OldIHC

Tires come in two types, Tubeless and tube type. Tires also come in two constructions, Radial and bias. Both types come in both constructions I.E you can have a tube type radial or a bias ply tubeless, and vice versa.

Tubeless tires

In this type of tire, the inner lining of the tire is airtight. They mount on one piece rims that are also air tight. Most modern car tires are tubeless. The rim is a “drop center” rim, meaning there is a trough in the center of the rim that is a smaller diameter than the edge by the lip where the bead of the tire seals. The trough is neccery to allow the tire to be mounted on the rim. The inner diameter of the tire is less than the outer diameter of the rim. In order to allow the tire to be mounted, the bead of the tire goes down into the trough while the other side is being mounted over the lip.

Tubeless tires are considered to be an improvement over tube-type tires because they have fewer pieces and can be efficiently installed by machines. They are harder to mount by hand, though, and require that the bead be seated before they hold air. This is done with bead expanders or an air tank that blasts a large shot of air to force the bead out against the rim.

Tube-type tires:

Tube type tires have been around since the beginning. They are easier to mount but require some knowledge on how to assemble. Neither the tire nor the rim has to be air tight. The tube holds the air and is supported by the tire, flap, and rim. In some uses they are preferred over tubeless. Field repairs are easier to and for that reason alone, they are often found on trucks that go off-road. Tube types generally come in 20? and 22? rim sizes while the equivalent tubeless sizes are 22.5? and 24.4?

Tire sizes:

Tube type common sizes are 7.50 X20, 8.25 X 20, 9.00 X20, 10.00 X 20 etc.To replace with a tubeless tire of the same outside diameter, you add one tire size and 2.5? to the rim size. I.E. a 9.00 X 20 has the same diameter as a 10.00 X 22.5. A 10.00 X 22 has the same diameter as an 11.00 X 24.5. Not all tube type sizes have a corresponding tubeless size. Some of the smaller tube types are not made in tubeless and some of the smaller tubeless sizes that are made are very hard to find.

Part 2: Rims and Wheels

Rim width and tire sizes:

Rims are made in different widths. Each size tire has a design width rim and acceptable alternatives. I.E. a 11.00 X 22.5 is designed to go on a 8.25 width rim but it might be acceptable to use on other width rims. The tire manufacturing spec sheet will tell what rims you can put it on. Stray from their guidelines and you will have problems.

BuddWheels:

The Budd Corp made disk wheels and it has become a generic term for disk wheels. Disk wheels are like car wheels where the rim is attached to the hub by a metal disk welded to the rim (the outer part that holds the tire) and lug nut toward the center of the hub. Disks can be made of steel or aluminum and have the lug nuts toward the center. Because the lugs are toward the center they need to be very tight?between500-550 ft/lbs. to keep the wheel from flexing.

Dayton rims

Like the Budd Corp, Dayton made rims for spoke wheels and ?Dayton? has since become a generic term for all spoke rims.

People often use the term wheel and rim interchangeably but that is not technically correct. A wheel is a rim with the attaching disk. Spokes are the wheels in the case of the ?Daytons?. They also have been called ?California wheels? or ?wobble wheels.? Spokes require a little skill to install correctly. Everybody has seen a set going down the road wobbling back and forth looking like they are about to fall off. The Spoke set-up is quite rigid and requires less torque on the lug nuts because they are farther out near the rim. This makes them easier to change by hand. The rim-tire assembly is lighter than the wheel-tire assembly of Budds so it is easy for one person to install.

Both Dayton and Budds are made in tube type and tubeless rims. While you can change sizes on disk hubs, I.E. go from 20? or 22.5? to 22? or 22.4? wheels without changing the hub, you cannot do that with spokes. 20? spokes accept 20? or 22.5? rims and 22? spokes accept 22? or 24.5? rims. To go up in size you would need to change the hub-spoke assembly.

Part 3: The scary stuff?mounting tires

First let me say the ONLY APPROVED method for mounting any tire is by trained people using a safety cage. Knowing how and what can hurt you will help in you decide what you do.

