pnichols wrote:
For a given tire size between the two tire types that the C-Metric version is a more rugged/stronger tire?
i.e. That the C-Metric version has more plies? If so, if carrying capacity is not an issue ... should one use the C-Metric type tires if they wish for more puncture-proofness - as in occasional offroad travel with their Class C?
SJ-Chris wrote:
To me, yes...it means the Commercial rated tire is stronger and thus less likely to have a blowout.
Would anyone like to share the downside of getting Commercial rated tires at least on the rear? The cost (in my experience) is minimal.
Downsides of a C-Metric tire are brand specific.
With the Michelin Agilis Cross Climate tire, a tire which has been vetted, approved, and installed by Ford Motor Company on the E-Series Cutaway motorhome chassis in production as fleet orderable upgrade option, there are some differences between the C-Metric version of this tire, versus the LT Metric version that Ford installs on the E-Series Cutaway.
The main downside is that the C-Metric version is DIRECTIONAL. With 6 tires on the ground, and one on the spare tire rack, the spare is only good to replace 3 of the tires without playing musical tires on the side of the road in order to have all tires rolling in the right direction.
And unless one carries two spares, fitted with a directional tire facing each direction, there is still a 50% chance that the tire that blows will be a tire which is in the opposite direction of the spare, leaving one with 4 tires in one direction, and 2 tires in the other direction, when one really needs 3 tires in each direction.
Not having to worry about which tire faces which direction simplifies a lot of factors with tire procurement, maintenance, rotation, and emergency replacement in a pinch. For a dual rear wheel application, the Michelin Agilis Cross Climate in C-Metric designation having a directional design is a significant disadvantage in convenience, that to my mind outweighs the C-Metric versions overcapacity in weight rating.
Now to refer to what Michelin has to say about their two versions of Agilis Cross Climate tire in the 225/75R16 size:
Q: What is the difference between the MICHELIN® AGILIS® C-Metric sizes vs. the LT sizes?
A: The C-metric convention can be thought of as the European equivalent of the LT-metric. Just as LT-metric describes a tire with a higher load rating and higher pressure than the equivalently sized P-metric tire, C-metric describes a tire with a higher load rating and higher pressure than the equivalently sized European Metric tire.
Q: Why is the MICHELIN® AGILIS® CROSSCLIMATE® tire offered in two different tread designs?
A: The MICHELIN® AGILIS® CROSSCLIMATE® C-Metric tire was designed in Europe specifically for the European style vans that are also offered in the North American market. The C-Metric is a directional tread pattern. The LT sizes are non-directional and were designed by the North American Research and Development team to best suit ¾- and 1-ton
pickups and vans.
Both treads offer comparable performance.
The PNichols question is whether or not the C-Metric version of the tire is "tougher" traversing unavoidable potholes at speed than the LT Metric version of the same tire.
Well, the C-Metric version weighs 37 lbs, while the LT-Metric version weighs 39.9 lbs, making the LT-Metric version 2.9 lbs heavier than the C-Metric version. If this extra weight is due to there being more ingredients in the LT version of this tire, does that make it tougher?
If so, then the toughest tires in this size range might be the Michelin XPS Rib, the Bridgestone R238, or the Goodyear Endurance RSA ULT... all weighing in at more than 50 lbs per tire, due to the additional steel belting in these tough commercial tires that traverses the carcass from bead to bead. Heck, the Endurance RSA is over $500 per tire in the LT225/75R16E size, and is retreadable, so it had better be tough. Yet the tread on some of these ribbed all position steer tires is designated as "Summer" only.
That's fine for a lot of RV users, but what about those who travel through the rains of the Pacific Northwest, or those whose Chalet branded coaches serve as ad hoc ski chalets in the Sierra? These usage cases need not be blazing through blizzards, but light snow flurries where no 4WD nor chains are required shouldn't send a coach skidding into an embankment for lack of tread traction or sufficient sipes in the tires.
So for all season recreational uses, an all season tire would be preferable over a "summer" tire. And for more adventurous RV'rs, an all terrain tire might even be considered. At the very least, a tire with a Three Peak Mountain Snowflake Rating (3PMSF) should be considered as minimum verified threshold of wet and unexpected light snow performance.
And the lack of a 3PMSF symbol introduces another potential downside of some C-Metric tires. While both versions of the Agilis Cross Climate have 3PMSF certificaton, neither version of the Nexen CT8 HL are certified 3PMSF.
Like Michelin, Nexen offers their commercial CT8 HL tire in both C-Metric and LT-Metric versions, neither of which are 3PMSF rated, but both of which are heavier in weight, at 42.76 lbs, than either version of the Michelin Agilis Cross Climate.
Note that both C-Metric and LT-Metric Nexen CT8 HL's weigh exactly the same, at 42.76 lbs. So which tire has more ingredients? Which tire has more belts? Which tire is tougher? And unlike the directional versus non directional tread design difference in the Michelin Agilis Cross Climate, to my understanding, there is no difference in tread between either version of the Nexen CT8 HL.
However, Nexen makes 5 commercial tires in the 225/75R16 range (not including their snow tire that receives studs). Other than the two CT8 HL tire versions, the three remaining Nexen light truck tires are 3PMSF certified. Nexen's latest tire, their new ATX, weighs in at 43.50 lbs, which is about a pound heavier than their C-Metric CT8 HL.
So which is tougher on the day to day, irrespective of weight rating?
I'm not qualified to answer to that question, but will close with one more interesting difference between the two versions of the Michelin Agilis Cross Climate.
As previously discussed, the peak weight carrying capacity of a C-Metric tire is rated at 83 psi, which is also the maximum cold inflation pressure rating of the tire.
Typically, an LT Metric load range E tire has a maximum cold inflation pressure rating of 80 psi. However, the LT Metric Michelin Agilis Cross Climate has a maximum pressure rating of
90 psi, which is higher than the 83 psi max of C-Metric version of the same tire.
Now get this... there is no change in weight carrying capacity rating between 80 psi and 90 psi on the LT Metric version of the Agilis Cross Climate. The tire is simply designed to withstand more internal pressure. One would think that means that the tire is tougher...to be able to hold nearly as much pressure as a steel sidewall load range F tire, at 90 psi. Yet no additional load capacity is stated for when the tire is inflated past 80 psi, and let's not forget that the OEM wheels on this platform are limited to 80 psi cold inflation rating.
An advantage that an LT-Metric version of this brand and model of tire may have over a C-Metric version of the same tire, is that in the summer, while traveling for hundreds of miles on hot Arizona roads, with heat expanding the air within the tire while increasing the tire's internal pressure... having a 10 psi margin of allowable pressure build up all fall within the 90 psi rating of the tire, offers some comfort not unlike the comfort felt with having a larger margin in tire weight carrying capacity.
