No matter how powerful your engine is, or how finely tuned the suspension is, or how honed your driving skills are, your remote control (RC) car isn’t going anywhere fast if the tires come off. Super gluing tires onto wheels seem straightforward enough, but RC tires (especially rear tires) experience a lot of side-load pressure, which can cause weak glue bonds to separate.
How do you glue RC tires the right way?
1. Prepare the wheels and tires by creating vent holes, trimming foam and manufacturing slag to size, and cleaning and scouring the surfaces to be bonded.
2. Ensure the tire is properly mounted and secured before peeling the tire back to apply glue evenly around the bead.
3. Allow the glue to dry for 10 minutes before gluing the other side.
While it sounds easy enough, there are plenty of minor mistakes you can make that will weaken the bond between the wheel and the tire. Considering the high speeds and power of today’s remote control vehicles, these minor mistakes could lead to a tire coming off, costing you the race or causing damage to your RC car. You will want to follow these steps to ensure a good bond.
1. Prepare the Wheels and Tires
There are a lot of options when purchasing tires for your RC car. Which tires you select will depend on the specifications of your vehicle, the terrain you plan to drive on, and your driving style.
Whatever tires you purchase, they won’t be ready to mount right out of the package. There are a few things you need to check and do to make sure the tires fit properly and perform at maximum capacity.
Add Vent Holes
Unlike the tires on your bicycle (which has an inner air tube) or your real life car, RC tires are not designed to be inflated. Instead of being filled with air, RC tires are filled with foam inserts that hold the shape of the tire but allows flexibility to increase traction.
An RC tire with no air holes acts like a balloon, in all the ways you don’t want a tire to act like a balloon. When going over bumps, the tires bounce, causing the car to lose control and traction as it loses contact with the ground. A properly vented tire, on the other hand, temporarily “deflates,” increasing the amount of surface contact with the ground, then quickly “reinflates” to its proper round shape to continue driving.
Add a couple of air vents into the wheels themselves.
Most wheels come with perforated spots marking where these holes should be. The holes should be 2mm and on the opposite side of each other. The advantage of air holes in the wheels is that they are on the inner diameter of the wheel, so the tire coming in contact with the ground never blocks the hole.
Add a couple of air holes in the tires.
This can be done best with a leather punch, though you can also use a pair of fine-point scissors. Again, the holes should be 2mm wide and on opposite sides of the tire so that when one hole is blocked, the other is open to vent.
The advantage of having air holes in the tires and not just the wheels is that any dirt or water that finds its way into the holes will be flung to the outside of the tires via centrifugal force when the wheel is spinning. If there are vent holes in the tire, this debris can escape, but if there are only air holes in the wheels, it is trapped in the tire forever and can cause damage to the tire and the glue bond.
Trim Tire Bead Slag
If you’ve ever assembled a model car or airplane, you’re familiar with the concept of manufacturing slag. Small plastic pieces are often produced in a large sheet, and after punching the pieces out of the sheet, you often need to trim excess plastic off the piece. You will need to ensure the slag is removed from the piece that was connected to the sheet to ensure that the part is the proper size and shape.
RC tires are made by pouring liquid rubber between two formed plates that are pressed together. The negative space created between the plates is the shape of the tires. Sometimes, however, some of the molten rubber seeps between the plates, creating a thin flange of excess plastic attached to the bead of the tire.
This manufacturing slag needs to be removed to ensure that the tire fits snugly within the glue channel of the wheel. You can trim this slag off with a razor blade, craft knife, or small scissors.
Scuff Wheel Glue Channels and Tire Beads
Imagine your stuck down a well. The sides of the well have been formed by pouring concrete, so the walls are relatively smooth. There aren’t any cracks, ledges, or gaps to stick your fingers and toes into in order to climb out. There just isn’t any way for you to get enough grip to climb out.
