Still confused on wheel sizing

[machoheadgames]

It certainly does, and this is where we simply guide him to not get an overly wide wheel…so he can then skip worrying about offset and focus on his BS. The hope is to help set him up for success without him needing to work so hard.

I understand the offset stuff largely from using it to figure out the BS in my midnight wheel shopping days when BS wasn’t made available. But offset doesn’t really matter if you know what BS to get and what wheel widths work for your setup and tire choice.

I don’t disagree, but if someone is speaking in terms of offset and asking questions, I’ll answer in that format. I get that in Jeeps, BS is utilized more by the forum folk, but in reality, either will get you the dimensions you need, if you can understand how they’re measured.

There is one person who started the “focus only on BS, offset is for cars” argument and really that argument never made any sense, other than BS may be a bit easier for a beginner to comprehend. The stock Jeep wheels only have offset listed on the back of them. Both are just methods of measurement, neither is primarily geared towards any specific type of vehicle. That’s all I’m trying to say. For what it’s worth, I use BS plenty myself; but the question was about offset and so I answered that.

 

[chili_pepper]

and i know im confusing folks here
im asking alot of questions that fold over onto each other
my other(BETTER) half is already steaming with the cost im going to spend dropping this thing down
SHE is HAPPY it will be lower and easier for her to get into (I will miss giving her a helping hand into it )

and i have too many options rims, tires -them rubber/plastic fender do-hicckies
worrying about driving a costly tire into the metal fender edge and dishing out more money for a mistake

I found a local shop 8miles away that will order the tires for me and mount them so thats a good thing
He says" keep the rims you have (size is posted on my other thread) and the flares they should work with 30inch tires
until i can save up and get a set of rims i like then go back to original flares (springtime)
and i read here that wheels that push out from the hubs short BS can cause problems with my axles failing
BUT
i dont know how much of a JEEP guy he is
hence my questions here

cheers all
john

Might not have picked everything up from your previous thread (or this one), but I gather you are looking to return the vehicle to stock ride height/suspension components and you would prefer to get rid of the wide (very) non-stock fender flares currently installed AND your tires need to be cover so as to avoid issues with the fuzz and/or state inspection.

I had a somewhat similar situation when I picked up my LJ last year from out of state. While the suspension was stock with no lift, it came with standard width factory flares and aftermarket "soft 8" style steel wheels sporting 31x10.50x15 KO2's. They cleared everything inboard of the wheels, but stuck out well beyond the flares and therefore would not pass my state's mechanical/safety inspection required to register the vehicle. To correct the issue, I selected a factory wheel style I liked (Ravine) and hunted down a set of Rubicon width factory flares.

As delivered, no bueno in the People's Republic of Maryland for inspection:



After remounting the 31" KO2's on factory Ravine wheels with standard width factory flares. Still an issue for inspection, but we're getting there:



After installing the Rubicon width factory flares...winning!



In my case, both backspacing and offset were important in selecting a wheel that would work. Going with a factory wheel likely made it easier to accomplish what I needed to do, but I had to worry about wheel/tire interference inboard and exposed tire outboard in this case.

Speaking of...here's some info the webmaster compiled on a number of stock offerings, with data....

STICKY Post in thread 'Wrangler TJ Factory Specifications'

Oct 29, 2015

Wheels

Standard SE Wheel

* 15x6 steel
* 5 on 4.5" bolt pattern
* Backspacing = ??
* Offset = ??

——————————————————————

Name Unknown

* 15x7 steel
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Offset = +38 mm

——————————————————————

Name Unknown

* 15x7
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Chrome finish
* Offset = +38 mm

——————————————————————

Grizzly

* 15x7 aluminum
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Offset = +38...

• Chris

• 

 

[machoheadgames]

After remounting the 31" KO2's on factory Ravine wheels with standard width factory flares. Still an issue for inspection, but we're getting there:

I wonder if this is why only 30x9.5 was the max stock non-rubi tire. The outer bead on the stock 8” wheels themselves stick out past the flares. Mount the tire and it’s the same deal, although with a narrow tire like a 30x9.5, it will end up with the tread just inside the flare, while the sidewall is outside the flare slightly. Guess I just found it a bit surprising that this is how stock was.

