MM and Crah,
I believe that the tag axle hub is exactly the same as the drive wheel hub it's just that the tag axle wheel has been turned inside out. You can mount a wheel either with the hub facing outward or the hub inward. Prevost chose to mount the tag axle with the wheel hub facing outward and the tag axle inward. All drive axle wheels are mounted with the hub inward so that it can bolt to the inside wheel that is mounted with its hub outwards. They are probably the exact same wheels.
The real question is why? It certainly doesn't look good. My guess is that they needed room inside the wheel for something. Maybe it was just a part of the design of the coach, maybe it's to make it easier to clean the wheel. I'm just curious.
Now in terms of fiberglass vs. Kevlar, I am genuinely confused as to why Kevlar would lead to a smoother finish. The fibers on both are imbedded in the composite and you do not see them from the outside. I am not sure how they construct kevlar structures but I have seen them form fiberglass and the process should lead to a very smooth exterior if done correctly and I would imagine that Kevlar would yield the same results.
When a fiber structure is formed, they start with a smooth mold and spray the mold with a release. The composite is formed from the outside in as they add layers. The outside layers are smooth and then they add the fibers. As I said before, glass fibers can still result in a very smooth finish. Perhaps the Kevlar is better because it is more flexible or it is applied in a different way that prevents warping after the product is released from the mold.
I'm not saying you are wrong. I think you are probably correct and the process Prevost uses results in a smoother finish than the typical fiberglass panel, I'm just trying to figure out why that would be.
