tried searching but didnt come up with much...i would like to upgrade to an
18"x9" wheel with a lower profile terra grappler tire...i wont be doing any offroading but like the look of an offroad xterra...my main concern would be the correct offset/bs...would like them to go out past the fenders just a bit...i was hoping to keep the stock height but am open to the pml...anybody running that size wheel? thanks

I think the Matte Black MB72 would look great on there. With stock suspension I would recommend a 285/60R18. It looks like the Terra Grappler is available in this size.

Let us know if we can help you with your purchase. Here's a few links.

MB 72 18" (http://www.discounttiredirect.com/direct/searchWheelsByVehicleAndSize.do?bp=&yr=2002&wd=18&rw=&vid=008897)
285/60R18 tires (http://www.discounttiredirect.com/direct/searchTiresBySize.do?sw=false&cs=285&ar=60&rd=18)

what offset would that be? will they go past the fender?

what offset would that be? will they go past the fender?

Just to clarify this for you, the offset is not what makes the tire protrude more, that's a function of the backspacing.

Stock BS is 5.5", LESS BS makes the tire stick out further, more BS makes it tuck into the wheel well more.

:D

Note that actually having too little BS will increase the amount of rub, as with less BS, on an IFS rig, the tire is swinging in a larger arc, hitting things it would have missed with more BS....

This means a smaller tire is required when you decrease the BS.

Food for thought.


:wink-big:

Backspace and offset are very easy to confuse. I'll try to keep this simple. I know this comes up a lot.

Actually, offset does tell you how far in or out your tire will protrude. Back space and offset are two different ways of looking at the same thing. Both can tell how far in or out your wheel and tire assembly will sit on the vehicle.

Here's a link that explains offset, It doesn't tell you what your vehicle needs but it is a good explanation of what offset is: What is Offset (http://www.discounttiredirect.com/direct/brochure/info/tmpInfoWheelOffsets.jsp)

In terms of offset: When looking for the correct offset (or backspace) you need to select a wheel that locates the wheel and tire in the deepest part of your wheel wells. (Think of your wheel wells as bowl shaped). If the offset it too high the wheel and tire may tuck in too far, if the offset is too low, the wheel and tire may stick out too far. Either extreme may limit how wide and tall of a tire you can run without modifications.

The MB 72 above is an 18x9 with a 18mm offset. With a simple calculation this can be translated to a 5.7" Backspace.

Well, off set can be used to CALCULATE how far out you might protrude, but, you will protrude a DIFFERENT amount for two rims with the SAME OFF SET, if their widths are different....

...but two rims with the same BS will protrude the same, even if the widths are different.

:D

Well, off set can be used to CALCULATE how far out you might protrude, but, you will protrude a DIFFERENT amount for two rims with the SAME OFF SET, if their widths are different....

Correct, Two wheels with different widths but the same offset will protrude out different as well as tuck in different.

Here's an example I sketched up for this:
http://i248.photobucket.com/albums/gg166/DTDForums/Mics/0offset.jpg?t=1268952416


...but two rims with the same BS will protrude the same, even if the widths are different.

:D

Actually, this is incorrect. The inside edge of the wheel will sit the same for both wheels but the outside edge will protrude different with different widths.

Heres an example I sketched for this. In this example both wheels have a 4.5"BS the first wheel is 8" wide and the second is 9" wide. You can see the 9" wide wheel will stick out (protrude) 1" further than the 8" wide wheel.
http://i248.photobucket.com/albums/gg166/DTDForums/Mics/45Backspace.jpg?t=1268953082

LOL

It was the TIRE protrusion he was trying to discuss, but, sure, the rim will stick out, but the inboard edge of the tire will remain the same, and so the outer edge of the tire will remain the same.


Moving the outer tire beads (Rim lips) in and out won't make much difference on a truck tire, as the tread will for the most part remain in the same place, while the sidewall bead areas pucker in/out.

As he was discussing how far the tire would stick out, the rim width, for the same BS, would be essentially the same.

Its more relevant to car tires, but there is some change in sidewall height, etc, with rim width, but, when we talk about truck tires and them protruding out past the fenders, its the tread, not the sidewall we are talking about, including at state inspections where they check that sort of thing.


I like the sketches though, very good illustrations.

You should put them on your site in a tech info section.

A sticky for this forum would be nice too, as this IS a popular topic to be confused by, with some people referring two the two terms interchangeably, thinking they are synonyms, etc.

:D

LOL

It was the TIRE protrusion he was trying to discuss, but, sure, the rim will stick out, but the inboard edge of the tire will remain the same, and so the outer edge of the tire will remain the same.


Moving the outer tire beads (Rim lips) in and out won't make much difference on a truck tire, as the tread will for the most part remain in the same place, while the sidewall bead areas pucker in/out.

As he was discussing how far the tire would stick out, the rim width, for the same BS, would be essentially the same.

Its more relevant to car tires, but there is some change in sidewall height, etc, with rim width, but, when we talk about truck tires and them protruding out past the fenders, its the tread, not the sidewall we are talking about, including at state inspections where they check that sort of thing.


I like the sketches though, very good illustrations.

You should put them on your site in a tech info section.

A sticky for this forum would be nice too, as this IS a popular topic to be confused by, with some people referring two the two terms interchangeably, thinking they are synonyms, etc.

:D

If you have two wheels with the same backspace, one is 8" wide and the other is 9" wide and both have the same size tire on them both the wheel and tire will stick out 1" further. Depending on the backspace, your vehicle may or may not have the additional clearance needed to keep from rubbing.

I'll try to post some pictures for you tomorrow. I have a test fitted a couple different wheels with tires that are similar to the examples above.

I hope you`re not expecting to keep your X clean.

ok, Here's a good example. This my 2007 Nissan Frontier, chassis and fender clearance should be identical to 2005 and newer Xterra.

These pictures aren't taken at the exact same angle but its close enough that you can see the details.

http://i248.photobucket.com/albums/gg166/DTDForums/Mics/285tireonfrontier.jpg

Notes:
If these wheels had the same backspace, the wider 17x9 would protrude 1.5" further than the narrower 17x7.5" wheels.
If the 17x9 Wheel pictured had a higher offset the wheel and tire would tuck under the vehicle further.
If the 17x9 wheel pictured had a lower offset the wheel and tire would stick out beyond the fenders further.

thank you for all the good info...my next question is-i want my wheels/tires to protrude out a little more than what your setup is...do i need to go with a negative offset? would you happen to have pics of anybody running a more protruding setup?

thanks again,
mike

thank you for all the good info...my next question is-i want my wheels/tires to protrude out a little more than what your setup is...do i need to go with a negative offset? would you happen to have pics of anybody running a more protruding setup?

thanks again,
mike

Thanks for the question Mike. If you want the wheel and tire assembly to protrude more you will want to go with a lower offset than what is pictured above. Doing this will restrict how tall of a tire you can run though. Think of your wheel wells as bowl shaped, if an offset is too low you are effectively pushing the wheel out to a shallower part of the fender well. If you are only leveled stick with a tire thats 32" in overall diameter.

Here's a picture of a 17x9 with a -10mm offset. (this sticks out about 1" further than what I have now)

http://i248.photobucket.com/albums/gg166/DTDForums/MB%20Motoring%20Wheels/DSCF0134.jpg