i chrono'ed my 54# bow yesterday and got 163fps with my usual dacron string. i also tried a D97 string and gained 6 fps. that's a 3.7% gain in speed.

question...could i expect a similar gain out of my 69# bow considering that the gr/# is very close to my 54#?  or is there a point of diminishing returns?

I think 5-6 fps is pretty normal when going from B50 to D97. Some may do a bit better, few worse.

For me, the point of diminishing returns in string comparisons is the beginning. I just don't care anymore.....but I hope you get answers that help you.

You should see a similar gain with the other set up too going to D97. Let us know how you make out.

if thats the case i should have a 790gr arrow at 170fps!!

For me I like a good solid dependable bow string,I like D97 on my bows that are made for low stretch string materials.I like D97 for the feel of the shot and not for any speed increase.It makes the bow feel more solid to me,some bows it can decrease handshock.It doesn't feel springy like dacron can feel to me.

QuoteOriginally posted by ozy clint:
if thats the case i should have a 790gr arrow at 170fps!!

Boy that sounds like a tank buster.

How much always depends on what size string you are replacing with what size string.How many fps difference also depends on how heavy of arrow you are shooting.If you are shooting real heavy arrows you will see an increase but maybe not as much as if you were shoot light weight arrows ect.It is all in percentages.I have never seen a bow slow down any by giving it a good string however so you have nothing to lose.:)With 10gns/lb arrows replacing the stock rope on a Martin Stick gave me the biggest increase of any bow.A whopping 16fps increase.Most times I get between 8 and 12 depending on how over built the string is I am replacing.jmo

Did you switch to a skinny string? If not expect even more improvement in speed when if you do.

the comparison was 14strand dacron vs 10 strand D97.

QuoteOriginally posted by ozy clint:
the comparison was 14strand dacron vs 10 strand D97.

yep, there ya have it - lower the weight and the speed goes up.  i don't string up with more than 8 strands of dyneema (d'02, in my case) and have been happy witht he 6 strand testing so far.