effect of wheel offset on mpg

[AeroModder]

Best way to test this is to pick up some hubcentric spacers and see what happens.

[wmjinman]

But how to test the opposite direction offset?????

[AeroModder]

Pick up a set of wheels with a high offset, then gradually move it out with spacers. If you change the wheel design, that will affect the airflow and it won't be an apples-to-apples comparison.

[rav]

Thanks for the replies just ended up getting one of the most lightweight and aerodynamic wheels that Honda made:

Best of all they are made for a Honda fit with the same offset!!

[Vekke]

I am at the moment doing CFD simulation to the offset matter. I am using a Drivaer 3d model with just drivers side and front wheel. Wheel is fully closed in the simulation so there is no cooling holes at the moment. So far it seems that if you move wheel inwards it helps with the drag. In first simulations wheel is not rotating.

- mm is inward movement
+mm is outward movement

+40mm 0,4961
+30mm 0,4870
+20mm 0,4908
+10mm 0,4896
STD 0,490
-10mm 0,4926
-20mm 0,4900
-30mm 0,4829
-40mm 0,4835

Next I will put convex hubcab there which will come outwards +20mm at the center. And for next runs I will also take down the actual forces as the frontal area changes little bit so the drag coefficient calculations are not exact. Frontal area grows from A=1,0218m2 to A convex capsels=1,0226m2

My guess for sweet spot is between -20 to -30mm range. Specially when wheels are rotating
After that I will try to put it then rotating. Pics will follow later

[Phase]

Originally Posted by Vekke

I am at the moment doing CFD simulation to the offset matter. I am using a Drivaer 3d model with just drivers side and front wheel. Wheel is fully closed in the simulation so there is no cooling holes at the moment. So far it seems that if you move wheel inwards it helps with the drag. In first simulations wheel is not rotating.

- mm is inward movement
+mm is outward movement

+40mm 0,4961
+30mm 0,4870
+20mm 0,4908
+10mm 0,4896
STD 0,490
-10mm 0,4926
-20mm 0,4900
-30mm 0,4829
-40mm 0,4835

Next I will put convex hubcab there which will come outwards +20mm at the center. And for next runs I will also take down the actual forces as the frontal area changes little bit so the drag coefficient calculations are not exact. Frontal area grows from A=1,0218m2 to A convex capsels=1,0226m2

My guess for sweet spot is between -20 to -30mm range. Specially when wheels are rotating
After that I will try to put it then rotating. Pics will follow later

any thoughts on the hyundai ioniq blues hubcaps?