There are a few issues in the hobby of slot cars that often cause a lot of debate. There's the tried and true "wood track vs. plastic track", the age old "racer vs. collector", and the more recent "digital vs. analog." None seem to compare to the lively debate that rises when someone brings up "magnet vs. no-mag." This page is NOT meant to pass judgement on either version of slot car racing, or the people who enjoy them. It's not meant to spark the next forum war on the subject. This page is meant only to inform those who are interested in trying out the side of slot car racing that does not use magnets to enhance traction.
Most new slot racers start out with magnet racing. Cars come with magnets in them, and the track rails are made of steel so that the magnets can pull on them. This is how sets are sold, so it makes sense to use them that way. It's also common for people to add magnets in order for the cars to stay on the track better, allowing them to put in faster motors and still stay on the track. Many people don't even realize that it's possible to run slot cars without magnets. If you're no longer interested in more magnets and faster motors, you might enjoy going the other way, and reducing or eliminating the traction magnets completely, and slowing the cars down a bit. Or, you've never raced magless before and wonder what it's like, or maybe you've tried magless before, but unsuccssfully.
This page has a few tips to help you give magless racing a well informed try. Remember, there is a lot more information out there than just what is on this page, so be sure to join and read a forum about the kind of slot racing you enjoy for the things I don't cover enough. Also note that if you haven't already read my general Tips page, you should do that first, because I'll refer to those things assuming you've read them.
- Add level skirting or borders
- Ensure good rear tire grip
- Reduce front tire traction
- Reduce power level
- Tune with weight
Non-magnet cars will drift out much easier than magnet cars will. It's vital that there is ample room beyond the edge of the track surface for the car's wheels to ride on. It must be the same level as the track surface, or the transition can upset the car and cause it to de-slot much more easily. It should also be the same, or close to the same texture as the track. It's a good idea to have extra skirts or borders everywhere possible, but at the very least the outside of every turn, and a little bit of transition room from turn to straight skirting is required.
If you're using a modular plastic track, ideally you would use the borders offered by your brand of track. The plastic borders will have the same texture as the track surface, and connect easily to ensure a level transition to and from the track surface. This can get expensive for a large layout, though, so many people seek more economical solutions.
If you make your own track borders, the most important thing is that they are level with the track surface. Quite often this means using two different thicknesses of products to add up to the correct thickness of the track. Some of the products/solutions I've seen people use are: cork tiles combined with rolled cork or model railroading roadbed; two thicknesses of foam-core poster board; self-adhesive weather stripping; drywall mud; plywood; carpet underlay such as Ecofoam (Canada only); neoprene sheets; foam rubber such as for play or exercise mats; and more! What you use depends on what you can find available for free or inexpensively. It also depends on if your layout is permanent or temporary. What works well on a permanent layout (mud, weather strip, etc) may not work well for a temporary one.
Once you've decided on the material, try a variety of surface prep ideas until you get one that has a similar level of grip to your track surface. Some people use paint, from matte to gloss, acrylic or enamel. I've also seen people use spray-on PlastiDip to overcoat their borders, which seems to have a grip similar to Scalextric Sport track. Don't be afraid to experiment!
Without a magnet to pull the car down to the track, you have only gravity to help your car get traction. Most cars weigh less than 100 grams. That's not a lot. That means the grip of the rear tires is even more important. Some tires will have so much grip that the car drives almost like it still has magnets. Check out NSR Ultragrips and how to prepare them before a race, and you'll wonder why people use magnets at all. Urethane tires have a good level of grip on most tracks, and tend to cope well with wear and dust/dirt on the track. Silicone tires work great on a smooth track, but tend to work best when everything is nice and clean, both the track and the tires. Rubber tires come in a variety of softness levels. Softer usually means more grip. Soft rubber also will wear out faster, especially on high traction track such as Ninco.
You don't have to replace your tires to get good grip, though. Check out the Tips page to learn how to true your wheels and tires. A perfectly round and flat tire will have much better grip than most cars come with out of the box. The more contact the tire has, the better it will be able to use its available grip.
