Getting more weight on my roof rack?

[BlueStreak]

I am wanting to carry 2 river kayaks on my Vibe, which has Yakima Q-towers at the front, and low riders at the back on the factory rails.However, at 43lb a piece, that would be in excess of the (Yakima) specified 75lb max weight. I'm assuming the problem is in the rear, as the matrix has a 125lb specified weight, and it uses 4x Q-towers.I've also noticed that 75lb is also the rating for the factory crossbars - does nyone know if Yakima is being particuarly conservative with their specs? Or whether the weak point in the system is the the factory rails themselves?One thought I had was to remove the rails and just install an additional pair of Q-towers like a Matrix. From eyeballing it, the rail mounting shouldn't get in the way.Has anyone else done/looked at doing this?

[joatmon]

My guess is that there is adequate safety margin in the 75lb rating to carry the 86 lbs. However, if you do it and it results in damage or other catastrophe, I am exempt from liability

[Digger]

It is not only the weight that they consider. The size of the Item and the center of gravity for the car. Too much weight on top will make it top heavy. I think you are safe as far as the kayaks. Just watch out for the Sharp turns since it might make it a bit top heavy.