Weight distribution test on CR2

[flipside]

Hi all!

I recently joined the atomic carbon team to drive the CR2, and have been testing a lot with the weight placement in the car.

I believe that weight distribution is a very important and dominant factor, which can greatly improve handling of any car.

When building the car, and bringing it up to around 1600gr of total weight by adding lead plates under the lipo's, the rear wheels have about 61-62% of the total weight on them. Compared to other cars this is very low, resulting in a lot of steering, but also a loss of rear grip.

When you start adding weight to the front also, the weight % on the rear can even drop to about 60%, which is really insane :-)

Many people also complain about the losi's front end rolling and nose diving too much in turns. Adding weight to the front will only aid in doing this. I also believe weight up front makes steering slower. Compared to a B4, the front end of the CR is already quite heavy out of the box (thick plastic parts!!).

So I have been testing the car without any weight up front, and then tried to remove weight from under the lipo's and putting it more backwards. The ideal solution to do this would be to make the anti squat block in brass. This is not easy to produce, so instead I made the carbon fibre plate that sits under the gearbox in steel. Also made it wider and didn't make the big hole in the middle.

Here is a picture of this weight plate installed in the car. The thing weighs about 70gr.


I also left about 90gr of lead under the lipo's, cut to 2/3rd of the size of the lipo's and moved it to the back (against the steel plate). That brings my car up to +-1650gr depending on which tyres that are mounted.

All this brings the rear weight % to around 64,5%. Ideally 65% is believed to be the perfect balance for a 2WD, so that's pretty close.

I have been testing with and without this plate, and the effect is huge. The car is much more stable in high speed turns, or when you have to turn in hard after the straight for example. It also keeps the nose flatter while turning. To me it makes the steering much more consistent throughout the turn. It also improves handling on low grip sections significantly.

Last weekend I have raced with this part at the petit RC race. Had a part made for Steven (teammate in belgium) and he also confirmed how well this worked for him. He made a solid C final in his last qualifier, which is very good out of 130 drivers... There were very slippery sections and also on these the effect was huge.

I hope to test it asap on outdoor dirt tracks too. I have read people are using exotic setups to get some rear end grip, I really believe that simply using a good weight balance will give the required rear end grip, while being able to use normal oil, piston and spring combinations.

Interested in hearing people's thoughts on this :-) Will keep you posted with any new findings or improvements!

wouter