Spoke Length Calculations - Compensation for Spoke Stretch & Spoke Hole Stagger?- Mtbr.com

# Thread: Spoke Length Calculations - Compensation for Spoke Stretch & Spoke Hole Stagger?

1. ## Spoke Length Calculations - Compensation for Spoke Stretch & Spoke Hole Stagger?

I will shortly be lacing up my first pair of wheels, but I need a second opinion about spoke lengths. I've been using Spocalc by Damon Rinard.
Spocalc, by Damon Rinard. A free Excel spoke length calculator.

Also note that I bought 8 of these rims very cheaply and may experiment with different thickness spokes. I plan to build two pairs of wheels for rim brake use and the other two pairs of rims I may try with disk brakes maybe next year. I just built up a Surly Troll frame that has both V-Brake pivot posts and is also set up to mount disk brake calipers.

Rims: Weinmann Goliath 36 hole 559-25 (26" x 25 mm inside rim width)
Weinmann Metal Products Co., LTD

ERD = 537.25 mm Measured from the bottom of the spoke nipple slot using the same 2.0 mm x 12 mm Sapim Polyax spoke nipples that I will be using for the build.

The spoke holes in the rim are staggered with about an equal 1.375 mm offset right and left of center.

I altered the spread sheet to subtract the spoke hole offset from both the Left and the Right Hub Center to Flange Center measurements. Does this appear to be the correct way to compensate for the spoke hole stagger?

=========================

Front Hub: Shimano HB-M590

Width from Center of Hub to Center of Left Flange = 34.215
Effective Width from Center of Hub to Center of Left Flange = 32.8 mm

Width from Center of hub to Center of Right Flange = 34.215
Effective Width from Center of Hub to Center of Right Flange = 32.8 mm

Left Side Hub Flange Spoke Hole Circle Diameter = 38.2 mm
Right Side Hub Flange Spoke Hole Circle Diameter = 38.2 mm

Spoke Hole diameter = 2.64 mm

3 Cross

Spoke Length = 260.4 mm

============================

Rear Hub: Shimano FH-M590

Width from Center of Hub to Center of Left Flange = 35.175
Effective Width from Center of Hub to Center of Left Flange = 33.8 mm

Width from Center of hub to Center of Right Flange = 19.525
Effective Width from Center of Hub to Center of Right Flange = 18.2 mm

Left Hub Flange Spoke Hole Circle Diameter = 45.3 mm
Right Hub Flange Spoke Hole Circle Diameter = 45.3 mm

Spoke Hole diameter = 2.64 mm

3 Cross

Non-Drive Spoke Length = 258.9 mm

Drive Spoke Length = 257.4 mm

Tension Ratio Non-Drive Side Spokes to Drive Side Spokes 0.54 : 1

=========================

Note: I weigh about 185 lbs clothed. My Surly Troll is probably about 35 lbs. I often carry about 30 lbs on the rear rack. I have hauled as much as 90 lbs on the rear rack while wearing a 30 lb backpack (On my old 1988 Schwinn High Sierra RIP).

=========================

Front Spokes: Wheelsmith XL-14 / 2.0 mm - 1.5 mm - 2.0 mm Double Butted.

It's a light spoke, but I'm also using 36 spoke rims.

From what I can see Spocalc does not take into consideration spoke stretch. I'm wondering how much do I need to subtract from the calculated spoke length of 260.4 mm to compensate for the spoke stretch of a 1.5 mm spoke?

I can't find any recommendation for maximum spoke tension for this rim and so far I have not heard back from Weinmann and I suspect that they will ignore my e-mail. But considering that I've had good luck tensioning generic single wall rims to about 120 Kgf, these box construction eyeleted rims should be able to handle at least that much spoke tension. I'm thinking of aiming for a spoke tension of 125 Kgf to 130 Kgf for the front wheels.

========================

Rear Spokes:

Non-Drive Side:

Wheelsmith XL-14 / 2.0 mm - 1.5 mm - 2.0 mm Double Butted.

Drive Side:

Wheelsmith DB-14 / 2.0 mm, 1.7 mm, 2.0 mm Double Butted.

