Backspacing and Offset - the never ending headache of wheel shopping

[33IMP]

I kind of have my heart set on 15” Weld Prostars like the blue Dart in the link I posted.

I think the prostars are available with 5.5 bs, but it's a ten inch wheel. Might be hard to fit.
Nice wheel, not cheap.
Summit and Jegs have very similar wheels (chinese knockoffs, I suspect) with house names on em, about half the price of real welds. May not have the bs you need.

 

[1971 CY Dodge Dart]

I think the prostars are available with 5.5 bs, but it's a ten inch wheel. Might be hard to fit.
Nice wheel, not cheap.
Summit and Jegs have very similar wheels (chinese knockoffs, I suspect) with house names on em, about half the price of real welds. May not have the bs you need.

Summit has 15x8” Prostars with 5.5” backspacing.
Weld Racing 96-58210 Weld Racing Prostar Polished Wheels | Summit Racing

 

[Daves69]

You could put her up on stands and check your clearances fairly easy. I think you need at minimum 1/2" - 3/4" clearance from inner wheel well, leaf springs, outer wheel well and the expected tire bulge. Check both sides not just one.

A straight edge off the brake drum and a tape to measure.

 

[toolmanmike]

Check both sides not just one.

This is very important.

 

[Unconventional]

Wow, looks like I screwed up!
Looks like Wheelsmith is still in business. I guess I was thinking of Stockton wheel.
My apologies if I misdirected anyone.

I just called Wheelsmith today with some questions I had for a project. Very helpful they were.

 

[64physhy]

This thread should be a sticky

 

[famous bob]

I prefer backspace. Offset seems to confuse people. Measure what you have and how much space you have left. That will get you very close to what works on your car unless you mess with too big of tires on too narrow of a rim. Like my 255-60's are just about too wide for my 7" wheels. The sidewalls bulge out and are close to rubbing.

agree^^^^^^^^^^ , if the wheel is the right width , and the back space is right , I don't give a rats *** about offset ...jmo

 

[72bluNblu]

agree^^^^^^^^^^ , if the wheel is the right width , and the back space is right , I don't give a rats *** about offset ...jmo

That's because you don't understand what it's telling you. Just like every wheel has a backspace spec, every wheel has an offset spec. And if you know one you can calculate the other pretty easily, as long as you don't use the examples in the first post of this thread.

Done!

Well that's too bad. The original post contains numerous errors, the offset to backspace conversion and all of the examples are wrong.

A 10" wheel with a 0 offset has a 5.5" backspace. That's because a 10" wide wheel measures 11" from outside lip to outside lip, so the wheel mounting surface to the wheel lip is 5.5", not 5".

This is for a 10" wheel with a +25 offset, but it's illustrated to clear up the confusion from the original post being incorrect.

 

[Unconventional]

Isn't wheel shopping fun? I have been shopping for a project I have in mind. The vision I have is quite simple as far as the look goes, but fulfilling the mechanical aspect could be expensive. The rear is simple 15"x10" with a bunch of negative offset or a medium amount of back space, and steel, looks unimportant because they will be sporting Bonneville Discs. The front vision is more complicated a 14" or 15" x 6" or 5" offset unimportant. Complicated part being the vision is of an OE GM SS wheel. They are available as new reproductions, but not in the size I seek. There are some alternatives, one of which being throwing a large aluminum billet into a CNC machine and pulling out the desired product, prohibitively expensive . The other alternative would be finding that OE center and having a custom wheel maker cut the center out and putting it in the proper sized rim.

 

[33IMP]

Oem GM SS wheel? Like a camaro/chevelle wheel or what?
Why not any old steel, and moon discs all around?

I found out that wheelsmith is still in business, and will make what you want, probably. I have no idea of the cost.

I've been shopping for a set of 15x5 or 15x6 steelies for my car trailer. Summit has some with dual bolt patterns for $50 ea.

 

[Unconventional]

Oem GM SS wheel? Like a camaro/chevelle wheel or what?
Why not any old steel, and moon discs

Just the vision I got. Those 5 narrow silver spokes on the front and the Moon discs on the back. I think American makes some similar, but they just don't fit the vision

 

[33IMP]

That's because you don't understand what it's telling you. Just like every wheel has a backspace spec, every wheel has an offset spec. And if you know one you can calculate the other pretty easily, as long as you don't use the examples in the first post of this thread.


Well that's too bad. The original post contains numerous errors, the offset to backspace conversion and all of the examples are wrong.

A 10" wheel with a 0 offset has a 5.5" backspace. That's because a 10" wide wheel measures 11" from outside lip to outside lip, so the wheel mounting surface to the wheel lip is 5.5", not 5".

This is for a 10" wheel with a +25 offset, but it's illustrated to clear up the confusion from the original post being incorrect.

View attachment 1716386596

Agree. I pointed out some mistakes in post#6.