Spine too stiff?

[Jon_G]

on Victory’s website it shows the 235 spine to be 11.1 GPI. I’ll attach it below, I used that and the FOC calculator on podium archery

11.1 GPI x 27 (arrow length) = 299.7
+ 100 (broadhead)
+50 (insert)
+18 (3 vanes)
+6 (Nock)

Total weight is 473.7

Great thank you. I was doing the math with 300s. I didn't realize you got to that weight with 235s. I am trying to go 4mm arrows as well but I think my arrow will be much too light if I keep the 100 grain BH's and the 55 grain inserts. That will put me at 403 grains. My current setup is at 425 which I am comfortable shooting an elk with. Not sure if 403 is much too light. I don't want to have to buy new 75 grain inserts lol

 

[Tupp]

Great thank you. I was doing the math with 300s. I didn't realize you got to that weight with 235s. I am trying to go 4mm arrows as well but I think my arrow will be much too light if I keep the 100 grain BH's and the 55 grain inserts. That will put me at 403 grains. My current setup is at 425 which I am comfortable shooting an elk with. Not sure if 403 is much too light. I don't want to have to buy new 75 grain inserts lol

I’d say play around with the podium archery calculators a bit, but I’ve been looking to utilize heavier arrows, which is another reason I went with the stiffer spine.
Not a fan of using wraps, when shooting, clipping a vane off or cutting the wrap I’d have to refletch the whole thing

 

[Jon_G]

I’d say play around with the podium archery calculators a bit, but I’ve been looking to utilize heavier arrows, which is another reason I went with the stiffer spine.
Not a fan of using wraps, when shooting, clipping a vane off or cutting the wrap I’d have to refletch the whole thing

I think I may just keep my current arrows which are the RIP tko's. Nothing wrong with them but I wanted to play around with something different just to tinker. I don't want to have to buy new components that don't already come with the arrows since the arrows themselves are not cheap

 

[Beendare]

The only people I’ve heard mention weaker being more forgiving is Dudley, and Levi. When Duds was doing all his ladder testing Hoyt had some of the worst nock travel available. Levi has only made the reference when referring to 3D. I think it takes that level of archer to notice. Even then people like Tim will say that there is no such thing as too stiff. I certainly have never seen it. Even with extreme circumstances.

Great comment Zac

I too have never seen overspined being an issue- but I am a minute of angle bowhunter.

.I can see where a pro like Levi will test and test different arrow configurations to get slightly better groups at 50y with FPs for 3d. I know another shooter that shot multiple 300 rounds at Vegas telling me he got 1 point per round better with a detuned arrow.

I think the point for the rest of us bowhunters concerned more with BH accuracy in the field on critters is; KISS. This is probably why every experienced bowhunter I know shoots slightly over spined arrows.

 

[Artemis]

my 2 cents if possible, buy 1 of each fletch em up and see how they tune. Shoot some broadheads down range and see what flies better. In my expericence if in between spines I go with the stiffer side as I have had fewer tuning issues. You can optimize weight/foc with different compenants and point weights. Just my experience, not a bow technician so take it with a grain salt.

 

[WSMHNTR]

Looking at several charts you're on the line with a 300 being too weak. I've always leaned towards a stiffer arrow myself and think you'll have better results over spined than under. Another option would be to add a wrap to the rear and it will help a little but not drastic. It will almost negate the added weight of the heavier insert.

 

[doc holiday13]

In a centershot compound, you can't get too stiff.

This. I

 

[Billy Goat]

I think what gets lost in the spine conversation is weight. A lot of times in stiffer spine, it's a heavier shaft. For me, at a point, heavier gets less forgiving.


I have currently same shafts, cut same, fletched same, same point weight, one is 400 "optimum " and the 300 is way stiff. 34 grs difference between them iirc.
Shooting fita rounds, my scores aren't changing but what I'd expect day to day.

 

[nphunter]

I find that I shoot more consistently accurate at with arrows that are on the weak side. I don’t notice any difference at close range but notice them to be much more forgiving at long range and they tend to group better more often.
I’ve shot very stiff, stiff and weak. I feel like the calculators aren’t taking into consideration the amount of shaft we glue shut and keep from bending. Using HIT’s or even long glue in points we are essentially taking all of the flex out of the first 2-3” of the shaft.
All of the spine calculators show me weak but the arrows fly absolutely amazing, the last time I shot an overly weak arrow I had the same results.

Here is my arrrow.



Here is my setup if I account for the 2” being glued stiff up front.

 

[Jon_G]

I find that I shoot more consistently accurate at with arrows that are on the weak side. I don’t notice any difference at close range but notice them to be much more forgiving at long range and they tend to group better more often.
I’ve shot very stiff, stiff and weak. I feel like the calculators aren’t taking into consideration the amount of shaft we glue shut and keep from bending. Using HIT’s or even long glue in points we are essentially taking all of the flex out of the first 2-3” of the shaft.
All of the spine calculators show me weak but the arrows fly absolutely amazing, the last time I shot an overly weak arrow I had the same results.

Here is my arrrow.
View attachment 709905


Here is my setup if I account for the 2” being glued stiff up front.
View attachment 709907

Damn. Very well put man.

 

[Tupp]

Looking at several charts you're on the line with a 300 being too weak. I've always leaned towards a stiffer arrow myself and think you'll have better results over spined than under. Another option would be to add a wrap to the rear and it will help a little but not drastic. It will almost negate the added weight of the heavier insert.

