vvill’s N + 1 Pointless Prize
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@Subby 136790 wrote:
So my running 23s at 120 psi is not optimal? Is that what I am hearing?
Depends. According to https://janheine.wordpress.com/2016/03/09/tire-pressure-take-home/ a lot depends on the actual tire suppleness (which actually kind of goes along with some of what the velonews article concludes).
Quote:What does it all mean? Here is the take-home summary:- Stiff casings always will be slow. They are even slower at lower pressures.
- Supple casings are fast, and pressure doesn’t matter.
- On smooth roads, tire pressure is a matter of personal preference (at least with supple tires). High and low pressures offer the same performance.
- On rough roads, lower pressures are faster. So if you want to optimize your speed on all roads, including rough ones, go with a relatively low, but safe, pressure.
- Your tire pressure needs to be high enough to avoid pinch flats. If you get pinch flats, increase your tire pressure, or better, choose wider tires. Pinch flats are rare with wide tires.
- On pavement, your pressure needs to be high enough that the tire does not collapse during hard cornering.
- The minimum safe pressure is higher for more supple casings. Stiff casings hold up the bike more, and thus require less air pressure.
- On gravel, you can run lower pressures than on pavement. On loose surfaces, the tires don’t collapse as easily, because the cornering forces are much lower.
- Don’t run your tires so low that the casing cords start to break. That happens only at very low pressures, but if you start seeing multiple lines across the casing where cords have broken, inflate the tires a bit more.
- Berto’s chart still is a good starting point. Inflate your tires to the pressures it recommends, then experiment by adding or letting out some air.
- See what feels best to you. That is the optimum tire pressure for you. Don’t worry about tire pressure any further! At least on paved roads, you won’t go faster or slower if you change your tire pressure.
Even simpler, here is a summary in two sentences:
- Ride the tire pressure that feels good to you.
- When in doubt, let out some air.
Velonews’s conclusion was
Quote:The bottom lineIf you want reliability and good rolling resistance, wide tubeless tires with sealant are the way to go. If punctures are not an issue, and you want pure speed and grip without having to worry too much about tire pressure, go with an open tubular with a great tread compound.
@KayakCyndi 136892 wrote:
You, sir, clearly have too much time on your hands!
Ironically says the one who rides all the hooky rides
N=1 @SarahBee’s 1990s era steel Cramerotti 54cm roadie, appropriately dubbed “Guido.” Riding this bike reminded me of the joy of riding when I built up my first roadie in High School for daily commuting (that was a 70s era Schwimn Continental, powder-blue edition) after having ridden handme downs typical of being the youngest kid in the family.
Guido sliced through the wind around HP like a knife, and absorbed potholes and roadside debries around the Mall like butter during an 18 mile spin between the Mall and DCA (and back). I felt like I could ride this bike all day and feel less beat up than on many modern day carbon bikes (of which I own N+1).
I admit that I’m partial to this bike, having rebuilt it after finding it rusting in shambles in @SarahBee’s shed, after she has been taken out on it by a deer while riding at night on the Anacostia trial system in PG county. Guido got upgraded to a used but not abused Campy Veloce gruppo and Hutchinson Fusion 3 bluewall tires ; new cables, housings, Rigida wheelset & 8-speed cog (not easy to find) and a.r.s. seat. I salvaged the original 53/39 Campy BREV crankset and added Speedplay Zero pedals. Guido weighed in at 22.5 lbs before she added all the bling.
Check out my 18.1 mi Ride on Strava: https://www.strava.com/activities/520590613N=2: @Sarahbee’s Titanium LiteSpeed roadie, 54cm, aka “Speedy Gonzalez”, which I rode while chasing #errandonnee points around DC, but found myself wanting to take this fine machine on the open road for a real ride.
This is an older Litespeed with almost touring-like geometry but the only frame marking is the serial number stamped on the bottom bracket, so I dont know what model it is; the seat stays have concave geometry to absorb shock in the rear triangle. The down tube on this thing is BIG. Someone switched out the original Ti fork for carbon, which is a pity, and makes the front end a bit harsher than originally designed. It has a Dura Ace gruppo with a 53/39 crankset, is light as a feather, and fast. Did I say fast?!
Check out my 13.5 mi Ride on Strava: https://www.strava.com/activities/509665120
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