Originally Posted by
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.
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.