Yea that’s where I was at too, I’ve noticed numerous charts showing I’ll be ok with 300 and others showing 300 being too weak.

Using the podium archery .166 outserts, only the first inch is glued into the shaft.

Waiting for the field points to arrive and test.

 

[rlsmith1]

qSpine/OT2Go says 150 gr on the front + 30 gr on the rear of a 27" 300 spine shaft would be slightly weak of "optimal." I think you would be fine with a 300, but a little stiffer wouldn't hurt either.

Bow inputs: 348 fps IBO, 80# DW, 28.5" DL, 29.5" ATA, 6" BH, 85% LO
View attachment 709149

Can you run the following for me please? Lift 33 set to 75# 30.5”DL @85% let off. 30” Pierce 250, TAC wrap, 4 fletch TAC 2.75” drivers, 20gr HIT, 25gr collar and 135gr head. Going 285fps (to match the IBO input). Not sure if I’m in line or weak, guessing weak based on broadhead flight.

I’ve never worried about being overspined only under.

I’ve been tuning with big fixed blades with only that in mind for 20+ years and it has never failed

How fast is your arrow going and how far do you shoot your broadheads? I’m having a hard time getting consistency past 50y with a 285fps arrow mentioned above

 

[Bump79]

Can you run the following for me please? Lift 33 set to 75# 30.5”DL @85% let off. 30” Pierce 250, TAC wrap, 4 fletch TAC 2.75” drivers, 20gr HIT, 25gr collar and 135gr head. Going 285fps (to match the IBO input). Not sure if I’m in line or weak, guessing weak based on broadhead flight.

How fast is your arrow going and how far do you shoot your broadheads? I’m having a hard time getting consistency past 50y with a 285fps arrow mentioned above

If you're underspined, it's only slight. The Syndercore system will stiffen that arrow some as well since it's deep within the shaft.

What exactly are your consistency issues?

 

[rlsmith1]

That's what I was thinking about the Snyder core and everything I've read is I'd rather be slightly stiff with a fixed head.

Inconsistency is left / right impacts at distance when I don't have an issue with field points (broken nocks at 50y and 75y this week).

Wondering how much wind hits a broadhead like the Iron Will? I notice left and right variation with wind at 80y+ but maybe it's just 50y+ with a broadhead? Waiting for a calm day here in Iowa take patience this time of year!

 

[Bump79]

That's what I was thinking about the Snyder core and everything I've read is I'd rather be slightly stiff with a fixed head.

Inconsistency is left / right impacts at distance when I don't have an issue with field points (broken nocks at 50y and 75y this week).

Wondering how much wind hits a broadhead like the Iron Will? I notice left and right variation with wind at 80y+ but maybe it's just 50y+ with a broadhead? Waiting for a calm day here in Iowa take patience this time of year!

Left right variances can be a lot of things. Broadhead flight at 50 yds with fixed blades is tricky.

You're either perfectly spined or ever so slightly stiff. A 200 spine would be great but I don't think it's you're problem. I'd suspect form, axis adjustments or tune issues before spine.

 

[rlsmith1]

Left right variances can be a lot of things. Broadhead flight at 50 yds with fixed blades is tricky.

You're either perfectly spined or ever so slightly stiff. A 200 spine would be great but I don't think it's you're problem. I'd suspect form, axis adjustments or tune issues before spine.

Much better consistency today with almost no wind (<5mph) so I think that was part of it. Elevation was generally spot on.

I've noticed wind deflection at 80yds+ with field points and I guess a broadhead just means wind starts to impact everything sooner. Really appreciate the feedback, wanted to make sure it wasn't a me issue before tearing everything apart!

 

[Lipka101]

Ive found no issues with being overspined but have had problems being underspined, when in doubt go stiffer. With your specs you would likely be fine at 300 but I don't think it would hurt to go 250 unless you there is a significant GPI difference on that particular arrow between the two spine and it brought the TAW higher than you want

 

[rlsmith1]

2 field points and a broadhead (single arrow in 6” spot) at 103y. Had to hold 1 pin right for points and 2 pins right for BH due to crosswind. Think I’m figuring it out, and it was probably wind induced!

 

[Tupp]

To report back, the arrows fly real well. Still kind of wondering if it would even be worth getting the RIP TKO’s in a 250 spine over the VAP TKO’s at 235, but it’s hard to think they’d fly much better if at all.

Below is one of my last groups at 70.
They performed real well at TAC OK too.

 

[4th_point]

Glad you got it dialed and thanks for posting a follow up!

For future readers:

The spine charts and calculators are just a reference.

Static spine is determined by hanging a weight and measuring the deflection.

You'll only know what is best by experimenting not just picking a static spine value.

When you try different shafts and arrow configurations, you really care most about the dynamic spine. That's not easily quantified, but you just need to shoot to see the results!

If there were no such thing as an arrow being too stiff, we'd all be shooting the same shafts right? That's obviously not the case.

Someone mentioned Dudley and Levi saying that a weak spine is more forgiving. But there are other pro archers who say the same. More specifically, that stiff arrows shoot better for shorter range matches and weaker arrows shoot better at distance.

The pros are super anal about their arrows. Supposedly Gillingham especially. That alone speaks volumes.

Rather than weak or stiff, we should strive for the best arrow for the person shooting the bow. It will have the correct dynamic spine, regardless if it matches some static spine chart or what someone else uses.