Extreme spoke angles with big hub motor wheelbuilds

[vulcanears]

I just built a 27.5" wheel with a voilamart motor and the angle between the spoke nipples and the spokes looks extremely dodgy and I'm concerned that it spokes will fail at that bend point. Is there any way to improve this with this build or my next one?

Would nipple washers improve it?

Thank you very much in advance!

[markz]

Your nipple angle doesnt look that bad, I've seen worse wheel builds.
You could use Polyax nipples.
You could drill the rim holes out.
Motorcycle and moped rims have angled nipple holes on the rim.


Polyax nipples

https://wheelbuilder.com/sapim-brass-polyax-nipples/

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Check out goatmans nipple angle
viewtopic.php?f=3&t=82383&p=1597016&hil ... e#p1596985

More info
viewtopic.php?f=3&t=108540&p=1587897&hi ... e#p1587897

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[Chalo]

Those spokes are likely to break at the thread roots, where they exit the nipples. The first step to correct the problem should be to use a drill (same size as the rim holes) to slant the rim holes in the direction of the spokes.

Conical nipple washers might help, but only if the holes in the rim are large enough to allow the nipples to tilt over in line with the spokes. I don't think your grommeted rims will allow that.

I use them to lace 14ga spokes into rims drilled for 12ga spokes.

https://www.jbi.bike/site/product_detai ... mber=56837

[ZeroEm]

by vulcanears » Nov 23 2020 6:56pm

I just built a 27.5" wheel with a voilamart motor and the angle between the spoke nipples and the spokes looks extremely dodgy and I'm concerned that it spokes will fail at that bend point. Is there any way to improve this with this build or my next one?

Would nipple washers improve it?

Thank you very much in advance!

Looks like mine but my wheel is 26", so it is worse. The good news as long as the spokes are tight you should not have any problems. I run over 2.5kw up to 35mph no issues.

[MadRhino]

That is exactly what we don’t want. To build a good wheel you need both, drilling the rim AND adapting nipple angle, either with the use of Polyax nipples and/or nipple washers. If your rim was smaller, a 24’’ for an example, spokes would start breaking in the first 500 miles even without any hard hit. Your 27.5 may last because the spoke angle is not that bad and quality SS spokes (if so) can take it pretty long, but it won’t stand any abuse.

[ZeroEm]

by MadRhino » Nov 24 2020 10:30am

That is exactly what we don’t want. To build a good wheel you need both, drilling the rim AND adapting nipple angle, either with the use of Polyax nipples and/or nipple washers. If your rim was smaller, a 24’’ for an example, spokes would start breaking in the first 500 miles even without any hard hit. Your 27.5 may last because the spoke angle is not that bad and quality SS spokes (if so) can take it pretty long, but it won’t stand any abuse.

It bothers me but have not had a problem, not all are bent one out of four. but will do it different, like the nipple washers.

[999zip999]

Nipple washers you have your nipples pierced ?
I worry more about putting brass washers on the heads by the motor end and take the slack out of there on that volimart motor. Next time. My spokes break at the head. 4to 1. Yes I break spokes and smoke motors. Bad habits.

[TommyCat]

I use the same size wheel with a no-cross pattern. No spoke problems in 2 years, and I forged my own...









Forging shown here at post #13... not that I'm recommending it to anybody.
https://electricbike.com/forum/forum/bu ... #post51586


Regards,
T.C.

[MadRhino]

I use the same size wheel with a no-cross pattern. No spoke problems in 2 years...

Low power, smooth surfaces, low mileage... many reasons for this to last, including luck.

Radial lacing is weak for any hard cornering and rough terrain. Some have no choice because they are building a large motor in a very small wheel but: Single cross pattern makes a much better wheel.

[Chalo]

Radial lacing is weak for any hard cornering and rough terrain. Some have no choice because they are building a large motor in a very small wheel but: Single cross pattern makes a much better wheel.

Radial lacing is not weaker than cross-lacing, at all. There are two problems with it. First, it has to wind up to be able to transmit torque (from pedal drive or a disc brake). This repeated movement can cause fretting at the hub holes and spoke elbows, and spoke loosening. Second, the hub flange may not be strong enough to withstand spoke tension straight outward, and a piece of the hub flange can tear out.

So for a rim braked front wheel, with a strong hub that won't tear out, radial lacing is as strong as any other cross pattern. Laterally, it can be stronger, because all the spokes can be laced outside the flange.

Radial lacing a hub motor is a good choice when the hub is large and the rim is small. In that case, there's no good way to cross-lace. Also, wind-up between hub and rim is negligible when the hub radius is large and spokes are short.

My Crystalyte 5305 radially laced in a 20" wheel has been one of the most boringly reliable wheels I've had, under quite heavy use and plenty of miles so far. No broken spokes, no loose spokes, and it runs perfectly true with no follow up since I built it.

IMG_20200924_203630860~5.jpg (469.64 KiB) Viewed 184 times

[serious_sam]

I use the same size wheel with a no-cross pattern. No spoke problems in 2 years, and I forged my own...
Forging shown here at post #13... not that I'm recommending it to anybody.
https://electricbike.com/forum/forum/bu ... #post51586
Regards,
T.C.

Full points for problem solving, I respect your efforts. Improvise, adapt and overcome.

But that's one area that I would never go diy. Rolling threads is one thing, fine no problem, but reforging the head, no way. Highly stressed. Cyclic loading. Heat treated materials. I'll leave that to the quality control, testing, and consistency of mass production. OTS spokes for me please.