Author Topic: Andra rim cracks  (Read 1091 times)

hendrich

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Andra rim cracks
« on: October 29, 2021, 10:07:07 PM »
Hi, seeking advice or knowledge of similar occurrences. The people of this forum have much first hand experience.

I built wheels for our tandem using Ryde Andra 35 (559) rims, 36 Sapim butted spokes, and Sapim polyax nipples. Sadly, after 6000 miles of heavily loaded touring, 4 of the spoke holes in the rear wheel have developed 5 mm long hairline cracks in the rim. The spokes are not next to each other, but in very different parts. The cracks are on the obtuse angle from the spoke along the center. The wheel remains perfectly true with average tension of 105 kgf (both sides, Rohloff hub) with 15% variation. The wheel experienced no dramatic shocks during that time.

From literature, the rims are rated for (each) 130kg and tension 140kgf. Our total weight, including the bike and all gear is 210kg and the spoke tension is 105kgf. Both values are well below the maximum rim rating.

This is one of the strongest rims on the market, was this rim abnormal? The front rim has no issues. Some people suggest that 6000 mi is good under such conditions, but I don't agree. I am also considering Sapim MG nipple washers when rebuilding. I have contacted Ryde and waiting for a response. Are nipple washers commonly used for these rims?

Thanks for your comments, Mike
« Last Edit: October 29, 2021, 10:52:54 PM by hendrich »

Danneaux

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Re: Andra rim cracks
« Reply #1 on: October 29, 2021, 10:26:08 PM »
Hi Mike,

I'm so sorry to hear of your experience with the cracked Andra rims on your tandem, the first failures of this rim I've encountered.

I have Andra 30s on my Nomad Mk2 with Rohloff hub and my Enduro-Allroad and Andra 40s on my own tandem, the latter two with derailleur drivetrains. Thorn built the Nomad wheels and I built the others. None use any washers and the spokes are sized to come with the ends at the bottom of the screw slots so the nipple is fully supported internally by the threaded spoke end. All use Sapim Polyax nipples and Sapim Race spokes.

One thing that pops out as a possible contributor is excessively high tire pressure. This is an issue I have to deal with constantly as I have a variety of stokers on my tandem and also use it for touring which includes hauling a trailer. It is not unusual to top out at 600lb/272kg for both riders, all cargo and the loaded trailer when considering a couple weeks' self-supported touring for two (26.5l/kg is typically water -- 58lbs). Unladen, the rig and riders may slot in as "light" as 350lb/159kg.

For sure, I've needed to adjust tire pressures to accommodate the range of loads and this gets very tricky when balancing the need to support so much weigh against the risks of generating excessive jacking forces against the tire bead that can be strong enough to split a rim down the centerline or fracture a sidewall. I seem to have found a compromise that works for my 26x2.0 Duremes; I run F/R pressures of 38/48psi with only myself and usual stoker on unladen day rides and boost that to as much as 45/55psi when fully laden. Under maximum load, I've never found stress cracks in the sidewalls (Schwalbe cautions this is a key indicator of running too long at too-low pressures) and the tires (miraculously!) don't appear to flatten much when viewed from the side by observers (it has so far been impractical for me to measure rim drop under load on the fully laden rig for a variety of practical reasons). I am reluctant to exceed those pressures, which correlate closely to Andy Blance's maximum recommendations in the Thorn Mega Brochure I have in my archives.

So far, I've had no problems with the Andras on these three bikes despite riding them extensively on very roughly ballasted logging roads, gravel, and cross-country, unladen or fully loaded.

Mike, could you possibly take and upload some close-up photos of the rim cracks? Though you've described the problem well, sometimes a photo gives additional insight beyond what words can convey. I think you were spot-on to contact Ryde for their take on things.

Looking forward to hearing more.

All the best,

Dan.

