QuestionAre RV Trailer tires which are manufactured in China as good a quality as those manufactured in USA or Canada.My four year old trailer has tires made in China and the sidewalls have vertical cracks all the way to and including the bead.
The proper tire pressure is maintained. Have trailed for over 35 years and have not experienced this problem.The tires are ST20575R15 load range C. The GVW of trailer is 8000 lb.Tandem Trailer.
AnswerBill,
I can't answer the question about quality. It's kind of a subjective question and really difficult to put one's finger on.
But I am going to assume that when you say "vertical" cracks you mean cracks extending outward along the radius of the circle (tire folks would call this "Radial") as opposed to around the circle parallel to the tread surface ( called the "circumferential" direction). If this is correct, then this sounds like cracks due to overloading.
It has been my experience that trailer manufacturers do not do a good job of sizing tires - and in many cases they are overloading the tires. So here's how to check.
Load the trailer up with as much stuff as you can think to put in it - a "Worst Case". If the trailer has water tanks fill them all, including the Black water tank.
Then find a scale and weigh each corner (if possible), but at a minimum weigh each axle. Add 15% to that value. That should be the minimum load carrying capacity of the tires at the usage pressure.
You've given me some figures so I'll work with those to illustrate the point:
An 8000# GVW should mean about 10% of the load is carried by the tow vehicle (tongue weight). I've heard some variations on this percentage, but for worst case, I am going to use the smallest value.
That means the tires on the trailer have to be able to carry 7200# - and assuming they each carry the same load - that is, front to rear and side to side, the load is evenly distributed (an exceedingly bad assumption), then the tires have to be able to carry 1800#.
An ST205/75R15 Load Range C has a load carrying capacity of 1820# at 50 psi. I think this illustrates my point quite well, not to mention that I have seen quite a few trailers where the GVW has been underestimated.
