What is acceptable spoke angle?

Hello,

http://www.ebikes.ca/tools/spoke-calc.html With the release of this excellent tool, I've been doing a lot of comparison on various hub diameters and the spoke angles they create with all the cross patterns. The general notion that I gather is that more crosses are better, I don't really know for certain, but I am certain that less spoke angle is better. Anyway, what I am wondering is, what spoke angle might be considered a limit? I imagine this differs from hub to hub as an ebike hub weighs much more than a typical bicycle hub, maybe there isn't a strict answer but more of a vague guideline dependent on the weight of the hub.

What are some things that can be done to aid the nipple seating with various undesirable spoke angles? I've seen sapim polyax (http://www.sapim.be/nipples/brass/polyax) nipples, I've read stuff about things like drilling the holes at an angle and maybe something more that slips my mind, maybe it was washers, maybe it was oddly shaped rim spoke holes.

probably brass washers - they are recommended by many. I just rebuilt my wheel and added them after the recommendations I'd seen here. The spokes certainly are a more snug fit and I kind of feel it will reduce wear on the hubs spoke holes.

alsmith said:

probably brass washers - they are recommended by many. I just rebuilt my wheel and added them after the recommendations I'd seen here. The spokes certainly are a more snug fit and I kind of feel it will reduce wear on the hubs spoke holes.

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I think there may be a misunderstanding or miscommunication.

This question doesn't specifically relate to spoke holes on the hub. This question pertains to spoke angle and spoke nipples, which relate to the spoke holes on a rim.

Thanks for the response.

Acceptable to who? There are many I would expect who might answer the spoke angle is acceptable if the spokes do not break. Me, I think if they even look crooked there is to much stress and I will drill the rim at the angle of the spokes entering it. In 10K+ miles I have yet not had a single problem with wheels built this way. I have another bike with 5K+ miles built the same and it has no problems as well. BMC V2S rear motor running 66V with 12GA spokes on inexpensive Weinmann DM 30 rims. Some trail riding involved but mostly commuting in the burbs. You have been around long enough to probly have a good feel for this by now so look at your builds and trust yourself. If you mess up you may break a few spokes and then you can start over and do it right. So probly not to big of a deal for many of us. Nice nipples but no 12GA units.

biohazardman said:

Acceptable to who? There are many I would expect who might answer the spoke angle is acceptable if the spokes do not break. Me, I think if they even look crooked there is to much stress and I will drill the rim at the angle of the spokes entering it. In 10K+ miles I have yet not had a single problem with wheels built this way. I have another bike with 5K+ miles built the same and it has no problems as well. BMC V2S rear motor running 66V with 12GA spokes on inexpensive Weinmann DM 30 rims. Some trail riding involved but mostly commuting in the burbs. You have been around long enough to probly have a good feel for this by now so look at your builds and trust yourself. If you mess up you may break a few spokes and then you can start over and do it right. So probly not to big of a deal for many of us. Nice nipples but no 12GA units.

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I was kind of hoping someone had deeper insight and a more specific answer like "Don't go over 15 degrees if so much weight is involved" or something. I understand there are limits, but where they lay seems exceptionally vague, I am skeptical that even trial and error will really give me definitive results in where those limits are as there are many variables here. I like the idea of angled drilling paired with other options.

5 is a fibonacci number so 360/5 = 72, this is the total angle between 2 spokes on opposite sides of the hub. 72/2 = 36 which is the angle from from the top flange to centerline. The actual angle from the spoke to the flange would depend on the diameter of the flange. A larger flange makes for a stiffer wheel [insert physics calculations here].

ekline309 said:

5 is a fibonacci number so 360/5 = 72, this is the total angle between 2 spokes on opposite sides of the hub. 72/2 = 36 which is the angle from from the top flange to centerline. The actual angle from the spoke to the flange would depend on the diameter of the flange. A larger flange makes for a stiffer wheel [insert physics calculations here].

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What?



If you look at this picture, you'll see a segment highlighted in red. Is this angle acceptable? If not, to what angle would be stated as acceptable?

My view on spoke pattern is simply that equal spaced straight radial is unacceptable! But pairing the holes in the hub rim or both can make a 0 cross radial pattern acceptable. As Justin pointed out in the thread introducing the new tool, a paired hole radial pattern on a hub motor will have a similar spoke angle to a multi cross set up on a bicycle hub, so will be as strong.
So any cross pattern will also have more angle than this which is acceptable. The limiting factor being can the rim accommodate the nipple angle? as a nipple that is not comfortably sat in perfect alignment with the spoke is also a big no no!

