Technical > Wheels, Tyres and Brakes
Andra rim cracks
martinf:
--- Quote from: hendrich on October 30, 2021, 03:28:46 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
--- End quote ---
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:
--- Quote from: martinf on October 31, 2021, 08:33:12 pm ---
--- Quote from: hendrich on October 30, 2021, 03:28:46 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
--- End quote ---
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.
--- End quote ---
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:
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:
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:
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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