Originally Posted by
Eric F
I still haven’t found anything compelling that tells me my choice for 40s at my last race wasn’t the right choice, for that course. I’m still very interested in finding some factual information that might change my mind.
“Wider is faster” isn’t universally true. There’s an understanding that a wider tire is faster than a narrow tire, at the same pressure. However, if you’re running wider tires, you’re also probably running them softer. BRR data shows us that the 40 Thundero is lower cRR than the 48. BRR also shows us that the same tire with more pressure has lower cRR. Silca’s testing showed the same thing…up to the point that it isn’t. Determining that breaking point is the magic trick, isn’t it? How do we (performance-interested amateur racer) determine that? There’s also the factor that the entire course isn’t the same texture. So, how do we make the judgement about the best overall choice? Until I have a better way, I’ll use my best judgment on width based on my experience/preference, use the Silca pressure calculator, and run (probably) a little less than that. Got a better way?
It's been two weeks since this discussion as live. Have you done any experiments? Gathered any further data to analyze? After a certain point all this talk has to enter into the real world and YOU need to take charge and figure out what is going on.
There is R Chung testing, there is rolldown testing, there are timed climbs, and on and on. Probably a easy half dozen different experimental types that could be easily replicated to produce data and further your knowledge and experience.
What have you done these past two weeks?
There is no argument against suspension losses being the overwhelming factor between close aero and crr tires. There is enough data to estimate on your own what the suspension losses will be and back into where and when wider tires (within this discussion bound) may be slower (never on any event billed as "gravel" in the USA). Suspension losses are too big of a factor. The research we have, that I have posted, demonstrates this clearly. I don't see there is any more I can contribute here. The other posters in this thread attack data and experiments without providing their own counter examples. Nobody else seems interested in performing any themselves.
Where do we go from here?
"Peter Stetina says..."
We might as well go back to 19mm tires at 110 psi for all the good the reams of testing and data produced the past decade has done. If it worked well enough for the Titans of our sport 50 years ago, it must work well enough for us, today.
