Rexus300

iTrader: (1)

I have these 4 new Michelin Primacy MXM4 tires on my 2013 Lexus GS F-Sport and they were road forced to 8, 10, 14, and 15 lbs which is Left front, right front, left rear, and right rear respectively.

The tires are smooth when warmed up but there is vibration in the front seats when I am getting up to 70 mph and around that speed to 75 mph or so I feel it for at least 5 miles before its smooth with a small residual vibration felt in seat around 70-75 mph. Now, I checked pressure daily to make sure and I also know it cannot be flat spotting as this vibration returns again when the car sits for about 4 or so hours on the parking lot in the hot sun or in garage during nights even when its 80 plus degrees outside. I am not getting steering wheel vibration so its the rear tires.

I had to replace 1 of the rear tire when it was 25 lbs and now its at 15 lbs with replacement tire. Since its dynamically balanced well I am not sure if this Lexus is ultra-senstive to the road force of the tires???? Should the rear tires be rematched to get the whole assembly below 10 lbs to prevent this initial drive off vibration when car sits and rear tires cool down leading to a warped condition? No other cars that I have had ever does this with Michelin tires. I know that flat spot occurs at cold temperatures in winter with performance tires so this case is very ODD. '

Anyone from tirerack can chime in? I might need to get at least 1-2 more tires replaced under warranty policy.

vwynn

iTrader: (4)

most likely flat spot as it parks. since you said it goes back to normal as you drive.

Rexus300

iTrader: (1)

I doubt it because i can leave my BMW 335 xi coupe with Michelin all seasons parkes in one place for few days or more during this summer and drive off with no vibrations. I think its the rear tires with high road force that need to be rematched to rim

mitsuguy

iTrader: (2)

Since it goes away, I would say vwynn is correct... Certain tires will exhibit it moreso than others... I've had the issue before and the higher performance tire you have, the more likely it is to happen... For example, a Michelin Pilot Sport will have more of a chance than say a Michelin Primacy... Some cars are more sensitive to it than others, I would definitely have the balance double checked to be on the safe side, but getting it less than 15 lbs of road force might be impossible without going through quite a few different tires and wheels...

If it is a heat issue and they only do it when cold, it is most likely because they used at least one layer of nylon belting in the tire. Nylon is a great thing to use in high performance applications because it shrinks, or tightens up as heat is added, but, to do this, it may be a sacrifice in that when it loosens up when it cools in one spot, it may cause a temporary flat spot... It always goes away when the tires get some heat in them though...

Rexus300

iTrader: (1)

Thank you mitsuguy. The primacy are the top rated grand touring tires and it summertime with warm temps so i am surprise at this. Isnt the primacy with polyamide belt like my bmw with the pilot exaltos a/s tires? The exaltos are smooth no matter what. I will get tires road force again to see if we can get it match mounted to around 10 lbs.

Rexus300

iTrader: (1)

Reason for vibration is due two rear bent rims. The car is only 3 months old and it is likely to be defective. So regional reps are coming to look at them.

mitsuguy

iTrader: (2)

Good you found out why, hope that is the only issue - generally a bent wheel doesn't go away after its driven a little while...

Rexus300

iTrader: (1)

You are right, It doesn't go away completely but is minimized as the tires get hotter. When its cooler the vibration is heavy at first and slowly diminish but present after 10-15 miles of driving around 70-75 mph zone. The rear left rim was hopping quite a bit and the right rear is slightly bent. No potholes and only 3 months old car. Lexus dealer has contacted regional representative to come and look at the wheels and will hopefully replaced the warped ones since its likely defect production or improper transportation of the car. I have insurance for the tire/wheel just in case.

Rexus300

iTrader: (1)

Actually it wasn't bent rims at all. The tires have production date in mid-2010 and I bought them from tirerack 2 months ago and due to long term storage these tires all with the same production week in 2010 including the replacement ones are greater than 10-15 lbs road force and are junk tires, They vibrate all the time when the car sits overnight this summer and sitting during my day at work. They are garbage and I have never experienced this on any Michelin tires ever. So I got tirerack to work with Michelin to get rid of these tires and get full refund. I will never ever accept tires older than 5-6 months regardless of how well they are supposingly stored in the warehouse...

I am getting the newer Bridgestone Turanza Serenity Plus tires this week and should be mounted and road force balanced this Wedneday morning at a tirerack installer.

mitsuguy

iTrader: (2)

I don't really think it has anything to do with sitting in a warehouse...

10-15 lbs is not necessarily high, in fact, that is very acceptable normally... I am still sticking with it being the way the high performance tire is designed - some tires just get "flat spots" when they sit that go away when they are warm...

Hopefully you will like the new Serenity's... The last ones were amazing... I get to go test them on a course in two weeks...

Rexus300

iTrader: (1)

But primacys mxm4 aren't peformance tires. I have pilot sports too in the house and they DO NOT flat spot in hot weather or overnight even when cold. I also have pilot exaltos a/s on another car and no vibration at all no matter how long it sits and these are higher performance tires while the primacys are grand touring tires. I also have Michelin latitiudes on a SUV with no issues so I know about tires and road feel and how they should run.

Anyways the Serenities are supposed to be nice and I look forward to them. Let me know how you like them soon.

BayAreaLex

I'm not too familiar with road force balancing, but what do you mean by "road forced to 8, 14, 15 lbs, etc?"

I8ABMR

I thought the standard for RFV on the balance was no more than 10 at Lexus

mitsuguy

iTrader: (2)

I don't know if Lexus uses a different number than the standard Hunter values, but the standard Hunter values are 18 for P- and Euro-Metric car tires, 26 lbs for P- and Euro-Metric SUV/truck tires and 36 lbs for LT truck tires...

Those numbers refer to how much variation in how round and how uneven the tire and wheel combination runs...