Tench said:

My view on spoke pattern is simply that equal spaced straight radial is unacceptable! But pairing the holes in the hub rim or both can make a 0 cross radial pattern acceptable. As Justin pointed out in the thread introducing the new tool, a paired hole radial pattern on a hub motor will have a similar spoke angle to a multi cross set up on a bicycle hub, so will be as strong.
So any cross pattern will also have more angle than this which is acceptable. The limiting factor being can the rim accommodate the nipple angle? as a nipple that is not comfortably sat in perfect alignment with the spoke is also a big no no!

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Concerning "a paired hole radial pattern on a hub motor will have a similar spoke angle to a multi cross set up on a bicycle hub, so will be as strong." There are still going to be advantages in higher cross patterns that are missed with paired spoke holes. In the thread, when they say "a stronger wheel" They don't mean this is as good or better than a 3 cross pattern, or even 1 cross pattern, but simply better than pure radial cross pattern.

As to the nipple not sitting in alignment with the nipple, that is what the question is about, how does one determine where to draw the line on spoke angle? How do you know how steep is too steep?

Sapim polyax nipples seem like they would be a good idea to use in ebike wheel builds, but even with that, the idea of spoke angle limitations would still be vague at best.

I just laced a 20" wheel with 0-cross paired hole spacing.
Before drilling the motor flange I measured the lowest possible angle without bending the spokes, it was 80 degrees, so I drilled the hole pairs accordingly. The real spoke angle is a bit less, because the spokes go outwards to the flanges (sideways from the rim centerline), but it looks ok.
I have another 24" wheel with 73deg spokes, that is not good, the spokes are crooked at the nipples, and I have all the problems with that (broken nipples, broken spoke, loosing spokes...)

bowlofsalad said:

As to the nipple not sitting in alignment with the nipple, that is what the question is about, how does one determine where to draw the line on spoke angle? How do you know how steep is too steep?

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That's unfortunately not a question with a single answer. The maximum divergence from straight out of the rim eyelet is a function mostly of the nipple's outside diameter and the eyelet's inside diameter and depth. If you use 4mm washers under the nipple heads, and lace 14ga spokes into a rim drilled for 12ga, you get a lot more available angle than if you use a rim with 14ga eyelets. You also get a lot more tendency for the rim to crack at the drillings.

Usually cross-1 lacing works with hub motors on 26 inch wheels. Usually radial lacing is required for 20 inch wheels.

bowlofsalad said:

The general notion that I gather is that more crosses are better, I don't really know for certain, but I am certain that less spoke angle is better. Anyway, what I am wondering is, what spoke angle might be considered a limit? I imagine this differs from hub to hub as an ebike hub weighs much more than a typical bicycle hub, maybe there isn't a strict answer but more of a vague guideline dependent on the weight of the hub.

What are some things that can be done to aid the nipple seating with various undesirable spoke angles? I've seen sapim polyax (http://www.sapim.be/nipples/brass/polyax) nipples, I've read stuff about things like drilling the holes at an angle and maybe something more that slips my mind, maybe it was washers, maybe it was oddly shaped rim spoke holes.

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The only thing I can give you in answer to your questions is that "it depends". :/

If you have small enough nipples and large enough rim holes that they will actually allow the nipple to be straight along the spoke's length at that angle, then the only issue I can think of is how well the nipple acutally seats on the rim inside the hole.

The less of the nipple's inside-rim portion that actually seats on the rim, the more force there is on the area of the rim and nipple actually making contact, making it probably more likely for the rim to fail (crack) at that point, vs the nipple seating fully and evenly around the hole, which it would do if it were perfectly perpendicular to the rim.

One way to help some with this could be to use washers similar to those in rim brake pad mounts, that have a cup in them that allows the whole nipple head to evenly press against the rim.


I have a plan to (someday when i find all the right stuff in my collection) test if actual rim brake cupped washers could be used for this, but one complication of using those is that none of the doublewall rims I've ever seen (which is all I have for this kind of test, AFAIK) have holes on the tube side of the rim that would allow the washers to go in there, so I'd have to drill those holes out a fair bit to allow me to get the washer in and manipulate it while lacing the rim. The other thing I'd probably have to do is change the shape of the flat side of the cupped washers so they more correctly fit the curved rim shape, and thus more evenly distribute the load onto the hole/rim.


I think it's already been done by others with other types of cupped washers, but I didn't want to have to go out and buy them and wanted to re-use the ones I have, hence my (probably bad) idea.

Thanks for the replies guys. It seems like what I am seeing is 6 degrees is an ideal maximum spoke angle under most circumstances, and maybe with sapim polyax nipples that is increased to 9 or 10 degrees, maybe 12 degrees but I am not certain. I think some get away with exceeding this, to a fair degree, but I prefer to play it safe and go with what is most likely to be reliable. So it looks like even with very large rims (559mm-622mm) and small hubs (q100h's hub flange diameter is 108mm for example), it'll still be 1 cross to be on the safe side, agreeing with Chalo.

The cupped washer concept sounds interesting, and experimental. The explanation of spoke angle and nipple contact created an excellent and vivid understanding for myself.

