Wheel/Tire Clearance Issues

[damnyankee36]

On my bagged 66, I decided to go with Boss 304 wheels, 20x8.5, 5 1/4" backspace. I plan on mounting 255/35-20's. This is my first attempt at big wheels and a bagged truck.

I have discovered that the rear wheelwells are about 10 1/2" wide and the tires are about 10", not much wiggle room. The tires rub the inner part of the wheel well when dumped. It's a little worse on the passenger side because the way the rearend moves to the left when lowered.

I think I can cut away about 1 1/2" of the portion of the wheel well that bolts to the bedside and also cut the bedside in the same area to gain clearance above the tire. (See pics) BTW, the tire that's mounted now is a 255/45, about 2" taller than what I plan to use.

With the wheel well cut, I figure I'll have lots of room to move the wheel out as the tire can now move under the part I cut.

Now, the only way I can see to do this easily is to install a 1/2" wheel spacer along with longer studs.

Is this problem something common? What has everyone else done? I figured the 304's were a common offset that would work on just about any truck since there wasn't another offset to choose from.

[lolife99]

Originally Posted by damnyankee36

On my bagged 66, I decided to go with Boss 304 wheels, 20x8.5, 5 1/4" backspace. I plan on mounting 255/35-20's. This is my first attempt at big wheels and a bagged truck.

I have discovered that the rear wheelwells are about 10 1/2" wide and the tires are about 10", not much wiggle room. The tires rub the inner part of the wheel well when dumped. It's a little worse on the passenger side because the way the rearend moves to the left when lowered.

I think I can cut away about 1 1/2" of the portion of the wheel well that bolts to the bedside and also cut the bedside in the same area to gain clearance above the tire. (See pics) BTW, the tire that's mounted now is a 255/45, about 2" taller than what I plan to use.

With the wheel well cut, I figure I'll have lots of room to move the wheel out as the tire can now move under the part I cut.

Now, the only way I can see to do this easily is to install a 1/2" wheel spacer along with longer studs.

Is this problem something common? What has everyone else done? I figured the 304's were a common offset that would work on just about any truck since there wasn't another offset to choose from.

Nothing is common about wheel backspacing and these old trucks.
What rearend do you have?
63-70?
71-72?
73-up?
All of these are a little different.

Plus. What type of panhard/track bar are you using?
ECE's Super Track Bar or others that are longer and adjustable,... and connect to the rearends passenger side trailing arm,... will help with left-to-right shift when dumping the air.

I think your mod to the wheel tub will help.

[damnyankee36]

I'm using the original rearend. A buddy has a rearend out of a 70ish which he says is about 1" - 2" wider. That would solve everything since once I cut the wheel well lip, I can move the wheel out up to 2" or more before I contact the outer fender lip.

I'm also using the stock length adjustable bar. I think the sideways movement can be accomodated with my spacer plans.

Only trouble is, my rearend is completly done as far as setting up the gears, new bearings, etc. His ratio is different too. I really don't want to spend more time rebuilding that one too and swapping the parts!

I found some scrap 5/8" aluminum, so I'll get the water jet cutter to cut me some spacers.

Oh well, I know what NOT to do next time!!

[roofingbloke]

That birdsye picture really helps, i plan on 20 x 12 for my 63 fleet, stock rear axle, with modifications to inner and very inner arches,