You can also increase the grip of most rubber tires by softening them. Most rubber tires will soften if they are rubbed with some kind of penetrating oil. WD-40 absorbs quickly, and will have a positive effect on grip levels for a few hours. Other treatments last longer. A good rub-in of a drop or two of 3-in-1 oil on each rear tire will last longer and have a positive effect. I've not tried them, but I've heard of people using a variety of tire softeners, such as: NSR tire oil; high SPF sun-screen; Ben-Gay; oil of wintergreen; and heavy motor oils. Not all oils will penetrate all rubber tires, nor will all have a positive effect. If you are not happy with the level of grip of your car's tires, and are contemplating replacing them, try some of the above ideas first. Worst case scenario is that the tire is ruined by something you try, and you replace it anyway. You might, however, find that the tire is softer and has more grip, and you don't need to replace anything.
Do NOT put a car on the track while the oil is still on the tire, though. Wait until all oil has been absorbed into the tire, and the tire looks dry again. If it is still oily looking after a few hours, remove any excess with a rag or paper towel, and allow the tire to dry completely. Once the tire looks normal again, give it a try!
Most slot cars do not have differential gears on their axles, nor do most have independent front wheels. While independent front wheels are becoming more common (see recent SCX cars), they are still in the minority. When two wheels are connected solidly by an axle, the one on the outside is not able to turn as fast as it needs to because the one on the inside is slowing it down... when the front tires have traction. Front tire traction most often causes excessive drifting in the turns, but can also simply slow the car down.
The easiest solution is to eliminate the friction on the front wheels. Some people replace the front tires on cars with special "zero grip" tires, but I've found even those tires can have some grip. Ideally, a wheel that is unable to rotate freely should have no friction at all. Enter nail polish or super-glue. I tried nail polish first, and it works ok, but I didn't like how it would crack for some tire types. I then found out about super-glue, and have come to appreciate that the most. It's cheap and easy and plentiful. It applies easily and dries quickly, and it sands down nicely as well, if you should glue some bumps into the tire. I usually apply it with a finger, making sure to keep the wheel turning so that I don't glue my finger to it. It can also be applied by brush or other applicator. Just be sure to be quick about the application, and try to keep it evenly applied. With a coat of super-glue on your front tires, the axle could be completely jammed and the car would still run fine.
Running cars without magnets for the first time can be quite a challenge for those used to the added traction of magnets. Magnet cars can go exceptionally fast, and hold on great in the turns at high speed. Magless cars will feel like they are all over the place and just can't even be driven. One way to help make the cars more controllable is to reduce the power to your track.
If you are racing with a standard out of the box slot car track, it's common for the power to be at a fixed level. The only way to change the power is to get a different power supply. Sometimes this means you can buy a similar supply at a lower voltage level, and plug it in, and sometimes you must learn how to connect a different type of power supply to the track. Ask your local hobby store, favorite on-line store, or your favorite on-line slot car forum for help choosing and installing a replacement power supply.
If you have a digital set, it can be even more difficult to reduce the power level, depending on the set and the control box. For Scalextric, you need the new Advanced 6 Car Power Base. It has built in power level options for each of the 6 cars. For Ninco and SCX there are controllers or "beginner" modes that you can use. Carrera digital has 10 levels of power programmable to any car. Check the details of your digital set for information on reducing power or making it easier for new drivers to control cars.
Finally, you can replace the controller. Most set controllers have very little sensitivity, and can feel more like on/off switches, especially to experienced racers. Fortunately, there are aftermarket controllers available for all set types. For analog sets, you can get controllers with higher Ohms of resistance. That means that as you gently pull the trigger, less power is allowed through than on controllers with low Ohms. You will always get full power at full throttle, but having lower power at low throttle makes it much easier to control non-magnet cars. There are also electronic controllers that offer a variety of knobs and buttons to control the power available to the car. Experienced racers often try a variety of controllers, and usually find a favorite one that they always return to time and again. Ask other racers you know, or your local hobby shop or on-line forum for suggestions on good controllers for your set type.
