Much has been said about how to "set up" the Weapon. Even more has been written on the topic. Team Losi offers setup sheets on its website reflecting the setups its drivers used to win particular events. These are helpful, but if you read on, you might agree with me that it could do no more than to point in the right direction for that particular track and that particular driver.

It depends on the driver

I am in the fortunate position to share the same track as our current national champion, who also races with a S/W. Every meeting finds me asking him for some setup tips. Some of these tips have been very helpful and others have not. Why? How is it possible that a racer like himself can have success with a particular setup and I, with the same settings, battle with the car on the track? Simple - he is such a good driver that he can take a badly set up car and still win. In fact, I am positive that I could give him a car that I find undriveable and he would be hard to beat. Driving styles and abilities go a long way in determining the correct setup for driver and car. My "ideal setup" might not suit the next person. This is the first reason for stating that there is no such thing as a perfect setup that will suit everyone.

It depends on conditions

Some time ago, I spent a day at the track, concentrating on a good setup. I finally left, feeling satisfied that I was ready for the next race. During the course of my practice session, I had changed the car to be more responsive. I, amongst other things, made use of the inner holes on the front suspension arms – the pro’s use this to get more steering. Armed with the knowledge that my car was handling well, I threw the car into the first corner of the first heat on race evening. Wow, what a surprise! I have never had the S/W do a traction roll on me – that was until I took that corner. The rest of the heat consisted of carefully negotiating the turns and trying to keep the car in a straight line. How could this happen? OK, you might want to say it’s because I’m a fool and I can’t set a car up properly and I can’t drive and……. Apart from all of that. Simple. My practice session was on a cool day. Race evening was preceded by a scorching day. Temperatures were well into the 90’s and the track was still very hot by the time the first Touring modified heat started. This resulted in the tires finding more traction, instead of sliding – as it did when practicing. So there we have it. Same car, same track – different results. This concludes reason number two.

It depends on the track

Every so often, I run through a few batteries on another club’s track. This track, situated in Durban South Africa, used to be 3 tennis-courts. It has been re-surfaced and a very neat track has been laid out. Due to the fact that tennis-courts are generally flat (how else?), this track is as flat as a tabletop. To get proper traction on this track, we have to stiffen up the rear end of the S/W considerably. This is achieved by using Trinity’s Yellow Congo springs at the back (purple springs will do as well). If, however, the same setting is used on my club’s track, the car will bounce all over the show and rear traction will be non-existent. Why? Our track was purpose-built. It lies against a gentle slope and has a couple of tight, cambered corners. One of the short straights leads uphill and the first corner after the main straight is sharply downhill (apart from the fact that it is a hairpin corner). This corner is followed by a short straight section and then a "kink". The trick part is that the "kink" lies in a slight "dip". This part needs careful negotiation as we tend to run straight – if you have enough speed, you can clear the dip (and the "kink" with it). It makes for spectacular viewing at a night race as the screws holding the rear shock tower in place, make contact with the tarmac, leaving a trail of sparks. The point is that the suspension works much harder on this track than on the Durban track. This, in turn, requires a different setup on the suspension. That concludes reason number three.

Other factors

There are various other factors that could influence your car. Clearly, the car will behave differently if you run a mod motor, compared to a stock motor. Every inconsistency, incorrect setup decision and driver error is magnified tenfold due to the speed of the car, when you run, let’s say, a 12 turn motor.

Your radio equipment could also, to some extent, cause you to resist the urge to follow the setup used by David Spashett when he won the IFMAR ISTC. If you own a JR R-1, Airtronics M-8 or a Futaba 3PJ radio, then this will not apply to you. If not, then consider the fact that dual rate settings are there to assist the driver. The same goes for exponential settings on the steering. Some of these radios offer a range of pre-programmed functions, which assists the driver with braking, steering and acceleration (to mention only a few). Consider further the difference that servo’s can make – a standard servo has an average response time of 0.22 seconds. A high quality servo has an average response time of 0.06 seconds. This means that the driver can brake later into a corner and has an overall faster response on his car. This factor alone can cut lap times by a second if the car is in the hands of a fairly good driver.

Ask yourself whether your equipment is in the same ballpark and then ask yourself whether you are going to copy David’s setup. IMPORTANT: The driver wins the race – not the equipment. My point is that a pro will set his car up with his equipment in mind. If I didn’t have a radio with steering dual rate, I would pay much closer attention to the maximum steering throw on my car. I would probably also tame the front end as much as possible. Due to my radio equipment’s abilities, I am able to select different settings on my car, well knowing that I can dial out steering if things get too hot.

