Broke two spokes today

[jamesm113]

Ariel Rider X-Class 52V with a 20" wheel. Figure I'll replace all of them.

Was reading that Phil Wood cut spokes are probably going to be a bit stronger. Is that accurate?

I've also noticed the spokes aren't fully seated in the spoke holes - is there a good way to address that?

 

[Base]

depending on where the spoke broke you could estimated what the issue was with the spoke. If the broke in the "elbow/hook" or the spoke at the hubs flange the tension was too low on the spokes (is most common issue)

to get a tight fit with theses spokes in these eyelets, use spoke washers. And during building the wheel, use a centerpunch to correctly seat the spoke heads in the washers.

 

[jamesm113]

I'm not very familiar with spoke washers - are they common items I can get from a bike shop?

 

[jamesm113]

Spokes broke at the hook

 

[Base]

right, presumably running low spoke tension for a while. spoke washers are a common thing

 

[RunForTheHills]

I'm not very familiar with spoke washers - are they common items I can get from a bike shop?

They are common, as are broken spokes. Most bike shops will have them and be able to fix this issue. You can also buy them online.

Some bike shops will have the Phil Wood machine and be able to cut custom length spokes. These are usually single gauge and not necessarily stronger than double butted spokes.

The problem is the steep angles of the spokes when lacing a big hub motor into a 20" rim with a cross pattern. Sometimes you even have to use a radial pattern in this situation.

 

[RunForTheHills]

This link may help: https://ebikes.ca/resources/getting-advanced/wheel-build.html

 

[Gionnirocket]

I'd replace the broken ones and then true the wheel with the proper spoke tension. There's videos available or bring it to a bike shop.
As already stated, it's the most common cause so replacement isn't going to solve the problem unless you true/tension properly.

Also check this from the article RftH linked

Seating at Bend
A common reason for spokes to fail on hub motors isn't because the motor puts extra strain on the spokes, or because the spokes aren't a thick enough gauge, it's because of fatigue failure from spokes that aren't held snug against the flange. If the spoke bend radius is too large or too far from the head, then it can flex up and down at the bend with each wheel rotation, eventually causing it to crack and fail.

This problem has been legendary with overseas built hub motors, and we had some Crystalyte shipments where about half the customers would experience spoke breakage on a recurring basis. Ideally the distance between the head and the bend in your spoke will match the thickness of the hub flange, and you won't have problems. But if not, there are two ways to address the situation. One is to insert a washer under the spoke head. The second way is to lace the wheel in an over/under pattern, such that the spoke tension compresses the bend part of the spoke into the flange.

 

[PCeBiker]

I remember a specific ebike where the hub motor was drilled for 12 gauge spokes, but it had 14 gauge spokes installed.

The loose fitting spokes kept snapping in the same way as your spokes.

The fix was to install 12 gauge spokes.

If this is the case with your wheel, you might need tapered spokes or a new rim with 12 gauge spoke holes for the larger 12 gauge spoke nipples.

 

[jamesm113]

I just measured them - they are 12g already, which matches what ariel rider says they should have

 

[Chargeride]

How past tense speaking and rim supports became the same word is beyond me.

 

[Gionnirocket]

That's why I use the updated speaks on all my wheels.

 

[Chargeride]

I thought free speaks was in your constitution

 

[Gionnirocket]

As is the freedom to bear arms

 

[sc00ter]

I've had 2 rear wheels crumble on my Xpedition. I put it down to machine laced wheels. Once I had them corrected by a human who knows what they're doing the first wheel is holding up just fine and the other is on standby. I'll take the rear wheel off my next new ebike and get it checked out by my wheel guru friend before hand, just to ensure it's correctly done. Broken spokes are horrible!

 

[fooferdoggie]

I just measured them - they are 12g already, which matches what ariel rider says they should have

actually this is the problem. The bigger the spoke the harder it is to fully tension because they tend to be stronger than the rim. so the spokes are not fully tightend so the wheel is weaker. going to 14g spokes and built well will make the wheel stronger.

 

[PCeBiker]

I've got 12 gauge spokes on my fat hub motor and the spoke angle at the rim is bending the spokes.

It looks REALLY Wrong but it's been working fine for ~8000 km now.

It is a double walled rim, so I guess it's stronger, but I don't think it's the right rim for a fat motor?

 

[PCeBiker]

For reference, this is what's going on at the hub,..



That doesn't look right does it?

I intend to leave well enough alone, but what do you guys think?
How would you fix it, or is it OK?
My spokes have always been torqued to spec.

It's a 27.5" rim