Dazed and confused re: wheels

[lwein]

I am trying to fit 215/60-15 Avon CR6ZZ Tires on the rear of my stock 1971S
I am planning on buying Braid wheels, or possibly group4's 7R replica.
BUT
It seems that everything I have read here points to the need for a 15mm spacer to make a 215/60-15 tire work. If that is indeed the case, why wouldn't a 15X7 Braid wheel with a 34mm offset work? 49-15=34.?
I don't want to flare the fenders. If the 911R wheel needed a spacer, why was the offset 49?
Did this wheel work with a specific tire?
Any help and or pics would be greatly appreciated. (Life was so much easier when wheels were measured by back side spacing)

[M_deJong]

Those with more experise will weigh in but I'll try.

7R's were intended for flat fender swb cars. I think they did the over the top backspace + spacer to allow the fit to be tailored to each car and tire fitting, keeping in mind the cars vary in dimensions.

On your LWB with its mild flares, you've got more room to work with. On the inside you'll rub the spring plates (and maybe oil cooler lines) and on the outside the fender above the lip if you go too far. The 7R+spacer equivalent offset in a Braid should work. I've been contemplating this for the rear of my 74. I've got 215's on the rear now on 6's with plenty of clearance in and out. So on a 7" wheel that has the same tire centerline (ET36) I should have about the same clearance as only the tire beads will move, not the tire shoulders... Well they'll move a little since they won't be as pinched.

Its a shame Porsche never offered a 7" ET36 wheel.

[gsjohnson]

The Braid wheels should fit with no problem but the 215s maybe a problem depending on the ride height and the camber. I run 7" steel wheels with 34mm offset and 205/60/15 Yokohamas on my SWB with no rubbing issues. I'm running 2 1/2 negative camber.

[sithot]

7R was widened to the inside. They needed spacers to clear the brakes and suspension. Harvey Weidman supplied a pair of hub adapters like the late model cars use.
No need for longer studs which allows for wheel swaps from the original 4.5's to the 6's and 7's (R) combination quickly.