One piece (tubeless) vs. multi piece.

One piece (tubeless) tires hold just as much air as tube type tires, so there is just as much potential energy to hurt you. Making sure that the tire is being mounted on the correct rim is important. I once saw a 22.5? tubeless tire mounted with a tube on a 20? rim. It held air and was on the front of a bus! It blew apart when the driver hit a curb parking!

Tubeless:

Place the rim (the disk or in the case of spoke wheels, the mounting flange) face down. Lube the bead area with tire lube or clothes detergent, do not use oil or grease which might attack the rubber. Work one bead on a little at a time forcing the bead down into the drop-center as you work the rest of the bead on. Done correctly you should need no tools to get the first bead on the rim.

Next work the upper half of the tire on the rim using one tire iron. Stand on the side of the tire holding the bead down in the drop center. Take little ?bites? so as not to damage the bead. Continue working until the tire is on the rim. Once the tire is on the rim, and if you are really lucky, you can inflate the tire and the bead will seat it self. Make sure the valve core is out so the air will rush in faster. After the bead is seated you can install the valve.

Dismounting

Remove the valve core! Even if the tire is flat, you need to remove the valve core so the bead can be compressed.

Breaking the bead (seal):

Use a tire hammer with the broad end strike right at the joint between the tire and rim. This takes some skill so practice on an old steel wheel before you do it on you aluminum rims! The bead should come away in one or two blows. Flip the rim over and do the other side. Lube both bead areas. Again place the rim face down. Using the thick end of one tire iron pry one edge of the bead over the rim while pushing down on the tire 180 degrees from where the tire iron is. Using a 2^nd iron, place the thin end under the bead as close to the 1^st iron as possible and pry the bead over the rim. Keep working out from both sides of the 1^st iron until the bead is over the rim. Stand the rim up; with the rim closest to you, the lower bead of the tire will fall into the drop center leaving a space at the top where you can put 2 tire irons (thick end). Place the 2 irons 2-3 inches apart, hold the irons and let the assembly fall toward you. Before it hits the ground pull up sharply on the irons. The falling momentum for the rim will pop the tire right off.

Tube-type:

A tube type tire consists of the tire, the tube and the flap. The flap is important to keep the tube from getting pinched between the tire on the rim and for bridging the gap around the valve stem so the tube doesn?t extrude thru the rim.

Split-rims, multi-piece rims

Most people use the term ?Split-Rim? to describe any kind of multi piece rim. This is not correct! There are many kinds of multi-piece rims, only one of which had the rim split. There is great fear of these type rims because people have got hurt servicing them. They have been around since the pneumatic tire was invented. I have a set of 63 year old rims on my K-7 that are just fine. There is some danger handling anything that has as much potential energy as a truck tire! All multi piece rims are constructed so that one side of the rim comes away from the rest of the rim to allow the tire and tube to slide off.

How they work:

There is a joint where the two parts come together, that joint must be able to hold the forces applied to the tire and keep the assembly in one piece. One of the oldest types is the split rim, it has a one-piece side ring and the rim has a crack all the way across and up the other side. The rim itself is split while the ring is solid. This is where the term split rim comes from. There are split ring rims where the rim is solid and the side ring has a split. These can be either 2 or 3 piece rims. There is a third type of rim called a semi-drop center rim or solid ring/solid rim type. In this case neither the rim nor the removable side is split but they are made in such a way that one ring can be passed over the other if they are positioned just so. Some people call these split rims but that is not technically correct. They were made in the 60?s and early 70?s and were thought to be a safer rim than the others. It proved not to be so and are not seen very much.

The Split rim:

In this rim, the rim is made of one long piece of metal rolled into a circle but not welded together. As long as the two edges butt up against each other the rim will hold its shape. The ring fits in a groove in the outer edge. Compress one edge as little as 1/16 or less and the rim looses is shape, one side passes under the other and is made just enough smaller so the ring can come off.

