Wheel back spacing

Pskhaat

2005 Expedition Trophy Champion
Actually, with a 7" wheel and the same backspacing you'll be tucked in only 1/2" not a full 1". I'd love to see those Tundra steelies on yours :)
 

xcmountain80

Expedition Leader
Yes that makes sense. This is why, I had the OE 4Runner rims on my 4Runner that were 16x7 4.5 or 4.25, and tires ran to close to the upper BJ, I used a 1" wheel spacer to kick them out. I bought a set of LX450 wheels 16x8 3.50, 3.75 BS and eliminated the spacers altogether. So the OE wheels were 4.5 BS include 1" wheel spacers put them at 3.5, same as the lx wheels. So with this line of thinking you are correct in thinking the other will suck in.

Aaron
 

deadbeat son

Explorer
Actually, with a 7" wheel and the same backspacing you'll be tucked in only 1/2" not a full 1". I'd love to see those Tundra steelies on yours :)

How's that? A 16x8 with 4.5" backspacing would have an additional 3.5" of rim on the opposite side of the mounting surface plane. A 16x7 with 4.5" BS would only have 2.5" of wheel on the opposite side of that plane.
 

Pskhaat

2005 Expedition Trophy Champion
How's that? A 16x8 with 4.5" backspacing would have an additional 3.5" of rim on the opposite side of the mounting surface plane. A 16x7 with 4.5" BS would only have 2.5" of wheel on the opposite side of that plane.

simpsons-the-doh-49005791.jpg
Doh! Yep kept thinking some bizzare form of offset! Yes, same BS would put it in ~1"




 

Hanley Noel

Observer
The ultimate end goal is to have 255/85's on 16x7 steel wheels that don't stick out past the fenders (flares removed) at all. With that said, the wheels should be at the maximum width to retain stability. Make sense?

So the question is...what is the correct backspacing/offset to meet the goal? Tundra steelies are 16x7 w/ 4.6" backspacing. Will those sit too far in?
 

Pskhaat

2005 Expedition Trophy Champion
Roughly, yes. If you're going a spacer you may even consider 1.5" (if you want to incur additional .5" outward) as to correct for the kingpin-contact patch angle. But again, 1" should put you about stock width.
 

Hanley Noel

Observer
can you link to some good spacers?

this stuff is confusing for me, sorry.

are the tundra steel wheels w/o spacers is a bad idea? If you could create the perfect 16x7 wheel, what would the backspacing be? 4"?
 

deadbeat son

Explorer
can you link to some good spacers?

this stuff is confusing for me, sorry.

are the tundra steel wheels w/o spacers is a bad idea? If you could create the perfect 16x7 wheel, what would the backspacing be? 4"?

It would depend on the application. What are the width and backspacing of the factory wheel? 16x8 with 4.5"? If so, then yes, a 16x7 with 4" of backspacing would net approximately (within 1/20" of an inch) the same ratio of backspacing to whatever the opposite of backspacing is. (Frontspacing?) Look at it as a ratio -- 4.5:8 is approximately the same as 4:7 (if I performed my algebra correctly.) This should keep the weight of the tires distributed over the bearings per the design of the factory engineers.

Personally, I don't care for spacers, but that's just my preference.
 

Hanley Noel

Observer
Ok. Using the info you just posted the Tundra wheels (16x7 4.6backspacing) are no bueno. Looks like I'm going to Stockton for some custom wheels.
 

Pskhaat

2005 Expedition Trophy Champion
Non-US LCs got 5.5, 6, and 6.5" (newer) rims. IIRC, they're all nearly at 0 mm offset (?) and thus sit further inward anyway. The big hullabaloo on 'mud is that the pre-91 cruisers required a maximum of 3.5" backspacing to clear steering components.

The bearings take it on two parts, one is from the offset (91-97 =0mm) and the other is kingpins during turning which you want to have the contact patch in the same location as you bump up in tire size. That angle is roughly in front of and centerto the contact patch. It is very hard to get both of these correct.

It is a matter of aesthetics more than anything at this point. If you want your tire absolutely flush with the side, you may need a ~1" spacer. As for components, the inside tire wall should be the ~ same plane as the 275 tire that came stock. I've run many spacers to correct for the above, but I also prefer greatly the look of an OEM tire where some folks do not.
 
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