Thus far it may appear as if I’m the personification of negativism. Sorry, it not the idea – I have simply learnt, the hard way, that blindly following setups of Pro’s does not work for me – and I know a few others who feel the same way. Let’s look at the positive things we can do to improve handling.

I need to make it clear that any ideas that I may offer are based on my own (limited) experience, the experience of others (including pro’s) and a substantial deal of reading and experimenting. It is only the opinion of an individual and I may very well be wrong on certain aspects. Please bear in mind what I said in the first couple of pages – there are an infinite number of variables, which could affect the final result. Consider the following as well: your car, with a low turn motor and properly geared, should reach speeds of up to 40mph. That is on a 1/10 scale. That translates to 400mph in full scale. We are, as hobbyists, attempting to solve problems that perplex the world’s best automotive engineers. If you disagree with anything I suggest, please write and say so. And please don’t jump down my throat – I do not lay claim to having special knowledge – I simply hope to share some constructive ideas about the car that I race. The thought is to exchange ideas and learn from each other. I understand this website to promote the statement made above. I also understand this hobby to be fun and to be of the nature where we try to help each other.

Determine the problem – if you have one

In following this route, I am assuming that you mostly race on a single track or, if not, at least on tracks that are fairly similar. By virtue of what I have said thus far, you will, correctly, assume that I am not about to tell you to set the toe out to1 degree and use a light sway bar in front. Let’s look rather at the common problems that we all experience, at one time or another.

Traction

We all want 100% traction all of the time. I hate to disappoint you, but the laws of physics are against us. We can, however, improve traction when the car is misbehaving because of something we did incorrectly.

Let’s look at REAR traction first, since this seems to be the biggest single complaint.

Rear traction loss can be caused by any of the following factors or a combination thereof:

Tires – wrong type or wrong compound
Springs – too hard or too soft
Shock placement – too upright or too far down
Camber and the length of the camber arm
Sway bar
Damper oil
Rear ride height
Battery placement

Wow. That includes almost everything. Do you really think I am going to discuss each one in detail? No. The IWC kit includes an "Addendum manual" which deals with every option and the effect that it has. If you have the manual or the IWC kit, then you may find my ideas boring or irrelevant. The reason for this letter is to start a discussion. I have been able to track down so many different ideas and suggestions (from fairly authoritative sources) which are in conflict with each other, that I just had to see what other racers have to say.

The first step is to follow the recommended setup on the instructions included in your kit. If you have had success in the past with a setup that differs from the recommended one and you now have a traction problem, then you should ask yourself what it is that has changed since then. You have to, at least, find a starting point. Right, you have noted the rear end setup of your car and you don’t have proper traction with that setup. I am a firm believer of changing the easiest things first. That leaves us with 3 possibilities:

1. Change the rear tires. Use a softer compound or a softer insert. If you are running slicks, you can consider using a radial tire. It appears as if most pro’s have had success with Proline’s S3. Try it, it might solve your problem immediately. I prefer running on foam tires, for a variety of reasons that are irrelevant here. I use Ufra Pink Mediums at the back and find that they stick to just about any surface. This might also be an option to consider. The key seems to be to go softer.
2. Consider the springs you are running. If your track is flat and the suspension does not have to work hard (and different tires did not do the trick), then consider a harder spring. The opposite is true if you run on a bumpy track. Go softer on such a track.
3. Place the left side batteries in the "back position". The pro’s love the "left side forward" position. It gives them better steering response. Steering won’t help you if your car’s rear end slides all around the track. Get the weight of the batteries to assist you in gaining traction.

Let’s look at the other factors I mentioned.

• "Laying over" the shocks softens the rear suspension, or so I’m told (I have tried to gauge the correctness of this statement and remain convinced that it actually stiffens the suspension). Mounting the shocks upright tends to stiffen the suspension. OK, I won’t argue. Combining the results achieved by "laying over" or mounting upright with a different rate spring can further enhance or interfere with traction as explained in (2), above. Please note: Team Losi authoritatively states that "laying over" makes the shocks softer.

• Camber can influence traction. Obviously, some negative camber is needed, but take care not to overdo it. I doubt if 2 degrees negative camber will have a positive effect on traction. Between 1 and 1,5 degrees negative camber should be in the ballpark. More complex is the placement and length of the rear camber arms. The following principle holds true, however: a longer link provides less steering, but increases rear traction. This aspect is very easy to determine on the track. I have tried shortening the link by moving the outer ball stud in one hole. The difference was incredible. My own preference is to keep the car as stable as possible – I’m not the best driver around – so I stick to a longer link. Moving the height of the ball stud, on the holes provided on the shock tower, remains unknown territory for me. I understand, from a publication called "Touring Car Suspension Dynamics", that moving the height of the stud can influence the "roll center" and consequently "roll axis" of the car. I express no opinion on this because I do not, yet, fully understand the forces at work here. I have compared the setups used by the pro’s and they, almost invariably, use the middle row – outside hole.

