Rim cracks at spokes

[Flow-Rider]

Keep in mind that 120kgf, when you build will be less once you have mounted and inflated a tyre.

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Once you start the cracks from overloading the rim they usually get bigger and not smaller over time.

 

[Oddjob]

Once you start the cracks from overloading the rim they usually get bigger and not smaller over time.

That rim is fubar. I'm talking about the fresh build. I build my rims up to 120kgf and they end up around 100kgf once they have been de-stressed and have an inflated tyre.

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[ozzybmx]

That rim is fubar. I'm talking about the fresh build. I build my rims up to 120kgf and they end up around 100kgf once they have been de-stressed and have an inflated tyre.

You are tool connoisseur, what kind of tension meter would Oddjob have ?

 

[Flow-Rider]

That rim is fubar. I'm talking about the fresh build. I build my rims up to 120kgf and they end up around 100kgf once they have been de-stressed and have an inflated tyre.

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If your tension gauge is inaccurate you can pump the tyre up to what ever you want, it is possible the damage is done in the preliminary stages of the wheel building.

 

[Oddjob]

You are tool connoisseur, what kind of tension meter would Oddjob have ?

The Park one. But it gets calibrated to a fancy digital Sapim one every now and then. I'm pretty sure the lbs has a regular maintenance/calibration regime for tools.

If your tension gauge is inaccurate you can pump the tyre up to what ever you want, it is possible the damage is done in the preliminary stages of the wheel building.

My tensiometer isn't perfect but it's reasonable and calibrated, see above.

I've got a cornucopia of eyeleted Mavics, washered DTs, Velocitys, Enves, Praxis, Nexties, LBs and I haven't had a nipple bed failure yet. And I weigh a lot more than most.

My most common failure type is busted old fatigued spokes and nipples.
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[ozzybmx]

The Park one. But it gets calibrated to a fancy digital Sapim one every now and then.

Good to hear you are still scumming it with us mortals

Yeah its a bit like a shock pump, working out the happy spot for those of us who dont have a calibration instrument to check against may actually be as much as the 20kgf @Flow-Rider has seen.

Quoting Kilogramme-force recommendations of +-20kgf from 100kgf to 120kgf could all be down to the tension meter.

I have numerous shock pumps, at 100psi disconnect, they are at a span of 40psi between them and quite evenly spaced inbetween.

 

[PJO]

If your tension gauge is inaccurate you can pump the tyre up to what ever you want, it is possible the damage is done in the preliminary stages of the wheel building.

I doubt it unless you're guage is miles out. And you should be able to tell because you'll get heaps of spoke wind up if you're over tensioning. Damage is usually due to brute force, sharp hit, when the wheel is loaded.

Good rule of thumb to know your in the ballpark is that double butted (DT comps) twist about a 1/4 turn before you actually tighten when you get to final tension (ballpark 100kgf).
Straight guage twist a bit less maybe a 1/6...
Assuming you have used some sort of lube on the threads: oil, boiled linseed or Loctite (before it sets).

 

[Flow-Rider]

I doubt it unless you're guage is miles out. And you should be able to tell because you'll get heaps of spoke wind up if you're over tensioning. Damage is usually due to brute force, sharp hit, when the wheel is loaded.

Good rule of thumb to know your in the ballpark is that double butted (DT comps) twist about a 1/4 turn before you actually tighten when you get to final tension (ballpark 100kgf).
Straight guage twist a bit less maybe a 1/6...
Assuming you have used some sort of lube on the threads: oil, boiled linseed or Loctite (before it sets).

I've got four rims here with dents in them that I built up, you're free to have a look if there are any cracks in the rim beds but I'll doubt you'll find any. It's easy to over tension a rim if you don't build wheels every day. If you stress relieve in stages as you build you'll get minimal spoke bind anyhow. Anyway, something isn't right with the OP's build, it's where I would start as the only spokes holes that are cracked are the higher loaded side on the rear drive side.