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REAR DOOR FAILURE

Re: REAR DOOR FAILURE

Postby Peter Connan » 10 Jan 2017 15:24

There is a huge weight difference between a tough tire (BF or Cooper, 3-ply sidewall and about 18mm deep tread) and a more normal AT like the Bridgestones 694.

I think the BF's can be almost double the weight of a same-size street tire.
Mag ons ons kenniskry met lekkerkry aanhoukry.
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Re: REAR DOOR FAILURE

Postby Picasso » 10 Jan 2017 15:31

Hi Cedric

I think the weight difference Matt is referring to is about 10 kg (285 BFG Mud vs 275 Joko AT), plus one needs to consider the leverage effect (mounting point wheel / hinge).

The wear on the hinges you can only really see / feel if the hinge is completely detached from the door.

The conclusion in my particular case:
I would assume that the previous owner of my vehicle might have used the RH barn door more frequently than other people would normally do.

Therefore the hinges were exposed to more ware than normal (in my case I did not have an over-sized / heavier tyre). This ware on the hinges caused the door to sag over time whereas there was no adjustment done to compensate for this ware. This caused additional stress on the door-frame (while closing the door) and combined with the poor design of the reinforcement piece caused metal fatigue on the top edge of the reinforcement plate. :eureka:
Last edited by Picasso on 10 Jan 2017 15:46, edited 1 time in total.
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Re: REAR DOOR FAILURE

Postby ricster » 10 Jan 2017 15:39

I didn't realize the weight difference was as much as 10kg.

Wear on the hinges makes sense though.... thanks for the info!!! :thumbup: :thumbup:
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Re: REAR DOOR FAILURE

Postby jonathan » 10 Jan 2017 15:41

Picasso wrote:

To Jonathan

I think that the "bending force" / i.e. load on this specific area which causes this kind of crack / metal fatigue mainly occurs during the closing process of the door. When the door is closed there should be very little force on this areas as everything is locked and held in place.

This bending force during the closing process will be even bigger if the door is sagging / not properly aligned.
If the door is misaligned you have virtually a double impact.

The more you open and close the right hand side the more wear on the hinges.
You could also say that the increased weight of a bigger tyre will have an effect on the wear of the hinges.

So.. I think it is important that the alignment of all components of the barn-door assembly is as good as possible in the first place to avoid premature fatigue failure.
At the bottom of your RH barn-door you have a horizontal striker (round bolt) .
This striker slips into a tapered guide mounted on the vehicle side.
Make sure that both components are aligned perfectly.

:thumbup:


This is quite possible, but I have a feeling the damage was done in the time before I had the vehicle. It was serviced by Graham a couple of times before I bought it and on one of the job lists I saw he had his hands on the rear door. So it probably was not so lekker, which he then sorted. Perhaps the metal was almost at cracking point and the increased weight and force of closing the door, it just couldn't handle it anymore, I don't now :think: . Either way it's busted and needs a fix!

Peter is right, I recall my disbelief in the weight difference when loading and unloading the old and new tires. The 285's are moerova heavy!
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