Triheaven wrote:
Hi. Currently i have the HED Jet 6.9 plus on my Trinity. If i were going to upgrade wheels one at a time, would I be better off changing the front first for a 90mm or getting a disk for the back? Purely interested in which would make the bike faster.
Thanks.
Some thoughts:
- the disc will be the bigger difference for sure
- the deeper front won't make much difference
- tire choice is a bigger issue than the front wheel 6/9
[Technical appendix: evaluating discs is difficult because the magnitude of the savings is very sensitive to yaw angle and also because they have considerable savings in "watts to spin", which is not possible to measure in existing wind tunnels. Thus, you will see a wide range of opinions even among smart people on how much discs actually save, and I honestly don't think anyone knows precisely. I've seen at least one smart person say it's not much, but he was basing that on his own extensive wind tunnel testing which isn't capturing everything, and I disagree. He probably was also assuming zero yaw angle, which isn't realistic. I've done a ton of testing of all sorts, but in all honesty haven't spent much time on disc/non-disc for rear wheels (who has?), so my opinion is based partly on front wheel testing and partly on reading lots of wheel-only tunnel tests by others. The front wheel question has been tested a ton in all sorts of ways by lots of people.]