EDIT: I did find note of an Andra rim failure here: https://2londoners1bike.com/tag/andra-30/
This link may be helpful as well: https://www.cyclingabout.com/the-best-rims-for-bicycle-touring/
« Last Edit: October 29, 2021, 11:00:14 PM by Danneaux »

JohnR

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Re: Andra rim cracks
« Reply #2 on: October 30, 2021, 08:11:27 AM »
One potentially relevant point is that Thorn told me (in response to a question about a broken nipple) that they normally use boiled linseed between nipple and rim which acts as a lubricant and stops the nipples loosening.

B cereus

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Re: Andra rim cracks
« Reply #3 on: October 30, 2021, 10:44:17 AM »
Has the wheel been ridden in all-weather conditions?

Winter road salt  will significantly reduce the fatigue limits of aluminium alloys through stress-corrosion cracking. The drilled holes for eyelets are especially vulnerable.

Its interesting that SJS use boiled linseed oil between nipple and rim. The usual practice is to apply the oil to the spoke threads; it initially lubricates and later dries to provide a degree of thread-locking.  I imagine that applying  between nipple and rim would provide useful corrosion protection. I've seen similar recommendations to use Waxoyl around rim eyelets for corrosion protection.

hendrich

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Re: Andra rim cracks
« Reply #4 on: October 30, 2021, 03:28:46 PM »
Dan,
Thanks for the reply, I have posted a picture. There are 4 of similar size. Regarding tires... when on tour 2" Duremes (55psi), sometimes 1.5" M+ when in goathead country, and around home on day rides, 1.6" Supremes (70 psi). I also follow Andy Blance's maximum recommendations from that brochure. Prior to building these wheels, I have read all the cyclingabout.com pages on building strong wheels. That information and the Thorn brochures are the reason I use Andra's. I decided to use 35's, since they support wider tires.  In the link you sent, I believe they cracked a (DT swiss?) EX rim and replaced with Andra 30s, i.e. the Andra's did not crack. The total weight I gave includes all our camping gear/food/water, perhaps we are 220kg sometimes (all on bike's 2 wheels).

You are higher in weight and yet have no cracking, but those higher weights are only with derailleurs? And a significant portion of that weight is on a trailer? For derailleurs (no Rohloff), the spoke angle is closer to 90 from rim and thus better nipple-rim pressure distribution.

I have also attached rim cross sections from Ryde literature models 30, 35, 40. I notice that the 30's have an additional metal bulge at the spoke holes, which may strengthen those rims against cracking, but max specifications are the same 1400N, 130kg/tire. The 40's hole surfaces appears to be planar, relative to the 35's, and so nipple washers on the 35's may not work well.

Regarding other peoples comments, I used oil on the threads and the spokes have not been exposed to salt.

mickeg

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Re: Andra rim cracks
« Reply #5 on: October 30, 2021, 05:29:06 PM »
I was unaware of the MG nipple washers.  After reading a few internet sites I can see where the MG washers would be a good idea on a rim built for heavy duty use, especially with high spoke tension.   

On one of my bikes I used Sapim nipple washers on the drive side on the rear wheel on a derailleur bike.  These are what I used.  I do not recall them as being called an HM, I thought they were the only Sapim nipple washer available.
https://www.bikehubstore.com/Sapim-Nipple-Washer-Round-PolyAx-p/spw-hm.htm

I have used Sapim nipples on all my wheels since I built my Nomad eight years ago.  That said, I have always been a bit nervous that the nipple shape is analogous to being a wedge that could cause a rim crack.  The HM washers should alleviate any problem with the Sapim nipple wedge shape.

If you use nipple washers, adjust your rim ERD in your calculations for spoke length.  In my case I found that I could use the same spokes on the drive side and non-drive side on the wheel I was building if I used the older style (HM) nipples on the drive side because of the way that the washer thickness changed the ERD that I used for spoke length calculations.  That is why I used the nipple washers on that wheel.

Side note - I have often heard people refer to nipple washers as spoke washers.  So, be careful with word choices, as some people confuse the terms.