 

[MikeE024]

I don’t disagree, but if someone is speaking in terms of offset and asking questions, I’ll answer in that format. I get that in Jeeps, BS is utilized more by the forum folk, but in reality, either will get you the dimensions you need, if you can understand how they’re measured.

There is one person who started the “focus only on BS, offset is for cars” argument and really that argument never made any sense, other than BS may be a bit easier for a beginner to comprehend. The stock Jeep wheels only have offset listed on the back of them. Both are just methods of measurement, neither is primarily geared towards any specific type of vehicle. That’s all I’m trying to say. For what it’s worth, I use BS plenty myself; but the question was about offset and so I answered that.

I certainly don't mind that you answered the question.

I’ve simply learned that it’s easy to focus on BS and wheel width to get where we want to be.

 

[chili_pepper]

I wonder if this is why only 30x9.5 was the max stock non-rubi tire. The outer bead on the stock 8” wheels themselves stick out past the flares. Mount the tire and it’s the same deal, although with a narrow tire like a 30x9.5, it will end up with the tread just inside the flare, while the sidewall is outside the flare slightly. Guess I just found it a bit surprising that this is how stock was.

In some states only the tread needs to be covered, others require sidewall and all...and with many rides here as evidence, some states don't give a shit if you cover them at all. I suppose it's possible that a 30"x9.5" with less aggressive tread may well pass if only the tread itself needs to be covered (with standard width flares)?

The combo of 31"x10.50" and the Rubi flares worked out well, they just cover the rubber completely.

 

[machoheadgames]

In some states only the tread needs to be covered, others require sidewall and all...and with many rides here as evidence, some states don't give a shit if you cover them at all. I suppose it's possible that a 30"x9.5" with less aggressive tread may well pass if only the tread itself needs to be covered (with standard width flares)?

The combo of 31"x10.50" and the Rubi flares worked out well, they just cover the rubber completely.

30x9.5 on 15x8 was pretty common stock combo, and I’m not aware of it being only in certain states, so I guess it worked out fine. The stock tires were all pretty mild so it probably didn’t matter too much. Of course there will also be less sidewall bulge (almost none) on a 9.5 vs the 10.5 you have installed, so it would definitely be more under the flare as shown.

I was mostly getting at the fact that the wheel itself is not fully under the flare, so definitely can’t expect the tire to be either. And that being stock is what surprised me (yet that’s how they all are).

 

[Mike_H]

I wish you all would stop saying offset doesn’t matter…it’s another way to know where the wheel rides in relation to the mounting surface, just like backspace. Let Jerry go, fer cripes sake!

It’s pretty easy…to get back space from offset…take your wheels width, say 8 inches. And an inch to account for the bead flanges. So, in our example, 9 inches. Then devide by two, get 4.5. So, a zero offset, 8” wide wheel is 4.5” backspacing.

If that same wheel is -19 (3/4”) offset then you take 4.5 and subtract 0.75” to arrive at a backspace of 3.75”.
See…easy. Offset is just as useful as backspacing, it’s just a different way to represent the information.

 

[JMT]

View attachment 568782

My bad. Dumb autocorrect. I will definitely fix that. Tag me man. I don’t like bad spelling and grammar. I know we’re talking about the flare and not having flair. Hopefully I have some flair in the way I’m saying this.

 

[LONGJP2]

I wish you all would stop saying offset doesn’t matter…it’s another way to know where the wheel rides in relation to the mounting surface, just like backspace. Let Jerry go, fer cripes sake!

It’s pretty easy…to get back space from offset…take your wheels width, say 8 inches. And an inch to account for the bead flanges. So, in our example, 9 inches. Then devide by two, get 4.5. So, a zero offset, 8” wide wheel is 4.5” backspacing.

If that same wheel is -19 (3/4”) offset then you take 4.5 and subtract 0.75” to arrive at a backspace of 3.75”.
See…easy. Offset is just as useful as backspacing, it’s just a different way to represent the information.

Not disagreeing with your math.
However, if you tell me the backspace of a wheel, I instantly know if my tire will be closer to or farther from my frame.
If you tell me the offset, I will also need to know the width of the wheel to calculate the backspace.

 

[MikeE024]

I wish you all would stop saying offset doesn’t matter…it’s another way to know where the wheel rides in relation to the mounting surface, just like backspace. Let Jerry go, fer cripes sake!