Possible alternate: Wheelsmith DH-13 / 2.3 mm - 2.0 mm Single Butted

Spocalc indicated a tension ratio of 0.54 : 1 between the non-drive and drive side spokes. In order to tension the non-drive side and drive side spokes to nearly equal percentages of their ultimate tensile strength, you need to use lighter gauge spokes on the non-drive side. I also believe that using a lighter spoke on the non-drive side will reduce the possibility of spoke loosening.

The cross sectional area of the Wheelsmith XL-14 is 1.54"2.

The cross sectional area of the Wheelsmith DB-14 is 2.27"2.

The cross sectional area of the Wheelsmith DH-13 is 3.14"2.

The ratio of the cross sectional areas of the XL-14 and the DH-13
is 0.49 : 1, which is very close the calculated tension ratio between the drive and non-drive sides. This should stress the non-drive and drive side spokes nearly equally and the spokes should stretch equal amounts on each side. This should provide the best reliability, except for the fact that the DH-13 is only a single butted spoke. For this reason I'll probably use the DB-14 double butted spokes.

The ratio of the cross sectional areas of the XL-14 and the DB-14 is 0.72 : 1. Not as close to being tensioned to the equal percentage of maximum tensile strength, but better than using the same spoke gauge on both sides. And the spokes on both sides are double butted, which should make them fairly reliable.

I would think that if 130 Kgf would be acceptable for the front spoke tension, that the rear drive side tension should be much more than this, as the non-drive tension will only be about 54% of the drive side tension. About 91 Kgf spoke tension non-drive side and about 168 Kgf drive side. This would result in the same average tension on the rear rim as the front rim.

But could the individual spoke holes on the drive side and the spoke nipples handle that much spoke tension?

I'm hoping that I can get spoke lengths correct on the first try. But that might be wishful thinking on my part.

I welcome your comments on this proposed wheel build.

Scott Novak

2. I'm no expert but a couple things jump out at me and perhaps I'm getting this wrong, so here goes anyway.

Your tension sounds high. 130 is usually the max for rims and I think most hubs are somewhere around there. Some Stan's rims are 90 or 100 I believe. 168 is way too high, and you'll likely destroy the nipples at a very minimum trying to get there. As far as spoke stretch goes, I don't think you'll see anything that's going to make any difference. Once I've built a set of wheels, ridden and retensioned once or maybe twice, they are done. It's rare that I have to mess with them again. If this does happen it should happen evenly all the way around to so that I minimal adjustment would be given to all spokes since all spokes are subjected to the same forces evenly.
That's my take on it, you've certainly done your homework and put some serious thought and effort into this. Have fun with it and let us know what you find on your experiments.

3. I have never made any accommodations for spoke stretch or hole stagger in my calculations, and haven't had any measurement problems due to that.

I have no experience with that rim but I'm guessing you're about right with your estimation for 130 Kgf on the front wheel for tension, and I would match that for the drive side rear. Trying to bring the drive side up to 168 Kgf so the rear wheel has the same average tension as the front seems crazy high. I always get the drive side to the correct maximum and let the non-drive side be what it is.

4. Originally Posted by Scott Novak
I altered the spread sheet to subtract the spoke hole offset from both the Left and the Right Hub Center to Flange Center measurements. Does this appear to be the correct way to compensate for the spoke hole stagger?
Yes

Originally Posted by Scott Novak
I'm wondering how much do I need to subtract from the calculated spoke length of 260.4 mm to compensate for the spoke stretch of a 1.5 mm spoke?
It depends on tension and spoke length. For a 260mm spoke at 100kgf you're looking at about 0.7mm.

Originally Posted by Scott Novak
I can't find any recommendation for maximum spoke tension for this rim and so far I have not heard back from Weinmann and I suspect that they will ignore my e-mail. But considering that I've had good luck tensioning generic single wall rims to about 120 Kgf, these box construction eyeleted rims should be able to handle at least that much spoke tension. I'm thinking of aiming for a spoke tension of 125 Kgf to 130 Kgf for the front wheels.
On the high side for a 36h rim, but not crazy.
I'd be surprised if they recommend going that high.

