Weights of Olympic ILF limbs are marked for 23 and/or 25-inch risers. Generally, the rule of thumb I've read for determining the draw weight for those limbs on shorter risers is to add a pound of draw weight for every inch shorter than the Olympic riser. For example, 30# limbs on a 25-inch riser would be 36# on a 19-inch riser.

However, I'm thinking the weight variance per inch of riser length might be more or less depending on the initial draw weight of the limbs. For example, it might be 3/4# or less for light limbs (say 30#) and 1 1/4# or more for heavy limbs (for example, 60#).

I'm interested in specific examples, particularly for lighter weight limbs, say 30-35#@28 inches. How much do they gain per inch when you put them on shorter risers? No guesses. I'm looking for specific examples with your set ups.

Who knows, with enough responses, maybe we'll be able to develop some sort of chart that can help others make limb selections. Or, maybe we'll find that the 1# per inch of riser length holds across all limb weights.

You're right the general rule is 1# per inch, but I've found it actually works in percentages (of gain or loss).

A chart, if someone would put it together, would be very helpful.

I'll weigh my limbs and get back with the numbers for you later in the thread.

Don't think you can get an answer on that one, because there's more than one variable. Riser length is one thing, but then you have limb bolts turned in as many as 5 different turns, not to mention different limb pad angle.

I think limb bolts is the big one though. I thought that all bolts should be turned all the way down and then one turn out - that's maximum. Now, I've also heard of limb bolts (Gillo ?) turned all the way down for max.

I could be wrong though. Just thinking of the same brand/model riser it might work. Like between a Excel 23 and 21 inch.

Bowmania

Bowmania

Plus tiller changes.

Bowmania

Limb bolt depth certainly makes a difference. Optimally it would be nice to have all the comparisons made at maximum weight, i.e., the limb bolts turned all the way down, then back 1/4-turn or whatever the manufacturer recommends.

Too, some builders mark their weights at different settings, i.e., maximum, mid or minimum weight. With enough measurements, could develop a profile for each type of measurement. Doubt we'll have that many though.

Jim: I've also read "about a 10% difference in weight from maximum to minimum." That's the potential percentage change on a given riser. Doesn't get at differences between riser lengths though. I look at it as a measure that can be applied once we know at least one weight on a given riser.

Jerry, Unfortunately manufacturers mark their limbs at different settings; max., med, or min. So until that practice can be standardized I don't see a way to make a reliable chart. Also limb pad angles and limb bolt position on the riser can make a difference. I have a Win & Win Black Wolf riser and a Hoyt Satori riser both rated 17". However the limb bolts on the Satori are positioned a little farther apart, out toward the ends of the riser, than on the Win & Win. If I put the same limbs on both risers they always weigh a little less on the Satori than on the Win & Win. This is another factor that would need to be standardized before any accurate chart could be made.

As said above, so many variables that a chart would be difficult and certainly not always accurate due to so many gozintos. That said, if limb pad angles stay the same, and bolt depth creates the same pull weight, then your back at about 1# per inch of riser length.

Jerry,

I wasn't referring to the 10% adjustment range. I was referring the weight gain and loss being in percentages, rather than the "standard" 1# per inch gain/loss.

Let's say 40# limbs (on a 25") riser will weight 48# on a 17" riser.

So... that's a 20% weight gain.

If a 30# set of limbs will gain 20%, that's a gain of 6#, or a gain of 0.75# per inch on a 17" riser.

If a 50# set of limbs will gain 20%, that's a gain of 10#, or a gain of 1.25# per inch on a 17" riser.

That's what I've found to be the case. Then... we get back to Todd's list of variables that throw's a wrench in things.

What I'm thinking is, if we could get enough participation, we may be able to say definitively,

Your X riser at X length will have a X% of weight gain/loss of what the limbs are marked on a 25" riser.

"Let's say 40# limbs (on a 25") riser will weight 48# on a 17" riser."

