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Backspacing?

2K views 16 replies 9 participants last post by  TARM 
#1 ·
When you say maybe like 5.5" backspaced does that mean the tire is going to stick off the truck more or less? Like the center of the wheel is set deeper or more shallow? btw this is talking about a 20x10 Moto Metal 951
 
#2 ·
Pretty sure it will stick out less and sit further in your fender well.. the center or hub is shallower looking at the wheel... I could be wrong, maybe somebody else will chime in..
 
#3 ·
yeah i just want to be sure, don't want a lot of tire showing when you look down the truck from the front ;)
 
#4 ·
Well i wanted the samething as you.. So im running 05+ wheels on my 01..
+11 on the offset on 22x9.5 wheels.. So i have the wider tire look but there not sticking outside the fenders...
 
#8 ·
so the lower the number the deeper the center is set?
 
#9 ·
The backspacing isn't the frame of reference, it is merely an indication how deep the wheel is from where it mounts. The offset is more important, since it is an indicator how much offset your wheel is from the centerpoint.
LINK
 
#11 ·
Actually...If the rim width is known, backspace can be calculated from offset and vice versa. They are just two different ways of measuring. Typically for a front leaf sprung truck, the backspace number is easier to reference as if it is too deep there is a risk of the tire rubbing on the leaf pack (as well as on the radius arms on 05+ superduties)
 
#14 ·
So with a 4-4.5" lift on 35 nittos... what should the proper backspacing be for the 20" moto metals to allow them to stick off say an or two when looking down the truck
 
#15 ·
If this is on a 01 in your sig you will need a min of 5" backspacing. But most aftermarket wheels run somewhere between 4.5-5. The leaf spring is fixed and the so is the arc of it. When you go up in tire diameter its moving farther down the leaf but also it can turn closer into it so it kind of holds a typical relationship. What will get you more or less rubbing is the width of the rim in relation to the tire width. evne with the same backspacing the wider the tire and narrower the rim the more the tire bulges past the rim width. On the inside this causes it to decrease the distance between tire and leaf spring. Example: 38x15.5 on a 20x10 rubs the leafs bad. Same tire on a 20x12 does not or only at extreme and very lightly at most. As the backspacing was fixed, as was tire size, the tire bulging more to the inside was the reason for decreased clearance.
 
#17 ·
Very true when it comes to handling and bearing stress. I think the reason backspacing is focused on is that its the key to fitment and clearance on the inside. I think many never even think about the perf aspect and only little about the effects on bearing wear. It comes down to the issue with the leaf springs. They have to run 4.5-5" backspacing. More and they are rubbing the leafs.
 
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