I've been shopping around for rims for custom builds and have come across a couple questions I hope some of you wheel builders could answer:

1. For one group of rims I've been looking at, and I've only found it for this manufacturer, there are ratings along the lines of "max spoke tension (>300kgs) maximal strength (>100kgs) and torsional strength (50kgs) [and I assume "kgs" is kilograms]. I can't seem to find any other rim manufacturers who advertise these ratings. Do these ratings indicate possible suitability for tandem use? The manufacturer lists similar ratings for their smallest dish wheel (24mm), but the smallest rim does have a 90kg max rider weight.

Second, what is the structural difference between tubular and clincher rims? The rim weights seem to be significantly different (the tubulars often being over 100g lighter than similarly sized clinchers)?

Thanks,
LKW
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