What Is The Purpose of the 3 Places A Wheel Steps Down From Outside Edge to Inside?

Published 04/18/2018

Question:

What is the purpose of the dimples? They are right where the tire bead seals. I am somewhat concerned about this. See my pics. Dimples are circled in red.

asked by: Steve

Expert Reply:

On the Steel Trailer Wheel # AM20006, I assume the 3 dimples you are referring to are the 3 places the wheel steps down in size. The outside largest diameter point is where the wheel is outside of the tire for a little protection of the sealing bead. The second step is where the tire bead rests and seals against the wheel to allow the air to stay pressurized without having an inner tube. The third step is down to the mounting flange to give strength and stability.

Each tire will have all of these aspects but they look different based on the wheel design and size of the wheel.

If you have other questions or if I misunderstood, please let me know so I can help further.

expert reply by: Jason S

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Steve

4/18/2018

What is the purpose of the dimples? They are right where the tire bead seals. I am somewhat concerned about this. See my pics. Dimples are circled in red.

Jason S.

4/18/2018

I honestly was stumped and talked with our tire expert who said he hasn't seen that and that definitely is not the norm. We do not have those spots on the inside of the wheels we carry. I also reached out to the manufacturer and the Kenda 5.70-8 Bias Trailer Tire with 8" White Wheel - 5 on 4-1/2 - Load Range D # AM30155 does have the bumps on the outside you see and they are purely for aesthetics as the older style like you have had them, so it is just to look like the older version, but there is no break in the metal at those locations on the inside. It is sealed tight to retain the air pressure. My assumption is that those rivets were originally designed for hub caps, but were not the best idea and have been visually kept but functionally removed.