Originally Posted by
JAX_11
A discussion at Superweek yesterday and this question was posed!
Wheel A is 58mm deep and weights 1450 grams
Wheel B is 38mm deep and also weight 1450 grams.
Is rotational weight the same or is it easier to spin up the shallower wheel due to cutting through the wind on acceleration?
Does it make no difference as to depth if their the same weight?
It almost seems like its hard to start a sprint or acceleration on deeper wheels of the same weigh!
You're assuming the rims have similar % weight distribution. It may be that the 58mm rim has only a fraction of its mass in the 20mm of rim height (like a fairing for example). You're assuming similar hubs/spokes etc. If you have a 58mm superduper light rim and a clunky 38mm rim it's different than two virtually identical rims on different hubs.
Taller rims tend to weigh more and, generally speaking, across a manufacturer's line, taller rims are more aero (that's the assumption I think that applies to the two rims in question). If the taller wheels don't weigh more they should wind up faster if they're in fact more aero. If they're more aero they'll be much faster at the top end in ideal wind conditions (cross tail I think, and a slight cross head) - the wheel keeps winding up just a bit longer instead of hitting the aero wall.