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How do your spokes look?

Started by handlebar, July 05, 2022, 06:48:03 AM

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handlebar

On a routine check at 2500 miles, all my rear spokes sounded a little loose, and two had come out. That's the least common kind of failure, and it often results from a defective spoke. Checking the hub, I've found several that are sinking. The photo shows what I mean. The top spoke looks good. The second and fourth are gone. The third looks like it's about to go.

Will lubing the holes and tensioning the spokes help? Do yours show signs of wear?

I don't expect the replacements to arrive for several weeks. That bike is my only transportation. Is a new bike my best bet?

Altema

Looks like the heads broke off due to defective spokes, or metal fatigue from them being loose and moving. Have the spokes replaced, the wheel trued, and the tension set by a shop. No lube. I have 6000 miles on my RadMini with no spoke problems, but I do check and adjust tension as a part of maintenance.

handlebar

Quote from: Altema on July 17, 2022, 07:21:10 PM
Looks like the heads broke off due to defective spokes, or metal fatigue from them being loose and moving. Have the spokes replaced, the wheel trued, and the tension set by a shop. No lube. I have 6000 miles on my RadMini with no spoke problems, but I do check and adjust tension as a part of maintenance.

The spokes arrived. The half-pound package took 12 days to leave China, 3 days to cross the Pacific, and 6 days to cross the US.

I'd measured the old spokes, but the new ones seemed much too long. You have to bow them to fit between hub and rim, to get to the hole in the rim. With such short pieces of 12-gauge steel, that took a lot of force.

Rather than ruin the rim liner, I cut a little hole for each nipple I had to access. Replacing the two broken spokes brought the other 34 pretty well into tune. The broken ones were on the chain side. One on the disk side didn't sound tight enough, and I discovered that it was already adjusted as tight as possible. The head was a bit sunken, so I replaced it.

I covered the nipple holes with little squares of 1mm polypropylene. I put duck tape over the squares to keep them in place and give the tube a slick surface. I put the tire back on, but the wheel on the bike, and gave it a spin. It was out of true. With a stick braced against the chain stay, I found a 6" section that was out by 1 or 2 mm.

After I'd tuned the first two replacements, they had relaxed enough for the spokes on the other side of the hub to pull the rim out of line. Retuning the replacements brought the rim into line. The end of the stick dragged evenly against the rim all the way around.

On the head of the third spoke I'd replaced, not even the enamel was damaged. The diameter is 4.6mm. The diameter of the new ones is 4.9mm. That explained why it had sunk somewhat into the countersunk hole in the hub. The problem spokes were defective in head diameter. All three had J bends that had stretched to more than 90 degrees. It makes sense. If the head sinks too deep, the bend is no longer against the other side of the hub. As the angle increases, the pressure on the head focuses on one side. The explains why the heads had popped off on the first two.

If I hadn't periodically tightened loose spokes, they might simple have loosened and let the others carry the load.

I wish Radpower had taken the trouble to answer my inquiry about replacement spokes.




telocity

#3
Well at 4800 miles I had to have rear motor, hub and wheel replaced as it was cheaper than threading a new rim on old motor.   I had replaced most of the spokes by the 4800 mile mark and, in a effort to keep them from getting loose, I had over tightened the spokes and damaged the rim.    So now 300 miles on new wheel, a spoke broke, I decided to bring it in to have a proper fix and today 200 miles later another spoke has broken.     I ride the radwagon only on streets, but they do have potholes.   Average weight on bike is 320lbs with me and  cargo.      So this is a major issue I have with bicycles, if you look online as to average spoke breakage, even with proper adjustments, it is expected that 5 spoke will break in 6000miles.     Can you imagine motorcycle and even cars that have spoked wheels have to replace spokes that often?   There would be a huge outcry.    Anyway, guess I'm back to pulling off rear wheel AGAIN and fixing it myself as I can't afford $99 repair cost + gas to get it fixed at shop every few 100 miles.     

handlebar

Quote from: telocity on August 07, 2022, 11:40:31 AM
Well at 4800 miles I had to have rear motor, hub and wheel replaced as it was cheaper than threading a new rim on old motor.   I had replaced most of the spokes by the 4800 mile mark and, in a effort to keep them from getting loose, I had over tightened the spokes and damaged the rim.    So now 300 miles on new wheel, a spoke broke, I decided to bring it in to have a proper fix and today 200 miles later another spoke has broken.     I ride the radwagon only on streets, but they do have potholes.   Average weight on bike is 320lbs with me and  cargo.      So this is a major issue I have with bicycles, if you look online as to average spoke breakage, even with proper adjustments, it is expected that 5 spoke will break in 6000miles.     Can you imagine motorcycle and even cars that have spoked wheels have to replace spokes that often?   There would be a huge outcry.    Anyway, guess I'm back to pulling off rear wheel AGAIN and fixing it myself as I can't afford $99 repair cost + gas to get it fixed at shop every few 100 miles.     

In the 50s and 60s I rode bicycles a lot more than 6,000 miles, much of it on unpaved roads. I never even heard of spoke breakage. I've read that it's expected in modern road bikes, whose spokes are as slender as possible. I've read that they almost always break at the bend or at the opposite end.

On the spoke in the photo, I see that the head has popped off. That's supposed to be rare in road bikes. I also see that the bend has opened much wider than 90 degrees. That's how mine broke, and I'm sure I know the cause. If the head of a defective spoke is too small, it sinks too far into the countersunk hole. On the other side, the bend is no longer against the hub. That allows tension to stretch the bend. You find the tension low and tighten the nipple. As  you ride, the bend gets stretched more, and you tighten again. The pull on the head gets more and more lopsided until it pops off.

Defective spokes can be detected before they break because the heads make smaller bumps than good heads.

tacomanatx

Your spoke tension is gone causing the spokes to break at the hub.   My MTB tires get this kind of abuse so I end up getting the re-tensioned about every six months.

I had my Rad Wagon wheels trued about every 6 months- the bike weight on inexpensive rims causes issues.   Likely ought to do the same with my RadRunner.

Eric7

I check the bike every 300 miles for loose spokes.  And - there is always one or 2, especially on the rear tire. I just tighten them by feel. Of course, true wheels have benefits but I am trying to save money which is an important goal.


handlebar

Quote from: Eric7 on October 18, 2022, 06:48:00 AM
I check the bike every 300 miles for loose spokes.  And - there is always one or 2, especially on the rear tire. I just tighten them by feel. Of course, true wheels have benefits but I am trying to save money which is an important goal.

Now when I check and find a loose spoke, I feel the head to tell if it protrudes out from the surface of the hub flange as much as the others. (Is flange the right word?) If the head is too small, tightening is not a permanent solution.