This seems like a good thread for a question like this. I'm trying to weigh 2 paired spoke options with a 24" wheel and paired spokes on a 9c sized mxus hub. Seems like a judgement call between good angle and cross pattern. Rim would have eyelets and polyax sapim spokes.

Option 1:
Paired 20mm spacing and 1cross 13 degree spoke angle
Cross good angle questionable

Option 2:
Paired 20mm spacing 0 cross 5 degree spoke angle
Angle great but lack of cross questionable

So whats the priority for strength with 6kw peaks, crosses or angle?

Using bicycle rims and 14g polyax nipples, 8 degrees is my favored max. This usually requires drilling new holes in the hub for 0.5 cross pattern. On a 9 continent in a 26" rim it turns out to about 11 degrees with 0.5 cross which is acceptable. 12 degrees is really the limit to acheive proper tension without side loading the nipple.

DanGT86 said:

This seems like a good thread for a question like this. I'm trying to weigh 2 paired spoke options with a 24" wheel and paired spokes on a 9c sized mxus hub. Seems like a judgement call between good angle and cross pattern. Rim would have eyelets and polyax sapim spokes.

Option 1:
Paired 20mm spacing and 1cross 13 degree spoke angle
Cross good angle questionable

Option 2:
Paired 20mm spacing 0 cross 5 degree spoke angle
Angle great but lack of cross questionable

So whats the priority for strength with 6kw peaks, crosses or angle?

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I would choose option two without knowing the fitment of nipple into rim. It's enough angle to prevent spoke wind-up. Option one will probably bind the nipples. You could insert one and see how far it can naturally angle to decide for yourself. You can get about two additional degrees through eyelet deformation once the spokes are tensioned.

johnrobholmes said:

I would choose option two without knowing the fitment of nipple into rim. It's enough angle to prevent spoke wind-up. Option one will probably bind the nipples. You could insert one and see how far it can naturally angle to decide for yourself. You can get about two additional degrees through eyelet deformation once the spokes are tensioned.

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Thanks JRH. I was hoping this post would catch your attention. So it sounds like the lower spoke angle takes priority over the need for a cross. The rim will be a 24" dx32 or Rhyno lite xl and I would go with whatever spokes you recommended since I would be buying them from you anyway. Since you sell both of those rims I would assume you are familiar with the fit of the nipple and eyelet. Knowing that, would you still recommend the paired radial option? Thanks.

Just out of curiosity, what is a .5 cross?

Has anyone mentioned that assymetrically drilled factory made rims are available for purchase? They are called Rigida (Ryde) Andra series and the 40 model is plenty strong for any wheel. Makes cross lacing so much more reasonable on hub motors. And the spoke seats have a lot of material to work with.

Thanks for the info on that andra wheel but it looks like the angle drilling is not the direction i am worried about. That wheel looks angled axially not radially like im concerned with. Maybe they are angled that way too but the cross section on the website doesn't show it.

0.5 cross is a different way of saying 20mm paired spacing 0 (or 1) cross on the Ebikes.ca site. Technically still a 0 cross in your diagram, but since there is angles and the spoke holes are 1/2 the distance as normal I call them 0.5 cross. I've seen it used elsewhere too, but I'm sure it isn't industry standard in any way.


On a 26" rim you could probably use the 1 cross version of paired spoke holes, but on your 24" rim the 0 cross version will probably be the choice for the nipples.

DanGT86 said:

Thanks for the info on that andra wheel but it looks like the angle drilling is not the direction i am worried about. That wheel looks angled axially not radially like im concerned with. Maybe they are angled that way too but the cross section on the website doesn't show it.

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You could still fine drill the hole to your disired lateral angle. The Andra rim is very sturdy and has a lot of material around spoke holes. Also it has no nipple eyelets to mess around with.

Here is a couple of 20" 1 cross that a friend of mine laced for me. The spoke angles are very extreme but ive hit some gnarly bumps at 45mph with both of these wheels and they havent needed tensioning or replacement spokes. Spokes are 98mm in length. I dont build wheels myself so im just trusting the guy that built these for me. I havent managed to measure the angles yet...

Matt.

about 1000 miles is the point where spokes start to fail when laced improperly, on 30mph 26" wheels. Its just the right amount of flexing cycles for stainless to fatigue, and when they fail it is like a zipper coming undone. When laced properly, 15 or 20,000 miles is common before one or two spokes pop because of a hard hit. But the failure is localized to the few spokes that were brought past there elastic abilities.


That wheel is simply horrible. I'm sure it rides fine now, but you are working against the clock of failure.

John beat me to that. This build looks terrible. The eyelets make it even worse. Spokes and nipples are made for axial load, not lateral.

Like I say, I am not a wheel builder. The guy said if you start breaking spokes straight away then its no good but if it holds - keep using it. I had my doubts....