Lately ive noticed a lot of bows are made with larger idler wheels. What is the advantage of a larger idler wheel? To me it looks like it would decrease speed, and maybe even cause wobble. Can anybody explain it to me?

I believe it makes bow smoother when drawing back

Yea...thats the only thing i could think of too.

The size of the idler wheel has nothing to do with smoothness of draw. It's round. Think of a pulley and a rope- you wouldn't feel a difference if the pulley was 1" in diameter or 4".

Idler size can be dependent on the bottom cam. Cam design, tiller "equalness", and string lengths are the biggest factors to the size of the idler wheel.

Would this effect level nock travel? I also notice that is does effect smoothness of draw from one single cam to the next.

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Yes, to some extent...but then it falls right along the lines of what BF was stating....the cam and idler wheel need to be of equal diameter...and close to equal geometry in order for straight nock travel to be achieved.

Mathews was the first, that I can think of, to utilize the large idler with a post feed single cam. Several companies followed suit.

I would think that one could guess that since the cam needs to have more of a "rounded" shape in order to be of the same size and geometry of the idler wheel then a smooth draw might be the result.....but not in all cases.

It is my findings that Frank has the best explanation of the cause and effect of the larger idler wheel scenario. The nock travel does become much straighter and, in more recent examinations, like Hoyt's new dual track, more level. It would take a lot more examination to make an absolute statement pertaining to size and type.

thanks guys....I was petty much thinking the same thing. Just wanted some more input.

And here I thought it was just so manufactureres could advertise a shorter ATA length...