shoot thru rest question

[rml127]

In my never-ending quest for bowtuning knowledge and the best arrow flight I thought of a question last night. I have a golden key shoot thru rest. It has a knob on the side to adjust the spring tension on the prong rests. It makes them harder or easier to push down. I just realized that in 5 years of bowhunting that I have no idea why that spring tention is there and why it's adjustable. What does it do and when would I want to adjust spring tension up or down? Thanks!

[Jim Pruitte]

What it comes down to, is that the spring (set up correctly) will help to correct inconsistancies within our set up. In other words, a bad release, possibly inconsistant hand pressure, a nick on the shaft, a feather touching the launcher... see what I'm getting at?
To set it up correctly, you want just enough spring tension so that the launcher will support the shaft (not sagging) when an arrow is nocked and sitting in the braced position. This is the best place to start, but during tuning, you may find you need to tweek the spring tension some.

I hope this helps.

[CapstoneME]

rml127,

That's an excellent question. The consensus is often stated, "just enough spring tension to bring the arrow all the way back up, after pushing it down". However, I've never seen that in print from any rest manufacturer. In fact, I don't recall ever seeing ANY instructions on setting spring tension. Most everything you read and hear are people's opinions.

I can't disprove anything that Jim said, but I don't think he can prove them either. I do know that even a slight change in arrow tip height at the rest makes a pretty significant change in impact downrange. So, if the rest "flexes" on bad shots, I would argue that those shots are still going to be way off the mark.

I believe that the spring adjustment is there simply to allow the rest to be knocked out of the way when struck by a departing arrow. The "fine tune" comes in because you want a) the rest to swing away with zero resistance (ideally) if hit, so you set the spring as weak as possible and b) the rest to hold the arrow at the exact same point on every shot, so you set the spring with enough tension that it raises the arrow to a solid stop every time. If you don't have enough tension, the rest doesn't provide a repeatable nocking height. If you have too much tension, the arrow ends up being deflected as it leaves the bow.

As nice as it sounds, I don't think the spring is supposed to "smooth out" the departure. I don't think that would be repeatable enough to produce consistency.

Also, even if the tension is very low, if the arrow or fletching contact the rest, it will have an adverse effect. There is some force there that is resisting the way your arrow wants to go. That's what sold me on a drop-away style rest. I can shoot any arrow and not worry about clearance issues. Also, there's no worry about the rest performing some "magic" during the shot. If I've got flight problems, I KNOW that it's not the rest.

Not much "fact" there, I know, but at least you have another opinion to consider.

[IMN23D]

Bodoodle Pro-Lite instructions say to set the tension so the arrow will "sag" while nocked and at rest, and "no sag" while at full draw.

[rml127]

Thanks for the help. I would be curious to see what happens to the rest during a slow motion video. I have heard that it is pushed down but I don't think it would shoot consistently if this were the case. Mine is set fairly tight, I may try to loosen it a bit to see what happens.