Hi guys,
I'm looking to get a new string and was hoping to get some opinions from people with experience using X99. Generally I hunt in quite hot weather. Is the increased heat stability of X99 (with the vectran) a consideration in picking it over mercury (straight SK99 dyneema)? I realize these are similar in cost and these are likely very small gains in performance. I need to make a decision though on material, so I appreciate opinions on this.
Mike

I live in Phx Az area. In summer I shoot in 100*+ temps. Chad makes me BCY X strings, endless loop, which DONOT stretch. If I am using a certain bow from week to week it stays strung.
It may not be the material all the time. It can be the maker. One reason I deal with makers who prestretch the strings.

X99 is the replacement for BCY X. X is no longer being made as the manufacturer of the primary base material - SK 90 Dyneema - went to the newer SK99. X was 83% SK 90 and 17% Vectran - which made it extremely stable especially in heat. X99 is 80% Sk99 and 20% Vectran. All feedback so far is that it has lost nothing to BCY X. I haven't heard of any direct comparisons that conclude X99 is better/worse than Mercury. I personally cannot see/feel the difference. There are a few bowyers who are not comfortable with blended materials - I would check with yours.

Thanks for that. From what I see on BCY, you're describing "452X" which is 67%dyneema/33%vectran.
I see the X99 being listed as 80%dyneema/20%vectran (similar to BCYX as you say).
I guess i'm wondering if anyone sees why someone should go from a pure dyneema string to a string blended with vectran. I'm not sure what the logic is behind it, if it's the extra heat stability that's desired, because otherwise dyneema seems pretty great.
Thanks and I appreciate your thoughts!
Mike

I was wrong on my %'s and corrected them. Also many feel that X and X99 are just a touch quieter.

Ok thanks!
Steve i've been looking at your site and i'll be ordering one.
Mike

I have some of both.  I don't know that i've noticed a difference in building or stretch of the x99 vs the X.  I do know that x99 is a good bit skinnier.  If i remember correct, it takes about 16 strands to get the same diameter as 12 of X. 

My BCYX strings stretch a lot.  300 to 400 shots to "settle in" and then a twist or so every few hundred shots for a while after that.  Is that because of the Flemish twist?  I've heard endless loop have less stretch.

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Quote from: GCook on March 06, 2019, 06:50:49 PM
My BCYX strings stretch a lot.  300 to 400 shots to "settle in" and then a twist or so every few hundred shots for a while after that.  Is that because of the Flemish twist?  I've heard endless loop have less stretch.

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Prestetching before serving and shooting make a huge difference. I have a calibrated stretcher. I twist both loops, put 50 lbs on and add my twists. Then run it to 100 lbs for 20+ minutes - this "sets" the splices. Then 200#'s for at least an hour. Make final length adjustments and do center serving. Few more minutes at 200 and ready for the bow. After 10 so shots it may need 3 or 4 twists and most report that is the final adjustment. This is for 16 to 18 strand BCY X.

Thanx.  I may need to try the X99.