Rohloff hub bolt spoke cross

[StuntPilot]

After a look at many photographs of the Rohloff speedhub bui via Google and other sites, I noticed that many were built differently to my Rohloff wheel. Most photographs show that the spokes do not cross the hub bolt - but mine does!

A separate thread on another forum discusses hub fractures and breakages and shows the contrasting arrangements but has no definite conclusion ...

http://yacf.co.uk/forum/index.php?topic=25882.0

I was just wondering how most people's Rohloffs are laced - 'between' the bolt, or 'over' the bolt as in my picture below? The Rohloff manual (page 55) states that ...

Spokes must not cross directly over the hub cap fixing screws on wheels which are 24" or smaller in diameter!


So, technically, it is OK on my Rigida Andra 26" standard rims. However most photographs in the Rohloff manual show that the spokes do not cross the hub bolt. Personally I think there is no difference and would not mind if it was built with the spokes not crossing the bolt as the hub I am sure is very strong and I have full confidence in any good wheel builder. I am not inferring a right or wrong here.

So ...

1: Any engineers out there think one would be stronger than the other?
2: Anyone know how the standard wheel with a Rohloff is currently built?
3: Any thoughts either way, why some are built differently, and respective merits? Is it a personal wheel builder thing?
4: Any experience with wheel building with a Rohloff?

Food for thought and discussion!

[Danneaux]

Richard,

I may be able to offer some comfort to ease your concerns.

1) In my research on Rohloff-related failures (See: http://www.thorncycles.co.uk/forums/index.php?topic=3955.msg18463#msg18463 ), I do note the broken flanges occurred on hubs that have been laced "properly" -- that is, with the spokes not crossing the hub bolts.

2) Somewhere in the course of that research (it may have been an entry on the CTC forum), someone posted a photo of their Rohloff hub that had been laced one direction, and then was relaced in another by a LBS (perhaps to avoid the hub bolts?). In any case, someone from Thorn -- Robin or Andy as I recall -- cautioned against relacing the wheel in a different direction -- i.e. of it started "wrong", leave it so, rather than changing the pattern. The reasoning was the spoke elbows take a "set" in the flange holes that could comprise a stress riser if reversed. As someone who has built a lot of wheels and rebuilt new rims and spokes on reused hubs, I think this is reasonable advice. I that same post, the Thorn spokesperson said they had changed their preferred lacing to avoid crossing the hub bolts as a means of ensuring hub life, but I don't believe they expanded from there. I will see if I can find the post for you.

Beyond that, I'm afraid I don't have any personal experience with the Rohloff hub and can't offer anything more meaningful than speculation. I'm guessing if any of us could answer definitively, it would be Dave (Expr), who has a great deal of experience with the intricacies of Rohloff internal service, and whose opinion and skills I greatly respect.

All the best,

Dan.

[StuntPilot]

Dan

Thanks for that. I have slightly modified my post as I believe there may be no right or wrong here. I have full confidence in any Thorn built wheel.

As for changing it - NO! I understand that it is not a good idea to re-lace a wheel (or re-use the spokes etc). I will be changing to CSS rims in the future when the current rim wears down (a long time away!) and would go with any build at Thorn without questioning. I have given Torla a good off-road thrash and its solid! No question about re-rigging!

Just curious!

Best

Richard

[Danneaux]

Found it, and on Forum member Paulson's own website, Flamme Rouge:
http://paulmor.wordpress.com/2011/01/14/new-rim-and-a-rohloff-spring-clean/

Postscript: A word of advice from Robin Thorn himself, who spotted the new lacing on my spokes in the above photo.  He points out that if you have a Rohloff hub and are having a new wheel built, then be aware that some wheels will have had the spokes laced in a different way to the way it is generally done now, certainly by Thorn.  If this is the case, then lacing the spokes in a different pattern to the way they were originally laced may mean that you end up with dents in the hub flange where the spokes used to sit at about 90 degrees to the current spokes. This is a potential stress riser and may cause flange failure.

As a rule, any hub (especially Rohloff) should be laced the way it was originally built, even if it means crossing the spokes the wrong way over the valve (caused by Euro or US staggered drillings).

<nods> I think you're good on yours, Richard. Best to you and Torla!

Dan.

[StuntPilot]

Dan

So a new wheel rim and spokes laced the same way would be the go with my existing hub at time of renewal. That sounds like the plan then.

Until then its just use the bike! Still interesting stuff though.

Thanks for some great links on your other post - have not seen that one!

Richard

[JimK]

Here's my hub. My bike got shipped to me in November 2010, but hard to say exactly when it was built. My hub serial number is 127514.

[mylesau]

Mine was laced the same as JimK's above by Thorn (late 2009).

[il padrone]

Hmm..... My LBS (experienced with Rohloff to some extent) has laced mine similarly  

Spokes must not cross directly over the hub cap fixing screws on wheels which are 24" or smaller in diameter!

A crucial qualification is used there.

[StuntPilot]

Thanks everyone! Its good to know others are similarly laced across the hub bolt. My Raven Tour is from December 2009.

Richard

[fleur]

I got an interesting document from Rohloff explaining the cause of broken flanges and the choice of spokes to avoid broken flanges, see attachment (sorry, it is in german but I think it can easily be understood).

This document makes me think that Rohloff made an extensive study to understand why fkanges may break.

As you can read, the main reason for flanges to break they found seems to be wrong dimensions of the spoke head.

Re-lacing the hub in a different direction (to avoid hub bolts) is another reason.

[triaesthete]

I think the Rohloff caveat re not crossing spokes over the hub cover bolts when using smaller rims is purely a practical one.

With a smaller rim the spokes would exit the hub closer to the tangent and foul on the supporting material around the bolt hole.

This is a factor related to the spoke angles implied by the unusually large hub diameter, along with the need for two cross lacing instead of three and special rim drillings/nipple exit angle/spoke failures at the thread.

On rebuild an identical lacing pattern would be the best because of the flange hole stress raising issues mentioned below. ( The spoke elbows indent the hub holes and one per hole is enough).

I think Sapim 2.0/1.8/2.0 butted spokes meet all Rohloff technical requirements.

Ian