Originally Posted by Scott Novak
Spocalc indicated a tension ratio of 0.54 : 1
[...]
fairly reliable.
While I follow your logic and don't disagree, except for the mixing of some objective analysis with ill-defined terms like "better" & "fairly," I think these musings are of little practical value. Normal wheels work fine, and you will never be able to confirm or deny that lacing with lighter spokes on the rear NDS produced better reliability on your one wheel, so it's more about your own intellectual edification than quantifiable benefit.

Originally Posted by Scott Novak
I would think that if 130 Kgf would be acceptable for the front spoke tension, that the rear drive side tension should be much more than this, as the non-drive tension will only be about 54% of the drive side tension. About 91 Kgf spoke tension non-drive side and about 168 Kgf drive side. This would result in the same average tension on the rear rim as the front rim.
168 kgf is WAY too high for a 36h rim.
I think a better way to start wheelbuilding is to stay within the bounds of reasonable standards of practice, which are there for a reason: they are tried and true. Testing all the theories you have posited about what will and won't produce better reliability and matching average tension front and rear is not something I think will ever materialize unless you want to devote your life and hundreds of thousands of dollars to it. Otherwise your sample size will never be big enough to mean anything.

Originally Posted by Scott Novak
But could the individual spoke holes on the drive side and the spoke nipples handle that much spoke tension?
Probably not... and what would be the reason/benefit again?

Originally Posted by Scott Novak
I'm hoping that I can get spoke lengths correct on the first try. But that might be wishful thinking on my part.
It would at least be a more grounded goal.

Originally Posted by Scott Novak
I welcome your comments on this proposed wheel build.

Scott Novak
Very ambitious.

5. With compensation for Spoke Hole Stagger Offset of 1.375 mm

Front Wheel Spoke Length = 260.35 mm

Rear Wheel Non-Drive side Spoke Length = 258.93 mm

Rear Wheel Drive side Spoke Length = 257.36 mm

Spoke Tension Ratio: 54.05%

---------------------------------------------

WITHOUT compensation for Spoke Hole Stagger

Front Wheel Spoke Length = 260.53 mm = Difference of 0.18 mm

Rear Wheel Non-Drive side Spoke Length = 259.11 mm = Difference of 0.18 mm

Rear Wheel Drive side Spoke Length = 257.46 mm = Difference of 0.10 mm

Spoke Tension Ratio: 55.89% = Difference of 1.84%

---------------------------------------------

Granted, it's a fairly small difference in spoke length and it probably only makes a difference when your calculated length is in the middle of two standard spoke lengths. But I'd rather try compensate for as many variables as I can and buy a set of spokes that works on the first try. Mistakes are expensive.

=======================

I did measure the ERD to the bottom of the slots in the spoke nipples. With a DT spoke they will screw in 1.3 mm past the bottom of the slot in the spoke nipples.

If the estimate of 0.7 mm spoke stretch at 100 Kgf is correct, that would mean a stretch of 0.91 mm at 130 Kgf. Subtract that from the calculated length and that would be a 259.44 mm spoke length for the front rim. So would it be better to use a 260 mm spoke length or a 258 mm spoke?

For the rear I think I should be using 258 mm long spokes for the non-drive side and 256 mm long spokes for the drive side. What are your opinions?

==========================

If a spoke tension of 130 Kgf was considered reasonable for the front rims, then why shouldn't we expect the same total average spoke tension to be used on the rear rim, except for components not being up to the task?

Either the average rear spoke tension is too low or the average front spoke tension is too high. You can't have your cake and eat it too.

You may all be quite correct that the spoke nipples and/or hub flange and/or rim holes cannot handle a drive side spoke tension of 168 Kgf and a compromise with a lower spoke tension is a practical necessity.

As far as the hubs being able to handle the extra spoke tension, there isn't much data online to indicate what the hubs can handle, which leaves personal empirical data the only data available.

I will build the front wheel first as that seems simpler. If the spoke nipples don't complain about the tension too much I may try a higher spoke tension on the drive side of the rear rim and see what happens. I do have 8 rims to play with and my hubs are not particularly expensive.

One reason that I would like to use the highest practical spoke tension on the rear wheels is that I plan to use thinner spokes on the drive side. With a higher spoke tension I think that there should be less difference in lateral stiffness in the right or left direction. But no way to know for sure unless I actually try to measure it.

