Slowman wrote:
stevej wrote:
You didn’t really answer his question. Is your 28 mm tubeless tire @ 65-70 psi faster than a 23mm tire w/ latex @90 psi? Or a 25mm tire w/ latex @85 psi? Let’s ignore aero for this exercise and assume same wheels (eg; enve 7.8), same tire (just different sizes), and no flats. Quick edit: let’s assume the same course… Kona or the queen k.good question. i'm going to let the data speak for itself. just, i think there are facts not in evidence. up higher in this thread is a filtered result from BRR. but i think BRR is about as bad as it gets for the platforms i think we'll see more of (22mm to 25mm inner beads, 28mm to 30mm tires, certainly tubeless, often hookless). i hope to interview josh poertner again and talk more about this. i don't want to speak for him, but i think he'd say that the testing rig that captures everything that goes into this equation is rarely found in the labs testing rolling resistance. and this doesn't begin to touch on what biomechanical or physiological losses there might be associated with muscle vibration. i'll probably spend some time with bio_mcgeek on questions like that (if he's interested in engaging on this), tho i don't know if he's ever studied that in particular.
so the answer is, i don't know the answer. authoritatively. yet. but i expect that you and i will by mid-year.
I will be very very curious to hear information about the bio-physiological losses of vibration and if the difference in vibration has been quantified between say 28mm tires at lower pressures vs 23mm at higher pressures along with just raw rolling resistance. People have been alluding to physiological losses due to vibration however most examples are with something extreme like cobbles riding. In the case of the Zipp TSE white paper they were riding over a dirt road in real world testing and "rough roads" which has ~15 dB/hz (32x more vibrational energy)! higher PSD values than their new condition roads. Which is not at all applicable to tri or the vast majority or road racing. I would this to fade into irrelevance on good roads which is why Zipp was cherry picking dirt roads for their numbers, and they didn't even mention that those numbers were for dirt in the press releases to mislead people!
Also talking to a friend who was a former McLaren engineer with regards to rolling resistance of tires, he was really surprised at how tires have been tested for cycling. As the rollers/drums that are used completely ignore microtexture which was found to be a big contributor to how formula tires behaved.