linderpat wrote: ↑Fri Nov 20, 2020 10:23 am
One thing I think is that 18's are really too big for the car from a handling perspective.
Factory 18" (and bigger) wheel sets for the later cars are heavy. I weighed my wife's 11.5x20" 991 rear summer wheel last week and it was ~58 pounds. The front <whatever>-x20" was ~51 pounds IIRC.
It's all about keeping unsprung weight as close as possible to what the factory suspension "wants." The wider tire is, itself, likely - if not definitely - going to be heavier that an OE-sized tire, thus making it more important to get a light wheel.
That's actually one of the open questions I have for augment: weight of various offerings. You can get forged magnesium which is nicely light. On the other hand, probably not a great idea for a street car that might see potholes. They ain't exactly cheap either.
Now, you can run a heavy wheel on a 928 but not with the stock dampers. You'd need custom valving for the dampers if not stronger springs too. I used to have a client that was a suspension idiot savant who could drive anything, come back and say "You need x% more/less bump and y% more/less rebound" and damn if he wasn't right every time. His 928 was *set up* and had some big-assed 18" wheels.
If you want to experiment you can order (maybe still order) Bilsteins (from them directly) with "Leguia 928" valving that might just work better with heavy wheels.
Hanlon’s Razor: Never attribute to malice that which is adequately explained by stupidity.
Heinlein’s Corollary: Never underestimate the power of human stupidity.
Worf’s Razor: Never attribute to stupidity that which is adequately explained by laziness.
Worf's Corollary: Once you've mitigated risk from stupidity and laziness in your endeavors, failure is usually the result of insufficient imagination.
My 928 Inspection Guide