I think I've made up my mind and am getting the Smoothie IIs for my 1972 Chevelle. I'm getting 17x10s for the rear. They are custom so i get to choose the backspacing. So whats the optimal BS to get in the rear? 5.5 or 5.75? Running a 12 bolt with drums, but will be adding rear discs. Running a tire thats gonna be a 275/40 or 285/40. Thoughts?

I have 17x9.5 in the rear w/ a 285/40 tires, the wheels have 5in BS and it fits fine w/ rear discs, I considered 17x10's and was told by a rep at American Racing that I'd need 5.5in BS for that, anymore in my opinion you might have to do something about your exhaust, but it wouldn't be anything drastic, you will have more than enough room in the wheelwell for that size wheel/tire regardless.

Nick

I have the TT II's on my 71.

They are 245/40R17 on 17x8 4.75 BS and 275/40R17 on 17x9.5 5.25 BS.

http://www.donmega.de/oct2005/DSC02052.jpg
http://www.donmega.de/oct2005/DSC02112.jpg
http://www.donmega.de/oct2005/DSC02082.jpg

Olli

So 5.5" for a 17x10 is optimal?

No, 5.25 is... but 5.5 will do just as good.

No, 5.25 is... but 5.5 will do just as good.

Zero offset for a 9.5" width is 5.25".
Zero offset for a 10" width is 5.5".
I would order either a 5.5" or 5.75" backspace for a 17x10.

Thanks for the clarification. It seems that the 5.5 is the 'safest' bet. What would i be gaining (or losing) by going to a 5.75. Maybe i need to understand BS just a lil more :) I want to go to atleast a 275/40 tire, preferably a 285+/40 tire with a 11.5 tread width

Zero offset for a 9.5" width is 5.25".
Zero offset for a 10" width is 5.5".
I would order either a 5.5" or 5.75" backspace for a 17x10.

Oops, thanks Clint for correcting me! :clonk::thumbsup:

Olli