Originally Posted by
RiderThigh
I have a Trek 7.2 and have done the usual lightweight upgraded parts such as stem, bars, seatpost, fork, SLX cassette and tires/tubes. Ive seen a noticeable improvement at every stage of upgrade.
Now theres not much left to upgrade except for the wheels themselves, the bike now weighs 9.2kg....but OMG wheelsets are freaking expensive and im not looking to spend $500 for a pair of new wheels, sooooo....
If i were to rebuild the wheels with lightweight spokes, maybe even aerospokes and lighter hubs, it would run me about $150, which i think would be good enough. So my question is would simply using more aerodynamic spokes, or lighter weight double butted spokes and lighter weight novatec hubs with sealed bearings be worth it?
No. Aero spokes are only worth 1W at 30 MPH and 0.5W at 20. It takes me about 200W to cruise at 20MPH, and 700W to reach 30 in a sprint.
Weight almost doesn't affect speed on flat ground, and up the steepest hills the change is proportional to the difference in total weight.
Assuming you weigh 62kg for a 71.2kg total weight saving 100g is only going to make you 0.014% faster and a full 500g just 0.7%. If you're 5-25 seconds away from breaking 1 hour in a hill climb those savings are worthwhile, otherwise they're not.
Accelerating the impact doubles as you approach the road surface, although that's still insignificant.