Broken spokes (2 in 15 days) - followup questions

[christob]

Hi folks;
During June, I've had 2 spokes break on the rear hub wheel. The first broke a week into riding the new bike. The second (about half way around the wheel from the first) broke this week. Each time, they sheared off exactly at the point where the spoke exits the nipple on the rim. These are (I'm pretty sure) 14-gauge spokes, though of course shorter length as they run to a larger 750w hub motor. And I'm a bigger guy at 6'2" 267lbs today. (Curiously, while I was even heavier, and on an identical-model bike - I racked up 850 miles without a single spoke breaking.)

The guys at VEB (bike maker) have proposed that if another one breaks after this repair at my LBS, they would prepare a whole new rear wheel for me with DT Swiss Alpine spokes (which have a taper from 14 to 13 gauge) for beefier spokes.

However, the master wheel builder at my local shop (Bill Mould) said that won't solve the problem -- the problem he believes is that each nipple's angle is very slightly off -- forcing each spoke to have a slight, subtle bend at the point of exiting the nipple, in order for the spoke to "get in line" with the necessary run over to the hub... the nipples can't articulate enough in the current holes, to prevent this. Bill proposes that the proper next step (if another spoke breaks) is not to use beefier spokes, but to delace the wheel, and carefully, individually modify each rim hole with a Dremel, to adjust the inner edge of each hole so the hole allows the nipple enough articulation space to properly "orient" itself in the exact direction the spoke needs to exit, to reach the hub without introducing that bend... (obviously, he would do that work, not me!!)

Just curious for some feedback on both approaches...

 

[rich c]

I’m not sure that just a bigger hole will help. If the rim has spherically stamped recesses, the nipple can stay straight to the spoke. But if it’s just a hole, the flange on the nipple will stay perpendicular to the rim and bend the spoke when tightened. This bend is very obvious on my recumbent tad pole trike with 20” wheels. I’ve broken 2 spokes with only 440 miles. But I ride a crushed stone rail trail. Between the chipmunk holes and washouts, it can be a rough ride! Glad I was able to replace them myself. Pretty sure I’ll be doing this a lot!

 

[J.R.]

One of my bikes has a large diameter 500 watt direct drive hub laced into a 26 inch wheel. Direct drives are much larger and heavier than geared hubs. I know that bend you speak of and I have broken spokes. My breaks have always happened in winter, riding rutted ice packed trails. I'm 6'2" at 188 lbs, so less weight didn't stop the breakage.



My breaks always happened at the sharp bend into the hub. I think one winter I broke 4 or 5 spokes riding on the bumpy ice, which remained on the trails that year for 3 months.

I don't know if altering the rim will help. I own the Park Tool tools to repair and true my wheels. What seemed to help me was truing the wheel often. And I didn't tension the spokes as much as they were from the factory. That allowed the spokes to give a little more, but required more frequent truing.

There are so many different types of spokes and nipples. It's good you're trying to learn your way through this problem. These sites might be helpful, so you can approach whoever repairs your wheel with knowledge.

https://www.sheldonbrown.com/wheelbuild.html

www.wheelbuilder.com/spokes-nipples/

I think your issue can be resolved. I don't think your weight is too much for most quality wheel builds. Good luck.

 

[Nova Haibike]

Beefier spokes won't help, because the bigger gauge is at the hub, not at the rim, which is where you are having the problem. Without seeing the wheel, I cannot say if Bill's idea is the correct one either, but his theory is definitely more likely the problem. I would be more inclined to merely use DT Pro Head Pro Lock nipples, which are designed for the exact purpose of compensating for the acute angles caused by larger hubs/shorter spokes.

 

[christob]

I know that bend you speak of and I have broken spokes. I'm 6'2" at 188 lbs, so less weight didn't stop the breakage. My breaks always happened at the sharp bend into the hub.
I think your issue can be resolved. I don't think your weight is too much for most quality wheel builds. Good luck.

@J.R. interesting that yours are breaking at the other end (hub side) than mine!
Equally interesting, I do remember that on the first bike I got from VEB (no spokes broken in 850 miles), many of the rear hub spokes seemed to have a lot of give/looseness (compared to the front wheel where each was quite rigid.)

