String material type vs Brace Height

[Brazos]

I just got my new FF string from one of the sponsors.  It's a work of art.  I measured my existing string (68" HHA longbow) and it was around 64-1/8"-64-1/4" so I told the maker to go with 64-1/4".  My existing string is the stock, non-FF, string.  I put the new string on and my brace height was around 7-1/2".  I untwisted the string as much as I could without it no longer having any twist.  I let it sit for a few hours and my brace height is around 6-7/8".  My existing string is braced around 6-3/8" which is typically recommend for a 68" HIll style bow.  My fear is I ordered a string that is a little short.  Out of curiosity I took the new string off and laid it next to my existing string.  My existing string is actually nearly an 1" shorter.  Now I am scratching my head.  They only answer I can come up with is that my non-FF string has some spring to it so it stretches at the point it is braced.  I have not shot the new string, if it shoots good with the higher brace fine but my guess is I will need a longer string  to get the BH down.  Just not sure what length I would need since my non-FF appears to be shorter.

[Brazos]

I need to revise some of my above info as I just remeasured everything and I was incorrect that my existing non-FF string is almost an inch shorter. I just remeasured everything and here is what I got:
Stock HHA Non-FF string is 64-1/8" and shows a 6-3/8" brace height.
New FF string is 64-1/4" and has a brace height of 6-7/8" and not much twist left to take out.

[Thare1774]

Dacron strings that I've used stretch out like crazy compared to my comparable length FF strings. It can be irritating, which is one reason I only shoot FF strings on my bows that can handle it.

[eflanders]

The original string should be measured for length after it has been on the bow for a while at the preferred brace.  If you measured your string while it was off the bow for a while (especially if it is a flemish twist string), the string length measured can vary due to stretching that occurs while the bow is strung up.

[normf]

If the FF type string has padded loops they might take a while to settle in.

[ddauler]

Yep I use fast flight primarily so I don't have to wear and arm guard. Dacron stretchs to much. Use it on self bows to so I can make brace hight real low.

[macbow]

Even though a 1/2 inch difference is a lot I'd suggest shooting 50 or so arrows to see if the string wants to settle in more.
A lot depends on if the supplier did some pre stretching.
Being down to a couple of twists per inch would be OK.

[hvyhitter]

brace height from bowyer is only a suggestion and starting point,  your tuning will tell you what works with your bow/arrow combo.....I've had to retune or go to stiffer arrows when going to fastflight from dacron so shoot it and see...........

[Brazos]

Thanks.  I guess I learned a little bit.  All my string experience has been with HHA strings as in the past I just called them up and said send me another string for my 68" bow.  Never had to measure anything.  I figured since I have been using this string since June it was fully stretched.  There must be a little bit of "spring effect" at play with a Dacron string once it's unbraced and off the bow.  I did shoot the new string and it did well.  It surely seems faster.  My arrows flew nice and straight and hit hard.