Found a few references to this article in the archives but doesn’t seem like anyone has actually tried this?
Zipp, Conti, and I believe even Michelin websites tend to recommend tyre pressure for 22/23mm tyres around 110-120psi with a F/R bias of maybe 5-10psi max (and yes, lower by 10psi if wet). Zipp I believe even went a step further and suggested that for TT you keep both front and rear tyre pressures equal at 118psi for their tangente 22 line.
This seems totally contradictory to the study cited in Bike Quarterly http://www.bikequarterly.com/images/TireDrop.pdf whereby the authors suggest that for racing, a 40/60 bias be used against their graph of wheel sizes and suggested tyre pressures.
I am 66-68kg and assume bike is 7kg. At that weight, the 40/60 ratio suggests that for 23mm tyres, I should run 70psi in the front and something like 115psi in the rear.
Admittedly I have not tried this yet, but has anyone? Any anecdotal evidence this is better/worse than what tyre manufacturers seem to recommend? I think 70psi is actually way below the minimum inflation most makes suggest already.
There is no way I would ever go below 90psi due to the risk of flats. I am just guessing the tire manufacturers specify a minimum pressure due to the risk of flats and rim damage.
I have to question the validity of an article published from a little known source compared to the R&D of every major tire manufacturer. They don’t say how they measured performance, but refer to an article from 2006. I think tire technology and testing protocol have moved on a bit since then. I’m going to keep relying on the data from other sources than this.
I’ve been a big proponent of wider tires at lower pressures (and lower pressures in general) for years now. I weigh 62kg and with 23mm tires I run 70 psi front and around 90 psi rear. Never had a pinch flat in all of the group rides / races I did. With 25mm tires I run 60 psi front / 75 psi rear. On my daily commuter (entry-level CX bike with rack and panniers) I run 32mm tires at 40 psi front / 50 psi rear. Even when I haul 15 lbs. of stuff in my panniers I never pinch flat.
Bicycle Quarterly actually did a follow-up article recently to the one you’re referring to - their general conclusion was that tire pressure really didn’t matter all that much; rolling resistance is more a function of how supple the tire material is. In other words - good tires are good tires and running them at lower pressures does not slow you down. Nor does inflating them to ridiculously high pressures make you faster. The test was done on dozens of different tires - they also tested clinchers vs. tubulars, effects of wider tires on rumble strips (to simulate riding on cobblestones). Data was recorded using PowerTap and SRM to determine the effect of changing variables. It was a very nicely done study and I highly recommend checking it out.
Note: edited to correct tire pressures at 23mm and 25mm after looking back at my notes from years ago. I stopped running 23mm a while ago once I discovered I was able to run 25mm tires at a comfy 60 psi / 75 psi. Lately I’ve been trying out 27mm tires on my crit / race bike to see if they will fit (they will - barely) and how they ride (awesome comfort and no noticeable speed decrease). I’m running the 27mm tires at 50 psi / 65 psi.
Actually the only time I’ve ever had a major problem with pinch flats in the last 3 yrs. was when I decided to try out 20mm tires - had them inflated at around 100 psi front / 120 psi rear and pinch-flatted BOTH tires on the same training ride. I ran them again the next weekend at 120 psi front / 140 psi rear with no problems, but the ride was absolutely horrible. High pressures / narrow tires FTL.