It’s pretty easy…to get back space from offset…take your wheels width, say 8 inches. And an inch to account for the bead flanges. So, in our example, 9 inches. Then devide by two, get 4.5. So, a zero offset, 8” wide wheel is 4.5” backspacing.

If that same wheel is -19 (3/4”) offset then you take 4.5 and subtract 0.75” to arrive at a backspace of 3.75”.
See…easy. Offset is just as useful as backspacing, it’s just a different way to represent the information.

Help me out.

If I know the BS and wheel width, then why should I care what the offset is?

I’ve used offset to find my BS, but I’ve never worried about what my offset is once I know my BS and wheel width.

 

[chili_pepper]

If I know the BS and wheel width, then why should I care what the offset is?

If you're concerned about the wheel/tire fitting within a fender or under a flare, then both matter (along with the wheel width). Many Jeeps here have partial to no coverage from the fenders/flares (assuming they actually have either). In that case, you would be more concerned with all things inboard to avoid interferences.

 

[MikeE024]

If you're concerned about the wheel/tire fitting within a fender or under a flare, then both matter. Many Jeeps here have partial to almost no coverage from the fenders/flares (assuming they have either). In that case, you would be more concerned with all things inboard to avoid interferences.

But I know how it fits by knowing my BS, wheel width, and tire size (and experience). If the offset is then changed, then so is my wheel width.

That’s how I understand it, so lmk if that’s not correct.

 

[2005 wrangler X ?]

Might not have picked everything up from your previous thread (or this one), but I gather you are looking to return the vehicle to stock ride height/suspension components and you would prefer to get rid of the wide (very) non-stock fender flares currently installed AND your tires need to be cover so as to avoid issues with the fuzz and/or state inspection.

I had a somewhat similar situation when I picked up my LJ last year from out of state. While the suspension was stock with no lift, it came with standard width factory flares and aftermarket "soft 8" style steel wheels sporting 31x10.50x15 KO2's. They cleared everything inboard of the wheels, but stuck out well beyond the flares and therefore would not pass my state's mechanical/safety inspection required to register the vehicle. To correct the issue, I selected a factory wheel style I liked (Ravine) and hunted down a set of Rubicon width factory flares.

As delivered, no bueno in the People's Republic of Maryland for inspection:

View attachment 568836

After remounting the 31" KO2's on factory Ravine wheels with standard width factory flares. Still an issue for inspection, but we're getting there:

View attachment 568837

After installing the Rubicon width factory flares...winning!

View attachment 568838 View attachment 568839

In my case, both backspacing and offset were important in selecting a wheel that would work. Going with a factory wheel likely made it easier to accomplish what I needed to do, but I had to worry about wheel/tire interference inboard and exposed tire outboard in this case.

Speaking of...here's some info the webmaster compiled on a number of stock offerings, with data....

STICKY Post in thread 'Wrangler TJ Factory Specifications'

Oct 29, 2015

Wheels

Standard SE Wheel

* 15x6 steel
* 5 on 4.5" bolt pattern
* Backspacing = ??
* Offset = ??

——————————————————————

Name Unknown

* 15x7 steel
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Offset = +38 mm

——————————————————————

Name Unknown

* 15x7
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Chrome finish
* Offset = +38 mm

——————————————————————

Grizzly

* 15x7 aluminum
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Offset = +38...

• Chris

• 

are the Rubicon factory flares wider than my TJ "X" original flares?
the last pic is what im looking for on Mine,
and ive learned from you all here Its the bump stops that keep the tire from hitting the steel fender edge

so to keep my wide rims and wide flares until spring
aluminum American racing rims on it now
MT-058
15x8J
ET-28
and ADD bump stops to fit

Then in spring find the 7inch rims with the dimensions you posted, or sooner if i can swing it

THANK YOU

 

[TheBoogieman]

My bad. Dumb autocorrect. I will definitely fix that. Tag me man. I don’t like bad spelling and grammar. I know we’re talking about the flare and not having flair. Hopefully I have some flair in the way I’m saying this.

That was meant for the OP, but now I see your flair too.

 

[2005 wrangler X ?]

did a search on those Ravine wheels
15x8
5x4.5 (5x114.3) lug
offset 25.4
backspace 5.5

this helps me a lot with all the crazy numbers when looking for wheels

 

[Mike_H]

Not disagreeing with your math.
However, if you tell me the backspace of a wheel, I instantly know if my tire will be closer to or farther from my frame.
If you tell me the offset, I will also need to know the width of the wheel to calculate the backspace.