Now imagine the walls of the well were formed by laying bricks instead of pouring concrete. This scenario creates a sort of cobblestone wall as opposed to a smooth paved road. This would provide you with crevices and ledges for you to use to put your fingers and toes into in order to climb out.
The difference between a smooth, concrete well wall and a creviced, brick well wall is similar to the difference between smooth, manufacturer-fresh wheels and tire walls and wheels and tires that have been scuffed.
By scuffing the binding areas where you will be applying glue to the wheels and tires, you can create a lot of scratches and crevices that give the glue little pockets to fill and increase the surface area of the bond. This will ultimately result in a stronger bond.
Clean Wheels and Tires
Previously we described the process in which RC tires are made. Liquid rubber is poured into the cavity formed by two shaped plates pressed together, then allowed to cool. To ensure that the tires release from the molds after the rubber dries, the molds are coated with a non-stick solution that acts in the same way as spraying Pam on a frying pan.
This non-stick coating, however, creates a residue covering the tires themselves. This means that the tires (and wheels), when fresh out of the package, are covered in non-stick residue that must be removed to ensure a good bond between the wheel and the tire.
Simple rubbing alcohol is typically the easiest and cheapest option. People also often use Windex, motor spray, or brake cleaner for this purpose as well. The important issue is that the cleaning agent doesn’t leave any residual residue that may interfere with a strong bond. For this same reason, you should use a clean cotton rag or lint-free cloth for cleaning.
2. Mount the Tires on the Wheels
Before gluing the tires to the wheels, you want to make sure everything is properly aligned. If there are gaps in the bond area or the tires aren’t properly aligned, the tires will be uneven. If this happens, it will cause the RC car to drive unsmoothly, or for the tires to come off completely.
Install Foam Inserts
Instead of air, RC tires are filled with foam. Two types of foam are used to fill the cavity between the wheel and the tire: open-cell foam and closed-cell foam.
·Open-cell foam is white and generally puffier than closed-cell foam. It will often be cut a little wider than the tire because a little bit of compression won’t affect its performance. You will, however, need to ensure that the closed-cell foam is set evenly within the tire. To do this, you may want to trim the edges of the foam to fit the shape of the tire better.
· Closed-cell foam is blue and stiffly formed into the exact shape of the tire cavity. It is often also directional, so it is important to check the orientation when installing. Closed-cell foam shouldn’t need to be trimmed to size.
Whatever type of foam fills your tires, you will want to make sure it is distributed evenly throughout the tire by rolling the wheel and tire between your hands. While doing this will should be checking for bulges or lumps.
Mount the Tires
The wheels and tires are manufactured to fit together snugly. You’ll want to make sure the two components fit snugly together before gluing. If there is any bulge or gap, the glue will not be able to bond the parts properly, and the tires will be more likely to come off during use.
Secure the Tires
Once the foam and tires have been properly mounted on the wheels, you will want to make sure they are held securely in place. You can do this by wrapping a thick rubber band (or tire band) around the tire near the edge you plan to glue first (see below). This will not only keep the tire in the proper orientation, but it will also create even pressure holding the two components together while the glue cures.
While thick rubber bands work for this application, the advantage of tire bands is that they have molded tabs at regular intervals making it easier to set and adjust the placement of the band where it is needed most.
3. Glue the Tires to the Wheels
This is the moment of truth. Once you have the wheels and tires properly prepared, and the foam and tires properly aligned, it’s time to set everything in place permanently by gluing the tires to the wheels.
If done properly, the bond between the tires and the wheels will be so secure that it will hold essentially forever. Ideally, the tires will wear down before the glue bond fails. If this happens, you will have to boil the tire remnants off of the wheels if you want to reuse the wheels for remounting your next set of tires.
If improperly glued, however, the tires will separate from the wheels when put under enough pressure from turning.
Start on One Side
You can only glue one side of the tire at a time. Most wheels have the same diameter on both sides (see below for the exception), so you could theoretically start on either side. If you are gluing tires for the first time, you may want to consider gluing the inside seem first because it will not be easily visible. That way, as you become better at the process, you can create more eye-pleasing results on the sides that will show.
