Built Bridge Problems

(Didn’t see any threads that already covered this)

So, Our team had Just finished a bridge to test on and we ran into a balance problem.

Our bridge’s center of balance is off and we cannot find out what is wrong.

We built the bridge according to the low expense blueprints, it’s made out of plywood, it can hold the required weight, but balance still off.

Has Anyone else had this problem? If so, how did you guys fix it?


A bridge built out wood and based on the drawings that FIRST gave us does not give you the proper balance and properties. You need to add weight to the ends to make it performance like the one used on the game fields [which are metal].

Ah, That explains it.


Our bridge is more sensitive to balance than the values given. So, this means we need to really calibrate our balance code to a finer level.

Good, we like it like that!

Interesting, Did you follow the same blueprints as we did?

Our bridge passes the battery test… but only with 140 LBS of weights on the bottom!!!

Just wondering, what did you use as the weights?

Hey guys,

Our bridge has a good center of balance, but it is too sensitive to tipping. Has anyone else had this problem? Does anybody have any ideas? ::rtm::


Plate weights, kind of like these: http://s00.wos.com.au/images/999760-5.jpg .

  • They are separated into 4 stacks, each with a 25lb weight and a 10lb weight.
  • Our machinist made shaft adapters with an od the matches the inside of each weight and an id, that matches a 1/2" bolt.
  • 4 bolts are somehow (I can’t remember) attached to the underside of the bridge.

We slide the adapters into the weights and the weights onto the bolts, then put a nut on the end and voila. This way the bridge is properly weighted, but we can easily remove the weights, so that we don’t have to carry a 200lb bridge everywhere.

Please read the thread, the answer is right in front of you.

Sorry, read this post earlier in the day and didn’t notice the new posts :yikes:

There’s already a good thread on this: