I replaced the rear tires on my 08 550 with hankook v12 275/30/19 after reading some good reviews on it. The front tires are still stock continental sport contact two 245/35/19 with 50% tread. The tires were mounted and balanced at a well know tire shop with GSP 9700 hunter machine but now I'm having vibration around 70 mph mainly feeling it on the seats. I went back couple days later to have it re-balance but the same problem occurs. I call the place where I got the hankook from and they told me the problem is due to the mismatching tires and the continental front is much softer then the hankook rear.

I just want to ask you guys who have same setup having this problem? or take it to another tire shop to balance? They both summer tire so I didn't think it would matter.

Thanks for the help

 

Ask when the machine was last calibrated, and if they have a fifferent machine available to check the wheels on. I would also check that the tyres are mounted correctly, if directional are they on the rims the correct way around. If they are okay I would ask for the tyres to rebalanced from scratch, i.e. remove all the balance weights and start afresh. Also check the fronts, they may be out slightly too. As the fronts have been on the car a while they mave gone out of balance aftre hitting a pot hole or similar.

 

its not the tires or the wheels you might need a hub ring depending on what wheels you got.. the wheel center hub on a 5 series is normally 72.6 mm ( if i'm not mistaken) the wheels you got probably has a bigger... double check and good luck

 

I did check the direction and it's mounted correct. Had all four tires balanced when they were mounting the wear and went back to get all four rebalanced but the problem still there. The vibration is usually at 60-80 miles. Mainly the seat is vibration the steering wheels seen to be fine.

 

I have stock Mtech 19" wheels.

 

that is strange for a stock mtech wheels

 

That's why I am asking if the mismatched oem continental front and hankook rear would cost vibration or I need to take it to another tire shop to re-balance

 

Generally vibration felt in the seat is a rear tire balance issue. Since you are running wheels previously used I presume they were tested for run-out (out of round condition). It's possible that one or both tires have some irregularities that can't be balanced out. And, before running to another shop - and paying twice - be sure the shop you are using has tire techs who are properly trained to use the equipment. Last item, some tires need some run-in time before they settle in. That said, even tires need some break-in time before they are run at speed - maybe tell your shop you'll put on a few miles and give them another shot at getting the balance correct OR help you out with some $'s to get the work done correctly somewhere else. (ASSUMING it's their equipment or service and NOT a defective tire).

Let us know how it all works out for you.

 

howcome you didnt do all 4? Im just asking, cause if you didnt have the vibration before you changed the two rears then obviously it must be cause they are mismatched. I mean that seems like the logical answer being that they were mounted and balanced correctly and the wheels are not bent.. Your talking about stock 172's right?

 

WOW... I bought the same rear tires for my car and I have the vibration around 70 as well. I was thinking that they weren't balanced correctly. I didn't have the virbration before the new tires either.