O.K i purchased a 2004 patriot and i love it.I was thinking about installing leaches on the string.Now my question is----how much speed is lost with all the string and cable silencers installed at the factory.Not looking at my bow now but i think there are at least 4 of them.I know bowtech didn't do the speed test with these installed.

The speed on the birth cert is with them on plus a brass nock.
Both my Black Knights right out of the box shot what was on the BC.

The advertized IBO speeds are for a bare bowstring and the birth certificate states the speed of the bow before it went into the box before shipping. All BowTech bows that I've tested were very close to, or exactly what was on the birth cretificate. Chronographs can vary so the speed you see may be due to chronograph differences, lighting or where the arrow passed through the screen of the chrono. I've seen quite a difference on my chrono if I shoot accross the screens too high, usually about 3 to 4 inches above the top of the chrono will produce consistent results from week to week to months between testing the same bow. The chrono needs to have the proper amount and quanity of light to read the shadow of the point of the arrow as it passes above the screens. I've had my chrono for about 12 years and it's been as dependable as ANY of the best of my hunting and shooting gear.

As stated by others, the birth certificate speed rating is with the hush kit (which includes the string silencers) and a single brass nock installed. My string silencers are almost gone so I'l probably be putting leeches on myself. They claim no more than an average of 2 fps speed loss depending on where they are placed on the string. The closer to the center of the string they are placed, the more speed loss you will see.

I believe that the birth certificate states a loss of 3-5 fps with the hush kit installed....and the birth certificate is also tested at peak weight...not necessarily 70 lbs. Both of my bows came listed with peak weights of 71 and change.

Thanks for the replys guys.My mistake,i had the understanding that the speed test was done without the string silencers.I think i will be putting on the leaches soon though.
Another question?-------My bow has a B/C of 309 @29 inch draw----I swapped the module for a 28 inch,im actually drawing a little over 28,my arrows are 27.5 inch easton epics(unknown weight)And im drawing 71.5#'s----any idea as to my speed approximately----sorry also shooting with a brass nock and a peep---thanx----100Grain tips also

why would you want to put on leeches when you already have factory string silencers on the string which IMO are far superior to the Leeches?

there isno way for anyone to give you a fair estimate of the speed of the arrow if you dont know its weight.

best thing to do is take your bow to the pro shop and have them shoot it thru a cheonograph.

Without knowing your exact arrow weight it is difficult to make an estimation based on the information presented. Head over to www.bowjackson.com and use his arrow weight calculator to determine this.