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[ronnyd]

When I we're a lad, sat in the back of dads van, we relied on gravity.

Oh yes, those were the days.  Luckily there wasn,t the amount of traffic/crap drivers there are today.

[Andy H]

Bending the loops was necessary as the fixing surface on car was tilted so loops would be pointing too much upwards when bolded in.

Bending angle is so small that I dont see risk of weakening the loops.

It depends on the grade of steel used. Chances are that Ford used a grade with good ductile characteristics and no harm done.

The problem that you might have is that safety equipment is normally inspected for signs of deformation and condemned if deformation is visible.

[Doctor Gollum]

And a 200 km/h impact is a head on on country road or spinning into the barrier on a motorway... Neither of which has ever happened... 

Not against the idea, just questioning the execution (no pun intended)

[mandula]

No pun taken, I get the questioning but when handling the actual product it could be noticed that there wont be any issues recarding to safety. Wich you cannot notice from pictures taken.

[Doctor Gollum]

The glare on the post bending picture makes it difficult to see much of anything, but the only way to be certain that bending the loops has had no effect would be to xray the piece before and after bending.

Still not sure that I would chance it with my kids

[mandula]

This is all very theoretic discussion going on here, but I don't believe Ford xrays those loops after bending them in shape before welding and they bend them 90 degs several times. But of course everyone handles this as they please, I see no safety issues here.

[Doctor Gollum]

This is all very theoretic discussion going on here, but I don't believe Ford xrays those loops after bending them in shape before welding and they bend them 90 degs several times. But of course everyone handles this as they please, I see no safety issues here.

Your own maths suggest that they won't survive a solid impact at speed...

It would be interesting to see what your insurers position is as well. They're your kids though...

[Kevin Wood]

Once the seat is secure enough to survive a collision that will impart more decelerative G force than the body can withstand it has done its job so no need to over think it .
Arguably, you might be better off with it leaving the vehicle like an ejector seat by then.
For practical purposes, that mod looks good enough and a favourable alternative to just using an adult seatbelt to secure the seat, from a perspective of both convenience and safety.

[mandula]

This is all very theoretic discussion going on here, but I don't believe Ford xrays those loops after bending them in shape before welding and they bend them 90 degs several times. But of course everyone handles this as they please, I see no safety issues here.

Your own maths suggest that they won't survive a solid impact at speed...

It would be interesting to see what your insurers position is as well. They're your kids though...

They would not survive even without modifications based on my math. Of course my maths do not know all the conditions and are very rough. Maybe lower speed would give some better perspective for outcome.

As said, they do the job and if they dont then I have made some serious overspeeding that my insurance would not like.

By the way, Im now more comfortable to put my kids to seats as they are now really attached to car. Once you isofix them, there is no going back.

[Doctor Gollum]

I hope you never find out. 

[mandula]

This is so intersesting case that I ordered one more isofix anchor for testing to hang test load from unmodified and from modified (bent) anchor loop to see is there any difference.

I have tractor I can use to lift and hang 1000 kg's load from each loop one at a time, this is same load that 33 kg child+seat (max load isofix should withstand) causes with g force of 60 (total of 2000 kg on two loops -> 2000 kg / 33 kg = 60,6).

So if one modified loop can withstand 1000 kg of load, two modified loops can withstand 2000 kg and that is far more g force than human body can withstand in crash.

Sorry that I used again actual numbers on internet forum  But just to get clear is there any difference between theory and practice.

[Andy H]

This is so intersesting case that I ordered one more isofix anchor for testing to hang test load from unmodified and from modified (bent) anchor loop to see is there any difference.

I have tractor I can use to lift and hang 1000 kg's load from each loop one at a time, this is same load that 33 kg child+seat (max load isofix should withstand) causes with g force of 60 (total of 2000 kg on two loops -> 2000 kg / 33 kg = 60,6).

So if one modified loop can withstand 1000 kg of load, two modified loops can withstand 2000 kg and that is far more g force than human body can withstand in crash.

Sorry that I used again actual numbers on internet forum  But just to get clear is there any difference between theory and practice.

Are you intending to test it until it breaks?

I would be interested to know what happens if you bend the loop to 45 degrees and then pull it straight with your tractor test rig.

I suspect that the grade of steel chosen should accommodate a lot of deformation before any cracking occurs but the danger zone will be near the welds as electric welding (mma/mig/tig) tends to cause hardening of the steel in proximity to the weld.

[Doctor Gollum]

If one loop breaks at 1,000kg, the so will the second. Also you are only measuring static load rather than a dynamic shock load such as an accident would produce. Besides it isn't just the loading from a frontal impact you need to consider

[mandula]

If I can get enough mass gathered, I'll try to get it break. Also it was on my mind to bent other loop even more after first test.

That static 1000 kg load is the dymanic shock load that peaks when 33 kg mass decelerates at 60 g's. . Based on constuction of isofix, all other directions where connection can move are "flexible"/jointed/hinged so most pulling force is caused to loops on frontal impact on car.

[mandula]

If I can get enough mass gathered, I'll try to get it break. Also it was on my mind to bent other loop even more after first test.

That static 1000 kg load is the dymanic shock load that peaks when 33 kg mass decelerates at 60 g's. . Based on constuction of isofix, all other directions where connection can move are "flexible"/jointed/hinged so most pulling force is caused to loops on frontal impact on car.

Sorry, meant to say "That static 1000 kg load on one loop is the dymanic shock load that peaks when 33 kg mass decelerates at 60 g's." So if one loop does not break when hanging 1000 kg on it, two loops can hold 2000 kg without breaking. But we will see.