a limb Tiller question for everyone

[Tajue17]

I'm starting to find bowyers who when asked about their bows being tillered for split finger draw tell me they tiller their bows to shoot both split and 3 under,,, is this called Positive Tiller 1/8" ???? 

my question to everyone is this, do any of you notice a difference with any of your bows that are specifically tillered for your style of shooting and others that may be "positive tiller" do you feel a bit of mushiness/ vibration after the shot or is the string nock at a different place on the string to accommodate for the limbs being off?             I'm oldschool I guess but where I shoot split I want my bow to be tillered for such,,,, but I'm open-minded and don't want to be pest about it if I cannot tell the difference. 

I shoot with a very low elbow, I've been shooting stickbows since 86 and I know something is up when the string nock is 1/2" higher than normal and my point of Impact is different than the 3 other bows the same exact weight,, bad bow or positive tiller?

[Hermon]

Most of my bows are 1/8"-1/4" positive tiller (I shoot split).  I shot a pass around bow this month that was tillered 1/16" positive and it shot great for me.  Thinking of having a bow tillered that way in the future.

[tippit]

I have a few bows of all types with tillers all over the place. The only difference for me is finding the sweet nocking point.

[Al Dean]

I had a bow tillered for 3 under that could not be shot split.  Never had a bow split that could not be shot 3 under.  I try to tiller my split bows 1/8" positive.  And I do tiller exactly 1/8".

[MPaul]

For me I have tried 3 under and split finger on all my Bows. I am able to make them all shoot either way I just have to adjust nock point.

[McDave]

I think bows should be tillered so that the limbs return to brace height at the same time after being shot.  This may result in a bow tillered 3/16" positive for spilt or zero tiller for 3 under, but to say the reverse is putting the cart before the horse.  That is to say, different tillers may arrive at the optimal result for different bows.

[Orion]

An ILF is about the only bow on which you can adjust the tiller. Well, you can also shim bolt on limbs, I suppose.  Most bowyers tiller their bows about 1/8 to 1/4 inch positive.  If you ask for a 3-under tiller, they'll usually go with even tiller, maybe even negative tiller. 

Regardless, my experience is the same as Tippit's and MP's.  I have bows with each, and can shoot any of them three under or split.  I generally shoot split finger with my nock set at about a half-inch.  However, I can shoot the same bows three under with the same nock point and get good arrow flight.  By raising the nock 1/8 inch to 5/8 inches, I quiet it for 3 under shooting and I can still shoot it split. Get good arrow flight with either, though 3 under is noisier.

Now I pretty much shoot three under at close shots of 20 yards and under (which pretty much enables barrel sighting) and switch to split for longer shots (with the same bow and nock point height).  Works for me.   

In considering 3 under vs split finger, it's also wise to determine how high above the center of the bow the arrow rest is positioned.  A good number of bowyers position the arrow shelf 1 1/4 inches above the center of the bow.  Just as many position it 2 inches above the center of the bow. (I've been taking this measurement on bows for more than 30 years.)

My three shooting fingers span about 2 1/8 inches.  So on a bow with the arrow shelf 1 1/4 above the center of the bow, plus my 1/2-inch nock height minus the thickness of the nock, say 1/4 inch, my lower finger will be on the string about 5/8 inch below the center of the bow, placing my middle finger on the string just about in the center of the bow.  If the bow shelf is 2 inches above the center of the bow, my lower finger is about 1/8-inch above the center of the bow.

Now, if I switch to split, my two lower fingers are about 1 1/2 inches across so on a bow on which the riser is 1 1/4 inches above the center of the bow, the bottom of my lower finger will be on the string right at the center of the bow. With an arrow shelf 2 inches above center, the bottom of my lower finger will be on the string 3/4 inches above the center of the bow.

I point this out only to demonstrate that where the arrow shelf is cut determines where we place our fingers in relation to the center of the bow, which in turn impacts the vertical torque on the limbs and how we adjust to it by adjusting the tiller (on an ILF) or the nock point.

I should note, too, that my records show that most bowyers who cut the arrow shelf 2 inches above the center of the bow, which makes for equal length limbs, tend to make the bows equal our neutral tiller, whereas most who cut the shelf 1 1/4-inch above center, in which the top limb is longer than the lower limb, give their bows a positive tiller.

I haven't really determined which works best.  One would think the 3 under hold on a bow cut 1 1/4 inches above center, which centers the three fingers on the string at the center of the bow, would be best, but I'm not sure that's the case.  For me, 3 under seems to work best on bows cut 2 inches above center. Go figure.

[Tajue17]

wow that's getting pretty deep,, determining where the shelf is?   makes perfect sense though.... I guess I'll stick with my original plan of buying instock bows I can return if they seem to nock too high

[Crittergetter]

IMHO....
It's not just tiller that has to be considered.
Placement of the center of throat, shelf height, tiller, and how someone grips the bow all play into how a bow shoots for split vs 3 under.
I personally tiller between 0-1/8" positive for both spit and 3u.

[hvyhitter]

Have shot dozens of bows over the years 3 under. Never measured tiller on any. Just tuned and shot. Some were supposed to be tillered for 3 under but never noticed a difference. All nock points ended up around 9/16-5/8 above the shelf so that's were I start and rarely have to move it. Not worth sweating the tiny details............ YMMV

[Overspined]

Arrows are more important than how or what bow you shoot (don't tell the bowyers, me included).. Tune good arrows with the correct nock point and you're in business. Almost any bow will shoot, twisted, canted, crooked, bad tiller..just have to find the right arrow to shoot out of the right spot