Danneaux

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Re: Andra rim cracks
« Reply #6 on: October 30, 2021, 05:59:41 PM »
Hi Mike!
Quote
In the link you sent, I believe they cracked a (DT swiss?) EX rim and replaced with Andra 30s, i.e. the Andra's did not crack.
You're absolutely right; I should have read more carefully before posting the link in haste.  :)
Quote
You are higher in weight and yet have no cracking, but those higher weights are only with derailleurs?
Yes, the tandem at present has a derailleur drivetrain with a Rohloff waiting in replacement. The current hubs are Suzue high flange, about 73mm as I recall, but still much smaller in diameter than a Rohloff so spoke angles are indeed less severe. The freewheel hub is double-threaded and a heavily used Arai drum/drag brake is on the offside, so the spokes and rims are subject to braking as well as drive forces. No problems to date.
Quote
And a significant portion of that weight is on a trailer?
My Danneauxbuilt 2-wheel trailer weighs 17lbs/7.7kg empty with hitch assembly. Full, the trailer has weighed up to 125kg/56.7kg...usually split between water and food for two. Tongue weight carried by the tandem's rear axle is a fraction of that, usually about 10-15% depending on how the load is distributed in the trailer.
Quote
The 40's hole surfaces appears to be planar, relative to the 35's, and so nipple washers on the 35's may not work well.
<nods> I see your reasoning in thinking the nipple washers might distribute the stress over a larger area, but I am concerned a) they will be incompatible with the 35's internal profile as you are, and b) they seem likely to offset the advantage of the rim's directional drilling.

As mentioned, I have Andra 30s on two of my singles. I decided to bypass the 35 in favor of the wider 40 for my tandem, the goal beong to maximize internal spacing between the sidewalls, so I did not spend a lot of time researching the 35s. When looking to source the 40s, I did find some listed "Rohloff-specific" directional drillings and others simply mentioned only "directional drilling" and a "smart bead" for the nipple (keeping in mind some of the ad copy was machine-translated from German to English). I'm not at all sure they are the same.

Mike, did you use Sapim's Polyax nipples? They have a rounded profile that nicely matched the dimpling on my Andra 30 and 40 rims.

Yes, the photos helped a lot, thanks. It brings to mind two memories from my past wheel builds, both having to do with the notch-sensitivity of aluminum:

1) Back in the day, Mavic produced a couple of classic box-section road rims, the MA-2 (polished) and MA-40 (hard anodized); both had clinched ferrules. While the MA-2s lasted forever (I am currently running a pair with more than 32,000mi/51,500kms on them), the MA-40s had a tendency to crack where the ferrules were clinched into the hard anodizing, creating a notch where cracks originated and then propagated from.

2) A lot of early 1980s touring bikes used Araya 16A(3) or 16A(5) rims. These used a channel section similar to the old Wolber Super Champion Mod. 58 -- but without ferrules. When these were supplied OEM in factory-built wheels, the spoke tension was usually on the loose side and the rim had no problems with cracking. However, a few of my bike shop friends increased tension and began to find longitudinal cracks starting at the rim holes. When I undid the nipples, we found they had gouged crescents into the rim's inner surface and that where the cracks began. Of course, these were machine-built wheels and no lubrication was used in the build, so the gouging may have been a direct result of the process as much as the design. I had no problems with the one I built.

This is not a universe of cases, but it makes me wonder of perhaps your rim might have had some burred spoke seats or perhaps the nipples you used might not have been fully compatible with the seat profile. Just a thought. It'll be interesting to hear what Ryde says in reply to your inquiry.
« Last Edit: October 30, 2021, 06:01:29 PM by Danneaux »

hendrich

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Re: Andra rim cracks
« Reply #7 on: October 30, 2021, 08:11:16 PM »
Mickeg,
Thanks. I have attached cross section pictures of Sapim MG and HM washers. Agreed, these are nipple not spoke washers. The conical shape of the HM washer presumably mimics the spherical shape of the polyax nipple, and so I guess someone could use the HM washer with regular nipples to achieve better nipple angulation.

The Sapim MG washer seems ideal for my application. Based on the rim cross sections, it appears that the Andra 35 bed is not as planar as the 40 bed. However, the non-planarity is small for a 7.5mm washer, and the washer may conform (bend) a bit to the non-planar surface. The polyax nipples can still rotate in that washer as needed and then the washer expands the pressure contact area of the rim. Seem right?

