D3 Wheel Offset - Will ET32 Fit?

[JohnS8]

I'm looking at a set of wheels in the AZ classified for my 08 S8, and wanted to see if any of the wheel gurus here could provide some of their expertise about whether a 19 x 8.5 rim with ET32 offset will fit running 255/40/19 tires?

Any information you could provide would be greatly appreciated!

Thanks!

John

[basso]

Think stock offset is higher than that so they will be closer to the outside lip of the fender but they may well work.
Not sure what the stock off set and width is on the 08 s8, i run 20mm spacers on some 43 offset rims and they are fine in looks and ride on my 02 s6.

[DirtyJerzey]

Yeah it will fit fine. They're not that drastic of offsets.

[Darry_99]

Standard offset is 45~48. ET32 will extend your tires out by 13 ~ 16 mm, so will just clear the fender. Upside - better handling, downside - more stress on the wheel bearings.

[A8LOOONG]

Standard offset is 45~48. ET32 will extend your tires out by 13 ~ 16 mm, so will just clear the fender. Upside - better handling, downside - more stress on the wheel bearings.

Are you sure about that?? I have these on my D3 A8L with Blizzak 255\45R18's (offset is 35mm) on them and they fit under the fenders perfectly. Also, why would this affect the wheel bearings? The wheel rides on a hub (or it should) so all force is transferred to the axle evenly.

http://www.oewheelsllc.com/Wheels-fo...39296-3-1.html

[silverd2]

Leverage...contact patch is farther away. The wheel rides on it's own center. Don't know if it will hurt...the bearings are tough, but mathematically there IS more stress.

[A8LOOONG]

Leverage...contact patch is farther away. The wheel rides on it's own center. Don't know if it will hurt...the bearings are tough, but mathematically there IS more stress.

That's not accurate. The center of load is at the hub (where the lugs revolve around it's center) a bigger offset will stress the individual spokes of the wheel. As long as you're not using spacers that place the hub of the wheel away from the rotor's hub, then the load is the same. I think you're referring to cantilevering the load hung out from the hub. That only occurs when dummies use multiple spacers taking the wheel away from the hub. This stresses the lugs and bearings.

[silverd2]

That's not accurate. The center of load is at the hub (where the lugs revolve around it's center) a bigger offset will stress the individual spokes of the wheel. As long as you're not using spacers that place the hub of the wheel away from the rotor's hub, then the load is the same. I think you're referring to cantilevering the load hung out from the hub. That only occurs when dummies use multiple spacers taking the wheel away from the hub. This stresses the lugs and bearings.

Sorry, you're wrong. I'm afraid it IS dead-on accurate. And less offset has exactly the same effect as spacers...spacers merely create less offset, as they become a solid/integral part of the wheel when tightened. The hub does not support the weight...the bearing does. The hub is just the first part of the extenion that coninues with the wheel, which becomes a longer extension with less offset. The hub does not carry weight..it transfers weight to the sole weight carrier...the bearing. The strut connects BEHIND the bearing, so everything from the bearing on IS hanging from the bearing...all force exerted by the weight of the car is transfered through a lever (formed by the wheel and the hub) to the bearing (the fulcrum)...the length of that lever is determined by the total offset and hub shaft length and follows the following law of physics.

The physical law of leverage states that the farther away (less offset) from the fulcrum (the wheel bearing) a given force (the weight of that corner of the car resting on the center of the tire) is exerted, the more torque (not weight) that results at the fulcrum.

Decreased offset moves the pressure created by weight farther from the bearings. 100% of the force placed on the bearings originates at the point where the center of the tire contacts the road...as this moves farther away from the vertical center of the bearings, leverage (torque at the fulcrum/bearing) is increased exponentially, using the same amount of original force (car weight). This increases the amount of torque (or side force, rather than load carrying) exerted on the bearings...not weight, but "cocking" force.

You've proven this yourself on many occasions, I'm sure. When a screw driver won't break loose 2 parts stuck together, you go to crowbar and exert the same weight at the far end, resulting in more separating power at the other end. Your hand is the tire (using the same strength), offset farther from the parts (the fulcrum) and infinitely more force (stress) is exerted, as a result.

Physics isn't an opinion, it's the law (Isaac Newton, etc. ). Engineers use these principles/formulas every day to determine strength needed in certain components.