In most cases, a well tuned car will be really light. A light car will accelerate faster and stop faster. Some cars, however, do benefit from small amounts of weight in the right places. The problem is that the best location and amount of weight differs from car to car, and so you will need to experiment to find the best way to tweak your car's performance with weight. Here are some of the rules I've learned from others on-line and from personal experience:
- If the car tips and rolls too easily, add some weight down low. This will lower the center of gravity. Lower CoG leads to more sliding than tipping.
- If the car slides too much, increase the car's weight transfer by slightly loosening the body screws, or if the car has a motor pod, the pod screws. If that's not enough, add small amounts of weight up high, such as the roof of the body, to increase tipping in order to add traction to the outside wheel in a turn. Another way to increase cornering traction without causing tipping is to put weight at the very outside edges of the car, but still down low. In most cases, you want this weight as far back near the rear axle as possible.
- If the car jumps out of the slot on acceleration or goes straight when it should turn, add some weight up front, as close to the guide or in front of it as possible. Weight up front will help keep the guide planted, even under hard acceleration with grippy tires.
- If the car has no brakes or acceleration you might need to get rid of some weight, or it might need more traction in the rear. The motor is also the brakes, so if the car has poor traction when braking, the rear wheels won't be able to use the motor to help slow the car down. Also, if you have too much weight up front, braking can lead to a reverse lever effect, lifting the rear wheels and reducing their traction. Some weight as close to the rear axle as possible is best.
- If you've tried a lot of these things and the car still doesn't perform the way you like, you can also try removing some weight. Some older Carrera cars were built like tanks, and had the acceleration and braking of a tank-like slot car. By removing some of the plastic that stiffens the chassis, or the body, sometimes enough weight can be eliminated to make it perform better.
Note that you can place the weight inside the car, or even under the chassis. Wherever you put it, make sure it is held securely to the car. If a weight comes loose inside, it could bounce around and brake things, or even short some of the wiring or electronics inside the car. If a weight comes loose outside, it could short your track. A lot of people use "wheel weights" cut into pieces to tune with weight. These are the weights that auto shops use to balance new wheels and tires on a car. They are thick, though, so a lot of people have also taken to use "tape weight" such as is used by golfers to balance or weight their clubs. NSR also offers pre-packaged self-adhesive weight in different thicknesses that can be easily cut to the shape you need to place in your cars. These weights are usually lead, so be careful with handling. Some people also use tungsten putty for a heavier weight in the same space, or blue tack for less weight in a given space. They can all work well if you spend the time to test and tune.
Don't take this the wrong way, but, learn to drive. :) Every car can be driven at its own optimal speed, but every car will drive differently. Every car can be fun to drive. The skill of the game of slot racing comes in being able to drive any car on any track. If you expect every car to perform the same as a well stuck down magnet car, then you will be frustrated by racing magless. The only way to truly enjoy magless racing is to give yourself time to practice at it.
The biggest change you'll have to learn when transitioning from magnet racing to magless is that slowing down before the turns, and maintaining an appropriate speed in the turn, is the most important thing. Just like real racing, the goal is to "scrub off" just enough speed after a straight such that you are left with just the right amount of speed for the turn. Just enough usually involves a SMALL amount of sliding, but nothing like a rally drift. You will still lose time by drifting out widely or snapping the car around, even if you manage to keep it in the slot. Any time you make by going too deep into the turn will be lost by the excessive drifting or snap out. Without magnets, the cars take longer to slow down, and so you will need to brake much earlier than with magnets. They also don't hold as well in the turns, and so less power will be used through the turn for the same car without magnets than with them.
Once you get the knack for proper braking, the next challenge is bringing up the speed again to carry your speed through the turn. You don't want to come to a complete stop and then go again for the turn, but you also don't want to go too fast through the turn such that you snap out or drift wide. Keeping the car over rails as much as possible will get you the fastest lap time to an extent.
Every car and track will be different, like I said. That's what makes it so much fun! Because of that, though, it takes a lot of practice to be able to pick up any magless car and drive it successfully around any track, and then to get faster and faster at driving that car.