It's not the wheel size that's the real problem, but the tyre diameter, particularly on the front. The original 600 x 12 tyre is a nominal 574mm in overall diameter. To maintain some semblance of good steering lock without footwell mods or rubbing, the trick is to keep the diameter of the new tyres as close to this size as reasonably possible.
A little larger will be OK, but the bigger the diameter, the bigger the problem.

A 195 x 50 x 15 is a nominal 577mm in diameter & with a suitable offset & width of rim, will probably work just fine. Rears can be bigger of course.

Kegs - I doubt you could find a tyre with a low enough aspect ratio to keep it close to the factory rolling diameter. I have a calculator somewhere so I'll look it up later.

Your car will handle worse than if you fit, say 15's.

this is because, in a road car, the suspension has a few inches of travel. As the wheel moves up and down (in an arc) you get a change in camber. 17 inch rims with ultra low profile tyres have no "give" in them, thus as the wheel hub changes camber angle, the tyres' camber angle will change by exactly the same amount.

as for 15 inch rims and tyres with more side wall. As the hub changes camber, the tyres' camber changes by a smaller amount (a good thing). This because the 15 inch tyre will flex and so, keep in contact with the road.

Racing cars are different because the suspension does not move alot, thus the camber of the hub, and tyre remain the same.

Also, as a GENERAL rule, the lower the profile the tyre has, the noiser the tyre.

u want something unique, use a kewl set of 13inch rims and put on a set of hydros!!! Den u can bounce bounce!!!

Not many datsuns can do dat.

What is the max width you can fit under a sedan with out flares? Ive rolled the gaurds and I need to get the best/most amount of grip I can, say 14s with 215s? And by the way Matty what is that pic? it looks like a severed hand?!@!

same rule applies in victoria

total rolling diameter (wheel & tyre combined) can be 1 inch more or 1 inch less than standard without being approved

but i beleive the same rule applies to the width which is what creates the problem with legalities when using 6 inch wide wheels

In NSW, width for cars requireing to comply with ADR24 (after 1/1973) and under 800kgs can only be approved with 1 inch wider rims.
Cars before 1973, under 800kgs can be approved to run up to 6 inch wide rims.

Add struts or diff from another car - diameter and wheel track rules now apply to the donor vehicle measurements. Wheel track now being the donor vehicle minus how far the struts were brought in, or how much the diff was shortened.

Kegs - I checked my tyre diameter claculator and you're right you can get a similar rolling diameter in a 17" rim. You would need to keep the aspect ratio to 30 or 35 and the tyre width would have to stay under 225. Big dollars to make your car handle worse!

Just to expand on Datsik's point about road and race suspension. Race tracks are usually (not always) smoother than public roads so road cars generally have more suspension travel and in addition use the tyre sidewall as a buffer too. Race cars generally use tyres with stiffer sidewalls to prevent tyre squirm. They don't need as much suspension travel and cushioning due to the smoother surface that they are driving on.

Quinn - It's my left thumb that I recently cut on a V slicer. I'll change it soon as there have been complaints of nightmares from a couple of the site's regulars.

i think perspnally 17'' is way 2 big for the 1200's 16'' is biggest i would go, makes em look like 4x4's unless it u have no suspension and the rims sit in the gaurds allround then its not practicall. i went with 15'' rims so i could buy slicks for drag meets cheaper tyres for everyday driving and also makes the ute look lower, u can also get 225 50 15'' tyres which are wide enough for the ass end for some traction suit's my ute when i need 2 get of the line in a hurry...

I think if you want 17s - go for it. You can get them to fit, you can get them approved.
Not everyone cares about how a car handles on a racetrack. Yeah there are potholes and stuff on suburban roads but its not a race track. Most people run cheap heavy arse mag wheels that cause the car to handle crap anyway. Most people lower their cars and put stiffer suspension as a result. Is that suited to good handleing on suburban streets?
I say build your car for yourself. If you like the look - do it. Its your car. #### what others say, Its not their money.