Extra stress resulting from decreased offset in wheels may be negligible, especially if the stress point is engineered past the strength needed (which it should be)... BUT it doesn't mean it doesn't exist.

[Gaspasser19]

Sorry, you are wrong. I'm afraid it's dead-on accurate. And less offset has exactly the same effect as spacers...spacers merely create more offset, as they become a solid/integral part of the wheel when tightened. The hub does not support the weight...the bearing does. The hub is just the first part of the extenion that coninues with the wheel, which becomes a longer extension with changed offset. The hub is not the center, nor does it carry weight..it transfers weight to the actual center (and sole weight carrier)...the bearing. The strut connects BEHIND the bearing, so everything from the bearing on IS hanging from the bearing...all force exerted by the weight of the car is transfered through a lever (formed by the wheel and the hub) to the bearing (the fulcrum)...the length of that lever is determined by the total offset and hub shaft length and follows the following law of physics.

The physical law of leverage states that the farther away (less offset) from the fulcrum (the wheel bearing) a given force (the weight of that corner of the car resting on the center of the tire) is exerted, the more torque (not weight) that results at the fulcrum.

In a case of a offset sufficient to place the center of the tire directly over the center of the bearing (not the hub), the result would be 0 torque (twisting/cocking force) exerted on the bearing.
Decreased offset moves the pressure created by weight farther from the bearings. 100% of the force placed on the bearings originates at the point where the center of the tire contacts the road...as this moves farther away from the vertical center of the bearings, leverage (torque at the fulcrum/bearing) is increased exponentially, using the same amount of original force (car weight). This increases the amount of torque (or side force, rather than load carrying) exerted on the bearings...not weight, but "cocking" force.

You've proven this yourself on many occasions, I'm sure. When a screw driver won't break loose 2 parts stuck together, you go to crowbar and exert the same weight at the far end, resulting in more separating power at the other end. Your hand is the tire (using the same strength), offset farther from the parts (the fulcrum) and infinitely more force (stress) is exerted, as a result.

Physics isn't an opinion, it's the law (Isaac Newton, etc. ). Engineers use these principles/formulas every day to determine strength needed in certain components.

Extra stress resulting from changed offsets in wheels may be negligible, especially if the stress point is engineered past the strength needed (which it should be)... BUT it doesn't mean it does not exist.

Just because you're correct doesn't mean he'll listen. The internet can be very frustrating that way ;)

[silverd2]

Thank you for that! ...and I know just what ya mean.
My wife asks me why I'm still at the computer past midnight and I answer, " I can't go to bed yet. Someone on the internet is wrong" :)

[A8LOOONG]

After doing some homework, I think I concur with your statements now. I can't seem to find the formulae to prove it but your ideas seem reasonable. Thanks for the description.

Now, back to the other comment you made, are S8 standard offsets really 45-48 mm? I thought this was the same for D3 S8's and A8's at 35 mm.

Oh and Tim, I listened.

[silverd2]

D2 S8 standard 18x8 are 48mm offset...same for D2 A8 17x8's:
http://www.originalwheels.com/audi-w...s82003rims.php
Later D3 19x8.5 A8 OEM's are 40mm offset.
I've used 18x8.5 OZ's with 35mm offset on an '01 A8 and had lots of clearance...noticable wider stance and really nice handling.

[Gaspasser19]

After doing some homework, I think I concur with your statements now. I can't seem to find the formulae to prove it but your ideas seem reasonable. Thanks for the description.

Now, back to the other comment you made, are S8 standard offsets really 45-48 mm? I thought this was the same for D3 S8's and A8's at 35 mm.

Oh and Tim, I listened.

It takes a big man to make such a post. I'm impressed! BTW, the OEM D3 S8 wheels are 20 x 9, ET 45 (2008).

[.Mad Hatter.]

LOL @ worrying about wheel bearing stress with a mild (at best) change in offsets.

[silverd2]

Discussing an interesting aspect of car specifications, design and engineering is not "worrying"...it educational and just good brain exersise.
The more you understand, the less likely you are to be fed a load of crap, without realizing it...the case with 99% of all car owners :)

[4ringAR]

Its an engineering math-off!

[silverd2]

Its an engineering math-off!

No wagering, please...for entertainment purposes only!