Understanding BS and Offset
#1
Understanding BS and Offset
Pretty new to the site, proud owner of 11' FX4.
I thought I could get a thread going were you guys can explain BS and offset to us new guys. Theres alot of repeated posts about what size tires/wheels fit on stock 4x4 or 4x2 trucks with or with leveling kits. I for one would like to put 305/55/20 Nitto ATs on Ballistic Jesters 20 x 9 (4.52 BS, -12 Offset) Im not sure how far that setup will stick out. I kinda understand what BS is but im getting confused about the offset and what it effects.
thanks to all that help clarify this issue.
Also not sure how to make this a sticky?
joe
I thought I could get a thread going were you guys can explain BS and offset to us new guys. Theres alot of repeated posts about what size tires/wheels fit on stock 4x4 or 4x2 trucks with or with leveling kits. I for one would like to put 305/55/20 Nitto ATs on Ballistic Jesters 20 x 9 (4.52 BS, -12 Offset) Im not sure how far that setup will stick out. I kinda understand what BS is but im getting confused about the offset and what it effects.
thanks to all that help clarify this issue.
Also not sure how to make this a sticky?
joe
#2
Thanks for thread, and welcome to the site. First quick answer is only a moderator can make a thread sticky.
Offset and backspace essentially provide the same data, just in two different forms, you can calculate one from the other. Essentially offset is the position of the mounting surface of the wheel either forward (positive number), dead even (0), or behind (negative number) the center line of the wheel (outboard flange to inboard flange measurement / 2). The more positive the offset the less a tire will stick out. However, when running larger wider tires you often need a more negative offset to get the tires away from the suspension components for clearance, however at this time you need more lift on the truck to clear them.
The tires you are looking to get are basically 33x12.50, the wheels should stick out about 2.5" further than stock wheels (unless they have changed specs on the 11 model and of course if my math is wrong). Sticking out that far may require some trimming to get them to clear, I am not too sure about the newer trucks. Hope this helps.
Offset and backspace essentially provide the same data, just in two different forms, you can calculate one from the other. Essentially offset is the position of the mounting surface of the wheel either forward (positive number), dead even (0), or behind (negative number) the center line of the wheel (outboard flange to inboard flange measurement / 2). The more positive the offset the less a tire will stick out. However, when running larger wider tires you often need a more negative offset to get the tires away from the suspension components for clearance, however at this time you need more lift on the truck to clear them.
The tires you are looking to get are basically 33x12.50, the wheels should stick out about 2.5" further than stock wheels (unless they have changed specs on the 11 model and of course if my math is wrong). Sticking out that far may require some trimming to get them to clear, I am not too sure about the newer trucks. Hope this helps.
#3
#5
I would go with the 0 over the -12, maybe the +12 if offered, UNLESS you plan on lifting in the future.... Here is a page with some +12 18" with 325 https://www.f150online.com/forums/wh...c-jesters.html. I think the 305 on the 0 would look great too.
#6
#7
So to make it simple:
Backspacing- distance from inside rim edge to face/hub of rim
Offset- Distance face/hub of rim is from the center
Example 18x9 rim
0 offset = 5 inch bs - you have to had a 1/2 to the rim width to account for lip of rim
o offset = 5" bs
-12 offset = 4.53" bs
+18 offset = 5.68" bs
Backspacing- distance from inside rim edge to face/hub of rim
Offset- Distance face/hub of rim is from the center
Example 18x9 rim
0 offset = 5 inch bs - you have to had a 1/2 to the rim width to account for lip of rim
o offset = 5" bs
-12 offset = 4.53" bs
+18 offset = 5.68" bs
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#8
I would go with the 0 over the -12, maybe the +12 if offered, UNLESS you plan on lifting in the future.... Here is a page with some +12 18" with 325 https://www.f150online.com/forums/wh...c-jesters.html. I think the 305 on the 0 would look great too.
#9
So to make it simple:
Backspacing- distance from inside rim edge to face/hub of rim
Offset- Distance face/hub of rim is from the center
Example 18x9 rim
0 offset = 5 inch bs - you have to had a 1/2 to the rim width to account for lip of rim
o offset = 5" bs
-12 offset = 4.53" bs
+18 offset = 5.68" bs
Backspacing- distance from inside rim edge to face/hub of rim
Offset- Distance face/hub of rim is from the center
Example 18x9 rim
0 offset = 5 inch bs - you have to had a 1/2 to the rim width to account for lip of rim
o offset = 5" bs
-12 offset = 4.53" bs
+18 offset = 5.68" bs
#10
very helpful, i see what you mean about the offset now. that looks perfect. what do you think about going with 0 and putting bushwackers on or would the bushwackers look ok with the +12. I dont want the bushwackers to overlap the tires, i hate that look. That guy should of went with the chrome ones, there so much hotter than the black!
#11
This is my truck with +12mm offset rims. Personally I wish I got something that stuck out a little further but I have zero rubbing issues with setup at all with no trimming so I'm not going to complain. The flares are aftermarket and just a bit bigger than the stock fx4's. I have more pictures in my gallery if your looking for an idea of what kind of spacing your going to get. Also, the tires are 305/65/18 and there is a 2" level.
#12
I put the ballistic jesters with -12 offset with 35x 12.5x18 trail grapplers on my 06 fx4 leveled and have bad rub on the back of the front wheel well. thought the - was better than factory backspace. looks sick but sounds awful at 3/4 turn. I guess I need to lift 6 or body lift 3 w level
#13
I put the ballistic jesters with -12 offset with 35x 12.5x18 trail grapplers on my 06 fx4 leveled and have bad rub on the back of the front wheel well. thought the - was better than factory backspace. looks sick but sounds awful at 3/4 turn. I guess I need to lift 6 or body lift 3 w level
#14
This is my truck with +12mm offset rims. Personally I wish I got something that stuck out a little further but I have zero rubbing issues with setup at all with no trimming so I'm not going to complain. The flares are aftermarket and just a bit bigger than the stock fx4's. I have more pictures in my gallery if your looking for an idea of what kind of spacing your going to get. Also, the tires are 305/65/18 and there is a 2" level.
#15
I've had no rub issues whatsoever. Keep in mind the +12 rims do stick out about an inch I would guess with no flares on the truck. These flares are about 1.5 inches I think so it looks like they stick in a lot more than they do. If you have the stock f150 flares or no flares it will look like they stick out a fair amount. But I do agree, I wish mine stuck out another half an inch or so. All that being said, I'm pretty sure they would rub somewhere without the level. Theres no rubbing, but theres not a whole lot of room in there either