But there is also the effect of different bracing angles between the drive and non-drive side on stiffness. Would the greater bracing angle on the non-drive side leverage any additional stiffness, so that using a thinner spoke on the non-drive side might in effect balance the lateral stiffness in both directions? I haven't seriously thought this one through yet.

I never trust the status quo. I don't think there is enough objective data out there to show that we are doing things as best we can. Better to ask the questions on the chance that something has been overlooked. The answers that I have received on this website have helped me a lot. At the very least they make me seriously think about the various issues.

I do appreciate your comments.

Scott Novak

6. ## Spoke Length Calculations - Compensation for Spoke Stretch & Spoke Hole Stagger?

I get that you're trying to build the best wheels possible, but what's your goal with these wheels? As for not trusting the status quo...take a look at the wheels you see on the fastest bikes out there. Start with that, it's guaranteed that those guys are making an effort to have the best available and look at even the smallest details.

7. ## Spoke Length Calculations - Compensation for Spoke Stretch &amp; Spoke Hole Stagger?

Originally Posted by Scott Novak
I did measure the ERD to the bottom of the slots in the spoke nipples. With a DT spoke they will screw in 1.3 mm past the bottom of the slot in the spoke nipples.
Actually it varies.

Originally Posted by Scott Novak
IIf the estimate of 0.7 mm spoke stretch at 100 Kgf is correct, that would mean a stretch of 0.91 mm at 130 Kgf. Subtract that from the calculated length and that would be a 259.44 mm spoke length for the front rim. So would it be better to use a 260 mm spoke length or a 258 mm spoke?
A 259.
What you're going to find is that pre-cut spoke length will vary about +/-0.5mm

Originally Posted by Scott Novak
If a spoke tension of 130 Kgf was considered reasonable for the front rims, then why shouldn't we expect the same total average spoke tension to be used on the rear rim, except for components not being up to the task?
You answered your own question. Total average spoke tension is a meaningless metric. Max is what matters. Your hub geometry determines the ratio.

Originally Posted by Scott Novak
Either the average rear spoke tension is too low or the average front spoke tension is too high. You can't have your cake and eat it too.
No... you have assumed a fallacy (that total average tension should be equal) with no logical basis that you have shared and are now operating as if your assumption were a law.

Originally Posted by Scott Novak
You may all be quite correct that the spoke nipples and/or hub flange and/or rim holes cannot handle a drive side spoke tension of 168 Kgf and a compromise with a lower spoke tension is a practical necessity.

As far as the hubs being able to handle the extra spoke tension, there isn't much data online to indicate what the hubs can handle, which leaves personal empirical data the only data available.
How much personal empirical data are you basing these opinions on? We're not spending our time posting advise to **** with you.
Have you ever seen a broken hub flange, or stripped a nipple's flats, or seen a hub's bearings fall out because the shell is distorted from tension? These are the reasons and they are real. The only reason you'd like to build to 168 (do you know if you even have the practical ability to set such a specific tension accurately) is your assumption about total average tension.

Originally Posted by Scott Novak
I will build the front wheel first as that seems simpler. If the spoke nipples don't complain about the tension too much I may try a higher spoke tension on the drive side of the rear rim and see what happens. I do have 8 rims to play with and my hubs are not particularly expensive.
Great. Post up your results.

Originally Posted by Scott Novak
One reason that I would like to use the highest practical spoke tension on the rear wheels is that I plan to use thinner spokes on the drive side. With a higher spoke tension I think that there should be less difference in lateral stiffness in the right or left direction. But no way to know for sure unless I actually try to measure it.
You are incorrect. There is no tie between tension and stiffness... and no reason why lighter spokes on the NDS should require higher tension. In fact, I don't agree with your justification for doing that in the first place. Again, you have made an assumption, in this case that equal spoke elongation left-to-right will lead to better reliability, and are running with it while not understanding the fundamentals.

