loimpact

Curious as to what folks might do. I'm currently running Conti GP regulars right now and typically run 110psi rear and 100psi front (700 x 23). I do that cuz I feel it's best for speed for me. (I think mine are rated up to 130 but would never run them that high for comfort's sake)

I recall one shop I test rode a few bikes at this summer always had mushy tires. I *think* they wanted the test rides to be "cushy" so if I had to guess, I'd say they were at around 80psi. But this was all the typical race bikes from C'dale, Spesh, Fuji, Giant, etc.

No way those tires were rated at that so wonder if they'd expect folks to ride like that regularly.

Anywho....I know we've talked a lot about going over but wondered how far "under" folks might go.

TIA

Igualmente

I find with 25 and 28mm tires that the minimum pressures are a few psi high for the actual weight on the front tire of my bike. The rear doesn't have the same issue.

bengreen79

I usually fill my 700 x 23's up to 120 and ride it all week. By the next time I fill them up, they might be as low as 80 if there was a lot of temperature changes. I would say 90-100 rides the best for me (no speed difference, more comfortable) but I'd rather not fill them up twice a week.

SevenTwentyNine

My Bontrager clinchers are rated at about 100psi-115psi. I run them at 125psi-130psi rear (depending on how hot it is and how fat I feel that morning) and 125psi front. Upgrading to tubulars and you can bet I'll be in the 150-160psi range. I don't know what comfort is.
Oh how LOW will I run them ... excuse me while I show myself out the door.

zvez

I ride 100-105 psi, I weigh 160 pounds. No issues with flats or anything. WHen I started riding last year I was running 120 or so but the lower pressure is definitely much more road friendly.

loimpact

LOL.....

Actually, if you haven't ready already (and I know it feels like it's got to be counterintuitive) there's lots on how a larger, wider, lower pressure tires has less rolling resistance than the opposite. It does seem weird, but apparently it's true. (Thus mfgrs' move to 25mm tires for roadies)

Even so, I still have days I want to pump up to about 150psi just to feel like I'm riding on uncompromising balloons but......

SevenTwentyNine

Oh I've read, I'm well aware, but with the tires I run, they are faster, more responsive, and corner better (actually maybe not so much on the cornering) with the pressures I run them at - first hand experience.
I currently run 700x23 clinchers ... I stopped taking them up to 140psi when a tire exploded on me once. It was a long walk to an alternative source of transport. Now I keep it at 130psi maximum.

What you'll learn from engineering is that the suggested range of tolerances are very different from actual range of tolerances and stresses many compounds are capable of sustaining.

pdedes

at ~180, running 95f, 98r on schwalbe ultremos zx.

hueyhoolihan

at 160 pounds i ride my 20 thru 25mm tires at anywhere from 75 to 80 PSI.

they are mainly 700c Vittoria Corsa's and Continental Supersonics. two bike ahve some very old and very narrow NOS 27 inchers. i have a pair of touring 28mm Continental Ultra something or other's. i run them at 65PSI. then on my 1x1/4 MTB's, about 60PSI.

Bunyanderman

I had 38mm at about 40psi, no problems and ran very comfortable but felt like I was riding in syrup.

StanSeven

Do a search of the tests and you'll find all of what you said isn't quite right. Wider tires do have less rolling resistance at the SAME pressures as narrower tires. That's key. Then rolling resistance doesn't decrease with less pressure. Youll find tests showing how resistance starts to go up with less pressure in the same tire. So what you do with less pressure is make tradeoffs between comfort and resistance.

znomit

I put a new wheelset on a few years ago and accidentally went out with 60psi in both (25c GP4000s usually 85/90ish).
Best ride ever.

alexaschwanden

I usually run the pressure at around 100 psi, but some times for comfort i do 70-80psi.

gsa103

I don't usually go under the MINIMUM recommended pressure. I've done it some just to see if it improved the ride.

My MTB is running ~18psi on 26x2.35in tubeless.
My road bike is usually 75/85 f/r on 700x23 road tubeless. If I were on 700x25, I'd definitely be under the minimum pressure.

LesterOfPuppets

I've had some with a 160 max. Took em up to 120 a couple of times but usually just 95 f, 100 r.

Lazyass

Oh my God.

OldsCOOL

Never. One stone and you are snakebit.

rm -rf

I think some tire tests run the wheels on spinning metal cylinders. That might not be a good substitute for a rough, flat road surface. But anyway:

Here's a test with Continental GP4000 tires in different sizes. The 25c tires are still lower rolling resistance at "comparable" pressures, for instance: 115 psi for 23c and 100 psi for 25c.

I posted this in another 25c thread.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
My tire pressures. I weigh 170 pounds.

23c: 95-100 psi front, 110 rear.
25c: 90 front, 105 rear. So the rear is actually comparably harder than my old 23c was, but it's still comfortable.
25c on rough roads: 85 front, 95-100 rear. Then I'll try to be careful on potholes or rough railroad crossings to avoid pinch flats. And the tires feel a little slower on steering response at these pressures.

rpenmanparker 

crr is unitless. The 50 kg refers to the total load on the tire, which determines to tire compression and contact patch size. So these are the results for a 50 kg load.

canam73

Wait, isn't the date on milk a "sell by" and not "use by" date?

rpenmanparker 

Not according to my wife.

canam73

And men and women are equal. Bollocks to that.

Reynolds 

At 152, I use 95-100 on 23s, but I've tried as low as 80-85, comfortable ride, no problems except for a "soft" feeling.

caloso

I have some Vittoria tubulars that have a 200psi max rating but I typically ride at 60% of that.

popeye

You're using Supersonics on the road? I have them on my track bike but they are paper thin and I won't even roll them on the street into the velodrome.