My Opinion: The Next Step for Losi

So my favorite company has been swallowed up by the soul-less giant that is Horizon Hobbies. Kinwald doesnt run one anymore, Gil started over somewhere else, and Trinity became ( somewhat less than) Epic. What became of the invincible race dynasty of ten years ago?

Without the raw talent that is Gil, it seems the design team at Losi has some lessons to learn (although Jukka certainly appears to know what he is doing, having designed the eight). Since the release of the BK2, there really hasn't been much change to the XXX line. Slight changes have been heralded as "improvements" but it doesnt seem there is a lot of testing time behind them- who runs CR rear arms on their 2w?

I had a discussion with an Associated factory driver some time ago that was extremely interesting. This particular individual is well known for running different setups than anyone else, and trying new things on his car. He explained to me that any time he makes a change to his car, a call to the Associated engineering team will yield a complete breakdown on what change will do to the handling of the car. That speaks volumes, not only about the dedication of the Associated engineers, but also about the way design is accomplished at Associated. Taking a step back for a minute, lets examine why.

In order to be able to make predictive statements about vehicle handling, and how various tuning changes will affect it, a comprehensive mathematical model of the car needs to been in place. Given the complexity of the car, and the level of detail able to be predicted, my guess is this model is being run in either a high level mathematics program, or as a stand alone application.

The advantage to this approach is durability: as long as the model is continously updated with the latest geometry, tire, and power/weight data the hardest portion of the design is accomplished already. Releasing a new car becomes an excercise in deciding what the new parts should look like, and what the best way to manufacture them should be.

So what should Losi learn from all this? Car design is not a on time thing. It has to be an evolution, and have data supporting each design change. In speaking with several high-level former Losi drivers (A-mainers from the glory days) there is no comprhensive system behind car releases at Losi. Therefore the quality of the racecar is entirely dependent on the designer. If Losi is willing to build their franchise around one designer (like Kyosho and Shin Adachi) this approach will work as well, but Associateds approach will stand the test of time.

Building the Perfect Diff

The holy grail of off road race car building is building the smoothest, longest lasting diff possible. Many of us pony up big bucks for thrust bearings, carbide diff balls, and lapped flat diff rings all in the quest for the smoothest diff action possible. If this is you, and you race a Losi car, unfortunately the factory parts will never allow you to build the diff to its fullest potential. The manufacturing tolerances on several of the components are not tight enough to allow smooth differential action. Much like lapping diff rings (BFast RC sells pre-lapped diff rings) there are several easy things that can be done to take your diff to the next level of smooth, and make it last longer as well.

Think of your diff assembly like a gun barrel. The better everything lines up together, the better it will perform. The problem with the factory parts lies in their alignment: the ends of the diff spring and diff screw are not square enough (perpendicular) to allow proper alignment.

By chucking the spring and diff screw in a lathe and trueing up the ends, diff life is greatly improved, and its much smoother as well. Additionally, make sure to have a few diff screws on hand, as it is common to receive slightly bent ones from the factory. These should be discarded and not used.

Before assembling the diff, be sure to compress the diff spring several times in a vise so that it takes a set in the most even manner possible.

With just these few tips, your diff will be as good as the factory guys.

Welcome to Losi Fan

Welcome to Losi Fan! Having raced Losi vehicles for more than ten years, I am excited to have a forum to share ideas, tips and tricks about racing Losi cars. As a Mechanical Engineer, a large part of the fun I have in RC is the design, manufacture, and testing of custom parts- my cars never touch the track without some "works" part or another on them. This page will also allow the other brave folks who do this a place to share ideas.