front wheel conundrum

[nilknarf]

So I took the plunge and ordered a set of 17" wheels for my "hot-rod" 912 to replace my old basket-weave 3-piece 15" wheels that give me only one (very expensive) tire choice- my initial impulse was to do 9s on the back and 7s on the front, but I immediately second-guessed myself (but too late to change my order)- now I'm wondering what the benefits/downsides would be to swapping the 7s for 8s on the front...

Whichever rim width I settle on, I'm thinking 255/40 on the back (tread contact width=9", outer diameter of tires will be ~25") and 225/45 on the front (same diameter s back, 8.9" tread contact width) and the pricing between the setups isn't all that different by the time I factor in the required spacers to fill out my turbo flares (installed by the PO)... but with the 8s, the tire width won't stick out as far from the edge of the rim, and would only require a 1" spacer instead of a 2" spacer to fill out the fenders.

The deeper dish of the 8s look a little better in my opinion, and if the wheel is spaced out to where the outer rim edge is at the same place, my scrub radius issues would be the same with 7s or 8s... any votes from the community?

Steve- I was going to ask you about this at our last BnB, but as they say, the best laid plans of mice and men...

Curt

[Arne]

What wheels did you order? Euromeisters? If so, the dish and lip depth are the exact same on the 8" and 9", the 9s have recessed lugs.

To me, having the same dish front and rear would look odd. I'd stay with the 7" for that reason alone.

If the wheels you ordered were something else, ignore the above comment.

[nilknarf]

Thanks for the quick reply Arne, and yep- I did get the Euromeisters! The look of the setup definitely factors into my conundrum- the current wheels on my little beast are crazy deep-dish that don't use any wheel spacers at all and I actually kind of like the look! (all of my other cars have the same dish depth front and rear)

I've read posts from Bill Verberg on Pelican that as a general rule, there should be about 1" of difference in tire width between the rears and fronts- but I've also heard that one should go narrower on the front to achieve more understeer and wider to achieve more oversteer... with the 7" wheels, it looks like 225s might be about as wide as I can realistically go, where the 8s look like I might be able to manage a 235 if I felt so inclined to need more grip... I have to confess that the extra weight of the +2 cylinders out back is part of why I 'm second-guessing myself on how much potential grip I should look at- my car has the stock torsion bars (18 and 23- in '69 Porsche went to 18.8 on the front but otherwise didn't change them at all until '78) as well as the stock sway bars and I do not have an LSD, so that should lessen the tendency to "push" in the turns... I'm also interested to hear if the differences in widths would affect how the car "feels" at various speeds from running errands to attacking the back roads... so from a performance standpoint, am I just over-thinking this and I'll be so happy with my 225 choice that I'll never ever want it to be any different?

[Arne]

[nilknarf]

Hey Arne,
Thanks for your input- I do believe I'll follow your good advice! Here's what the 7s look like:
Euromeisters-7fronts.jpg

and here's what the 8s would look like (assuming they'd look just like the 9s):
Euromeisters-8fronts.jpg... I think the 7s do look much better!

_c