When air is pumped into the tube it pushes in against the rim as well as out aginst the tire. As long as the pressure is equal all the way around the rim holds it shape and the forces counteract each other The advantage of this is that the bead does not need to be ?broken? to remove the tire. The rim can actually be peeled away from the tire.

The danger is that the bead does not need to be broken to have the wheel come apart. In fact it does not even need to be deflated. If the rim has a concentration of force in one spot, a twisted tube for example, it can cause the rim to come apart with explosive force sending the ring flying with enough force to decapitate someone. Anything that prevents the ring from seating down in the groove (rust for example) can cause the rim to explode.

Split rims are only made for spoke wheels. The disk in Budd style wheels prevent it being used in that style. Once inflated and installed on the spokes, there is less danger as the spokes help hold the rim in shape. These type rims can be serviced with little more than a lug wrench, screw driver and tire pump. They were popular with farmers who did their own repairs. If a tubeless rim rusts so badly and to weaken the assembly it is unlikely that it would still hold air. This is not the case with tube type rims, as the rim does not hold the air. When a flat tire is left on the rim, water can get inside to rust the rim.

Split Ring rims:

These are by far the most common tube type rim. They are either 2 or 3 piece. In this type the long piece is rolled into a circle and welded. If it is a disk wheel the disk is attached by rivets or welding. The side ring is either split or has a separate lock ring if the ring is solid. It can be spoke or disk and are still made new today. In all cases the bead of the tire goes over the inside lip of the ring or lock ring forcing it into the lock groove. The tire must be deflated and the bead ?broken? to remove the lock ring. That is why these were thought to be safer than the split rims. If the lock ring is bent (by someone trying to remove it without full depressing the tire away from the edge) or the wrong ring scavenged from another rim the tire can force the ring out of the groove releaseing it with explosive force. Again, rust can force the ring out of position.

Semi-drop center rims.

In this type both pieces are solid and they can come apart at the edge like split ring or halfway toward the middle. If they are joined in the middle, it looks like to ?L?s facing each other to form a rim. The removable piece is solid with two ?notches? about 30 degrees apart. In both cases there is a drop center right where the two parts separate. The drop is not as big as with tubeless tire, just enough so the removable half of the rim can be mounted over the other half. In fact, the rim is assembled much like mounting a tubeless tire.

The thought was that the tire would have to be fully deflated and push in for the rim to come apart. They also thought that once the bead passed over the joint it could not help but latch the two halfs together. In fact, it turned out that a lot of rims were damaged by the way they were assembled. The removable part is a very tight fit over the fixed part. It was easy to egg shape one or the other parts making it very weak. Once assembled, the only way to see if the joint is correct is to stick your head right in the line of fire!

These rims are most often seen in disk wheels but could be made for spokes as well. They were an improvement that turned out not to be so and as such are not that common. They can be replaced by split ring rims.

All rims, not just tube type should be inflated in a safety cage. That is the best and safest way. They make portable cages or restraining devices to contain a rim and tire if an explosion does occur. Some people wrap a chain around the tire/ rim. I do not like this because if you wrap it too tight you will prevent the rim/tire from seating and will not be able to get it off. If you wrap it too loose it will be worse then nothing if the tire does explode, turning the chain into shrapnel.

A clip on air chuck that does not require you to hold it on the valve is a must. Add to that a hand held valve that you can use to stop the air flow from a distance and you are on the right track. Whenever a rim is disassembled, the inside should be wire brushed to remove any rust and painted. This will make it much easier to assemble and much less likely that the rim will burst. Look at all parts carefully. Is your life worth more than the cost of a $45 rim? If in doubt replace it. Make sure the parts of mutli-piece rims are correct for each other. There will be a part number and manufactures mark stamped on both pieces. At least make sure the manufacturer is the same for both pieces.

When inflating split ring rims, the split should get smaller as the tire inflates. If it is not or is getting bigger STOP, let the air out and find out what went wrong. With all multi piece rims, add a little air at a time and inspect. Do not clip on the chuck and walk away; you will only know there is a problem when it explodes, maybe while you are trying to mount it on the truck.

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