with RV tire expert Roger Marble
This is a bit of a continuation on the topic of “tire dressing” from last week’s post.
I do wonder how many people that complain of sidewall cracking or less-than-desirable tire durability makes the effort to protect their tires from the heat and UV degradation from direct sun exposure.
While there might be some benefit from applying something such as “dressing” or “shine” or other “stuff” to the tire sidewall for UV shielding, no dressing will protect a tire from the accelerated aging process due to being “baked” by the sun’s heat.
There is no standard SPF for tire dressings as there is for suntan lotion. But it would not be that difficult to measure the level of UV shielding by measuring the UV going through some clear plastic sheeting and then applying the tire dressing to the sheeting and measuring the level of reduction, if any, in UV rays.
In many cases, the rubbing of the tire sidewall when applying a dressing can remove the special anti-oxidants and UV protection provided by the chemicals the tire companies use in all tires.
All rubber, natural or synthetic, loses strength and gets stiff over time. The rate of degradation is also temperature-dependent with the rate effectively doubling with each increase of 18° F. As I have shown in my blog on the use of tire covers, sunlight can easily accelerate the rubber degradation by 4 times, with 8 times not unreasonable in Southern states. This loss of strength and flexibility can eventually lead to a belt separation, which many sometimes call a “blowout.” Maybe that unexplained “blowout” in June was brought about by the eight months of direct sun exposure in Quartzsite, AZ, over the previous two winters.
I have confirmed, with temperature measurements, the significant temperature drop with the use of white vinyl covers on Class B, Class C and RV trailer sizes, and the use of flat mesh “Tire Shades” on Class A motorhomes. I would recommend against the use of black or dark color solid vinyl covers as they would act more like an oven by both transferring the sun’s heat to the tire and preventing cooling air circulation around the tire.
Read more from Roger Marble on his blog at RVtiresafety.net or on RVtravel.com.
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Tire shades produced by Magna Shade provide necessary cover without the heat build up….
when driveing off pavement like blm camp land sometimes rocks get wedged between the rear dual tires.and if unchecked can lead to failure or scareing the hell out of u when u get up to speed on the pavement and the rock flys out from between the tires and hits the coach.i check between the duals after parking offroad and as soon as i can after hitting the pavement again.
Would using a plywood sheet as a barrier work as well as the vinyl covers?
Probably as it would stop the UV and the IR that generates the heat. UV is only going to attack the surface of the tire that is exposed. Heat can affect the entire structure of the tire including the belt edges which are 3/8″ to 1/2″ deep in the structure but that is usually the most critical part of tour tire.
I got some old plywood sheets and painted them white. When we’re home I lean them against the trailer tires. Works great, and we no longer get all the spider webs we used to get under the ‘official’ tire covers.
I always enjoy reading you informative articles. Thank You.