Why do many high end bikes have more spokes in the rear wheel than in the front? I understand that the rear wheel supports more weight and it drives the bike. However when you brake hard weight shifts forward and most of the braking torque is thru the front wheel. I‘d think the front wheel should be as least as strong as the rear? Am I missing something?
You are correct that weight is shifted forward during breaking but it is due to momentum. When breaking the rear wheel is taking most of the force as it tries to slow the momentum of the entire bike and rider.
There is more weight on the rear tire but the torque starts at the hub and is transferred thorough the spokes to the rim and tire. When braking, the weight is transferred to the front wheel but the braking action is at the rim and is not transferred to the hub as torque.
The braking is on the rim. No torque is applied to the front wheel. Rear wheel carries 2/3 of the weight or more. Also must endure torque loads from the hub. I've never been a fan of less spokes. The weight saving is negligible. The aero improvement is imaginary, as more spokes approach a disc aerodynamically. Stiff wheels deliver power to forward motion more efficiently.
