Wschep, I got the info on the 17.5 upgrade after the fall rally. I posted it on here somewhere. The article was a quote from the Escapees forum. A couple of guys there dis a long research project on this. The jist of it was that with a 16 inch rim and G614 tires you have a load limit of 3750 lbs on each tire at 110 psi. On a 17.5 rim with Goodyear G114 tires you have 4750 lbs at 125 psi. Rather than working at almost the max rating of the G614s if you use the G114s on the 17.5 rims you are working at only the top 80% of the load range. This gives you some wiggle room if the tire is over stressed. At present we are at the very top limit of our Marathons all the time and if we whack a road hazard we have no room for safety. I would much prefer to have a bit more latitude in limits.
update:here is the
link to my original post on this issue. Within that post is another link to the
original article.