Had the flat tire occurred on the road or away from home, we could have easily installed the spare tire from the trunk. This is a ‘mini tire’ sometimes disdainfully called a ‘donut.’ It is intended to save space in the trunk by being about 2/3 smaller than the standard-sized tire for the model vehicle.

It is also considered to be an…
‘emergency use’ tire, not intended for extended use or even for full highway speeds. It will get you home or to the garage. That is about the extent of their usefulness.

Most people after having used the ‘donut tire’ once, discard (hopefully, ‘recycle’) the tire in lieu of a full-sized spare for the next time, such is the disdain for these ‘mini-tires.’

An option for a flat tire instead of installing the mini donut tire is a product called “Fix-A-Flat.” It is a foamy liquid that is pumped into the flat tire via the filler nipple on the can. The can either has a screw-nozzle that mates directly with the standard valve stem of the tire or a short flexible hose with the attachment nut those screws onto the valve stem.

Pressing and holding the discharge button on the can causes the foamy liquid and compressed gases to flow into the flat tire, giving it enough inflation to lift the car off of the rim and making the tire moderately drivable. You are required then to drive the car for a minimum of 15-minutes to evenly distribute the foam inside of the tire.

The sudsy properties of the injected foam product rolls around inside the tire, flattening out and sealing the minor leak. It will not effectively seal a hole that has a physical object in it (nail, wire, etc.) and the nail or wire will continue to shift around during normal driving, exacerbating the existing puncture site. It is intended mostly for puncture and withdraw incidents; cases whereby the offending puncture device does not stay with the tire. –Running over a board with a nail in it, for example. The board and nail do not stay with the tire. This is the type of puncture that ‘Fix-A-Flat’ specializes in fixing.

Mechanics as a rule don’t like the use of ‘Fix-A-Flat’ because it slightly endangers them when they service they tire. If they are later called upon to change or otherwise service the tire with a ‘patch’ or ‘plug’ (I’ll explain this next,) they need to be notified first that this product has been used.

Because the propellant gases that the Fix-A-Flat product puts into the tire are flammable, there is potential of an explosion. Steel belted radial tires have steel wires called ‘belts’ that run radially (in the direction of the tire when rolling) inside of the tire’s structure and when the mechanic is using metal tools to disassemble the tire, a simple spark could ignite the pressurized gases (including normal atmospheric oxygen) and cause a brief and startling explosion. In short; if you have ever used any ‘Fix-A-Flat’ or other tire-inflating product and your mechanic will be working on the tire, DO TELL THEM about this in advance.

I removed the flat tire in our parking garage and using my son’s little red wagon and brought the tire to my favorite mechanic. I had already spotted the offending culprit in the tire’s tread; it was a nail or other shiny metallic object. It was clearly visible just barely sticking out of the tread.

I felt some relief upon seeing this, for a nail puncture is more likely to be fixable than a glass puncture because the nail hole will smaller and more uniform in shape and size. Also, the hole was in the ‘tread’ part of the tire which bodes well for repair. Any hole in the sidewall of any tire is not repairable.

It is a notable distinction between a puncture in the tread surface versus a puncture in the sidewall. The sidewalls of tire need to be flexible. Sidewalls of tires need to be able to ‘compress’ and ‘bounce’ during normal driving. Besides, the sidewalls of tires are much thinner than the tread and would not accept a plug anyway. Any ‘patch’ or ‘plug’ on a sidewall would very quickly fail under even moderately normal use, perhaps with catastrophic results.

The mechanic inflated the tire to verify the findings. As he was inspecting the tire, we could hear air leaking out of the suspected spot. Using pliers he carefully extracted the offending piece of hardware and it was revealed to be a rather large nail.

The Actual Nail that was Removed from the Tire

(image by author)

Using a small ‘rat-tail file’ he inserted into the hole to ‘rough-up’ and clean the puncture in preparation for a rubber plug and adhesive. The rubber plug is like a big fat shoelace several inches long, threaded through a heavy-gauge needle-like device through an eye-hole at the end. The rubber plug is coated all around with this rubber adhesive and forcibly inserted fully into the puncture site and withdrawn about half-way. This seals effectively seals with hole. The tail that protrudes from the tire is then snipped-off even with the tread surfaces.

This type of repair is quite sound and reliable. Because the ‘rubber plug’ is in fact made of the same material as the rubber tire, it will behave just like the tires. It wears evenly with the tread and at the same rate.

This type of repair is quick (it only takes about 5-10 minutes for the mechanic to perform) and it is cheap (about $10.00.) If you had this on your car and the tire was not completely flat, the mechanic could quite possibly repair the tire while still mounted on your car. He’s just run it up on the hoist to have a better look at it, and repair the tire in~situ.

Steel Belted Radials have Steel Wires Inside the Tire

(image source) (although this steel-belted tire endured a car fire, it clearly shows the steel-wires that were mentioned earlier)

The important thing is to not drive on a flat tire for any distance unless absolutely necessary to get out of moving traffic. Driving upon a flat tire for any great distance (more than a few hundred feet?) will break the steel wires in the radial tread and these in turn will rip and shred the inside of the tire, rendering it irrevocably unfixable.

Original article: Flat Tire: Several Options to Fix a Flat Tire on your Car or Truck – written by thestickman on Factoidz