 

[christob]

I would be more inclined to merely use DT Pro Head Pro Lock nipples, which are designed for the exact purpose of compensating for the acute angles caused by larger hubs/shorter spokes.

@Nova Haibike Interesting -- do you think the DT ProHead would still be a benefit, if (as @rich c mentions) the nipple holes today might not have any kind of recess/spherical counter-sink -- they're just "straight cylindrical" holes?

 

[TForan]

Is this predominately a problem with hub drives ?

 

[christob]

Hi @TForan; My LBS says it is more common in hub drives. I don't have any past experience on a mid-drive, to compare, personally.

 

[J.R.]

@J.R. interesting that yours are breaking at the other end (hub side) than mine!
Equally interesting, I do remember that on the first bike I got from VEB (no spokes broken in 850 miles), many of the rear hub spokes seemed to have a lot of give/looseness (compared to the front wheel where each was quite rigid.)

Even when I reduced the tension, there wasn't what I would call a lot of give.

I have heard of bad batches of spokes over the years. So many bike companies buying spoke materials from the same manufacturers, a bad batch can involve tens of thousands of bikes. I think Giant had to recall many bikes 4 or 5 years ago and at the same time iZip ebikes had the same issues. I doubt any manufacturer was cutting corners, just a bad batch of steel. I don't think spoke issues are ever systemic. The bad press would eat any cost savings.

If VEB built you a new wheel, would you be out any riding time? If they build you a wheel and let you continue with your current in the interim, that would be ideal.

 

[ebikemom]

Can you return the whole bike?

 

[christob]

@J.R. - VEB would send me a new wheel laced up; I'd use the current wheel until the new one arrived---although this would be only if another spoke breaks since the 2nd spoke replacement done last Wed.
@Amy i doubt I can do that... this bike IS a brand new replacement of my original purchase... I bought the Cafe Mar. 2, and it suffered a mysterious electrical system death in mid-May, at which point they sent me a brand new Cafe bike and I sent back the dead one. It is this second, new bike that has suffered the two broken spokes (and knock on wood, no other issues!)

 

[tomjasz]

5 hub drives, another dozen builds and never a blown spoke. Take the bike to a good LBS for a tuneup.

Hi @TForan; My LBS says it is more common in hub drives. I don't have any past experience on a mid-drive, to compare, personally.

More common with poor hub drive builds, but a bad wheel build without a motor will also fail. Bottom line. More common with bad builds.

 

[Nova Haibike]

@Nova Haibike Interesting -- do you think the DT ProHead would still be a benefit, if (as @rich c mentions) the nipple holes today might not have any kind of recess/spherical counter-sink -- they're just "straight cylindrical" holes?

The DT nipples have a more spherical head which allows it to rotate in the hole more than a standard nipple. But if the holes in the rim are small and deep (because of wall thickness), then the nipples alone will not work.

 

[Ravi Kempaiah]

For what it is worth.

I have had a friend (Shane) who owns Haibike, Optibike and Stromer. His low-end optibike had some spoke breakage but not the Stromer/Haibike. He is at least 50lbs more than you and does his own maintenance.

The key is to use higher quality wheel and spokes (DT Swiss). I can attest that my ST2-s never had any problem even after some pretty hard use over thousands of miles.

The DT nipples have a more spherical head which allows it to rotate in the hole more than a standard nipple.

That's what she said.....

Nipples leading to broken spokes takes all the fun away...

 

[Alex M]

Choosing a higher priced ebike doesn't work for everybody, and you may still get ripped off after paying more. However, with ebikes this approach works more often than not.

In a full-size 1.5K-2K ebike you are being sold a battery, motor and assembling labor - this is what they are making money on. Mechanical components like rims, spokes, gears, pedals are either low quality OR not good enough to carry the weight and stress of a powered vehicle. Those spokes, rims and nipples would've worked forever on a non-powered bike.

If incidents like this would happen in a car, the company would've been buried in lawsuits, would lose thousands of customers and millions dollars in recalls. Bikes are not insured for injuries and manufacturing industry is not regulated to that degree. Anything goes.