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Tire pressure and ride comfort. Any correlation?(10 posts)

Tire pressure and ride comfort. Any correlation?128
Nov 3, 2003 12:14 PM
The below tire pressure question reminded me of a question I'd been meaning to ask.

Will say 10 fewer psi in 120psi tires (front and or rear) make a 'harsh' ride any 'smoother?' Or is this strictly a function of the bike's geometry and material?

Also
Any harm in underpressurizing 10 psi?? I routinely do for some unfounded, probably irrational reason.

Thanks.
definitely a correlation! (nm)jtferraro
Nov 3, 2003 12:28 PM
I run 'em at 100 psi - smoother ride, little loss in efficiency. nmBowWow
Nov 3, 2003 12:32 PM
Certainly...Difference is very noticable...biknben
Nov 3, 2003 12:35 PM
Pump those babies up hard and you'll feel every bump, crack and pebble in the road. Reduce the pressure 5-10% and you'll have a smoother ride. I have this strange fear of pinch flatting and I'm lazy. I pump my tires up to just below the max and then ride for two or three days before pumping them up again. After a day or two, the pressure will drop 10-15 psi. I notice it.

The pressure you use will depend on your weight and the quality of roads you ride on. The pressure should be just high enough that you don't have to worry about pinch-flatting. The benefits of going higher than that are hotly debated.
We need a tire FAQ.jw25
Nov 3, 2003 12:56 PM
First off, the max pressure on the tire sidewall is just that, the maximum pressure you should use. It isn't necessarily the right pressure for you.
Comfort is definitely increased at lower pressures, though the risk of pinch-flats does increase. Too low, and you'll get some disconnectedness in the corners. Too high, and you'll feel every bump in the road, and your cornering traction decreases, since the tires are bouncing over bumps and ripples, instead of flexing to absorb them.
I just got a set of tubular wheels, and since tubular tires can take much higher pressures on average than clinchers, found the effect to be magnified. At 200 psi, my Tufos were very rough, and felt sketchy in the turns, while at 80 psi, they soaked up most of the road chatter. I've settled on 130 psi for them, as they're on deep-section carbon rims for time trials. I'll take a little discomfort for maximum straight-line speed.
So, there's no harm in dropping pressures, and the 110 psi you use may still be too high.
I'm 150 lbs, and routinely run 23mm clinchers at 100 psi on smooth roads, and 95 on rougher roads. I watch for potholes, and have yet to pinchflat (knock wood).
I knew a couple female racers who ran 85 psi in 23's - can't say for their weight, but I'd guess 100 lbs, give or take.
Wider tires can run lower pressures, narrower need more psi, as a general rule.
Don't be afraid to experiment - the only time I take tires to the max. pressure is on the trainer, as it decreases tire wear.
re: Tire pressure and ride comfort. Any correlation?toomanybikes
Nov 3, 2003 1:29 PM
I run Vredesteins which have a max pressure rating of 145 PSI.

I can run 'em at 145 and really it's a lot like having concrete mounted on the rims - same shock absorbency.

If I drop them to 120 or 110 the ride is much smoother and there really is no other down side. If I ran them at 80 or 90 I might get pinch flats but certainly will not at 120.
re: Tire pressure and ride comfort. Any correlation?al0
Nov 3, 2003 2:11 PM
Take a look on http://www.roadbikerider.com. They reccomend 95 rear/90 front (100/105 for heavy riders).

BTW, some researches show that rolling resistance is constant (or almost constant) from 90psi and up (sorry, I have forgotten the source).
I'm just too lazy!Rich_Racer
Nov 3, 2003 2:42 PM
(Or less anal!) I tend to pump my tires up to 120 once a week and let them go down as the week progresses. I guess they get down to 80 on the last day. I do notice a comfort difference and other variables are too much greater to know if there's a performance loss. I haven't pinch flatted for about 18 months (6000 miles). They only flat's I've got have been from glass - I'm fairly sure tire pressure doesn't help with that!
Flats from glass...KEN2
Nov 3, 2003 3:38 PM
Actually, according to Uncle Al at the abovementioned roadbikerider.com, tires at max pressure are more likely to puncture from glass. Makes sense to me.
Thanks for the info. Interesting and helpful! nm128
Nov 4, 2003 6:15 AM