Tech Report from MIBO International

Last weekend, I attended the MIBO International race. Since there was no slow stock class, I was racing with all the more experienced the drivers in the fast stock class! In the beginning, I was worried if I could handle the speed of the car, and if I was going to be able to drive together with more experienced drivers. The stock class was the biggest class of the event with almost 70 entries, and I was able to finish in 46th position, which was an amazing result for me considering that I was racing with adults and way experienced drivers.

I received a huge congratulations and admiration from many drivers and spectators! They were amazed how great I was able to handle such a fast car in such a tricky track conditions. I was really excited about the positive feedback that I received from all those drivers, but I have to admit that part of my success was my car, and the set-up that my father Martin Hudy had prepared for me. I was able to overtake some of the drivers who are better drivers than me, but I could see they were struggling with their set-ups as their cars were oversteering, traction rolling and too loose. Therefore, I would like to share some set-up ideas with you, in case that you have such struggles, and want to make the car easier to drive.

When I start the race, the car was oversteering way too much. The car was very responsive, which made it difficult for me to enter the corners confidently.

To make the car way easier to drive on the corner entry, those setups changes were interesting:

- Instead of the traditional CFF upper arms which provide great amount of steering, I used the links. But not mounted in standard way on the caster bushing, but onto the upper clamps and top decks. The benefit of the longer links mounting is that it reduces initial steering and provides more cornering speed. It means that car is lazier on the corner entry, but that improves stability in the sweepers. The car is rolling less – it stays flatter. When the car rolls too much, less experienced drivers have issues with oversteering, especially off-power, when they lose the rear of the car. The long links mounting eliminates this issue. The reason why the link is mounted onto the top deck is that it makes it softer. If you mount the links further out, the feeling is similar to when you change the upper arm material from Soft to Extra soft. When you will try this setting, please note that the top of the upper clamp is 1mm higher than the caster bushing, and top deck is 3mm lower than caster bushing. So, when you, for example, like to use 2mm under upper arms, you have to use 1mm shim on upper clamp and 4mm on the top deck.
- A lower servo link mounting, as well as servo saver also greatly helps to make the car easier to drive on the corner entry, since the car is then less responsive. Lovering the servo horn will reduce initial steering and will reduce the sensibility of the steering, as more steering input is needed to reach the same amount of steering. Servo saver instead of servo horn will also help to reduce the steering response and will also protect your servo in hard crashes. Both these changes are recommended especially who are not that gentle with the steering wheel on the radio.
- An open front top deck is another great option to make the car easier to drive on corner entry. Thanks to the open top deck, it was easier for me to enter chicanes. Car stays calm, as reactivity is reduced, and thus, I am not losing the rear end as much. To make the rear more stable in chicanes, as well as off-power, I like to use both screws in the rear part of the top deck. Reducing rear flex reduces rotation and increases stability.
- A lot of bump steer shims is another great help. In the team's set-up sheets, you may have noticed that pro drivers are sometimes using as low as 1 to 2mm of bumpsteer shims. But, for average drivers, this is way too little, and means too much bump steer, and a lot of initial steering. So, if your car is too aggressive, don't be afraid to mount as much as 4mm of shims, as I was using.

Another issue which I could see was drivers had with traction roll. To avoid such issue, the below list te setup adjustments

- A lot of sidewall glue on the front tire sidewalls is the first solution. Many drivers know about it, but problem is that they apply too little glue and, they think that it will fix the problem. But, usually they glue so little that it actually does not have any effect. If you are struggling with traction rolling, you need to glue at least 60mm of diameter. My father did 61mm of gluing on my tires to make sure that I did not flip.
- Less front static camber in is another of the main set-up changes which I recommend. I usually run between 1 to 1.5 degrees of negative camber in the front only.
- A higher front hub greatly helps to avoid traction rolling as well. Experienced drivers like to use 0.5mm (kit) shimming under front hub - but for the less experienced, who have issues with too much steering or traction rolling, 1mm of shimming is a way better option. When raising the hub by 0.5mm, do not forget to lower the downstop value by 0.5mm as well, to retain the same amount droop in the car.
- A softer front spring, instead of traditional C2.5-2.8, which improves steering, I prefer C2.4-2.7. The softer front spring reduces initial steering and initial reaction and is thus more forgiving to drive. As the traction was increasing during the race, I could see that some drivers had issue with car over-rotating and losing the rear of the car in the middle of the corner.

To improve the car' stability and to reduce rotation, the following changes were made:

- One of the greatest set-up changes for these issues is the T-brace chassis stiffener. It helps to eliminate chassis flex in the rear of the car, which helps to increase the car's stability. At the beginning, I was using only the first and last center screw, but when the traction was high and car started to become too tricky as I was, I leaving the throttle, my father connected all the T-brace screws to make the chassis as stiff as possible in the rear part.
- Less rear droop, as well as a harder rear spring is another great set-up change for improving stability. Usually, top drivers are using on a lot of droop, together with soft rear springs, to get more off-power steering as well as rotation. For example, my father is usually using a 1mm shim under the rear hub in combination with only 4 downstop, and a C2.6 spring. This setting is way too difficult for me to drive, and thus, I prefer a downstop of 5, and C2.8 rear springs. The harder spring in the rear also helps to increase cornering speeds.
- More rear toe-gain (ARS) shims is another great option for how to improve stability. You may have noted from the team set-ups that top drivers use a range from 1 to 2mm of toe-gain shims. This is way too little for me, and I prefer 4mm to have more traction and easier car. The increased toe-gain on compression does just that – increases rear end stability.
- When the race started, and the track's traction was low, I preferred to use an Xtreme Twister bodyshell, but when the traction improved I changed to the ZooRacing Wolverine, to have better cornering speeds, which is very important in stock spec class. However, I mounted a Twister wing onto my Wolverine, which I prefer over the supplied wing, as it generates more traction (more downforce) and makes the car easier to drive.

I hope all these explanations above will help you to better understand the car, and what changes that needs to be done if you are struggling either with oversteer, traction rolling or simply the car being too loose.