"If it is aluminum then it will fail for sure as aluminum cannot take the strain of the belt over the areas not supported by the bearing, it gets brittle due to these stresses and breaks." -onehundred80 There is a lot of info about why they fail all over the forum. But then again, there are members who have good luck with them. It was mainly their 62mm pulley failing due to the size, so now EC's 62mm is made in steel. I still don't understand why they don't make their 65mm in steel. They never responded to me on why. I played it safe and just ordered this one:
This thread is about the dog bones, not the aluminum pulley itself. I have forecast the failure of these pulleys since the early days, I was pooh poohed often. The aluminum cannot take the stress from the rivets, this has been obvious since the Code 3 pulleys appeared. The rivets came loose in those and rattled.
One maker even admitted in so many words that the dog bones in his pulley were not springs and I contended that if they were not springs then they would not last long at all. The set up involved at least two adjustments to the shims because the dog bones would stretch and the clutch plate would not return to the stops. Using more shims puts the pulley more and more out of alignment to the rest of the pulleys.
I think all the springs from the North American ones are just machined from stainless steel. The OEM dog bones are punched from sheet metal, rounded off on the edges, heat treated and surface treated against rust. That is an expensive proposition if you are not making thousands. They are also thinner than the after market springs because the after market springs need the extra thickness to be strong enough.
These pulleys were expected to make money but not enough R and D was done on them, they were made with little thought given to the design. As I said in an earlier post here, if the clutch plate does not return to the stops then the dog bones are not springs and if they are not springs they will fail like the one in post one of this thread.
Originally Posted by
chuK_138
I have to agree with onehundred80 on the "spring" you have pictured. That piece of metal looks to be stainless steel with no sign of heat treatment. The guy from Poland advertises his springs are made from a super alloy....okay?!? Yet he doesn't mention anything else about what alloy is used or how they are stronger. I have a problem trusting that, but that's just me. Someone needs to step up to 7 series aluminum or go back to stainless steel so we don't get more posts like these every month. That's four EC 65mm pulleys done in the last month. They may not post about it here on the forum, but four units in a bit over a month seems like something EC should rectify.
No matter what the aluminum used it cannot take the stresses imposed by the dog bones as designed now, the rivet will slowly work its way loose and start rattling. If the flange on the pulley was thicker then it might stand a chance, maybe two times the rivet diameter with the use of a good aluminum alloy.