Guy - Thanks again for you quick help. The mistake I made was thinking getting strings would be a simple process, if I knew the manufactures AMO bow length and subtracted 4" from that. So much for my simpleton thinking.
I went back to both stores yesterday with the results below. I was hoping for a learning opportunity. These shops (both very good) cater to differing archery segments (Trad and compound). So I figured I might get differing info (which I did).
With the goal of getting close to the recommended brace heights with a string out of the bag and moving to D97 strings, here’s what I found.
56” bow:
My wife’s bow had a true AMO measurement of 56” measuring the unstrung bow from string nock to string nock. From what I’ve learned (so far) this seems to be the preferred method for measuring recurves. This video outlines what I did.
With a true AMO of 56”, the ideal string appears to a 53” D97, which is 3” shorter than the AMO length. Exactly what LBR noted above!
This produced a brace of 8”, out of the bag. The manufacture range is 7-3/4 to 8-3/4. There were enough extra twists on the string to achieve 7-3/4, but I chose 8” for now. Based on the AMO standards I found from below link, the above is correct. AMO standards show a 3” shorter string from the actual bow length.
http://www.texasarchery.org/Documents/AMO/AMOStandards.pdf The string packaging for this string stated 53”, which was the actual string length, not the bow length. This seems a more specific packaging concept to me, but maybe I’m wrong.
60” bow:
My bow has an actual length of 59” (tip to tip), differing from the manufactures AMO rating of 60”.
The manufacture brace height range for this bow is 7 to 8, differing a bit from my wife’s bow.
Using the same methods I used for my wife’s bow, I got a 56” (actual string length) producing a 6-3/4 brace height out of the bag. With 16 twists I got it to 7-1/2 as a starting point. A 55” string probably would have been idea, but the vendor didn’t have one in stock.
In this case, it appeared the AMO standard of 3” below actual bow length (59” to 56”) worked. But the old concept of 4” less than actual bow length would have worked too (59” to 55”), and possibly better.
The string packaging for this string states 60”, which was NOT the actual string length. The actual string length was 56”. So it appears this packaging states the bow length NOT the string length.
The trad vendor actually measured the bow, agreed D97 was ideal and tried a few strings to determine the best match.
The compound vendor stocked only B-50 strings. The reason being was to eliminate any liability of tip failure if a customer used the wrong strings. I can understand doing this. My understanding is B-50 can be safely used on any bow without tip failure issues.
What I’ve learned (so far); -
1) The original problem was I stated the AMO bow length and that I needed a string 4” less than the bow length. I then stated what I needed, 56” for me and 52” for my wife, But in both cases, I got strings for that bow length (56 and 52), not the actual string length. Frank Bullit quickly and perfectly nailed this above!! Thanks Frank!!!!
2) You can’t rely on the bow manufactures AMO length. You must take an actual bow measurement, which may or may not agree with the stated AMO length.
3) You need to know what the string length number represents on the string packaging (bow length or actual string length).
Please correct anything I’ve still got wrong, or missed. It appears this can be a somewhat tricky subject. There are only a few trad shooters in archery clubs I below to and we are starting to get questions on trad shooting and setup. So I want to understand this so I don’t mislead others.
All this was simply to get the right length string for my bows. I haven’t even touched string material, number of strands, bundles, serving type, diameter, string stretch, creep, etc. I’m starting to think you need a master’s degree to understand bow strings.
Thanks again
Ken
Topic: B-50 Flemish String length and stretch? (Read 476 times)