Originally Posted by Scott Novak
I never trust the status quo. I don't think there is enough objective data out there to show that we are doing things as best we can. Better to ask the questions on the chance that something has been overlooked. The answers that I have received on this website have helped me a lot. At the very least they make me seriously think about the various issues.
It is good that you are thinking critically about it and approaching it in a way that makes sense to you. I will never tell you to believe something I say because I say it... it must make sense to you, however, you also have to know your own limitations.
All the "objective data" of hundred of millions of bike wheels lasting for years dwarfs your one datapoint, which will be meaningless, as I said earlier. Even your 8 rims and various experiments aren't going to give you any meaningful or significant results. The innate human tendency toward egocentricity has us inflate the relative value of our own experiences in our minds and that is important to keep in mind. You are also by far not the first person to approach wheelbuilding with this perspective; over complicating things on theoretical bases in an effort to optimize, which you will never know if you have accomplished.
Perspective...

8. "You are incorrect. There is no tie between tension and stiffness...

I was looking at the difference in lateral stiffness of left applied force versus right applied force with different thickness spokes on each side.

If you increase a lateral force in one direction I do believe that there is some transfer in force to the opposite side of the rim, with the rim pivoting on the spokes. If the spokes are tighter I think that more force may transmit through the rim to the opposite side with a net result of less difference in right or left lateral stiffness.

I know some people disagree with this concept. But I haven't seen any experimental data to prove or disprove it yet.

Scott Novak

9. "No... you have assumed a fallacy (that total average tension should be equal)"

I haven't seen anything to prove that claim yet.

Jobst Brant, Gerd Schraner, and a few others seem to think that optimum spoke tension (Optimum Rim Compression) is reached when any further tension increases cause truing problems.

I seriously doubt that you could reach optimum spoke tension on the rear rim without approaching a similar average spoke tension to the front rim. (Assuming that the front rims spokes are at optimum tension.) This would require considerably higher drive side spoke tension.

One way to prove or disprove this would be to tension the rear rim until it gets squirrely, which would indicate that the rim has reached optimum compression and then measure the total spoke tension of all of the spokes and compare that to the same rim non-dished.

"Normal wheels work fine, and you will never be able to confirm or deny that lacing with lighter spokes on the rear NDS produced better reliability on your one wheel,"

There are respectable wheelbuilders that do believe that it's advantageous to use lighter spoke on the non-drive side. It makes a lot of sense in terms of preventing spoke loosening.

But the possibility of a different lateral wheel stiffness with force applied to the left versus the right raises some questions. And whether or not the different bracing angle on the non-dished side increases stiffness. I haven't seen any stiffness data regarding rear wheels using two different gauges of spokes.

Damon Rinard's Wheel Stiffness Test (DRAFT)
Wheel Stiffness Test

3. Do dished wheels flex differently from one side to the other?

"Dished wheels do not flex significantly differently to the left or right."

However, this test was not performed with lighter spokes on the non-drive side.

But I believe his conclusion to be mostly true because I think that when a lateral force is applied to the rim, that force is also transmitted to the opposite side of the rim and the difference in stiffness between the lighter and heavier spokes mostly cancel each other out, provided the spoke tension is high enough and that the rim is relatively stiff.

Scott Novak

10. Wow.

11. I don't know if this is been stated already, but I understand your theory about the average spoke tension. What this points out is not that the rear should match the front, but that the front is much higher than necessary. Just because the rim and hub can handle 130kgf doesn't mean it needs to. 60% of your weight is on the rear wheel (if not more with your gear) and torque is applied only to the rear wheel, unless you have disc brakes. With your components you can easily bring down the front wheel spoke tension to 100 kgf and have nothing to worry about. 100 would give 36 spokes the same average tension as 18 at 130 and 18 at 54% of 130.

Make sure your tension meter is calibrated to read accurately. Many Park tension meters read high and therefore give you low tension.

12. Originally Posted by Scott Novak
"You are incorrect. There is no tie between tension and stiffness...

I was looking at the difference in lateral stiffness of left applied force versus right applied force with different thickness spokes on each side.

If you increase a lateral force in one direction I do believe that there is some transfer in force to the opposite side of the rim, with the rim pivoting on the spokes. If the spokes are tighter I think that more force may transmit through the rim to the opposite side with a net result of less difference in right or left lateral stiffness.

