Help me spec an offset for new wheels?

[Satatic]

I am going to get 20x10 wheels and 305/25/20 tires for my 68 camaro (on the rear) but after measuring out the wheel wells and axle everything else just confuses me. I made a ms paint drawing with my measurements on it.


The inside measurements are inside wheel well lip to spring. I would like to have the wheels closer to the spring because i fear that the tire could rub where the back part of the wheel well arc curves inward. I do not have rolled lips because of the aluminum trim.

The axle is not welded to the spring perches yet so i think the measurements should both be 5 5/32 to split the difference. And then use the smaller of the wheel well depths. Also there will be a disk brake on there so that puts 1/4 inch onto the axle flange.


For the front i have not taken any measurements yet but i want 18x8 with 245/40?/18. Its pretty stock up front the only thing I did was remove the stock disk/hub and install drum brake hubs onto the disk brake spindles. That made the wheel go in further I think, or out farther i cant remember which one. I will measure that sometime soon.



Well thanks hope to get some help i havnt had any bites on other forums yet.

[ProdigyCustoms]

Looks like you put in some shallow mini tubs? How wide is the rear axle flange to axle flange with or without the brake rotors (let me know)

[Satatic]

I am not sure what you mean. The tubs are actually a tiny bit wider than the measurement, i just measured to the spring. w/ offset shackles.

[ProdigyCustoms]

Normailly we see 14 1/2" clearance on Mini Tubs. 13 7/16 seems shallow, but I have seen them installed taht shallow.

Anyway, based on the width of the rear, I can help with backspacing.

[Satatic]

It is 14 1/2 deep. The measurement is to the springs. My axle is 60" outside to outside with no rotors.

[ProdigyCustoms]

11" wheel with a 7" BS and a 305 tire.

[Satatic]

The wheels I am getting only come in 20x10 so 6 inch?

[ProdigyCustoms]

What wheel are you looking at? What tire size combo you running. Can they weld the center in where you want it or is it a limited selection of BS. 6 1/4 may be more safe since 20s can be tall. Depends on the tire size. You just want to protect your front space. Keep you outer wheel profile where you want it so the wheels are not to sucked in (my pet peeve) or to far out is obviously a huge issue.

[Satatic]

http://www.bossmotorsports.com/custo...els.cfm?id=408 in black

[Satatic]

I saw this in the tech spec section is that close?
20x10 Super Finish Black 5 on 4.75 20 mm 6.225

[ProdigyCustoms]

Perfect!

[Satatic]

What do you think about the front?

[Satatic]

Looks like there is only one option for the front
18x8 Super Finish Black 5 on 4.75 +2 mm 4.517

Will that work too?

[ProdigyCustoms]

Those wont work. You will rub the outer fender.

You need at least 4.75 for the front, 4.875 is even a better fit.

[Satatic]

I mentioned that i have the drum brake hub on disk spindle up front does that change any measurements? I have 5 7/16 from the outside of the rotor to the outside edge of the fender, Where there is kind of a square edge. I am not sure that is the best place to hang a string from.

[ProdigyCustoms]

You still need that extra 1/4".

[Satatic]

My friend was saying when we were looking at the wheels that they are custom and come in any dimensions i want. I just figured he was mistaken when i saw the specs on the boss website. So i will run the numbers by him and see if maybe they do also do them custom.

[ProdigyCustoms]

Good luck, If you need anymore help, let me know

[camaro2nv]

Those wheels are cast and fitment is very limited.

[Satatic]

Maybe i could get 1/4 inch milled off the back side but seriously?