Hello to all, could somebody please help me figure out the draw on set of TradTech Black Max 2.0 45 lb Long limbs using an ILF 21" riser?

[Old Geezer]

I think TradTech rates these Carbon/Wood 45 lb Black Max 2.0 limbs on a 17" riser @ 28" and that is what is throwing a kink in my figuring. I'm just not sure about the weight for the tuning process. I want to put them on a 21" ILF hunting riser. That would make a 66" bow with my actual 29-1/2" draw. As best as I can tell without having a scale or a chart to go by, the string feels on the fingers at around 50 lbs. or so. Would any of you guys be able to lead me in the right direction to get the correct draw weight number so that I can tune this beast? I have some 400 spine shafts and hopefully they will work for this. I just wanted to make sure before I start cutting and gluing things together and screw up. Thanks for any help! Greg

 

[Rob5589]

17" to a 21" riser will decrease the weight by approx 4 lbs. (1lb per inch) But, limb pad angles and limb bolt position will play a part in that.

 

[nevadabugle]

@rob55is correct. If your 45 pound black maxes are pulling 50 on a 21 inch riser, there is likely a mistake on the marked poundage. But as he states limb pad angle can play a large part.

With all that said. Don't cut and glue anything until you tune one arrow to your set up. Take one of your 400s, leave it full length, glue in the insert, and see how the bare shaft flies. Then start cutting ( just pull the nock and cut from the back end) and playing with point weight until you have a good flying arrow.

Does that make sense?

 

[Old Geezer]

@rob55is correct. If your 45 pound black maxes are pulling 50 on a 21 inch riser, there is likely a mistake on the marked poundage. But as he states limb pad angle can play a large part.

With all that said. Don't cut and glue anything until you tune one arrow to your set up. Take one of your 400s, leave it full length, glue in the insert, and see how the bare shaft flies. Then start cutting ( just pull the nock and cut from the back end) and playing with point weight until you have a good flying arrow.

Does that make sense?

Absolute sense, thank you. There is a "pro" shop located in the next town from here, appx. 25 miles from me with a set of scales. For me to nip this in the bud and be sure of what I have , I might be better off to go up there and let them check it by scale weight. Then there's no question. Its raining and messy today anyway, might as well take a road trip. Thanks again !!

 

[Mighty Mouse]

These rules of thumb for estimating actual draw weight usually work pretty well:

• Subtract 1# per inch of increase in riser length
• Add 2# per inch of increase in draw length

Based on that, I would expect a set of limbs rated 45# @ 28" on a 17" riser to measure 44# @ 29.5" on a 21" riser (45# – [1#/in × 4 in] + [2#/in × 1.5 in] = 44#). However, as noted above by others, limb pad angle, tiller bolt postion, and brace height also affect draw weight. For tuning, I would start with a full length shaft and use heat reversible glue ("hot melt") to secure the insert.

 

[Old Geezer]

Here's an update. Just got back from the nearest archery shop in this area. I was wrong about my draw length. I'm actually at 30-3/4" full draw shooting this recurve, not 29-1/2" (my bad). Only 1/2" different from my old Hoyt Game Getter compound from back in the good old days, so there that is. As far as the the draw weight of this set up is concerned, it weighed out pulling on the scales at a solid 58 lbs. @ full draw 30-3/4". Now, I'm going to tune and tame this beast. Thanks for all the help, Greg

 

[Beendare]

Geezer, FWIW...we have almost the same DL and I can tell you our additional power stroke gives us a lot more arrow energy. I blew through 10 of 12 critters inc an 800# moose with my 47#/553g setup.

If you are struggling with that much weight....no worries just drop down....50# will kill anything in NA.

 

[Felix40]

For future reference…you can use a regular bathroom scale if you don’t want to go to a bow shop.

Put a little notch in the end of a 2x4 and mark it at your draw length. Stand it up on a scale on a work bench with the bow string in the notch. Zero the scale then draw the bow down to your draw length mark.