Hi guys, I have a 2014 Lexus IS 250 with the f sports package. I have Michelin Pilot Super Sports installed on the stock rims and when I make a tight u-turn, I notice that there is a number of noticeable bumps. It usually happens when making a u-turn at the light. The tires are properly aligned and have very little wear on them. Does anyone else have this problem? The car has around 44k on it and I was going to wait until my 45k oil change to address the issue. If anyone could provide their input that would be great. Thank you

 

With a staggered setup like the F Sport has, I've also noticed that when the wheels are fully turned, there's a feeling that you could desribe as "bumps". I think it's just due to the suspension geometry and the tire setup, so nothing to worry about.
Happens on my 2014 IS 250 F Sport and exactly the same on a 2016 GS 200t F Sport with 10k miles I had as a loaner for a few days.

 

I made a thread about this a while back. What you are describing is normal. There is a trade off for the class leading handling in this car:

http://www.clublexus.com/forums/is-3...d-turning.html

 

If the 3IS front end is like the 2IS, there is, I believe, an 8 degree castor on the front wheels at full lock. That's out out of parallel they will be at full lock. It's to help make sharp turns at faster speeds than you would do backing out. If you think about the car traveling in a circle the inner wheel makes a smaller diameter circle that the outer wheel which means it must turn slightly sharper. It is the nature of the car's suspension, but it does wreak havoc on inner tire wear. The rubbing you feel is the the tires being pulled sideways across the ground.

 

When I first got my IS I noticed a noise from full-lock turns getting in and out of my garage. The dealership looked at it and said there is no rubbing and could not identify the problem. It would have been nice if they explained the tires rode on the edge during full-lock turns. Took me quite awhile to figure it out on my own, but the first clue was all the rubber building up on my driveway. I guess it is the price you pay for a tight turning radius, but Lexus could save themselves a lot of money spent diagnosing "problems" under warranty if they explained what is happening when a customer calls to book an appointment.

 

Can't argue that point. However, if they were up front about it, they should also tell you DON'T DO THAT too much or you'll destroy your front tires in quick fashion. I guess they'd rather deal with diagnosing instead of people wanting tires replaced.

 

Thank you for all of your guy's insight. Now that I know that its the tire rubbing, ill try to minimize making tight u-turns. To be fair the IS has the best turning radius out of any car that I've driven so I guess it comes with a price