No they are not incorrect. Whether or not it rubs depends entirely on the wheel and its backspacing/offset. If you keep the same backspacing as stock, they may rub because you have to push the wheels OUT (by reducing the backspacing)...otherwise the added width interferes with stuff.

In fact, I THINK a 35x10.5 WILL rub if you don't move it out. At 14.5 it definitely will, from what I've gathered (not from personal experience). Someone else can confirm...

Look at this image from Mickey Thompson:


The stock tires have a high backspace and corresponding high offset, so the mounting flange is way to the left of center. This means the right side in the figure is way close to the components of the suspension because it's brought in (think about where the hub of the axle is).

When you reduce that BS/offset, the mounting surface moves right, meaning since the hub of the axle is stationary, the right face of the wheel moves LEFT and you can eliminate the rubbing on the suspension stuff...

 

4.75" is good but keep in mind that the smallest wheel spacer is 1.25" as the spacer has to cover the orriginal lug nuts. Wheel spacers come in 1.25", 1.35", 1.5", and 2" widths.

 

i couldn't figure why every one was running from 4.75 to 3.5 back spacing when stock is 6.25 but now that i think about it, it all has to do with the tire size change as well. i just thought you would want the same back spacing as stock but 35" and 6.25 b/s would never work the wheel would hardly turn. i am so smart ........... S- M -R -T

 

this is why I love this forum. You've always got a ton of people willing to help you out.

 

This has been convered numerous times, however this chart should help.............






This shows the relationship of wheel width to backspacing and what offset for those measurments.

 

So if a wheel is 8.5 wide and has +10 offset what is the backspacing? I dont see that on the chart..

Could the extra weight of the steel wheels have been contributing to the bad ride cause even when I added hub centric rings I did not notice that big a difference, or does changing the scub radius really effect the ride on the JK?

 

That would have a backspace of 130mm (5.1"). (You can google and use one of the calculators - the chart posted verifies if you interpolate)

Out of curiosity exactly HOW was your ride bad? Thing is people go even lower than that on the backspacing (down to 4.5") and are OK. You are affecting the scrub radius less than those people are by only going down to 5.1".

 

I was getting steering vibes and bad shaking over bumps. Replaced ball joints, welded the trackbar holes, balanced and rebalanced and it still persisted. Switched back to stock backspacing steel wheels and it was much better. Its still a rough ride and sends vibes through the steering when go over bumps but nowhere near as bad and I think that might be cause of my heavy front bumper and rubicon springs with spacers.

That is part of the reason I want to get alloys. To make the ride not so harsh over bumps. I think the weight over the steelies might be contributing as well.

 

WOW... I feel more stupid, less alone, and think I'm leaning towards the Rugged Ridge Black alloys made specifically for JK's that ARE HUB centric with seemingly the correct back spacing to handle 12.5" wide tires. They aren't cheap but seem like could be the answer.

Yeah, that's it... or maybe not.... did I say WOW yet???

 

I have a headache.