Floatyness after installing aftermarket wheels

[VIPZR6]

After recently installing aftermarket wheels on my 08 Aurion Sportivo, I have noticed at highway speeds (100km/h) it feels floaty, light and not planted to the road.

Hard to explain but more or less if you ***** the steering wheel slightly it takes half a second for the car to move, and then feels like a slight wobble back. This is directly compared to the standard Sportivo rims which are 17x7 and had 215's or something skinny on them, they felt very "direct" in comparison

Specs on the wheels and tires are as follows

F - 19x8.5" +40 with 235/35 R19 Nexen N6000's

R- 19x9.5" +45 with 245/35 R19 Nexen N6000's

Pressure is 35PSI all round (after reducing from 40 which is what the tire shop put in, feels alot better now even after that)

Should I further reduce the pressure, look into an alignment or something else? Help much appreciated :)

[trentmeyer23]

If you keep those pressures you will find the tyres wear more on the inner and outer sides of the tread. It may not seem much, but over the life of the tyre it will make quite a difference.

[VIPZR6]

So I should be putting in more or less pressure to get an even wear?

[bigVAN]

Do you have hub centric rims?

[trentmeyer23]

You should put the tyre manufacturers' specified pressures in.

[4ABHGE]

Lol manufacturers specs don't mean anything once you've changed rims and tyres... run whatever tyre pressure feels best to drive on.

The reason you're feeling this is 2 reasons. First is wheel alignment, with any change of size in tyres you should get an alignment. Tyres may differ in design and work better with a different alignment, not only that but the change in size will affect alignment as well.

Since its a bigger tyre the ride height would have increased which will change vehicle dynamics.

Another reason is the wider rear fitment. Since the rear is bigger and wider it will make the car twitchy and basically the rear will try to swap with the fronts, and spin. Its the same reason many fwd track cars run much wider fitment on the front in relation to the rear to make the car more stable.

You can band aid it with an alignment, run a bit more toe in on the rear - this may wear out your tyres quicker though.

Edited November 23, 2012 by 4ABHGE

[VIPZR6]

Have found running 33 PSI has made a pretty big improvement. feels alot more like it did. might try an alignment tho too :)

[trentmeyer23]

Lol manufacturers specs don't mean anything once you've changed rims and tyres... run whatever tyre pressure feels best to drive on.

I was referring to tyre manufacturers' pressures.

[4ABHGE]

There are other factors such as wheel alignment, type of usage and weight of the car that factors into longevity more so than pressures... every car and driver is different.

Also he is asking about the 'floatyness' not the longevity... let me clarify once more, he wants better feel.

[trentmeyer23]

There are other factors such as wheel alignment, type of usage and weight of the car that factors into longevity more so than pressures... every car and driver is different.

Yes and I did not argue that.

Should I further reduce the pressure

So I should be putting in more or less pressure to get an even wear?

These are the questions I was replying to, in order to try and prevent the OP from having to buy multiple sets of tyres.

[VIPZR6]

Small update; just had a wheel alignment done, which has had a massive improvement of the tracking, doesnt feel so twitchy anymore.

Now all thats left is to cure the boatyness with some lowered springs :)

[4ABHGE]

There are other factors such as wheel alignment, type of usage and weight of the car that factors into longevity more so than pressures... every car and driver is different.

Yes and I did not argue that.

These are the questions I was replying to, in order to try and prevent the OP from having to buy multiple sets of tyres.<br />

Yes, because changing tyre pressure will help OP save money on tyres, and fix the issue he had, more than a wheel alignment ever could...

Heads up: Once you lower it you will need a new alignment again.

Also to cure boatyness you need stiffer springs and correctly valved shocks, not just lowering springs, as lowering it may reduce responsiveness and induce more roll (and many more suspension problems) once lowered past a point.

What are your new alignment specs?

Edited December 25, 2012 by 4ABHGE

[STYLSH]

I fail to understand the staggered wheels setup on a fwd...

[4ABHGE]

Depends on your setup or what you are trying to achieve.

Aesthetically: FWD cars usually have huge rear guards, so to fill them in you have to run something a bit wider in the rear...

Performance: FWD like to understeer, so to reduce this you run narrower tyres on the back...

You can actually combine the two in a sense, ive seen someone running wider wheels on the rear but with a slightly stretched tyre to stiffen the sidewalls to increase oversteer tendencies... it worked well!!

Edited January 8, 2013 by 4ABHGE