Get The Sandwiches Ready - GSA Rear Wheel Collapse

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Just a thought... :rolleyes:

The owner said he replaced the brake pads with new ones, but didn't remove the caliper to do it.

In the Hayes BMW R1200GS(A) manual is suggests you remove the caliper (after pad removal) so that you can clean the pistons and push the pistons back, so that enough space is created to fit new pads.

If you don't remove the caliper from its mount, how did the owner push back the pistons with the caliper in situ, so that new pads could be fitted?

Knowing the alloy caliper mount is like cheese, and knowing the caliper bolts were steel and fully torqued up (in situ), could there be a case of lug fracture due to torsional twisting or flexing of the caliper (being heavy handed) while attempting to force the pistons back with the caliper in situ.

The pistons may have more resistance if there is pressure in the system or the brake reservoir wasn't unscrewed to allow the fluid to rise (or had been recently topped up)

If you were being heavy handed and were forcing the caliper in this way, would this leverage fracture the lugs or bolt mounts?

Or create a misaligned fitting which would be pulled and pushed each time the brakes are applied (like bending a spoon back and forth until it breaks).
 
Warlord said:
Just a thought... :rolleyes:

The owner said he replaced the brake pads with new ones, but didn't remove the caliper to do it.

In the Hayes BMW R1200GS(A) manual is suggests you remove the caliper (after pad removal) so that you can clean the pistons and push the pistons back, so that enough space is created to fit new pads.

If you don't remove the caliper from its mount, how did the owner push back the pistons with the caliper in situ, so that new pads could be fitted?

Knowing the alloy caliper mount is like cheese, and knowing the caliper bolts were steel and fully torqued up (in situ), could there be a case of lug fracture due to torsional twisting or flexing of the caliper (being heavy handed) while attempting to force the pistons back with the caliper in situ.

The pistons may have more resistance if there is pressure in the system or the brake reservoir wasn't unscrewed to allow the fluid to rise (or had been recently topped up)

If you were being heavy handed and were forcing the caliper in this way, would this leverage fracture the lugs or bolt mounts?

Or create a misaligned fitting which would be pulled and pushed each time the brakes are applied (like bending a spoon back and forth until it breaks).
Click to expand...

The Haynes manual is not always correct. The actual BMW notes on how to change the pads, is to lightly push the caliper (can use your foot), this will push the floating calliper in towards the disc and push the pistons back. You do not have to remove the caliper, whatever Haynes thinks you do. The only time you need to remove the caliper is if the pins are corroded and the caliper doesn't slide, therefore remove caliper, strip and clean.
 
Warlord said:
I was just looking at the pictures again, and somethings missing.

Where's the rear Mud Guard? All the mounting points have no bolts, and the mud guard is completely missing?

Why?
Click to expand...

But the giveaway is the bolt still holding on, that means the caliper has snapped off otherwise that bolt would be gone, if both the bolts worked loose and fell out, looks like one fell out and when the OP braked as it looked like in the video, that caused the caliper to snap off, as was weakened by only having one bolt holding it.
 
I've read much of this thread in a number of visits, but there's too many posts not to have missed a few. Have we established that the loose caliper was the cause of the wheel collapse rather than the wheel collapse also took out the caliper?
 
Sea Dog said:
I've read much of this thread in a number of visits, but there's too many posts not to have missed a few. Have we established that the loose caliper was the cause of the wheel collapse rather than the wheel collapse also took out the caliper?
Click to expand...

Interesting point

We asked BMW if the spoked rims are as strong as the previous model and they are adamant they are and dismiss claims that a new designed rim is on its way. However, they do agree the rims may be more vulnerable to impact because of the lower profile and softer construction of the tyres.

https://motorbikewriter.com/advice-riders-new-bmw-r-1200-gs/
 
fredaroony said:
I guess they all know better than BMW but are usually the ones whinging about faulty parts when they fuck it up themselves.
Click to expand...

Mine, from the BMW dealer, had copaslip all over the caliper bolts.
 
fredaroony said:
You even have complete idiots taking the one use only bolts off just to check them?!?!?!?!?!
Click to expand...

That'll be me then - glad I did as the bolts had copaslip all over the threads....

Of course when the bike was produced the bolts were not micro-encapsulated (and single use), that came later.
 
All bolts work by friction so copaslip ain’t a good idea in general.
 
Sea Dog said:
Have we established that the loose caliper was the cause of the wheel collapse rather than the wheel collapse also took out the caliper?
Click to expand...
This is the equivalent of the UKGSer air crash investigation team : nothing established , lots of guesswork from enthusiastic , but concerned, amateurs . Yes , wheel collapse could be the cause and the caliper may be the casualty. The answer must be there under forensic examination ,
From what I see, the spokes are mostly all severed , neatly at their mid points . I don’t know what that indicates .
 
Mr Bean said:
That'll be me then - glad I did as the bolts had copaslip all over the threads....

Of course when the bike was produced the bolts were not micro-encapsulated (and single use), that came later.
Click to expand...

Your logic makes zero sense then. Now if you said you were going to replace the bolts with new ones because you wanted to be sure...that would make sense. Knowingly reusing ONE USE ONLY BOLTS just to check them makes zero sense

So your bolts are different than other bolts on the same bike?

I just checked the service manual for the first run LQ bikes and the part lists...using the same one use only bolts
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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