[dukejoh]

Before I get flamed, I have searched the wheel database and this forum for an extended period of time and could not find exactly what I was looking for. I would like someone to double check my calculating.


I have a 1966 Skylark 2 door post that I just acquired a few weeks ago and wheels/tires is the first thing I want to change since it runs and drives so well with the lil 300 v8.

I have 18x9.5" with 7.125" BS, 2007 GT500 wheels for front and back. (left over from my totaled shelby last year RIP)

I always thought the Shelby wheels were very Z06ish and OEM corvette wheels were what I was looking at....and I would need to buy adapters anyways, so I thought what the heck.

The rearend is a 68-72 (55 inch) rear.

4 wheel manual drums!! It stops pretty good and I just mostly cruise around town.

After measuring the rear it looks like I need a hair over 6" BS to make a 9.5" rim center up well with the wider rear. This could be accomplished with a 1" adapter. ( I had a 1.5" adapter for mock-up and the wheel is flush against the wheel lip, so -0.5" and a light roll looks like it matches with my measuring) I also have 7/8 to 1" frame clearance with the 1.5" adapter so moving it 0.5" in should still clear.

My main issue is when trying to determine what BS is needed with a 9.5" rim on the front. The database does not provide whether the cars had drum or disc brakes...

I assume the drums have a narrower track width meaning less BS than the same wheel with discs??

Has anyone run a 9.5" front wheel and if so what BS worked out?
Also what is the front track width difference between drum and disc?

I mocked up one side with the 1.5" adapter I had and a 285/35/18 and it only touched the upper control arm at full lock but I think it may be pushed out to the fender a little far, especially when the back wheel is pulled in some more. My helpers (nephews) had left before I could get some assistance measuring the track width front and back.....

If I am picturing it clearly in my mind moving the front wheel in much further will cause rubbing on the upper control arm sooner?? Am I visualizing this correctly? I will definitely run a narrower front tire (245/40/18) but the 285 was convenient at the time.

I will post pics when I get everything sorted out. It really doesn't look bad with the GT500 wheels. A set of adapters is cheaper than a new set of wheels and if it looks bad I can always sell everything and start over...... Sorry for the essay

Caleb

 

[70GS455]

Might want to try posting over at v8buick.com

 

[Andy69]

www.v8buick.com

 

[1966_L78]

I have a 1966 Skylark 2 door post ... 18x9.5" with 7.125" BS, 2007 GT500 wheels for front and back. 4 wheel manual drums!!

After measuring the rear it looks like I need a hair over 6" BS to make a 9.5" rim center up well with the wider rear.
My main issue is when trying to determine what BS is needed with a 9.5" rim on the front. The database does not provide whether the cars had drum or disc brakes...

I assume the drums have a narrower track width meaning less BS than the same wheel with discs?? Has anyone run a 9.5" front wheel and if so what BS worked out?

Also what is the front track width difference between drum and disc?

If I am picturing it clearly in my mind moving the front wheel in much further will cause rubbing on the upper control arm sooner?? Am I visualizing this correctly? I will definitely run a narrower front tire (245/40/18) but the 285 was convenient at the time.

Caleb

Caleb,

I ran 9.5" wheels, all four positions, on my '66 Chevelle Convertible. BUT, they were 17" wheels with 275/40-17 tires...

That being said, my disc brake swap (C5 Corvette from Kore3) used drum hubs up front, so the only difference was the thickness of the rotor vs. the drum thickness... I also ran a thin spacer (about 1/8") so the wheel wouldn't hit the caliper), and I wanted to be sure the outside of the tire cleared the fender lip...

I ended up getting a 6" BS on the front wheels, cleared the upper control arm fine, because the wheel diameter... 18's should clear even better.

Without the spacer and rotor, I'd say 5.75" BS would work well... maybe 5.5", but I'd prefer to keep it away from the fender lip... the inside cleared, except it might have rubbed the swaybar at full lock (but this would only happen at slower speeds, and its not sharp so no cutting...

For the rear, I ran 5.5" BS, BUT I was running the earlier rearend (1/2" narrower than yours), so the extra 1/2" BS you got makes sense. I fit the 6.0" BS on the rear too, but they tucked in too far for my taste...