Draw curves for tuning the bow

by Pedro Ampuero

One thing I usually do for tuning the bows is using the draw curves to optimize the cycle.

The draw curve gives you information on how the cams are working, and how much energy the bow is accumulating in the draw process. Here is a quick example of a draw curve. It represents the draw force against the draw cycle. The stored energy is represented by the area below the curve, and it gives an idea on how much energy we will be giving to our arrow. The idea is to optimize that curve to make it smoother and to accumulate more energy in the process.

Here is the starting point of my PSE EVO. As you can see the curve can be improved by adjusting the timing of the cams. It can also give you an idea of moments during the draw cycle in which the cams timing is not right, and one cam is pulling in a different manner than the other one.

After playing a little with the cams, the draw curve turned to the following aspect. The bow has been lowered 8 pounds of draw weight and it is now developing more energy than before!. That can give you an idea on how important this tuning could be.

Finally the bow has been taken to the initial poundage, since the step before was just to show that the peak weight is just a factor of a more important equation, and that is more important to have the equipment properly tuned than the theoretical specs.

It is hard to explain this kind of things for me, but I just wanted to invite you all to do your own research. It worths! By the way, not any bow can give a stored energy of 106.5… The PSE EVO has the best results I have seen so far in relation to the stored energy.

Good luck in the mountains!

Pedro Ampuero


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s