Vauxhall Insignia Owner's Manual page 72

Storage 71
■ Driving with a roof load increases
the sensitivity of the vehicle to
cross-winds and has a detrimental
effect on vehicle handling due to
the vehicle's higher centre of
gravity. Distribute the load evenly
and secure it properly with retaining
straps. Adjust the tyre pressure and
vehicle speed according to the load
conditions. Check and retighten the
straps frequently.
The permissible roof load is 100 kg.
The roof load is the combined
weight of the roof rack and the load.