IPassGas

We have a new tandem with rohloff hub. Like the rohloff very much for tandem, but the large hub causes high spoke angles at nipples and so spoke breakage at nipples. Rims zac19/36 hole/26". We tour long distance, team+gear-bike=420 lbs, 3000 miles on bike. I have read much and working with maker and wheel builder to fix. I am interested to know if others have experienced spoke breakage at nipples with rohloff. If so, what was your fix. Thanks in advance for your info.

conspiratemus1

Does the spoke break in/at the nipple, or does the nipple itself break?

IPassGas

Well inside the nipple where the threading starts on the spoke. The nipples are not damaged and the spokes extend 1 mm out the back of the nipple.

conspiratemus1

No experience with Rohloff so take this with a grain of salt until you get something better. Good wheelbuilding practice is to make sure the spoke runs in a straight line from the elbow in the flange to the end in the nipple seat, the path that would be taken by a tautly stretched thread. In lacing a wheel, the stiff spoke wants to take a gradual bend along that course and will have a residual bend when the tension is brought up. The proximal end of the threads is a stress-riser where the movement resulting from fluctuating tension stored in this bend will eventually break the spoke. This effect is strongest when the spoke makes an awkward angle with the rim, and is also hardest to relieve.

The method ("Improving the Spoke Line at the Rim") is described in Jobst Brandt's The Bicycle Wheel which I heard is now out of print but it has been my resource for a score or so successful (amateur) tandem and single wheels. Essentially you are trying to convert the gradual curve (which stores tension energy) into a couple of fixed, "kinks" by over-bending the spoke at the rim (and the hub, separately) until it takes a set. I have done this on all my wheels and no spokes have broken in the nipple but as I say, no experience with a hub that big, just "ordinary" high-flange tandem hubs. Perhaps the builder of your Rohloff knows all about this and did it according to Brandt,so it's as good as it's going to get already. It's impossible to tell if it was done just by looking at the wheel -- it's subtle even with the spokes loosened.

I find improving the spoke line to be the hardest part of building a wheel, there's a lot of "feel" involved and it's physically demanding -- I'll cry if someone comes along and shows me it's totally unnecessary. The process is different (if somewhat related) to the stress-relieving done after the wheel has been fully tensioned.

As I say, until you get something better....

OneIsAllYouNeed

The best fix will be rebuilding the wheel with a rim that does not put a bend in the spokes. A lot of eyeleted rims and carbon rims over-constrain the nipple when used with large hub flanges. Velocity Cliffhanger, Velocity Blunt 35, and Ryde Andra have historically been good choices with Rohloff hubs. Co-Motion is spec'ing Astral Leviathan and Outback rims on their Rohloff tandems. I would specifically avoid any rim that's less than 20mm deep. It will also help to use double- or triple-butted spokes and Polyax nipples. Don't plan to reuse the spokes from the current wheel because they're most of the way through their fatigue life already.

LV2TNDM

^^THIS^^ Excellent post!

I'd say it's more akin to seating the spoke elbows into the hub flange and cold-setting the spokes as they leave the flange. Stress-relieving is more the process of eliminating spoke wind-up at the end of the build.

I've tried this technique but found it too challenging. I feared I'd crack nipples trying to bend the spoke right where it exits the nipple. But I have never had a wheel with extreme bend exiting the nipple, so never worried about it. With the Rohloff, this is definitely an issue.

I'd ask if the OP is using butted spokes. It wouldn't surprise me if using straight gauge, given the short length of spoke used (from what I've seen with Rohloff wheels.). But you would definitely want to try to source butted spokes to help address this issue, in addition to obtaining the proper nipple-exit spoke bend.

And I don't think you'll find a "rim that does not put a bend in the spokes." The shorter the spoke, the bigger the angle the spoke has relative to normal angle when it reaches the rim. I'd say the ideal solution would be a rim that angles the spoke holes to anticipate these angles. But that would be difficult, as it would have to assume hub use (flange diameter, mainly) and spoke cross pattern. Perhaps the easiest solution would be a rim that has a concave nipple seat and wide nipple hole to allow the nipple to rotate and meet the perfect exit angle from the rim. But this would introduce all sorts of design challenges with reduced strength where it's needed most: at the nipple/rim interface.

IPassGas

Thank you for your advice. I have read that part of Brandt's book. We have a new wheel build with DT prohead nipples (semi-spherical surface) and new spokes/rim. The nipples are now more angled. Using a straightedge, the line between the last cross and where the spoke enters the nipple is straight.

Each nipple is now against an edge of the spoke hole, so asymmetric in the hole. While the higher angle is good, I suspect the asymmetry weakens the rim at the point of contact with the nipple. Time will tell. Perhaps the typical rule of thumb spoke tension of 100kgf should be lower? I wish rim maker would make rims with higher drill angle and specify the value (hard to find). The evolution of the derailleur hub (phil wood) and 48 hole rims made tandem wheels virtually bomb proof for loaded touring. Tandems press the limits of components and some evolution is still needed for rims using rohloff. I hope our new wheels last and carry us to timbuktu, as we very much like the rohloff.

conspiratemus1

Interesting idea to reduce spoke tension. With the rim centred over the hub, the left side spokes contribute much more so good high average tension could be achieved with less on the right side. Someone needs to write a new wheel book for Rohloffs.

Are you really going to Timbuktu? If so (and even if not), you need this song:


Was delighted to find this on YouTube. We had the record at home when I was a little kid (Granddad was a railway conductor.) It was years later that I discovered that Timbuktu was a real place....and even later that I discovered the same about Kalamazoo.

IPassGas

Yeap, tension on both side is same, so rohloff says... comparable strength to 48 spoke derailleur wheel. Thanks for the Timbuktu tune, great stuff. My grandfather would say Timbuktu and Kalamazoo, perhaps paired from that record. No plan on going there, we are often in isolated places where we don't want to breakdown (not that we ever want to).

LV2TNDM

Rohloff would be smart to have proprietary rims made for their hubs. Wheel systems are now standard fare in the industry (Rolf, Shimano, Mavic, etc.), so providing a complete wheelset with perfect nipple placement and angle for their hubs would be a good solution. They would also be able to source custom butted spokes as well. The result would be quite nice. But the price would be pretty high!

The only downside to this approach would be the way it affects OEM and retail hub sales. You don't want to pigeonhole your product by implying it only works with Rohloff-specific rims. That could prove catastrophic for overall sales.

Lowering spoke tension shouldn't make a difference with your failure scenario. I know Wheelsmith recommended slightly lower spoke tensions for tandem wheels. However, I wouldn't go much below 90kgf. It would be a problem if you're nearing zero tension during the rotation cycle. Loaded tandem touring would increase the chance of this happening. And shorter spokes utilized with Rohloff hubs have less elastic range, straight gauge even more so. So be careful pursuing that idea because if it's a problem, fatigue failure will happen even sooner.

BTW, were you able to utilize butted spokes? That would be my main concern after pursuing a wheel rebuild with durability in mind.

IPassGas

Yes, or at least get Ryde or some other rim company to offer it. Recommended Ryde rims still do not have sufficiently high drill angles to center nipple even though they are advertised as rohloff compatible. Thanks for the tension recommendation, we are at an average of 90 kgf. We used straight gauge. If the wheel does eventually fail from spoke breakage at hub (knock on wood), we will know why. Bang on wood, replacing spokes from either side of rohloff hub in field is relatively easy.

geoffs

As a wheel builder I'll just wade in and say that lowering the spoke tension would make it far more likely to have problems. Jan at Wheelfanatyk who was one of the founders of Wheelsmith makes no mention of this. I think you may have either misheard or misconstrued the information. As was said earlier a straight spoke line and even, high tension is the best recipe for a long lasting wheel. I use Sapim washers with Sapim nipples on heavy duty wheels and also with carbon rims. Butted spokes will last longer than straight gauge spokes also

IPassGas

yes, thanks. I was wondering if my park gauge was calibrated, so I built a jig to tension a spoke connected to a weight scale. My gauge was low by 1 park unit (not a standard physical unit ). Tension is actually at average of 105 kgf, feel better about this. Probably the spoke holes will be fine.

LV2TNDM

No, this Wheelsmith advice was in print, but I cannot remember the source. It was while I was managing an LBS and building up my first tandem. We were a Wheelsmith dealer, so it may have been a Wheelsmith industry newsletter. Sorry I can't provide the source, but it was 25 years ago! And I agree with you about high tensions, which is why I advised not dropping below 90kgf on his wheel. And I, too, have argued vigorously for butted spokes for years, rebutting the "buy thicker spokes for a stronger wheel!" assertions I hear all the time.

That said, thanks for the additional input.

IPassGas

The wheel is working good for now at 110 kgf +/- 15%. The spoke line is good with DT prohead nipples. I would like to poise at higher tension, but I am concerned that the spokes might then eventually pull through the rim. Perhaps a reasonable compromise for a rim without eyelets, time will tell.

Rikathedog

I had the same problem with my Rohloff on a Rodriguez tandem with 26" Sun Rhyno Lite rims. 11 at one time! I changed to Ryde Andra 30 rims to solve the problem. The Andra 30 has the spoke entry holes drilled at an angle so the spokes can enter the rim straight are not stressed they way they are with other rims (with no angled entry points.) I also made sure that the wheel was built with Sapim double butted spokes. The butted spokes are better able to take the stress of a slight bend in the spoke given the large flange on the Rohloff hub and the short distance of a 26 inch rim.

IPassGas

Hi, thanks for your reply. Yes, similar experience, we started with Andra 30 (26") but had many broken spokes, specifically breaking at nipple not flange. The shop had more trust and experience with ZAC19 rims so, given their experience, we switched to ZAC19. Sorry to say, the same problem happened again. I convinced them to use spherical nipples and we are now ok. Most important are spherical nipples Saprim proax(?) or DT swiss prohead that allow a greater spoke angle. DB spokes may help in this regard, but spherical nipple heads are more important. We still have ZAC19 and they are holding up ok after a few 1000 miles with prohead nipples, but I wish we had kept the Andra 30. The Andra is thicker at nipple bed, and so you can put more tension on spokes without concern of spokes pulling though. Higher tension is important for tandems especially if loaded with gear. If we break down again, we will switch back to Andra 30. Unfortunately, most experienced US wheel builders are not aware of Rohloff requirements.

Rikathedog

Yes - I forgot to mention that I used DT Swiss Pro-head nipples (rounded). That makes a big difference.

Doge

I have purchased several sets of Mercury and ax-lightness (4 sets) and the two are very different. The ax-lightness are light, but they mold the spoke holes, rather than drill them.
Mercury is an outstanding value, but I didn't think for a tandem, the same as an ENVE. I was wrong.
I heard ENVE was a premier brand and someone said they molded holes too. Not in mine. They are drilled.
I have ENVE 24hole rear, 20 hole front, internal nipples - tubular.
I had them built tightly by a guy who has been building 30 years. I built 100s myself. My guess is he builds to a feel that is about 120kgf. I like higher as the ax are 140kgf.
I broke a rear spoke, at the rim/nipple. That kinda surprised me. 1st time in 20 some years. The reason is the sharp hole edges knick the spoke. For the money - ax-lightness are worth what they charge.

IPassGas

Indeed carbon components have come along way, but I would not trust carbon rims for long distant remote touring with a heavily loaded tandem. In addition, wider tires (>35) are important for those times that we must leave the road or the road surface is bad.

Doge

As always - it depends.
These days - a cell phone. credit card, Lyft and AAA go a long way in the USA. Other place, sure, I'd go different. I don't tour anymore.
A 28mm tubular is kinda like a 32mm clincher in air and what it can take in a hit. The rim design was my issue, and next time, I'd go with the lighter ax-lightness rims and have more reliability on my 400# tandem.

geoffs

Carbon rims are much stronger than aluminium rims for the same weight and are a much better option if you are using disc brakes. It's also possible to specify a custom heavier layup (costs about $20) for carbon rims for extra piece of mind. Our rims for our tandem weigh an extra 100gr more than the standard rim and they are incredibly strong. When building carbon rims I use Sapim proloc nipples with matching SS washers. I also use s washers when building rims for heavy duty tourers

geoffs

Ax-lightness rims might be rated at 140kgf but most hubs aren't. CK, DTswiss etc are only rated to 120kgf, I9 are 90 to 105kgf.
So what hubs were you building to 140kgf?
I build to just under manufactures recommended maximum and use a Wheel Fanatic spoke tension meter to make sure spoke tension is perfectly even.