zandoval 

Been popping spokes on an old wheel set. Its the rear freewheel side spokes that have been popping after a slow climbs. Supposedly they are straight stainless 14ga spokes on a 700c Wheel Set I purchased off the sorely missed Harris Cyclery site many years ago. I am replacing them with Swiss DT 14ga stainless spokes and have had no problems.

I got out the micrometer and the old spokes measure 1.96mm and the Swiss DT measure 2.0.

Is this normal?

Bill Kapaun

And .04mm is how many inches?
A brand new drawing die may produce even thinner than that?

What does your mic read when it's zeroed?

Moe Zhoost

Insignificant difference. We're talking less than the diameter of a human hair.

Steelman54 

In manufacturing there is a tolerance on drawn wire. 0.04 mm = 0.0015 inches. I would hazard a guess that +/- 0.002 inches is normal tolerance here, so no issue. Spoke breakage is due to several factors that come to mind such as improperly tensioned spokes or old and failing due to fatigue.

zandoval 

Understood... Yes it is zeroed and multiple spokes were measured over thier entire length with almost no variance.

Good... That's what I thought. I figure the old spokes are closer to 14ga rather than 15ga and they are generic.

Yes Sir... Just like me...

I think the next time I put a wheel set together I will go for Swiss DT 14ga and use Swiss DT 13ga on the rear dive drive side of the wheel. I hover around 235 to 250 pounds and have not had any problems with popping spokes except on my old wheel sets on the rear drive. Most of my rides are slow and up and down so that rear wheel really gets a workout!

KerryIrons

Please explain "popping spokes." Are they breaking, and if so where. If they are pulling out of the spoke nipples then that suggests you have the wrong size nipples for the spokes you are using. If they are breaking somewhere else, then spoke gauge micro differences can't possibly be the reason. If they are breaking at the end of the threads, then you most likely have some defective spokes.

zandoval 

Sorry for not giving better description as I have never had a spoke fail anywhere but at the J bend. This particular wheel set has over 10 years use on some pretty rough roads with a heavy guy on top of them. I really am mot complaining but when I measured the spoke diameters I noted the difference. They are closer to 14ga than 15ga and it is really a minuscule in difference.

In the future I am considering the Sapim Strong spokes. 13ga at the neck and 14ga on the length and just a little cheaper than the Swiss DT Alpine III

KerryIrons

Consistent failure at the bend most often suggests insufficient wheel tension. The extra flexing of the spokes due to the low tension causes the breakage at the bend. The general rule is that if one spoke breaks, it's a fluke. If two break it's a cause for concern. If three break then the wheel is most likely compromised and a rebuild is in order. It sounds like you're well past that point.

ThermionicScott 

Rather than thick tent-stake spokes, you probably just need more of them.

zandoval 

Thank You for the note. I did a close inspection of the wheel and found a few things. I am lucky enough to have a still in the box, new, unused wheel set of the same manufacture. I found that over all the spoke tension was a few points lower on both sides of the old rear wheel. The spoke nipples are the same on both sets but on the old set 0.05mm more of the nipple was showing above the rim. Also on removing the old spokes from the hub I found indentations from the hub in the crook of the J bend. I have over the years been careful about keeping my wheels true and have made minor adjustments to keep them so. But I have not paid attention to the over all spoke tension over the entire wheel. I will in the future make a point of measuring original spoke tension of new wheel sets before use then attempt to keep that over all tension during maintenance checks.

As a solution for my current problem, I replaced all the spokes on the drive side with new Sapim 14ga spokes. I then loosened to sloppy the entire wheel and then trued laterally, radially and set the dish. The current tension on the spokes closely matches the new wheel set. I am confident the rebuilt wheel has new life and expect my spoke popping to be solved.

As to the OP: It appears that a difference in spoke diameter of 0.04mm is insignificant. The diameter of the old spokes at 0.96mm make them closer to 14ga then 15ga.