The results you got are likely heavily influenced by you being so specific - race wheels on your tri bike. Most low crr 23mm tires test faster than 25mm tires when aero is factored in. Plus, many frames still do not fit wide rims with 25mm tires.
For myself (n=1), it comes down to aerodynamics, what wheels I’m running, and what fits in the bike frame I’m riding. On my old TT bike, a 25mm tire was the widest I could comfortably run in the rear, and this was a 25mm tubular. I’m not sure my current Jet Plus disc with a 23mm Corsa Speed which measures > 26mm on the rim would fit on that bike.
My current wheel setup is a HED 3+ front and a HED Jet Plus Disc. I have a Conti SS 20mm on the HED 3+ which measures around 24mm and a Corsa Speed 23mm on the Jet Plus Disc which measures > 26mm. On my tubular wheel set, I have a 23mm front tire and 25mm rear tire, which more than likely measure narrower than the clincher setup I’m currently running.
For training I run wider tires, but for racing it’s balancing aerodynamics, wheel/tire interaction, and rolling resistance.
splain me this. and tell me if i’ve got a problem with my reasoning.
25mm is testing better than 23mm in most rolling resistance tests.
in the limited amount of testing i’ve seen, isn’t 28mm outrolling 25mm?
wider tires are also likely to be more comfortable (lower pressures).
but…
almost 6 in 10 are choosing 23mm or thinner.
yes, there are aerodynamics to consider as well. is this your argument? or is there something wrong with my chain of reasoning above?
One thing to consider is that wide-rim clinchers increase the effective tire size. For example, a 25mm-wide (external) / 21mm-wide (internal) Hed Plus rim makes a tire labeled 23mm inflate to about 25-26mm actual. So - is the poll asking about labeled size, or measured size when inflated?
And, frame fit is an issue. I have a custom tri bike that can fit 30mm tires. But it’s an extremely rare bird. It was outstanding when I used to live in Michigan, with their abysmal road quality. I never understood how people rode 23mm tires at 100psi or more in that state. Newer tri bikes are slowly accepting wider tires, but it’s often capped at about 25mm actual/inflated size.
Most low crr 23mm tires test faster than 25mm tires when aero is factored in. Plus, many frames still do not fit wide rims with 25mm tires.
i’m not disputing you, but do you know this? how many tires have been tested on how many wheels? seems like there must be a lot of aero testing left undone in order to make a broad claim like this. if the 25mm tires on balance outroll their 23mm siblings, then the 23mm tires MUST perform better aerodynamically just to get back to even.
In my case, they simply came with my bike. When it’s time to replace, I’ll consider 25s. Edited to say, my current tires are pretty nice (Schwalbe One, tubeless)… so can’t really see ripping them off till they’re done.
If anything happened to this wheelset I’d get a wide rim wheelset and 25mm tires, if the tires could clear the frame. But not going to go out of my way to change the wheels for a few seconds over 40Km.
On my road bike running 25mm on a Mavic Ksyrium wheelset. Whole different game there. Frame clearance is better, brakes open to allow wider tires, and rear brake isn’t hidden behind the BB making wheel swap a pain in the ass.
6 in 10 of us are too poor/cheap to have a wheel/frame setup to take advantage of anything wider than 23. In the big scheme of things, there aren’t that many rims with internal widths of more than 17mm (though this isn’t much of an issue if you are buying new).
Other factors include the Corsa TLR only being available in 23, up until very recently, some of the TT crowd are still running SS 20s on HED/Specialized Trispokes, and wheels like the Flo 30s being really fat with a 23.
For me, it depends on the wheel and the bike. Shiv with RZR92s - 23 (Vittoria tubulars) as manufacturer recommended. With Hed C+, 25 IRCs which measure 30+. With Eurus, 23 Michelins. Reynolds Assaults (old) 23, Enve 3.4s, 23 (measure 26 and 25). Flo 60s, 23 (measure 25).
I was in my LBS the other day. A 25 Conti 4000s2 on Hed Jet 6+, Pinarello FP Quatro was rubbing on the brake. New tire and it was too big. Sadly there were rub marks on the chains stays where the previous 23 had rubbed, too.
What I wonder about all the width testing is, how specifically is it tied to nominal tire width?