I recently talked with an older age-grouper who said she discovered her disc wheel was actually slowing her down. She had an issue with it on race day with no time to fix, so grabbed her spare wheel. She found she was faster with it vs the disc. Opinions?
Is she a strong cyclist?
I recently talked with an older age-grouper who said she discovered her disc wheel was actually slowing her down. She had an issue with it on race day with no time to fix, so grabbed her spare wheel. She found she was faster with it vs the disc. Opinions?
I’m skeptical.
What exactly did she discover. Meaning how did she quantify it?
My guess is rotor drag. I’ve picked it up several times when aero testing people. Even a slight rub can be as much as 4-6w drag. it can also negate any advantage a disc wheel may have. Now if you have rotor rub on your deep back wheel as well, I’d take the disc with rub over the deep dish with rub assuming the rubs are the same.
How does one quantify that? That’s the rub.
My rule of thumb is to always use my disc wheel. ALWAYS.
RP
I want to know the elevation of that course and tires on the disc and regular wheel. I’m a wheel whore and have tried so many different combinations to figure out the fastest setup. Disc is faster but if the course is hilly, yes it’s hard to spin the disc wheel climbing up.
As mentioned, the disc could have been rubbing. Some discs have more lateral flex than other wheels and can have some brake rub at the rim if the pads aren’t centered and while cranking out of the saddle (very hard to generate this while seated though).
There is also the possibility that she just had a good day on the bike, nothing to do with wheel choice (correlation, not causation).
Discs are faster, period (unless you are doing the Alpe d’Huez triathlon). It’s kinda their whole reason for existing. Of particular note is that there is not a minimum speed you need to ride at for a disc to be faster, so it’s not like only pros and FOP AGs will see a benefit. Slower riders will actually save more time with a disc than faster ones (they get a smaller % gain, but are on course longer).
On top of what has already been said on this thread, rear derailleur rub is also something that can happen if it’s a course with steep inclines.
Thanks for all the replies, rim brake, flat tt course. Time for a couple of test rides! Thanks again!
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
Very likely way too much pressure.
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
90-100 is way too much. Try 60-80(?) depending on your weight.
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
Agree with above…
She has no idea what she is talking about.
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
90-100 is way too much. Try 60-80(?) depending on your weight.
If I ran 60 to 80 psi I’d be pinch flatting on 25s all day, that’s way too low. Even Silca recommends 91 psi for someone 160lbs
Maybe on 28s or 30s but not on 25s
Remember most disc wheels have a fairly narrow internal width. On my disc a 25mm tire measures 26 or 27mm, which at my weight means I’m also running around 90psi
Thanks for all the input! Flat TT course, rim brake. Time for a few test rides! I use 25mm Zipp Tangente w/ latex tubes at 90-100 psi.
90-100 is way too much. Try 60-80(?) depending on your weight.
If I ran 60 to 80 psi I’d be pinch flatting on 25s all day, that’s way too low. Even Silca recommends 91 psi for someone 160lbs
Maybe on 28s or 30s but not on 25s
That depends on how wide a 25mm Tangente is on that particular wheel. On my wheels (various FLO and HED), 25mm tires typically measure out to 28-29mm. So with a typical “25mm” tire, Silca recommends that I run 76-80psi (and I’m pretty sure I’m a lot heavier than you)…
All things being equal, I don’t think this is an opinion. The odds say a huge percentage chance the disc is faster, unless it is an all uphill time trial (not found in triathlon). Hard to believe she was faster on the spare wheel, again, all things being equal.
Agreed…my opinion is that all things were not equal in her testing and set-up and/or her testing was biased against the disk wheel set-up.
202 lbs plus bike
85 psi on 23 GP conti 5000 with latex tube
HED disc is max pressure 75 psi
Silca’s calculator is out of date
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I must have some terrible roads, when I tried that I flatted all of the time. I never went through so many CO2 cartridges in a season 
I’m probably not going to be able to articulate this very well, but you have to know how to ride fast and be aero and take advantage of the various equipment you have. I think some people will ride the same speed no matter what bike/wheels/setup they have. I’ve seen plenty of people get in to the sport, buy a budget bike, then eventually spend $10k on something decent and never get any faster.