Check the orientation of your wheels, tires, and foam inserts. While some are omnidirectional, many work best when aligned in a certain direction. This orientation will determine which way the components should be assembled as well as which side of the tire will be exposed.
Exception For Short Course Tires
In most cases, though the direction of the wheel may be predetermined, the diameter is the same on either side of the wheel. Some short course wheels and tires, however, are designed such that the outside wheel diameter is smaller than the inside wheel diameter.
This difference is designed to increase the RC car’s traction when making many sharp turns, which are common on short courses. The consequence, however, is that it creates an additional surface of contact between the wheel and the tire that can result in lumps and bulging if not properly glued in place.
When installing short course tires with different interior and exterior diameters, always glue the bead of the smaller exterior bead first. Once it has dried for at least 10 minutes, flip the tire inside out and glue the tire to the wall created by the difference in diameter in order to secure the tire to the wheel and prevent bulging. You’ll need to weigh the wheel down with a full soda can or something of similar size while the glue sets.
Once the inner wall has been glued and set for at least 10 minutes, you can reinstall the foam and turn the tire right-side-out again. Make sure everything is properly aligned properly and then glue the interior side of the wheel.
Apply Glue Evenly
It’s finally the moment of truth. Once everything is properly aligned, it’s time to start gluing. The goal when gluing is to apply a thin and even coat of glue along the entire wheel’s glue channel. This will ensure that the glue dries and cures quickly at the same rate, ensuring a proper bond.
Some people will suggest thinking of the wheel as a clock and applying a drop of glue at 12 and 6 o’clock, waiting for it to dry, and then applying drops at 3 and 9 o’clock. The theory is that because the glue spreads out so much from the application site that this is all that is needed to create a good seal.
While it is true that too much glue actually results in a weaker (and messier) bond, this procedure could result in gaps in coverage between the 1 and 2, 4 and 5, 7 and 8, and 10 and 11 o’clock points on the wheel. A better method of distribution is to apply glue to one spot, press the tire into the wheel’s glue trench to spread it, then apply another drop of glue on the edge of where the last drop has spread, to ensure total, even coverage.
You don’t want to apply too little glue because you want the entire surface of contact between the wheel and the tire to be coated with glue. You don’t want to apply too much glue for two reasons. Excess glue will be pushed out of the channel, creating a sticky mess on the outside of the channel. If there are any pockets or gaps in the connection between the wheel and the tire, too much glue will create a weaker bond.
Glue a Seal Around the Seam
After you’ve ensured that the wheel’s glue channel is bonded to the tire, you’ll also want to seal the seam between the wheel and tire on the outside of the tire.
To do this, drop a bead of glue on the seam between the two components and rotate the tire, so the drop travels all the way around the seam. This will create a barrier that prevents dirt and water from infiltrating between the wheel and tire.
Allow Time to Dry
If you’ve applied a thin, even layer of glue to the wheel channel, it should only take about 10 minutes for the glue to dry. If it takes longer, you may have applied it too thick in some areas, resulting in a weaker bond.
After the glue has set for 10 minutes, pull on the tire to ensure that it has been properly sealed to the wheel. If gluing a short course tire with different interior and exterior diameters, see above for instructions. Otherwise, you can flip the tire over, adjust the rubber band or tire band to secure the other side of the tire, and repeat the process.
Want to watch how to do it as well? Below is a video from Horizon Hobby that gives some great tips on how to glue your RC tires right the first time.
I hope this article has helped you learn what tires you need, how to properly install the foam in them, where to make vent holes, what purpose they serve, how to mount the tires. how to properly glue them, and how to install the tires. RC racing is loads of fun but doing all the prep can be an enjoyable part of the hobby as well.
As long as you have cautiously performed each step correctly, you should now have securely glued your RC tires the proper way, which will keep them lasting longer, and keep you in the race!