Tire sizes / Handling, Need a pros thoughts Options

[ruby914]

I got a 911 front end and a set of 7 & 8 x 16'' 5 lug fuchs for my WRX914, not from the same car.
The Fuchs had a set of used tires that I have not yet replaced.
The front tires 205/55 had heavy wear on the inside tread when I got them.
The rears are 225/50
After doing an alignment I found the steering heavy and didn't center out from a turn.
If do a tight U-turn, best I can explain it, it feels like the tires are buckling over them selves or washing out?
I added a little more toe-in to help the centering but no change.
My first question: Would that wear on the inside tread make the steering heavy and not straiten out?

So, I need new tires.
Here is my delima...
On my other stock 914, I have 195/50 x 15 and really like the feel, very light, low and quick response with the smaller diameter tires.

The WRX914 will be a daily driver.
1st, I wonder if new tires will correct all the current problem?
2nd question, I think of going a step lower profile to 225/45 and 205/45. Does this choice sound reasonable?
But there is something else I feel I must consider.
When the turbo kicks in, in 2nd gear ( 914 transaxle ) if I am pushing it on a curved freeway on-ramp or if the street is a little damp it breaks loose easy.
So, I think of 245/45's in the rear and 205/50 up front.
But that is not doing much in keeping the diameters lower.
This is the tire size calculater I have used http://www.1010tires.com/TireSizeCalculato...p?action=submit
Is there any option that I have missed?

BTW
I now have GT flares sheet metal screwed to my car marked for trim and welding.
I have one uninstalled set of 21mm wheel spacers and I think I will need one more set, maybe the same offset.
I think, I should get my new tires worked out before I look at the spacers again.

[Mike Bellis]

The different feel can be atributed to the change in scrub radius caused by the wider offset of the new wheels. More caster may help a little. Driving and getting used to it will help also.

http://en.wikipedia.org/wiki/Scrub_radius

[SirAndy]

The different feel can be atributed to the change in scrub radius caused by the wider offset of the new wheels.

I doubt that's the problem. I run wheels and tires much wider than his in the front and the steering feels anything but heavy.

I think the clue is in the recent alignment ...
(IMG:style_emoticons/default/popcorn[1].gif)

[ruby914]

The different feel can be atributed to the change in scrub radius caused by the wider offset of the new wheels.

I doubt that's the problem. I run wheels and tires much wider than his in the front and the steering feels anything but heavy.

I think the clue is in the recent alignment ...
(IMG:style_emoticons/default/popcorn[1].gif)

Thanks Andy
More caster solved one problem.
I am happy with my rough alignment for now, until I get new tires.
A combo of more tire on the ground (compared to my 195/50 x 15 on the other car) and scrub may be all I feel.
I also have the steering column from the WRX in the car that changed the geometry just a little.
I don’t think the WRX column is an issue but after tires I will fine tune the alignment and address any other issues.
I think my first battle is tires

[John]

The different feel can be atributed to the change in scrub radius caused by the wider offset of the new wheels.

I doubt that's the problem. I run wheels and tires much wider than his in the front and the steering feels anything but heavy.

I think the clue is in the recent alignment ...
(IMG:style_emoticons/default/popcorn[1].gif)

Thanks Andy
More caster solved one problem.
I am happy with my rough alignment for now, until I get new tires.
A combo of more tire on the ground (compared to my 195/50 x 15 on the other car) and scrub may be all I feel.
I also have the steering column from the WRX in the car that changed the geometry just a little.
I don’t think the WRX column is an issue but after tires I will fine tune the alignment and address any other issues.
I think my first battle is tires

You have a WRX steering column or steering rack? How does a different steering column effect suspension geometry?

If you have lowered your car from stock height (and I'm betting that it is), you would need to compensate for the angle that the tie-rods make with the horizontal. In an ideal situation, the tie-rods should be level. If not, bump steer can have an effect. The more the angle, the more the effect. This is why there are spacers made to space the steering rack higher in the car.

There isn't a good way to modify alignment settings to compensate for ill worn tires. Pony up and get a new set of tires. Even cheap new tires would probably be an improvement over what you have.

just my $0.02

BTW, we have been running 9x16 wheels (on all 4 corners) on the track car with 245/45-16 tires for many seasons. It's steering is not heavy.