How does wheel track change affect handling?

Generally a wider track (going outward) will give you better handling but I think steering can get heavier. So I would say going inward would give the opposite of these effects. These are just simple things I remember. There are probably some other effects. I'm sure someone will chime in that is much better versed in this area than I.

In any event with the small numbers you are talking about I don't think it is a concern or that you would notice any difference either way. I would go for what you think will look best or the best price. I would probably go outward since a lot of people end up wanting to go to spacers on these cars (F-cars in general) for better looks anyway.

 

Yes, it is enough to effect handling and feel --- the question is will the driver notice it? And, that depends on the driver's abilities / sensitivities and how he intends to use the car.

In addition to changing the contact centerlines of the tires, the wheels may have differing structural geometries as well, which can dramatically affect how chassis loads are transmitted through the entire system. Also, the effect of moving centerlines alters tire grip by increasing / decreasing "scrubbed" area ----unless the suspension is also modified to counter this.

Unfortunately, there is no simple answer to your question. Only, the engineers who built the Mondial are going to be able to predict what the exact effect will be (without testing it), as they know the dynamics of the entire system. Books and books and books have been written on this topic. If you're the studious type, you may get some insight by reading a few of them, but for the most part, performance suspension design is a "black science" --- usually developed with a lot of trial and error --- almost more of an art than a science.

As to whether it is "better" in versus out, that is up to the driver --- some may prefer one, some the other. Your best bet would be to see if others here have done this mod (personally, I have not), and see what their impressions are.

Short of that, you probably will just have to experiment for yourself. I can assure you that, provided you don't push things real hard, while you are "testing" various configurations (within the small range you've indicated), you won't be in danger of anything safety-wise --- just keep it well within limits until you develop confidence and feel for what the handling characteristics (and limitations) are.

Since you've suffered through my discourse, I'll now reward you with some practical information ----
In general, moving things outboard will increase stability and reduce precision (this can be good if the car started out too "twitchy" for your liking). Moving things inboard will accentuate most responses and driver inputs (this can be bad if the car started out too "twitchy" for you).

A word of warning, moving in or out too much can both really upset the car's balance and make it unpredictable --- only attempt changes that have others have some good history with running safely. Also, whatever change you decide on, do it the same on all 4 wheels at first --- if not you will change the track ratio between front and rear, and this can be very unstable. Purposely, changing the track ratio to optimize the setup can be done, but it really should be left to professionals with race experience to do this for you.

Good luck, and have fun.

 

I think you've done your homework well, and you shouldn't sweat too much about anything less than ~5mm on a rationally-used road car. Visually, I'd go out at the rear, if possible, but at the front maybe smallest deviation would be best -- are you going for same size all around (same error at all positions?) or different sizes front and rear?

 

A change in the range you are talking about will not be enough for you to really feel, one way or another. Especially a Ferrari street car.

The tolerance on total trackwidth on a production car is in the 5mm range. You are generally within that tolerance!

Remember the Mondial/308/328 chassis are all very similar, yet tire sizes (and track width) have definitely grown, with new/different offsets/ etc.

 

I like that option too, and adds value IMO.

 

Bob ---

Geeeez! I just noticed that your offset numbers are in "millimeters" --- When I first read your post, for some reason I thought (assumed) that they were in "centimeters". In that case you can pretty much ignore most of my comment. You won't even know anything's different with changes that small unless you also go to a substantially different tire (the tire itself can influence the handling alot, of course). In fact, your eyes must be sharper than mine because I likely wouldn't notice the change visually myself... as far as things looking wider or narrower...