I know some people disagree with this concept. But I haven't seen any experimental data to prove or disprove it yet.
I understand what you said, which is why I said I disagree.
I think you actually have seen experimental data that would at least provide some insight into why this theory is incorrect, as I explain below.
Keeping things in perspective, I still think it is mental masturbation (which is a fine way to spend time if you enjoy it) and will not produce a tangible benefit for you, even if your theory turns out to be correct.

Originally Posted by Scott Novak
"No... you have assumed a fallacy (that total average tension should be equal)"

I haven't seen anything to prove that claim yet.
Prove what claim?
You made the claim that front and rear total average tension should be the same. Why?
You haven't offered even a logical basis for the premise you started from.

Originally Posted by Scott Novak
Jobst Brant, Gerd Schraner, and a few others seem to think that optimum spoke tension (Optimum Rim Compression) is reached when any further tension increases cause truing problems.

I seriously doubt that you could reach optimum spoke tension on the rear rim without approaching a similar average spoke tension to the front rim. (Assuming that the front rims spokes are at optimum tension.) This would require considerably higher drive side spoke tension.
Well... you couldn't know that until you have built at least two wheels, could you? Rather than speculate, since you are about to build your first wheels, maybe keep an open mind and save the serious doubts for when you have some experience to inform your opinion.
You are still applying the average spoke tension theory which still has no justification or basis that you have offered. Since your idea is new and contrary to all manufacturer specifications and experienced wheelbuilder practices, don't you want to have at least a logical basis for why you think it should be the driving design goal? If you do, would you mind sharing it?

Originally Posted by Scott Novak
One way to prove or disprove this would be to tension the rear rim until it gets squirrely, which would indicate that the rim has reached optimum compression and then measure the total spoke tension of all of the spokes and compare that to the same rim non-dished.
Why don't you do this and report back? Are you confident that your first build ever will be of sufficient quality that you can rule out any other interfering variables?

Originally Posted by Scott Novak
"Normal wheels work fine, and you will never be able to confirm or deny that lacing with lighter spokes on the rear NDS produced better reliability on your one wheel,"

There are respectable wheelbuilders that do believe that it's advantageous to use lighter spoke on the non-drive side. It makes a lot of sense in terms of preventing spoke loosening.
If you "don't trust the status quo," don't cite what other wheelbuilders do as support for your idea. That's having cake and eating it pretty clearly... or hipocrisy. There are plenty of experienced professionals in all fields and trades that do things that are of no demonstrated benefit.
If spoke loosening is a problem for you or these respectable builders, in consideration of the fact that it is not a problem for many others, one might examine the quality of the builds first before delving into theories that don't have any empirical verification (or even a logical basis yet).

Originally Posted by Scott Novak
But the possibility of a different lateral wheel stiffness with force applied to the left versus the right raises some questions. And whether or not the different bracing angle on the non-dished side increases stiffness. I haven't seen any stiffness data regarding rear wheels using two different gauges of spokes.

Damon Rinard's Wheel Stiffness Test (DRAFT)
Wheel Stiffness Test

3. Do dished wheels flex differently from one side to the other?

"Dished wheels do not flex significantly differently to the left or right."

However, this test was not performed with lighter spokes on the non-drive side.
But what it did do was demonstrate that the difference in bracing angle did not produce a detectable difference in lateral stiffness side-to-side. If you think of bracing angle as effectively changing the force:deflection relationship, which is what it does, it can very easily serve as a surrogate for spoke thickness, since what that changes is the force:deflection relationship. So this result could easily be applied to your theory. Unfortunately, the difference in bracing angle produces a much larger change in force:deflection than the difference in spoke gauge you are talking about, which would very strongly suggest that your theory is not viable.

Originally Posted by Scott Novak
But I believe his conclusion to be mostly true because I think that when a lateral force is applied to the rim, that force is also transmitted to the opposite side of the rim and the difference in stiffness between the lighter and heavier spokes mostly cancel each other out, provided the spoke tension is high enough and that the rim is relatively stiff.
I think you are correct, and as I pointed out, through the direct analog of changes to each side's force:deflection, his result can be applied to your idea without even a stretch of logic required. Going to lighter gauge is directly analogous and can be easily quantified in terms of reducing the NDS bracing angle with the same gauge, which also doesn't support the idea of increasing stiffness.
Interesting discussion.

