Got my rear wheels assembled last night with wider Speedline inners sourced from the maestro, Jim Dorociak. Shown is a trial fit and a macro of the wheel. Width from inner lip to inner lip is 10-3/4 inches; 12 inches outside edge to outside edge.
Clearance to the trailing arm is 6 mm. I'll have to re-check where the tires (295-30's) end up after they are mounted tomorrow.
Now I'm beginning to look forward to spring!

 

More info for our database.
295-18-30's fit with 10-3/4 RH wheels using the offset RH sells for our cars (don't recall what that is).
There's about 4 mm of clearance where the tire is closest to the trailing arm. I'm going to remove the cast line to gain another mm.
Do I dare to fit 315's?

 

Did you have those made???

 

Those look awesome Paul

 

Guys there is only so much room to work with. I had a spare set of new 8.5 Speedline inner rims that Paul bought to make a wider rear wheel. Because the RH wheels do not use a crush ring like Speedline does they use different inner rims. Stock RH is 54 ET 10" 2.25 plus 7.75 so what we did was increase the inner rim to 8.5 and 2.25 making 10.75. The inner rims really did not go inward 8.5" but rather 8.25" (no crush ring) So the next issue is the tire. I built a set of 9.75" Speedline wheels for a 94 Speedster and the Pirelli tire had a curb protector cast into the case and that protrusion hit the rear trailing arm. It is tight no matter what you unless you change to the narrow trailing arms. Jim jdorociak@gmail.com

 

Guru, did you have any issues clearing the 295/30s? What brand of tires and whats the rear alignment info ?

 

The extra width is to the inside, which yields 5-6 mm depending on how it's measured. I machined back the casting parting line to give me another mm of clearance.
I've been running 295-30's for two years now. No clearance issues with those so far but we'll see if they rub the trailing arm due to hard cornering.
I'm running -1 degree in the rear and was running that before the width increase so it isn't a concession to the extra width.

 

I just finished the restoration of a set of 3.6 Turbo wheels. My Porsche friend has a white 965 and wanted black centers so here they are. Came out great. jdorociak@gmail.com Jim

 

Thoes look great Jim..

 

Another thing to consider is tire manufacturer. The numbers might be the same but the actual tire size can change a bit. When we're up against the limits like in these cases this should be considered. With that said I'm running 295/30 18" Hoosier A6's with ~6mm of clearance at the tire to swing arm. The wheels are FM5's...specs below;

Front: 18x9" 57mm offset
Rear: 18x10.5" 51 mm offset

And a pic...(my cars on the right ;-)

 

Wow, nice, Guru

And Jims black center speedlines perfect one

 

Has any one fitted 295 35 18s on the rears. I would like the extra rolling radius for longer gearing in a top speed event? This would be on 3.3 trailing arms.

 

My 30's are really close to hitting the trailing arms so 35's might not be do-able.