Jim, You think those weights are calculated at mid range on the risers, not max?

Yeah… probably at mid-range. There’d have to be some kind of standard I imagine. Once you start changing from maximum preload to minimum preload, you’re changing the angles and the percentages would change with it.

It also depends on limb pad angle,some risers will add more then the 1# per inch shorter.I have a Morrison 17" metal riser that adds 2# per inch shorter.I put some 38# on a 25" riser,when I scaled it was around 52#.I had a couple of Dryad ILF risers a few years back one was +15# on limbs and the other was +8# on the standard limbs.

Agreed, that there are a lot of variables. Could just work with a few of them at a time, For example, test all limbs when they're maxed out on the riser, that is 1/4 turn out or whatever the manufacturer recommends. Then, if we can do that with the same set of limbs on different length/brand risers, we would begin to get an idea as to how much X brand limbs weigh compared to the marked weight, and how that changes for different riser lengths. Do this across a couple of riser brands and lengths as well as limb brands and lengths and we would soon have a pretty good representation that would take some of the guess work out of selecting limbs.

In other words, what Jim said in his second post above. "Your X riser at X length will have a X% of weight gain/loss from what the limbs are marked on a 25-inch riser." That would be good enough for me.

Jim, how did you come up with the 20% figure? It seems to yield the result I postulated. If it's accurate, we may not need to go any further. Or maybe we need to add a few more cases to support the hypothesis.

Back when this ILF/DAS stuff started, I had a Titan riser and DAS Master riser; both are/were 17" risers. I had a set of 40# limbs and on each riser at mid-range both bows came in at 48#.

I also had a set of 36# limbs; They weighed right at 43# on both risers; that translated to 1# less than the 1# per inch rule. That meant the 20% rule... well.... ruled. :^)

I didn't have a digital scale at the time. I used a hanging scale so I was only close at best. Now I have a digital scale and not 17" risers to check my "best guess" for sure.

A buddy had a set of 50# short Hoyt limbs. When we weighed them, they came in at 60# on his Titan riser at mid-range. That was 2#'s more than the 1# per inch rule but was still a 20% gain.

I will check a couple sets of limbs this evening on my 21" Satori risers with digital scales and see what happens with them.

I don't have the answer, but have another fly for your ointment. When you start getting into the shorter hunting type risers, the bowyer's don't always have a standardized limb pad angle formula and you can end up with different draw weights from the same limb set on two different brands risers of the same length

Bottom line is, don't get hung up on *exact* draw weight. Approximate, then deal with it.

Think of it this way - if you ordered a true 'custom' bow from a small shop maker, would you get hung up over one pound difference in draw weight?

Not worth making yourself crazy over. I doubt one archer in twenty could tell the difference in one or two pounds draw weigtht change.

32# Uukha Hx10 Evo2 limbs on the Satori 21” riser at mid range = 37.25#

… or… about 16.25% gain

38# Uukha Ex1 Evo2 limbs on the Satori 21” riser at mid range = 44#

… or… about 16.25% gain.

Hmmmmmmmmmm.

Interesting. Consistent across limbs for that riser. You shouldn't have any trouble deciding what poundage to get your next set of Uuikha limbs for that riser should you need to do so.

Most of us have one or two experiences like that. If we could ever get all of the data together in one place, we'd have some pretty specific parameters to guide us. Unfortunately, that's a big job, and I don't think I want to take it on.

I expect someone like John Wort at Lancaster Archery, who works with hundreds of riser limb combinations weekly, probably has a lot of this stuff committed to memory. Few of us are in a position to be able to do that.

Guess I'll just keep struggling and sometimes be hit or miss in my limb selection. Oh well, keeps the used bow/limbs market hot. :>)

Yes sir, it would be nice to have/see a "quick reference" put together. Looks like we're certainly not going to get enough participation here to even start--save for Uukha limbs on a 21" Satori riser huh?

:^)

If you have already registered, please

sign in now

For new registrations

Click Here