MARATHON COACH - BEAUMONT, CA

[Coloradobus]

How about, "It's doing it again!!"

[travelite]

Along with you're excellent essay Jon, I'd add that Prevost is also between a rock and a hard place with their motorhome chassis. I suspect they are pretty close to being tapped out on any future gross and axle weight increases. The obvious limitation is the Federal axle weight restrictions on roads and bridges, which are already exceeded in many buses. The not so obvious limitation is the safety margins built into the vehicle itself. With every increase in steer axle GAWR, I doubt that there's a total redesign. More likely, the existing axle is tested and re-rated for the increased load. On occasion this may require a redesign of a critical component (tie rod end for instance), but in the usual case I suspect Prevost is simply eating into safety margins. It's not likely that the 19K steer axle enjoys the same safety margin as its 16K counter part. What this means is fewer cycles to failure; a shorter mean time between failure. The motorhome chassis, supporting that kind of weight, is probably not a 2,000,000 mile chassis. We've already seen rapid failure of steer axle suspension bushings. Again, the onus is on the converter to scale back on load. You're absolutely right, tougher times ahead.

I have to retract some of what I said above. I checked the parts manual. The 18K IFS has redesigned uprights, upper control arms, lower control arms, and probably other components that I haven't yet checked. Good on you Prevost. My apologies for any confusion created. I'll return to my corner now...