It is difficult to find the MG washers. The places I can find on web are all in UK, so may order from there.

Dan: I was careful to deburr the spoke holes before building. With polyax nipples
« Last Edit: October 30, 2021, 08:38:53 PM by hendrich »

martinf

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Re: Andra rim cracks
« Reply #8 on: October 31, 2021, 04:27:32 PM »
I've sometimes used brass spoke washers under spoke heads when building on steel-flanged hubs (notably old Sturmey Archer).

Not sure if it made any difference or not as sometimes I have built similar wheels without and they have been fine.

I've never used spoke nipple washers yet, but a quick web search found this : https://www.sapim.be/tools/washers which doesn't show the MS and MG washers.

The round nipple washers appear simply to be 5 mm stainless steel washers, which I already use in three or four outside diameters for various bike-related things. The biggest outside diameter is particularly useful when bolting stuff (such as mudflaps) onto thin metal or plastic mudguards, so I imagine it would spread the load of a spoke nipple quite well on a rim with a flat profile such as an Andra 40. I recently got 2 of the latter to use when any of my current 26" rims wear out, so I will probably try round washers then, taking account of Mickeg's remark on adjusting the spoke length calculation.
 

mickeg

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Re: Andra rim cracks
« Reply #9 on: October 31, 2021, 06:32:42 PM »
...
The round nipple washers appear simply to be 5 mm stainless steel washers, ...

I think that is a brilliant idea, thanks for mentioning that.

Next time I am removing or adding a nipple to a spoke, I will need to experiment a bit.

As I noted above, I have had a concern that the shape of the Sapim nipple could act as a wedge, if just putting in a flat washer would reduce the stress on the rim, I would be all for that.  And a 5mm flat washer is of minimal thickness.  I do not know if the ERD that I used for my Andra 30 rims was off slightly, but the spoke length I used on my Rohloff wheel would probably have to be the next longer size if I used any nipple washers on that wheel.  I have a few threads showing at the top of each nipple.

martinf

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Re: Andra rim cracks
« Reply #10 on: October 31, 2021, 09:33:12 PM »
I have also attached rim cross sections from Ryde literature models 30, 35, 40. I notice that the 30's have an additional metal bulge at the spoke holes, which may strengthen those rims against cracking

That additional bulge on the Andra 30 might be the reason Thorn recommended them on their bike builds, even when a wider rim like the Andra 35 or 40 would seem to make more sense with 50 mm and wider tyres.

mickeg

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Re: Andra rim cracks
« Reply #11 on: October 31, 2021, 09:52:58 PM »
I have also attached rim cross sections from Ryde literature models 30, 35, 40. I notice that the 30's have an additional metal bulge at the spoke holes, which may strengthen those rims against cracking

That additional bulge on the Andra 30 might be the reason Thorn recommended them on their bike builds, even when a wider rim like the Andra 35 or 40 would seem to make more sense with 50 mm and wider tyres.

Dave W., formerly a mechanic at SJS has stated that was the reason.  He was responding to my comment that the Andra 30 is much narrower than I would like for my 57mm tires, I commented that the Andra 40 made more sense and that I was perturbed that they promoted the narrower rim as much as they did. 

I built up my Nomad Mk II eight years ago, at that time a lot of people were still using rims that by todays standards are a bit narrow.

I did not buy my rims from SJS for my Sherpa, I built that up 11 years ago.  My rims on my Sherpa are wider (internal width 21mm) than on my Nomad Mk II with the Andra 30 (internal width 19mm).  I specifically wanted a rim of about 21mm for my Sherpa because I planned to run 40 to 50mm tires on it.  But, I just blindly bought the Andra 30 rims for my Nomad Mk II on SJS recommendation without realizing how narrow they were.  But after paying a lot for the CSS rims, I went ahead and used them on the Nomad.  But if I had realized how narrow they were I likely would have bought wider rims and not bought the Andra 30 from SJS.



hendrich

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Re: Andra rim cracks
« Reply #12 on: October 31, 2021, 11:09:29 PM »
I have an extra Andra 35 rim. I can lay a flat washer on a spoke hole, and can see that it does not sit flat on the hole due to the side-to-side rim curvature. I don't believe that the 2mm thick stainless MG Sapim washer would bend/conform to the rim, rather it would likely sit on side edges and cut into the rim. The attached pic shows usage with a flat rim. Some people use the Sapim HM washer for a curved rim surface, but those washer just mimic the rim contact of polyax nipples (which I am using) and do not increase strength.