Backspace requires a lot less thinking...but just because that is the case, doesn't mean offset doesn't matter.

 

[Mike_H]

Help me out.

If I know the BS and wheel width, then why should I care what the offset is?

I’ve used offset to find my BS, but I’ve never worried about what my offset is once I know my BS and wheel width.

You don't have to care about offset....Only making the point that offset is a valid measurement, and demonstrating that you can get the info you need from it, if you know how to convert. I see it happen quite a bit on the forum. Newbie wants wheels, and every one tells them go shopping for a certain backspace and say "offset doesn't matter" or some variation of that. When looking for wheels, its hit or miss if the backspace is listed, but close to 100% of the time, offset will be given for a particular wheel.

 

[chili_pepper]

are the Rubicon factory flares wider than my TJ "X" original flares?

Based on your profile photo, you do not have factory original flares. The factory Rubicon width flare option would be narrower than the aftermarket flares you currently have (5.5"-6" wide?). By how much I cannot say for sure. Allegedly, the standard width factory flares are 3.5" wide, factory Rubi width are 4.5". I didn't measure the difference on mine though it seems more like 1.25"+ to me (and based on the 2nd photo I posted above). But I'm just eyeballing it...

the last pic is what im looking for on Mine,

For clarity, my LJ is running stock suspension, no body lift, running 31"x10.50" tires with the factory Ravine wheel (15x8, 5.5" BS, +25mm offset) and factory Rubicon width flares...the result being the last two photos I posted above. My LJ required a slight adjustment to the stop bolts to limit steer angle a little, this is not an uncommon adjustment to make.

and ive learned from you all here Its the bump stops that keep the tire from hitting the steel fender edge

That may be, but if the bump stop stays the same length (say factory length) and you increase the overall diameter of the tire without adding lift to the body/suspension (say adding a 33" tire), the tire has the potential to impact the steel fender edge before the bump stop does its job in stopping the wheel/axle travel upward. I believe with stock suspension and no body lift, 31" is the largest tire that will work without interference (in regards to suspension travel).

Then in spring find the 7inch rims with the dimensions you posted, or sooner if i can swing it

15x8 will work fine (unless you want a 7" width), you just need to be mindful of what the backspacing and offset will do to the relative position of the wheel/tire. My rough calcs suggested that the combo of wheel, tire and flare I listed above would get the rubber covered for inspection and not cause any interferences.

If you go with a factory wheel, you likely won't have any issues. If going aftermarket, find one that matches the data of one of the factory offerings and you should be good to go.

 

[chili_pepper]

did a search on those Ravine wheels
15x8
5x4.5 (5x114.3) lug
offset 25.4
backspace 5.5

this helps me a lot with all the crazy numbers when looking for wheels

The link posted above to another thread here will give you that information for a number of factory wheel offerings. Follow the link to the thread for the full list.

 

[mrblaine]

I don’t disagree, but if someone is speaking in terms of offset and asking questions, I’ll answer in that format. I get that in Jeeps, BS is utilized more by the forum folk, but in reality, either will get you the dimensions you need, if you can understand how they’re measured.

There is one person who started the “focus only on BS, offset is for cars” argument and really that argument never made any sense, other than BS may be a bit easier for a beginner to comprehend. The stock Jeep wheels only have offset listed on the back of them. Both are just methods of measurement, neither is primarily geared towards any specific type of vehicle. That’s all I’m trying to say. For what it’s worth, I use BS plenty myself; but the question was about offset and so I answered that.

The problem has to do with how the rim is constructed. Generally, offset is calculated (near as I can tell) by rim width which is the inside dimension that the tire beads butt up against. Offset math generally moves that back and forth but it never exceeds the actual rim width.

Backspacing doesn't care about the published rim width.

This is how we all measure backspacing. Note how flat the rim lip is.

Then you have a rim like this and if they were the same width, your backspacing number would vary from the above.

Versus this-

Versus this-

Point being, if we're trying to move from a 3.5" back spaced wheel to something closer to 4" to tighten up our steering with an improved scrub radius, it is probably best to see the wheel in person and do some actual measuring.

BTW- if you swing by my house with a rim and measure it like this, just know you have invited a swift kick to the taint for being a dumbass.