Roof load is limited to 75kg including roof rack system according to the manual. Obviously it's a safety reason behind this limitation but I want to know which one exactly.

 

Do you think is limited to only 75kg because:

1. The car will become too unstable when cornering due to the higher center of gravity

2. The roof won't hold much more -> (hard to believe because of number of reasons)

 

Can't think of anything else. I'm only asking because with a roof box and two bikes up there I am quickly at the limit so if something like cornering instability is the main reason it's not a big problem if I go over it a bit. Octavia is quite a lightweight car and usually heavier cars have at least 100kg of permissible roof load.

 

What is your opinion? 

I think it's most likely that the roof rails/roof bar restraint systems is the weakest link. Think about how they are actually attached. They would likely be at their safe working limit at around 75kg if then subjected to emergency braking or other forces present in an accident.

I would hope the roof could actually support the weight of the car, if you ever happen to find yourself inverted.

I would hope the roof could actually support the weight of the car, if you ever happen to find yourself inverted.

 

My thoughts exactly.

Roof load is limited to 75kg including roof rack system according to the manual. Obviously it's a safety reason behind this limitation but I want to know which one exactly.

 

Do you think is limited to only 75kg because:

1. The car will become too unstable when cornering due to the higher center of gravity

2. The roof won't hold much more -> (hard to believe because of number of reasons)

 

Can't think of anything else. I'm only asking because with a roof box and two bikes up there I am quickly at the limit so if something like cornering instability is the main reason it's not a big problem if I go over it a bit. Octavia is quite a lightweight car and usually heavier cars have at least 100kg of permissible roof load.

 

What is your opinion? 

 

I suspect it is more likely to be the stress on the roof bar mounting points that limit the overall load.

 

You don't want the mountings to break in an emergency stop or sudden change of direction.

Whatever it is I'm sure there is a safety margin just want to know how big it is - 5, 10, 20%? More? Probably a question which won't be answered.

My mate has had 120kg of steel fence on his 2012 Polo (similar 75kg limit).  It didn't seem any worse after a 75km trip but he did crash / emergency brake / hit big potholes either.

I seem to remember Top Gear landing a 600kg helicopter on a platform weighting 100kg itself mounted on the roof of a Skoda Yeti. I would imagine that the yeti has a similar weight restriction to the Octavia. 

I would imagine the weakest part is how it's clamped on the roof. I would also guess that yes you can load the roof box with much more than 75kg (total weight) but by doing so would probably invalidate a warranty of insurance or anything else they chose to try and get out off!

 

I once had a whole garden furniture set on the roof of my fabia mk1 vRS, probably weighed over the 75kgs for sure. 1 Metal and wood table and 6 chairs!

The roof itself has to be able to support the whole car, otherwise it doesn't pass the safety standards in the EU and can't be sold here. 75 kg is a weight that the rack mounts are guaranteed to withstand in everyday driving conditions, including emergency braking and even some smaller collisions. It's possible to overload the rack without breaking anything but not recommended.

I seem to remember Top Gear landing a 600kg helicopter on a platform weighting 100kg itself mounted on the roof of a Skoda Yeti. I would imagine that the yeti has a similar weight restriction to the Octavia. 

 

I would also imagine that Yeti wasn't standard.

It seems as well the max load for most of roof top cases is 75kg.

Just more easy for everybody.

Why would they bother warrantying you on exotic loads?...

Edited 22 July, 201510 yr by JPH0091

The roof bars are not as good as the ones were on my old Passat which had three mount points instead of just one at each end. Those took 4 sheets of 18mm ply quite happily over a short distance, the even distribution of the load probably helped. Don't think I'd want to put as much on the roof of the Octavia although I've had 6 3metre lengths of 40mm thick wall box section on it.

I must confess I never checked the Max roof load in the manual Pretty stupid of me really :-S

Roofs are very weak in reality & do not full support the weight of the car in a crash situation as there is no rule for this. The Top gear stunt which someone says was 600kg helicopter & 100kg platform is 700kg total, a Yeti starts at 1259kg & goes up from there!

 

I wrote of a previous car (VW Polo) at 33mph by turning the car on it's roof & it landing on the spot above my head. The roof line on my side was straight from the bottom of the windscreen to the top rear most corner of the roof where the drivers door joins it. & those cars got very high NCAP marks!

 

Please remember that if your car lands on its roof it has to support the total weight of the car, everything inside it & the added bonus of the force created from the speed of the car as it hits the ground after it fly's through the air & lands on the roof. This is why all rally/race cars have "roll hoops" as a minimum specification, & work up to full FIA cages depending on race series etc.

Glad you've reminded me of that, I won't worry too much about over packing the roof box by a couple of kg anymore

(Helicopter Roof @ 5 mins in)

Sent from my iPhone using Tapatalk