13. Wow is right. That is an awful lot of theory and contemplation for building your first wheel.

14. "What this points out is not that the rear should match the front, but that the front is much higher than necessary."

I'll accept that as a possibility. I have yet to see a definitive method to determine optimum spoke tension, other than to increase the spoke tension until the rim gets squirrely and then back off the spoke tension a little. I don't believe that spokes are tensioned anywhere near their optimum point because of inadequacies of the available rims, spoke nipples and spoke threads.

I don't believe that it's actually optimum spoke tension that we are trying to achieve anyway. I believe that instead we are trying to achieve optimum rim compression. Whether this means that there is an optimum level of rim compression for a given usage, or if there is simply an optimum level of rim compression and the rim strength determines the acceptable usage, I don't know. I haven't seen a good explanation in any of the wheel building books that I've read.

I have seen rims get squirrely when the spoke tension got high. I thought it was because the rims were bent or poor quality, but it seems that is just the nature of a rim when it is compressed excessively.

"Many Park tension meters read high and therefore give you low tension."

I am in fact using a Park tension meter. I bought it used from someone that only used it for his own bicycle and it looks brand new with little usage. It agreed with another Park tension meter that I compared it against. However, that doesn't mean that either meter was accurate.

Scott Novak

15. ## Spoke Length Calculations - Compensation for Spoke Stretch &amp; Spoke Hole Stagger?

Originally Posted by Scott Novak
"What this points out is not that the rear should match the front, but that the front is much higher than necessary."

I'll accept that as a possibility. I have yet to see a definitive method to determine optimum spoke tension, other than to increase the spoke tension until the rim gets squirrely and then back off the spoke tension a little. I don't believe that spokes are tensioned anywhere near their optimum point because of inadequacies of the available rims, spoke nipples and spoke threads.
What does this even mean? If the spokes in a built wheel are tensioned as high as they can be without causing other problems, that's optimum. There are no independent optimums for individual components of a structural system. Each component's optimum must be considered in the context of the system.

Originally Posted by Scott Novak
I don't believe that it's actually optimum spoke tension that we are trying to achieve anyway. I believe that instead we are trying to achieve optimum rim compression. Whether this means that there is an optimum level of rim compression for a given usage, or if there is simply an optimum level of rim compression and the rim strength determines the acceptable usage, I don't know. I haven't seen a good explanation in any of the wheel building books that I've read.
Where do you get this stuff? Do you have any basis for these beliefs or just blind faith in your own whacky ideas?
The entire goal is to keep spokes from going slack under the intended usage conditions. If the wheel is strong enough for the intended use, additional tension is unnecessary and therefore not optimum. It does not add stiffness or useable strength, so here's a softball question for you: what would be the point of building a wheel to 168kgf if it would work just fine at 120kgf? For a 36h wheel in almost any usage optimum tension is around 110-120 kgf. How do I know? I've built plenty of wheels for extreme duty at that tension and they have done fine.
Typically the rim is the limiting component of the system, which is why rim manufacturers specify max (not total average) tension and a good wheelbuilder follows that spec.
What on earth is "optimum rim compression" and why would it be relevant?

If you ever get around to actually building any wheels, I'd be interested to see the results of objective investigations into your theories. Now it's starting to seem like you just enjoy your own monologue.

16. Originally Posted by Scott Novak
"I have yet to see a definitive method to determine optimum spoke tension, other than to increase the spoke tension until the rim gets squirrely and then back off the spoke tension a little.
Actually, there is. Hint: yield strength and fatigue limit. Also, you need to determine the cyclic stress on the spokes as the wheel goes 'round. From there you can derive the required tension for optimum fatigue life.

17. ## Spoke Length Calculations - Compensation for Spoke Stretch & Spoke Hole Stagger?

Scott, I'd suggest building a set of wheels first!
(before perfecting all inherent OCD discrepancy issues with how wheels have been built)
All the information others have given will/might make sense.

And once you've built your first set, you'll most likely discover that (if built correctly) they are as perfect as the sum of all their components.

As much as I'd like to see your first results, just build a set of normal wheels within guidelines found on this site.

Sent from my iPhone using Tapatalk

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•

# VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.