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Carrot failure @ Muline 20-Nov-2013 At 9:38:51 PM nmonteith

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On 20/11/2013 sliamese wrote:
>>That is what I in fact did - I responded to sliameses 'dont use tru-bolts'
>
>tru-bolts are totally bomber, just a pain in the arse to replace when
>it needs doing. given your experience climbing you would have seen the
>crags in europe that have 2 or generations of bolts that all have their
>own hole, all looking ugly! just saying think about those in the future.

PLEASE don't consider using these in the Grampians. You may think the Grampians rock is super bomber, but it is not. It has a softer core, especially in the Stapylton area - Tapian included. Myself and others used try-bolts for a few years at several crags and they all began loosening after a year or so. They won't fail, but they will wobble around and creep out bit by bit. They required constant tightening and eventual replacement. Amnesty Wall had particular problems due to very soft inner rock. Tru-bolts should only be used in very very hard rock - good volcanics.

They also have a bad habit of jamming when installing if the hole isn't exactly 10mm in diameter. A jammed bolt is then stuck half out of the rock, or even worse turns into a spinner - not matter how much you try and tighten it the whole bolt just spins in the hole. I reckon this happened about 1 in 10 tru-bolts we placed. You can't remove these jammed bolts so they need to be cut off, hammered in, then patched. Ugly.

On routes that don't get much traffic, or falls are not common (ie multi-pitch routes) tru-bolte will just require a tighten every few years - but at sport crags or popular routes this tightening is almost a daily annoyance.

Dyna-bolts work much better in the softer Grampians rock, and are easier to replace. BUT on steeper routes with high traffic even these get loose.

Regarding over-tightening. Although I don't use a torque wrench at the crag - I have used one at home to get a 'feel' for the correct amount of tightening required. Generally with 12mm dyna-bolts a good 'guide' is to use a spanner about 20cm long and tighten to max load with one arm. I've never been able to snap off the head of a 12mm dynabolt using this method. However in the smaller 10mm dynabolts (commonly used in the 90s) I have snapped the head off several by over-tightening in my early years.