Run Flat Tire Safety For RV's

February 8, 2009

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February 8, 2009

Last week, we looked at the added safety tire monitors can provide. This week, we will look at another product that may add even more safety to your coach travel.

Run-Flat tires were introduced to the automotive industry some years ago and were a great enhancement in tire safety, as well as the convenience . Unfortunately they could not be designed to handle large tires, like those found on trucks and motor coaches. However, there is a product and design that has been around for some time that may offer a similar run-flat experience.

It is a steel band that installs in two halves, over the recessed well that every wheel rim has on its inside circumference. This recessed well is required on a wheel rim to facilitate the installing or removal of a tire. It allows the inner circumference of the tire to be able to pass over the slightly larger rim diameter.

So how is covering the recessed well going to help? First we have to understand that if the recessed well was made to allow the tire to be removed or installed, what’s going to happen in a blowout scenario. Once the tire becomes flat, the bead, or the inner edge of the tire, pulls away from the rim and moves inward. A portion of this will find its way to the recessed well of the rim. Once in the well, the tires diameter exceeds the diameter of the wheel and starts flogging in an eccentric motion. The tire, now in a spinning elongated shape, makes contact with the fender liner and coach body. The wheel rim itself also strikes the pavement and may be the only direct support as the tire tears and possibly leaves the rim entirely. Driving control can be very challenging during this process and can well lead to total loss of steering control.

Now, let’s look at the same scenario, but with the safety bands installed. The bead, or inner tire edge again moves inward, but without the slopping drop of the well, stays relatively snug on the wheel’s inner circumference. There is no eccentric, off balanced motion. The tire carcass, although flat, stays on the wheel and cushions the rim while still providing the operator a reasonable amount of steering control. Namathelsa Tyrelok, one of the manufacturers of these, claims the vehicle can be driven for 10 to 30 kilometers on a flat if required. This could certainly be handy on some roadways that provide little to no stopping space.

Using internal safety bands on your wheel rims may offer far greater safety and also eliminate collateral damage in the case of a tire blow out. The two band sections are installed after the tire has been fully mounted, but not inflated. This is done by pressing down on one side of the tire and exposing the well. Likewise removal is done using the same process.

Currently only about 3% of the cars sold are equipped with run-flat type tires. Most are on higher priced vehicles. This number is believed to increase to 4% by 2010. The biggest drawback to them is replacement cost. The tire, itself, is more expensive and installation labor is about $60 per wheel. Additionally, some users claim the tires wear greater than that of a standard one. It appears, however, that with Tyrelok, or similar product, no such issues would be present.

The safety bands are made of specially coated steel and are suitable for use on either steel or aluminum wheels. The photo to the left shows a wheel with the recessed well exposed. Right of it illustrates how the safety band covers the entire well. This, once installed, will prevent the tire from being able to be removed or come off in a blowout event. Their cost is reported to be about a quarter of what a tire would cost. They can be re-used and moved from one vehicle to another. Installation seems very simple and does not require any special tools. It can actually be removed using a screwdriver if required. All in all, the product claims are quite impressive.

So, are there any users out there of this, or a similar product? If so, we would sure like to hear from you as to your experience.

With A New Product View – Lug_Nut – Peter Mercer