg day 2: 51 mpg day 3: 53 mpg I do expect some tire "bedding"/wear will improve mileage, but doubt I'll reach Michelin energy numbers of 59-60 for my usual commute, but we'll see... Greg Quote Link to comment Share on other sites More sharing options...
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