Ya, sure do Flyer,

There will be pulleys available very shortly, a lot cheaper than what's currently available, and in many sizes.
In the next couple of weeks, I'll have them available. They are being cut as we type.

thanks for asking,

allen

 

Sweet! I'll be in touch.

 

Here's the deal. The stock Radix pulley, as well as others pulleys on our trucks (crank? water pump?) are ridged, but on top, the ridges are flat, whereas the Pulley Boys ridges are pointed. I'll try to illustrate this difference here in ASCII:

Stock pulley ridges (facing down): \_/\_/\_/

Pulley Boys pulley ridges (facing down): \/\/\/

Now, the spacing between the ridges is the same between the two different pulleys (correct distance), but I couldn't accurately illustrate that fact here. It is the way the ridges are formed on top that is the critical difference, and there is a definite difference between the two types of pulleys.

The recessions in the belt match up perfectly to the stock pulley ridges, so it is obvioius that Pulley Boys made design or manufacturing compromises, or perhaps an error. Whether or not this difference translates into decreased performance, belt slippage, or increased/accelerated belt wear is unknown to me. I would think that slippage would occur sooner with the Pulley Boys pulley than with a better designed pulley, once the belt becomes worn a little.

Like I said in my email to you Allen, I hope you gave your new vendor samples of the stock Radix pulley and not just the Pulley Boys pulley.

 

I inspected another stock pulley I have laying around here. The ridges were pointed on the stock one. There were no flat spots on the belt surface.

Allen said that the pulley was on backwards causing the belt to not be straight. That would definantly cause a belt to wear at a faster rate. That turned out to be the cause of the belt problems too.

 

umm speed engineering doesnt sale radix pulleys????

 

Which pulley are you looking at - a stock Radix pulley, or a stock pulley from somewhere else on the motor (crank, water pump, etc.)?

So perhaps this is not a big deal - the ridges being pointed - but there is definitely an extreme difference in the two pulleys I am looking at - the ridges on the one pulley are at least 3 times wider than the ridges on the Pulley Boys pulley. It's hard to believe this would not affect performance, but perhaps it doesn't.

 

of course it will, less total surface contact area, unless there is some really huge benefit to the teeth not lined up, why even have teeth then?

 

I understand what you're saying NakedAV, I have many stock, magnacharger, pulleys laying around and they all look very close to the pulley boys pulleys I have, maybe magnacharger changed their design. Just a thought. If your pulley has flat surfaces and others don't, that might explain it. If you take a new belt and bend it to where where the ribs are facing outwards, and press it up against the pulley ribs, both pulleys match up just fine. Like anything, I guess there could be some variance when the pulleys are made.

later,

allen

 

Maybe your pulley was built on a Friday afternoon?

Seriously though, I think there could've been a design change like Allen said. Maybe Blown will chime in with some insight.

I doubt Pulley Boys or Magnacharger's CNC messed up. That's hard to do, at least when you're doing mass produciton runs.

A more pointed ridge on the pulley might increase belt wear, but on the other hand, the normal force (which is proportional to the force of friction) is increased on the pointed ridges. This could be the reason why this is so. I have never seen either pulley, but this is just a thought.

 

As soon as I can figure out how to get my digital camera to take close-up pictures, I'll try and get some snaps.