Hi All;

I am new to this forum so please forgive my ignorance if the question I'm about to pose has been done so already.

I recently sold my 2007 Blue Acura TL Type S with a tear in my eye. Loved that car!

Anyways I got a great lease deal on a 2014 Lexus IS350F RWD in black with red interior. See attached image.

I notice when I do a sharp turn that the car looses grip from the front wheels. It almost turns in too much (Understeer?)

I am surprised at this b/c my Acura definitely had more grip which was using Michelin Pilot AS Sport+ tires. The Lexus uses Brigestone tires I believe. I noticed the tread wear on the Brigestone are only 140 which is pretty lame TBH as my Michelins with more grip were 500 rated.

So my question:
Is this steering issue I noticed an inherent design flaw of the Lexus or a function of underwhelming tires?

Other than this problem and the fact I have no space to put my wallet and cell phone, I love the car

PS. Why no LED's for the interior lighting and background LED lighting on the interior roof and footwells during night time driving? This is an almost $50k car!!!

 

i think most people will agree that the stock Turanzas are pretty crap.

 

Probably just the tires, swap out the Bridgestones for the Michelin Pilot AS Sport and you should be fine

 

Hi guys;

If it's just the tires then I will definitely wait till they wear out to replace them. Kinda sucks that you spend all this money on a car to get tires like that. The Michelin's are actually much cheaper and have longer treadwear.

 

If it turns in too much it's oversteer.

 

Its the tires.
Lexus equipped it with the worst tires in its class.

 

^^^ yup...

you're coming from a FWD car which is understeer happy. throwing a FWD HARD into a corner (which is a recipe for immediate oversteer) cancels out the nature of the car which wants to understeer and you create this false sense of "grip" in a FWD... much what AWDs feel like minus the LSD to exit corners effectively but anyways,...im getting away from the point.

Point is you're in a RWD now and throwing a RWD into a corner takes a higher level of skill to reach that grip you're looking for. And the grip is not the same feeling as the grip in the FWD. You're going to slide a little bit in the IS. Not as much as a 3series but you can feel the rear coming out a tiny bit. if you keep the stock setup you'll still have some understeer anyway thats closer to a FWD. Just give it more gas earlier in the turn to stay on your line. I've driven with FRSs through the canyons at nasty speeds with their stock wheels and tires.....same tires as a stock prius' ...lol! So tires are part of it but it's not the entire story.

if you really miss the way your FWD handled....get more tire in the front. a square setup sounds like it might be what you're looking for.

 

Hmmm...I thought the equipped tires depends on the dealer, becuz mine comes with michilin tyres.

 

In regard to treadwear yeah, I was pretty shocked when I saw that the UTQG on the stock tires were 140. Most people will associate a treadwear of 140ish with a autocross/drag radial tire. Unfortunately one can't think that low UTQG=grip, even though if you look at different classes of tires it seems that way. I know that the UTQG is assigned to the tire after it is ran on a track and assessed for it's wear, but you'd have thought that they may have seen the tire wear vs. performance and decided to go another route. I wonder what Bridgestone was thinking when they made this tire? The other variable is that you can't look at a 140 in one manufacturer and compare it to a 140 in another because manufacturers grade them independently. Kinda sucks. Either way, I'm not hoping for many miles out of these tires.

 

You mention losing traction from the front tires while turning. Yes, this is understeer.

I assume this is for more track or canyon driving you are talking about. You should not be getting oversteer or understeer driving on normal roads that have speed limits and all that.

I suspect your biggest contributor to understeer right now is traction control. Traction control on this car will destroy the outside front tires on this car when pushed at the track. I went through a set of tires in one lap day. With trac control off, the car will still understeer at the limits, just not as bad.

If you want this car to drive more neutral (more like a RWD car is meant to drive), as was suggested, you could
-square tire setup
-upgrade rear swaybar only
-overinflate the rear tires a bit (40psi rear/36psi front)
-order springs with a higher rear spring rate like the RS Downs

Mike

 

It's the tires and the staggered setup. I'm wanting to go square, but I can't confirm if 245 fronts will fit yet. A 235 all around seems wimpy.

I ran a 255/40/19 on my G35x Sedan and that was very good with good rubber and a rear sway upgrade.

 

the staggered setup has almost nothing to do with it. The car is RWD and front-weight biased. Control the weight balance better throughout a turn and you'll find the car can handle rather neutrally. Tons of RWD cars that have a decent amount of hp will have a staggered setup, it's natural that you need more rubber to control that power. If you have neutral throttle when you begin your turn and then start applying throttle lightly and consistently increasing throughout your turn, you'll find the car stays perfectly balanced. If you're on the brakes even a little when you begin your turn-in, of course it's not going to grip as well around the turn. Tires only have so much grip, and that grip can be used for either going, stopping, or turning. Being a FWD car, going isn't an option. So you have stopping and turning. If you're still trying to stop, you're taking away available grip for turning. Likewise if you're already turning and then hit the brakes, something's gotta give.

i'm going to bet you go into corners WAY too fast and the front washes out, as it would do in any car when you're driving it poorly.

Also, treadwear rating doesn't mean what you think it means. The lower the number the higher the grip and the quicker the tires will wear. However, there is no real standard to how that number is derived, so one manufacturer's rating of 200 won't be exactly the same as anothers, although they should be close. These tires on the IS 350 are fairly poor, for sure. Even being summer tires with a low treadwear rating, they feel like cement blocks a lot of the time.

 

At what speed are you going into these corners for the car to be understeering or tight?

Ed

 

I think not only Lexus uses cheap tires, but all other brands do the same.

 

Wow some great replies here. I leased this car so I won't be modding it unless I decide to buy it at the end of the lease.

I notice this problem if I accelerate from stop and do a U-turn quickly or if I make a left turn at stop and give it a good amount of gas. Again I could do this in my Acura with no problem but I am understanding what you guys are saying regarding the FWD giving a false sense of grip.

I don't recall this happening when I test drove a M235i but I didn't have the opportunity to drive that car on my usual roads by myself so who knows.

I do like the IS350F dynamics overall though I wish I could have the sport suspension and stiffer steering enabled all the time without having to put it in Sport+ mode with the more aggressive shifting and fuel guzzling. The car in normal/eco mode is a bit too plush and hoppy. I am not used to such a smooth riding car.

I honestly wanted a Porsche Cayman S but not the payment I loved the driving dynamics of the BMW but my wife hated the interior and the alleged reliability issues. So I took the road in the middle and got the Lexus. I was close to getting an Audi A4 until I realized the lease payment was $50/mo for a car that stickered for almost $4k less. The residuals on Audi's suck hence it's hard to get a good lease deal. Plus I can't imagine spending that much for a 4Cyl car with H-rated tires.

Honestly is it me or are these cars all becoming hyper-inflated in price? As time goes on, I notice cheaper and thinner plastics being used in all these new cars. My Acura had a much thicker glove box door, thicker plastics by the footwells and expandable side-door pockets. OK I'm way off topic now, but thank you all for your help.

When these tires wear out I will change them to the Michelins since I've had good luck with those and I will go with a wider tire on the front to match the size of the rears. BTW I bumped the tire pressure all around from 35PSI to 38PSI and it seems to have helped the grip a bit though the car is a bit more floaty now.