as for rope, you have several options.
a standard 6mm pull rope is good for around 5-700 lbs of break strength.
you can use boat anchor line as your pull rope, and that will get you into the 8-900 lb range.
then you get into my field of employment. tree trimmer
this line will get you 1650 lbs of break strength. https://www.knotandrope.com/store/pc...m#.UOHP3XfyhOY
i currently have a 5mm line as my pull rope that's good for a tad over 5000 lbs. this is what i use. https://www.knotandrope.com/store/pc...m#.UOHS0HfyhOY
friend that has climbed for well over 30 years, has used a different version of my rope in his sled for since '78. he buys a new sled, he just moves the rope to the new one.
its the sliding in the tube that goes over your brakes, that wears them out, and causes them to break. any pull rope out there, is not designed for that kind of friction. topped with the fact that your never pulling straight out the end of the tube, always sideways add lots additional friction.
also, if you look at the pull rope you had. it had the black diamonds. that is a lower quality, than the red. in reality, when looking for a rope, your looking for a jacketed rope. the jacket will at the least, make the rope last 6x longer.
also, when the diamonds wear out, and the rope looks all the same color, it's wore out, replace it.
for you guys that get a pull rope all the same color. when it starts to look fuzzy those are strands that are breaking. you would be suprised how few broken strands it takes, to lose well over half the available strength of the rope.
and if the sled was running, when the recoil rope broke, when it whipped in there, it probably got snagged on a little burr, and then because the sled was running, unwound itself, wrapped itself up, and caused itself to explode.
i had a chainsaw do the exact same thing yours did. mine broke about 3 inches from the handle, and wound itself up, and exploded the recoil case off the side of the saw.
your case is more stout than mine was. it contained everything.
also as a side note. if when you pull the rope, and you pull it all the way till it stops, that will cut the life of the rope in half. when you stop pulling, you need more rope that you could have pulled, if that makes sense. i wont get into it, it involves dynamic vs static pull on a rope. it's kinda involved.