The rim-nipple contact area (on outer rim side) for the holes with the hairline cracks shows no evidence of fractures. I still wonder if the hairline cracks are only in the surface anodization and so cosmetic.  After all this, I will do nothing unless Ryde can offer a solution. My opinion is keep riding and watch for crack growth over time or wheel true problems.

PH

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Re: Andra rim cracks
« Reply #13 on: November 01, 2021, 09:41:31 AM »
It's always possible with a sample size of one that it was simply bad luck. I had a Mavic (719?) crack like this around several holes after half the mileage of this one, wheel builder (Local with an excellent reputation) replaced it with the same, re-using spokes, hub and to the same tension and that one lasted till it wore out.
I've also had a couple of Rigida Grizzly CSS crack like this, both on Rohloff wheels, first around 5,000 miles, second about twice that, the two front and one rear derailleur wheels on the same rims have been fine, one of the fronts has done about 20,000 miles.


steve216c

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Re: Andra rim cracks
« Reply #14 on: November 01, 2021, 01:12:40 PM »
I've been a long term Rigida/Ryde user on several bikes with over approx 60,000 km ridden. I used to get my wheels made up by local bike store and went with their recommendations for durable sturdy rims that were not exorbitantly priced. Most of those 60k km had me as a rider weighing in at over 100kg before bike and luggage factored in.

My mainstay was Zac19 but I did venture to their 2000 model on my 26" MTB and experienced similar cracks after a time. The store suggested rims with eyelets would stop that, so the rebuild had same rim with eyelets. But eventually that developed same type of cracks. I presume the eyelets perform in similar way to nipple washers in terms of spreading the load over a larger surface area.

I eventually had a crack at replacing my own rims rather than asking a store, and generally tried to stick to Zac 19 rims for 26" and 28" wheels having a spare new rim of each at home for whenever a rim needed replacing. I've read mixed opinions on whether the eyelets really make a difference, but generally paid the EUR 2-3 more per rim on the off chance that they did. But most wheel failures were simply brake wear and tear erroding the surface, so cannot say in my real world if the eyelets added value or not.

On my Rohloff 28" Winora Labrador purchased 2nd hand, I got my kids to buy me a pair of Andra 30 for Xmas last year to replace worn but otherwise true 10 year old original Vision rims. I built the front wheel immediately with a brand new dynamo hub and Sapim spokes. And I rebuilt the back wheel about 6 weeks ago after the original rim started to bulge as overworn on the braking surface. I did wonder at the time why  Andra were not available with the option of with/without eyelets. But as the Ryde web site suggested they could cope with very high spoke tension, I presumed that the thickness of the rim at the nipple point was sufficiently strong to not need the eyelets. Now I see your photos, I do hope it is an isolated issue- perhaps with a bad batch.

So far, I have been pleased with the Andra rims. The front wheel has around 5,000km and rear wheel just 600km on the Andras. And although I have the Andra 30 and not the same model as your 35, I will keep an eye for micro cracks just in case.

I do wonder if the slightly wider rim of your Andra 35 and/or wider tyres puts additional stress at the spoke point that is stronger on the Andra 30? Or perhaps it is just bad luck and a bad batch.
Perhaps it is like my experience with the Zac 2000 vs 19, where one similar priced model was simply more robust that its counterpart?

Wishing you good luck in resolving. Please share any outcome that Ryde or your bike shop come to. Hopefully they'll replace for free as a sign of goodwill.

Steve
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