Originally Posted by
vinnys
I have been following this thread cause I'm in the market for a pulley. I thought that Stainless steel was softer or more brittle than steel. I was told that you could not use a Stainless bolt in a high stress situation. SS bolts have around a grade three rating. Could a thin wall on a SS pulley, under stress, sheer like the one in the photo? Just a thought.
I'm not an expert in this area but I know there are many different "grades" of stainless steel. While stainless steel
IS generally softer than carbon steel, it is still much stronger than most grades of aluminum. Experience in the field has revealed that most (or possibly all) pulleys that have failed have been the aluminum pulleys. Also remember that the Karmen pulleys were designed using a smaller bearing (smaller than other reduced diameter pulley designs) allowing for a thicker wall between the outer bearing and the gooved area. I personally have no concern about the stainless steel grooved part on the Karmen 62mm pulleys ever breaking apart.