17 x 8 4.5 backspace 0mm offset

S

silversx

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why do some wheels with this spec look sunken in to the fender.. and some members with the same specs but a different brand/model looks hella flush??

i currently have spidertrax on and im wondering if i should keep them on when i get my atx mojave installed tomorrow..

and btw it's not the tires.. the pics i've seen are all AT 265/70 tires
 
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there's NO ONE running spacers with aftermarket rims???

i've asked this before in a thread and got no response
 
Why don't you take off one of your wheels and put the spacer on to see if you like it sticking out past the fender.

Or just use a ruler and simple math.....it obviously will sit 1.25" farther out for the spacer and to go along with the Mojave's 1 inch wider rim and same backspace. That makes it 2.25 inches out from the stock wheel location. A wider tire will affect it a little too.
 
I personally like a wheel with a 12mm offset but all the wheels I want are 0mm I'm struggling with this very thing.
 
Can anyone direct me to a thread that explains all this? What's the difference between offset and backspace?
 
Turn_down said:
Can anyone direct me to a thread that explains all this? What's the difference between offset and backspace?
Click to expand...

Wheel Offset
Offset is measured from the centerline of the barrel of the wheel to the hub mounting surface. If that hub mounting surface were in the exact center of the barrel of the wheel the offset would be “0". If the mounting surface is away from the center of the wheel the offset is measured in millimeters. There are 25.4 millimeters to an inch. So if the mounting surface is 12mm from the centerline of the wheel it has a 12mm offset. That would also mean that it is about ½ inch. If the mounting surface is moved away from the vehicle that is a positive offset. The picture shows a wheel with the positive offset. A positive offset will cause the wheel to set in or tuck into the vehicle. Originally you found positive offsets on just front wheel vehicles. Due to that some people refer to positive offset wheels as front wheel drive offsets. Currently there are many rear wheel drive cars and trucks with positive offsets. The higher the positive offset the less it sticks out from the vehicle and it will have a higher Backspace. If the mounting surface is moved in toward the vehicle past the centerline, that is a negative offset. A high negative offset will produce a lower Backspace. Once again the measurement in millimeters is how far away from the centerline the mounting surface is. A -24mm offset means that the mounting surface is located 24mm or 1 inch from the centerline toward the vehicle. The wheel will come out farther from the vehicle and will have that deep dish look.

Width
The width of a wheel is measured inside the beads which are usually ½ inches. If you measure on the outside of the beads an 8 inch wheel will measure 9 inches

Backspace
Back spacing is measured from the inner edge of the wheel to the hub mounting surface. It is a convenient measurement in that, as long as the back spacing remains the same, the clearance to the suspension also remains the same. If you know the width of the wheel and the offset you can compute the backspacing. For example if you have an 8 inch wheel with a +24mm offset. An 8 inch wheel is actually 9 inches wide so if the offset were 0 the mounting surface would be right on the centerline and the backspacing would be 4.5 inches. With a positive offset the mounting surface moves off center 24mm or 1 inch toward the outer edge of the wheel. This will make the inner edge go more inside which will result in a 5.5 inch backspacing.
 
Great summary 1engineer. I'm still a bit confused about backspacing vs. offset. Are they inter-changable except that one uses center as a reference and the other uses the inner rim? This really is good info to know when looking for new wheels. Thanks for posting.
 
Okay, that confirms it. You ARE an engineer! lol

Thanks for the explanantion. I totally understood it. Now I see why there is a difference.
 
KCcarguy said:
Great summary 1engineer. I'm still a bit confused about backspacing vs. offset. Are they inter-changable except that one uses center as a reference and the other uses the inner rim? This really is good info to know when looking for new wheels. Thanks for posting.
Click to expand...

Yep, pretty much. Backspacing is just there so you don't have to do the math. Like the engineer said, it's a convenient measurement to make sure you clear your suspension. If you know the offset and the width, you can figure out the backspacing, and vice versa.

At least that's how I'm understanding it.
 
Turn_down said:
Yep, pretty much. Backspacing is just there so you don't have to do the math. Like the engineer said, it's a convenient measurement to make sure you clear your suspension. If you know the offset and the width, you can figure out the backspacing, and vice versa.

At least that's how I'm understanding it.
Click to expand...

Yep! I look for backspacing compared to stock.Great explanation by 1engineer too!
Here's another good learning tool that I use..... https://www.rsracing.com/tech-wheel.html
 
I've noticed on TireRack some of the 17X9 wheels have as much as 5.5" of backspacing. What is the maximum backspacing you can have? Is there a range we should stay within for our trucks? Are there variables like tire section-width, lift, etc. that come into play?
 
KCcarguy said:
I've noticed on TireRack some of the 17X9 wheels have as much as 5.5" of backspacing. What is the maximum backspacing you can have? Is there a range we should stay within for our trucks? Are there variables like tire section-width, lift, etc. that come into play?
Click to expand...

When you see 5.5" back spacing it is designed for a Chevy truck as that is about what theirs is stock and they use the same bolt pattern as us. If you put that on Toyota it will rub the UCA's when the suspension compresses. You can get 1.25" spacers to move it out but better to buy a wheel that was designed for a Yota!

I have wide tires(305/70/17) on a 8 inch rim so there is more tire sticking out past the rim(tire bulge). I have minor rub marks on my UCA's from full compression even with the 4.5 backspacing of my old Mojave rims. My new Konig rims have 4.1 backspacing and that shouldn't happen again as they move the wheel outboard .4 inches.
 
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