evelknebel
Member
How much back spacing is needed to fit a 10 inch wide rim on 2001 Eddie Bauer?
Question about wheel back spacing
- Thread starter evelknebel
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Thermo
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evelknebel, you will always need about 4.5" of backspacing. Whether the tires will rub with a rim like that is a function of how much sidewall and tread width along with how much you have altered the height of the truck. There is no simple answer to a question like you are asking if you are worried about rubbing when driving down the road. You give a little bit more in what you are thinking about doing and I can give you a best guess as to whether you will have rubbing or not.
dont know with backspacing...but i do know offset...we can run up to +45 offset pending size of wheel and maybe -20 pending on size of wheel...im on 26's and to turn with no probs i can go +30 easily
Thermo
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evel, to expound upon what Freeway is talking about, there are two measurements that tire shops use to talk about the same dimension. You have backspacing and you have offset. The difference is in how they are measured. Backspacing is easy to picture. You take a rim, put it face down, put a straight edge across the back of it and then you measure from the bottom edge of the straight edge to the backside of the rim where the studs go through. That distance is your backspacing. This is typically measured in inches.
Now, offset. This is a bit more involved and can be confusing, but at the same time is more meaningful measurement as I will describe. Offset is simply the difference between where the center of the rim is (front to back of the rim) and the surface of where studs go through the back of the rim. A positive offset is where the surface that the studs go through is more towards the front of the rim than the centerline of the rim is. This value is normally measured in millimeters (mm).
Now, why do they have this value? IT is rather simple. If you are worried about maintaining the life of your suspension parts, maintaining a constant offset when buying new rims is vital. If you start getting different offsets, you start putting torsional stresses on the spindles and wheel hubs leading to their more rapid wear. This is due to the fact that you have to have a certain distance between the center of the rim (front to back) and the center of the bearing. Tossing these two off from each other leads to what I mention above.
Now, lets put this into practical application as it relates to your truck. Your stock rims have 4.5" of backspacing. Since the factory rims are 7" wide, that would mean that your rim center is 3.5". The back side where the studs go through is towards the outside of the vehicle as it relates to the center of the rim. Since there is 1" of difference (4.5" - 3.5", or 25mm), this means that your factory rims have a +25mm offset.
Now, lets say you step up to a 10" wide rim, but you keep the same backspacing. This would then have the center of the rim at 5", but where the studs go through is still at 4.5". So, now the back edge where the studs go through is towards the center of the vehicle as it relates to , leading to a negative offset. So, now, you have a -12mm offset (4.5" of backspacing - 5" rim center).
Where this can really play into things if you are looking to maximize the width of the tire you can run, if you maintain the same offset, as you go with a wider rim, the tire starts to move under the truck some (half of the increase of rim width). So, in the case of going from a 7" rim to a 10" rim, keeping the offset the same, the rim would push the tire out 1.5" and also pull it under the truck 1.5". The problem comes with our trucks is that they don't have a lot of clearance between the back side of the tire and the body. So, the amount of room that you have can get eaten up quickly by going with a wider rim, leading to you being limited as to how wide of a tire you run.
I have found that running an 8" wide rim with a 12.5" wide tire results in the tires just barely coming in contact with the body when the truck is put under maximum articulation.
If you have more questions, let me know. Hopefully I have not information overloaded you with my descriptions.
Now, offset. This is a bit more involved and can be confusing, but at the same time is more meaningful measurement as I will describe. Offset is simply the difference between where the center of the rim is (front to back of the rim) and the surface of where studs go through the back of the rim. A positive offset is where the surface that the studs go through is more towards the front of the rim than the centerline of the rim is. This value is normally measured in millimeters (mm).
Now, why do they have this value? IT is rather simple. If you are worried about maintaining the life of your suspension parts, maintaining a constant offset when buying new rims is vital. If you start getting different offsets, you start putting torsional stresses on the spindles and wheel hubs leading to their more rapid wear. This is due to the fact that you have to have a certain distance between the center of the rim (front to back) and the center of the bearing. Tossing these two off from each other leads to what I mention above.
Now, lets put this into practical application as it relates to your truck. Your stock rims have 4.5" of backspacing. Since the factory rims are 7" wide, that would mean that your rim center is 3.5". The back side where the studs go through is towards the outside of the vehicle as it relates to the center of the rim. Since there is 1" of difference (4.5" - 3.5", or 25mm), this means that your factory rims have a +25mm offset.
Now, lets say you step up to a 10" wide rim, but you keep the same backspacing. This would then have the center of the rim at 5", but where the studs go through is still at 4.5". So, now the back edge where the studs go through is towards the center of the vehicle as it relates to , leading to a negative offset. So, now, you have a -12mm offset (4.5" of backspacing - 5" rim center).
Where this can really play into things if you are looking to maximize the width of the tire you can run, if you maintain the same offset, as you go with a wider rim, the tire starts to move under the truck some (half of the increase of rim width). So, in the case of going from a 7" rim to a 10" rim, keeping the offset the same, the rim would push the tire out 1.5" and also pull it under the truck 1.5". The problem comes with our trucks is that they don't have a lot of clearance between the back side of the tire and the body. So, the amount of room that you have can get eaten up quickly by going with a wider rim, leading to you being limited as to how wide of a tire you run.
I have found that running an 8" wide rim with a 12.5" wide tire results in the tires just barely coming in contact with the body when the truck is put under maximum articulation.
If you have more questions, let me know. Hopefully I have not information overloaded you with my descriptions.
are u looking to run a BIG rim or offroad rims?
evelknebel
Member
Thanks for all the replies. I think you answered my question Thermo. Not really looking to run large rims. I think the 17's on there right now are plenty big. I don't like the way the truck sits right now. The stock rims and tires look way too skinny to me, that's why I was wanting to put wider rims on there. If I understand it right, if I go with 10 inch rims and try to get them to tuck nicely in the wheel wells the tires will rub is that correct? Any suggestions on how to get the look I want would be greatly appreciated. The only mods I've done is get rid of the air ride and switch the front and back over to coil springs. The truck sit a little bit higher now, I think that's why the wheels look so narrow to me.