• The use of a sway bar has an influence on the on-and-off-power steering of the car. Not much has been said about its influence on traction. I tend to think that it "tames" the rear end somewhat and consequently contributes to better traction. As a rule I don’t use a sway bar, but only because I have sufficient rear traction on the tracks that I frequent.

• That leaves damping and ride height. Let me quote the Addendum manual to the IWC. Damping - "Heavier rear damping will increase rear grip". Ride height – "Lowering the ride height results in more rear grip. If the rear ride height is set too low the car may start the turn with understeer and instantly change to oversteer."

That is just about it for the rear end. A last point that I consider worthy of discussion is the influence of steering setup versus traction. We all know that an object travelling in a straight line tends to keep to that line. Its called momentum. The application of a force from an angle will cause the object to change direction. The object, by virtue of its momentum, will want to continue in a straight line, however. This is what happens when you turn the steering on your car – the car wants to carry on in a straight line. The more sudden and direct the change of direction, the more likely it is that the car will lose traction or roll. I apologize if I digress. The point is this. Any change that you make in order to achieve better steering response will affect traction. The trick is to get the right balance.

Let’s look at the FRONT traction now.

• All the factors that affect the rear end affect the front end. There is, however, a difference, and a very important one at that. To improve traction at the front, you have to reverse certain steps compared to the rear. Example: Stiffer springs at the back improve traction – SOFTER springs in the front improve traction. The same goes for damping.

• Ride height, shock positions and camber links mirror the position at the rear end, in other words, their settings have the same effect in the front as in the rear.

• Caster is a new item, which, obviously, is relevant in the front only. No doubt you are fully aware of the different options with the 0-degree bulkhead. I prefer 7 degrees in front due to the tracks that I race on. I have never raced on carpet and cannot comment on the 3-degree setting.

• Tires - I use Sprint 40 foams as a rule. I prefer the slightly harder compound (it has a higher rubber content), as I want the front end to slide rather than dig in, if I overpower it into a corner. I get excellent traction with these foams, but they are more forgiving for my mistakes. You lose less time in a slide than in a traction roll. On occasion I revert back to Losi tires and depending on conditions, I could use slicks on all four corners or slicks in front and intermediates in the back. There are too many variables to try and find rules here. I will one of these days, mix foams and rubber and see what happens.

STEERING

I have, once or twice, read articles where the writers have made suggestions on how to get more steering. The suggestions included advice on grinding off the bump on the spindle to get more steering. I presume this means more "throw" on the steering. I don’t understand this. My car has more steering than I can possibly use and I have not ground off any bumps. My opinion is that the car has more than enough steering, without modification, and that a lack of steering response is confused with a lack of steering throw.

Bear in mind that the suspension (in the wide sense) can be set up to make the car react quicker to steering input. Once again, the factors discussed above holds the key. Example: I promote a longer camber link in front because it makes the car more stable. If, however you want more steering, then shorten the link. Stability, or the lack thereof, will be the price you pay. Use heavier damping – that will make the car react quicker, but you will sacrifice traction. Same story with springs – go stiffer, but you will lose traction. That is why I mentioned earlier that the trick lies in finding the correct balance between traction and steering response.

What about a servo with quicker response time? At least you will not be sacrificing traction. If you believe that you car really does not have sufficient steering throw – and you built it according to the instructions – try this: run your car without the body for a couple of laps. Pay particular attention to the angle of the wheels into the corner (select the corner closest to the driver’s stand and run the car repeatedly through that corner). You might be amazed at what you see. The angle of the wheels will probably be much greater than the angle of the piece of real estate you are trying to negotiate. If this is the case, then it simply means that you have plenty of throw on the steering, but bad steering response. So don’t go grinding off bumps until you have correctly identified the problem.

I find that the standard setup of the steering is more than what is needed, and I leave it that way. I rather use the dual rate setting on my transmitter to eliminate excess steering. My transmitter’s setting is currently at 65% and I have enough steering to blast into and out of 180-degree corners.

Conclusion

So much for all my ideas. If you are a Losi lover (like me) and have better ideas, let’s have them.

I close with the following remark from the March ’99 issue of Radio Control Car Action: