IPassGas

Thanks, that seems like the way to go. I have no experience adding washers. For 0.5 mm thick, but perhaps additional space if the washer is not perfectly flat. Does this have much effect on spoke length calculations?

guy153

If you did 7000 miles on it which I think is what you said then that's pretty good. Aluminium fatigues. There's no getting away from this.

Sockets help and too much spoke tension makes it worse. But a heavily loaded wheel needs quite a lot of tension.

ThermionicScott 

True that aluminum fatigues and tandems are harder on wheels... but I disagree that 7000 miles was "pretty good". This wheel should have been bulletproof!

The Ryde Andra 35 is a heavy rim with thick walls... in ISO 584 size, it weighs nearly as much as the original steel rims (ISO 590) from my old English 3-speed! And with symmetrical dishing for the Speedhub, there are no extreme spoke tensions. So it should have been extra-kind to the rim, no spokes going slack or exceeding the tension spec under load.

Andy mentioned anodizing, and in poking around on the Ryde website, I learned that their "pre anodized treatment" means that the extrusion is literally anodized before the rim is rolled and machined. I thought the industry had learned not to do that, but perhaps it's why IPassGas had premature (IMO) cracking. I would imagine that he is out of any warranty period by this point, but it would be worth bringing up with the dealer and/or Ryde themselves anyway.

ThermionicScott 

You mentioned that the nipples still have a couple of threads left... two 56tpi threads is almost 1mm if my math is right. The ideal spoke would come right to the end of the nipple head. So if you're buying new spokes and planning on 0.5 washers, I'd add 1.5mm to what you had and round to the nearest available spoke.

blamester

Would a washer make much of a difference?
Its the eylet pulling thru the rim.
The tension on the eylet stays the same.
Maybe a small angle change.
​​​​​​

ThermionicScott 

These rims don't have any eyelets. The hope behind a steel washer is that it would spread out the pulling force of the spoke nipple a bit. (On aluminum rims without eyelets, chamfering the spoke holes helps do this a little.)

IPassGas

Thanks for your digging. Does rolling an anodized rim tend to cause the anodization to separate? I presume this would be of only a cosmetic concern. It still seems that the crack is a sign of an underlying problem, perhaps exaggerated by this anodization process.

ThermionicScott 

My understanding from reading Jobst Brandt's rants about it, is that the act of rolling the rims after anodizing causes tiny cracks to form since you're bending an anodized layer that's more brittle than the plain aluminum alloy. Then those tiny cracks can grow from riding on the wheels. Lots of other companies roll the extrusions into rims, weld them, and then anodize them, so they're not "pre-cracked."

Since your rims haven't deformed around the spoke drillings, it's possible that the cracks you see are just in the anodized layer and haven't spread yet. I'd be curious how much more riding it would take for them to truly become a problem. Some folks will take a Sharpie and mark the ends of the cracks to check whether they are growing or not.

canklecat

Both rear wheels of my 1980s hard anodized lightweight low profile rims cracked a year or so ago, after a few decades of use. The spokes pulled through. I'm not sure I even noticed while riding, other than some minor creaking or ticking sounds. I noticed when I did my usual spot check while airing up the tires. First was an Araya CTL-370, I think the lightest clincher rim of that era. Then the Wolber Super Champion Alpine, a little heavier. Great looking wheels for classic bikes. The front wheels are still okay.

Might have been operator error. Both wheels needed frequent truing. Usually I just tightened spokes with the wheels on the bike, eyeballing them until they were true again. I might have overtightened them, although I pinged and squeezed the spokes all around to roughly check the tension. But other users of the same rims said theirs were prone to cracking the same way after 10-20 years. If I get another set I'll baby them, detensioning and retensioning occasionally, on a proper truing stand with tools to check everything. Or not.

But I've switched to all higher profile non-anodized rims, Mavic CXP 30, and Reflex SUP UBI. They're stiffer, don't need truing as often, and seem sturdier. If they're any slower due to the weight, my engine isn't strong enough to notice.

The most bulletproof rims I've ridden are inexpensive Alex S500, semi-high profile. Take-offs from a friend's bike. I use 'em on one of my hybrids. Other than redishing the rear wheel to suit my bike, I don't think I've ever needed to true those rims. And that bike is ridden heavily on rough roads and gravel. Not light or fancy but durable.

guy153

Also surprising that there are no sockets on a rim intended for such heavy use. You do still get these-- I think it was a (fairly low cost) Rigida rim I saw them on recently. Brandt on the subject of pre-anodizing: https://www.sheldonbrown.com/brandt/anodized-rims.html. I have to say it sounds plausible.

Ross200

Ryde makes Andra rims specially drilled for Rohloff-the angle of the spoke hole drilling is optimized for the large hub flange so the spoke path from the rim is less severe. The one photo seems to show quite an angle at the rim. Are these wheels laced 2X as the Rohloff manual requires? Many problems with Rohloff based wheels seem to result from not following the detailed instructions while building.

Crankycrank

Shoot Ryde an email explaining your situation with photos and see what they say. They may have some advice on building the wheels differently or a remote chance they may replace the rim or may just have some valuable info. Nothing to lose by contacting them.

IPassGas

Yes, thank you, I am aware. All Andra rims have angled drillings. If one compares their rim angle drilling specifications to the 2x laced angles determined in a spoke length program (e.g. Freespoke), you find they match fairly well, both radially and laterally for a Rohloff hub. The nipple points in a straight line to the hub, no spoke bending at end of nipple. The angle is the nipple itself with respect to the rim surface, and polyax nipples aid in this angling. There is much talk of "Rohloff drilling" specific Andra rims angles, but I have personally contacted Ryde and they say there is no such thing, the rims are all the same. I followed Rohloff's detailed instructions when I built the wheels. Its not particularly difficult since the wheel has no dish. But, this angle is likely a stress point in the rim hole and so perhaps washers would spread that pressure point, not clear.

The cracks are very small, but a concern. We might bike towards Alaska next year if Canada leaves the door open I would like to determine what action to take on a new wheel to stop this problem. I will pressure Ryde for answers, but that is like sending an email into a black hole. I don't consider myself an expert, so it is good to have comments with different perspectives.

MNBikeCommuter

Is there any wisdom in removing the anodizing around the cracks and seeing if the cracks also exist in the aluminum? If the rim is fine, I'd say you're good to go, plus by removing the crack in the anodizing, the crack won't propagate into the aluminum over time and miles.

Ross200

Did you contact Ryde USA or Ryde NL? In my experience, Ryde USA isn't up to speed on all of Ryde offerings.

From the Ryde.nl website- "ANDRA SERIES
The Andra rims can be ordered in many different wheel sizes and with the drilling angle for the spoke holes optimized for the hub and application. All Andra rims are built to withstand and carry more load than regular rims and can ideally be used for not only regular e-bikes, but also transport bikes with or without motor support." That looks to me like different drilling angles are on someone's radar.

Are all of the cracks on only one side of the nipple and in the same relation to the angle of the spoke? From your pictures, I would believe even the Polyax nipples are not making proper contact with the spoke bed causing localized stress on only one side of the spoke hole. The nipples might be pushing down on one side of the hole and prying up on the other at that angle. 7000 miles of loaded tandem touring is very good service life if this is indeed the case.

If you do disassemble the wheel, you might put some marking ink on a nipple and actually see what kind of contact is being made with the rim.

Sapim makes three different profile nipple washers to match different spoke bed shapes which might help distribute the stresses around the hole. Your pictures suggest the nipples might be too short as is, but you will definitely need longer with the addition of washers. But if the nipple is unable to fit properly because of the angle and diameter of the spoke hole, they might exacerbate the situation.

IPassGas

Thanks for the reply. Yes, Ryde NL said "All Andra 30-rims have standard drillings – spoke holes under angles." And from Ryde literature those angles are 8/2 deg rad/axial. I contacted bike shops in England and Australia knowledgeable with Rohloffs that said the same. Independent of a rim marketed as "Rohloff specific", which I agree that term does exists, these angles are ideal for a rohloff hub. In addition, if I put a spoke into a hole and try to feel where it would best like to point, the angles do change from hole to hole in the correct direction to the hub for that hole position and at the above angles.

The 4 cracks are on the side of the highest stress point (the side on the obtuse spoke angle). I was thinking the Sapim HM nipple washer would be best, with a conic profile. However, I think the HM will just mimic the nipple surface contact and so NOT spread the pressure point at the rim hole. Sapim's literature is unclear on this point saying "HM Washers decrease friction of nipple", which does not equate to increased strength. IMO 7000 miles is not good. I am contacting Ryde, but in the meantime I will not change anything to learn if the cracks grow significantly in time. 105kgf is appropriate for these rims rated for 140kgf and also what rohloff suggests. Anything less for a loaded tandem would not be good.

Crankycrank

You could put a small amount of penetrating fluid on the possible cracks and put some baby powder in the inside of the rim where the suspect cracks are. The powder will make any penetrant more visible. Maybe a little difficult to get the powder through the double wall of the rim but a cotton swap could be used to apply it. This won't necessarily reveal every crack but if the penetrant does seep through you'll at least know for sure that it's a goner.

IPassGas

Thanks, I suspect my best warning will be the wheel going out of true near those spokes and that will take time. In the meantime I will press Ryde for what's wrong, not that I expect a resolution, but maybe they have a worthwhile idea.

bcstones

I wouldn't take a chance...replace the rims & consider 40 hole rims...not sure you can even find 40 hole hubs anymore, but it's a consideration with all that weight & milage

63rickert

Ryde Andra 40? Fully rated to 180kg.

Carrying load is plain hard on rims. On a single bike the rider is usually fully sprung weight. What is in the panniers is unsprung weight. And it bounces. Stoker on a tandem is usually at least partly unsprung weight.

Good suggestions above. Use washers. Try hard to get closer to even tension than +/- 15%. Use bigger tires if they will fit. I would not easily discard a 36 hole Rohloff, tandems are hard on front wheels too so use a 40 hole in front. And if cracks continue to appear you just qualified for steel rims. At possibly less than perfect those are still very strong rims no matter how you look at it.

Ross200

Bill Mould offers some interesting(in a science guy/engineer way) thoughts on rim cracking at the spoke holes in this video. Some thought provoking responses in the comments also.

urbanknight

The issue is probably not the rim itself, but rather the spoke tension. That being said, there has to be eyeleted rims out there, and/or a higher spoke count.

As someone who experienced the joy of flying over the handlebars when a rim failed and caught the fork (no cracks prior), I wouldn't ride one more mile on a cracked rim if I could avoid it.

IPassGas

Thanks, I generally appreciate his videos, very well done. He does discuss the Sapim MG washer (BTW, he uses a lot of great test gear!) He assumes that the washer is relatively flat against the rim. For the Ryde andra rims, the holes have a radial drilling of 8 degrees which is a good angle for Rohloff. So it would seem that the MG washer has a cross section that would help distribute pressure and be flat against rim. Any additional nipple angling would be taken care of by the conical shape of the polyax nipple. The HM washer would be a poorer choice, since the polyax nipple has the conical shape. Here are cross sections of MG and HM washers. Mould's video clarified that the MG washer is not just a simple flat washer from a hardware store.

davidad

The hard anodizing used in some rims will contribute to cracking. It is harder than the Al. and more prone to cracking and taking the crack through the al.