# Rohloff rim choice - spoke angle



## slaw (Apr 6, 2004)

I've just busted a couple of spokes on my Rohloff wheel with a WTB Speeddisc rim, 2 cross, DT Champion 14G spokes. I'd rebuilt it 2 months ago with new spokes having had about 4 go on me. They've all broken at the nipple due to the angle at the rim. The nipple wants to sit very straight, so there is a lot of tension there. In this build I put a kink in each spoke as suggested in Jobst Brandt's book, but I guess that didn't help.

So I'm thinking of replacing the rim. Also will try to get DT Competition spokes, but I couldn't get them in the right length here in Oz.

Any ideas for a 26" disc rim for mostly commuting and loaded backcountry touring? I'm about 150lbs but can carry an extra 50lbs when remote touring.

And any online sources of Competition spokes or equivalent in the shorter lengths?


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## estutjaweh (Jan 3, 2008)

Rigida do a number of rims (the Andra 30 being one of the best) that have the nipple seats drilled at an angle so that the spoke/nipple line resolves the bend and the potential breakage in this area. Can definitely recommend them.

The rim manufacturers are currently decreasing the size of the nipple hole (this seems to be a trend by all manufacturers) which in turn allows the nipple a lot less room to guide itself in the required direction. This increases the problem of spoke breakage at the nipple due to this acute angle.


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## vikb (Sep 7, 2008)

My Rohloff is built up in a Mavic rim...I've been wondering if I'll have any spoke issues. I may end up getting a Rohloff specific rim next time around if I do, but wanted to use locally available parts as much as possible.


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## ALMEIDA (Mar 23, 2008)

Best solution is:

Mavic tubeless rim:thumbsup:


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## vikb (Sep 7, 2008)

ALMEIDA said:


> Best solution is:
> 
> Mavic tubeless rim:thumbsup:


How is a Mavic tubeless rim any different than a Mavic tube rim when it comes to the alignment of the spoke holes with a Rohloff?


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## itsdoable (Jan 6, 2004)

The nipple - spoke angle is an issue with all large flanged hubs.

The main reason for failure there is usually due to insufficient tension and/or stress relieving. When there is not enough tension in the spoke, the angle acts like a spring under load, bending and straitening over the revolution of the wheel, which leads to a fatigue failure. Under higher tension, there is less bending, and when properly stress relieved, there should be minimal bending, even if the tension is on the low side.

Flange diameter has a larger effect on spoke angle then ERD, and there are a lot of heavily loaded Rohloff wheels out there that don't have spoke breakage issues - many laced on ~400gm rims. My guess is that you just need a wheel properly built for large flanged hubs.


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## slaw (Apr 6, 2004)

On the Rohloff site they mention use of Sapim polyax or DT swiss Prohead nipples. Perhaps I might try to source these.

The Rigida rim weighs around 700gm. Don't think I need a rim that heavy. On other bikes I've gotten by with 400gm rims.

Don't need tubeless. Bike often has slicks on it for commuting.


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## ALMEIDA (Mar 23, 2008)

There's a great difference between the Mavic tubeless and tube rim. The alignment of the spokes on the tubeless rim is much more straighter because of the special shape of the eyelets. The seat for the nipples is like a great inner ball shape.


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## prude (Nov 18, 2005)

itsdoable has a pretty firm grasp on the situation, here. I can't overemphasize the importance of stress relieving, as well as pre-aligning and high spoke tension. It also sounds as if you may need spokes that are 1-2mm longer. With a longer spoke, the threads are more likely to be fully engaged in the nipple. If the threads aren't fully engaged in the nipple(threaded portion), the exposed threads on the spoke become a stress-riser; the point at which the spoke is thinner(in the thread valleys), with a sharp edge, is a failure just waiting to happen. Full engagement with the threads of the nipple will eliminate that factor. I would also recommend Competition spokes; Comps will absorb a great deal of stress at the middle of the spoke, thereby reducing the stress which occurs at the ends.


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## slaw (Apr 6, 2004)

I'm gonna try a Mavic 717 rim. The local Rohloff distributor has Sapim double butted spokes in the correct length so I'll use those. See how we go.


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