Monday, February 21, 2011

TCS HobbyPlex Omaha 2011

Just some notes from the first Tamiya race of the year:

I got a chance to run on the HobbyPlex Omaha track for their TCS race. The bite was very high, as they had used the same layout for a recent enduro race. Luckily, my home track is pretty high bite too, but this was even more so.

The biggest thing was being able to dial in the front end adjustments in actual competition. Some of the stuff I was doing was ok for practice or screwing around, but the need to put in consistent laps/runs more clearly defines your setup.

I found out I needed to keep the spacers under the ball studs for the upper arm in the 2-3mm range. .5mm is an adjustment step that can be felt on the track. I started with 2mm, went down to 1.5mm, and up to 2.5mm. 1.5mm was too much front grip with the amount of traction out there. 2mm was ok, but 2.5 had the best feel for a neutral, linear steering car. It started out with the same feel as it ended.

Similarly, I did try more height on the kingpin on the upper arm. I default to to the largest ride height spacer on top of the arm. I tried the medium spacer, so the upper arm has a bit more inclination/camber gain. This produced a bit more of a twitchy feeling, and I went back to the large spacer on top of the arm-less height at the kingpin.

To put it in a nutshell, the lower and flatter the upper arm, the more the car will have a linear steering feel, and will be easier to drive in higher traction conditions. This is important as you can then start varying the tire traction to gain the amount of steering you want without making the car hard to drive. I coated 1/3 of the front, but I may have been able to do more. I didn't want to experiment too much in the mains. I think that 3mm under the ball stud on the camber plate would let me run 1/2 or even more dope on the front tire. This is important as I could go faster if the car had more steering. I was able to go .1 sec faster on hot lap and also have more fast laps with my car in the second round of qualifying. However, the car was difficult to drive (this was with 1.5mm spacers on the camber plate ball stud). My average lap was better with the more neutral car, but i could feel that it was a tick slower. More steering would deliver better lap times.

The picture below will show the black groove condition of the track-->

Track Photo


  1. Hi, just wondering. I am currently running a 104 pro with 103W rears and type A 104 fronts.
    I have just purchased the flex deck and look forward to trying it this weekend. The issue I have with the car is the hook steering. It is mostly gone now but find on hard 180's it hooks under speed.

    Will raising the ball studs at the front like you have by a few mills help that.

    I run a stock shock oil with a stiffer spring.

    As well I just changed to a stiffer front black springs in the front to make it a little less divey..

    Thanks the site.

  2. Sorry i did not see this sooner.

    Try to run a soft rear spring, softer than stock. The spring set for Tamiya mini cars are good and the right length.

    Raising the ballstuds calms things down a lot, but remember to remove the 2 spacers under the camber plate and mount it right on the lower arm. That will get you the correct height. Also, the arm must be lowered at the steering knuckle as well. Otherwise you will get massive camber gain.