Originally Posted by
redbones
I was wondering what the effects are of having longer rear arms (MP9, D815) vs a short one (MBX7, RC8B3). I'm assuming is has something to do with roll resistance... Need some techy guys here
Its not totally in the arm length. You have the hinge point of where the rear arm attaches to the chassis, how and where the hub carrier attachest to the arm and the length of the hub itself.
If you start moving pivot points around, you start changing roll centers, travel speeds and arcs...
Most buggies and trucks today are very similar in their demensions. Some , like you listed, use shorter or longer arms and compensate by using a longer or shorter hub and hub carrier.
A longer arm has to move at a faster speed to cover the same distance a shorter on does. But it allows the suspension to be used more finely thru the travel range. A shorter one doe the opposite. If you were to use a Kyosho shock ( set up with the kit settings) and attach it to a Losi, it would feel very stiff and over dampened. If you used a Losi on a Kyosho, it would feel soft and under dampened. Even though both shocks are close to each other in size and length, they are designed to work with their different vehicles because of the different designs.
Make sense...