How low can you go?

[exapkib]

(Not a thread on local politics--I promise!)

Question on tire pressure:

On the tail end of my ride this morning (and what a ride it was--nothing like fall in the mountains), I notice that my bike was riding exceptionally smooth. Almost too smooth, if you know what I mean.

When I got home, I checked the pressure in my tires--I was surprised to find that it was 80psi in the back and 70psi in the front.

I generally run 100psi in the back and 90psi in the front. I'm running Veloflex master (25) on Pacenti SL23 rims. I weigh between 150 and 155.

What is the collective wisdom on tire pressure? Was the 80/70 way too low? I rode 30 miles in the hills (including some significant stretches of rough road) without incident this morning--does that mean this is an acceptable tire pressure for me, or that I tempted fate and got away with it (this time)?

Thanks!

[Matt-H]

It was a great morning for a Fall ride here, too.

I am currently riding Veloflex Corsa 25's on Fulcrum 1's (20 mm wide). I am running 80-85 p.s.i. front and rear and, at about 145 lbs. really like the feel. Definitely smooths out the stiff Fulcrums (I love 'em) but the ride doesn't feel squirmy at all cornering at speed. I say if it feels good, go for it- unless you start pinch flatting the rear.

[JasonF]

Wheels: Campy Neutrons
Tires: Vittoria Pave 27c
Pressure: 90psi front/rear
My weight: 150lbs

Result: Heaven

[Lewis Moon]

On Michelin Pro4 25s I run 75/80 and I weigh 180. I need to watch the pressure because that's about as low as I can go w/o pinch flatting on bad bridge joints, etc. I run 55/60 in my Panaracer 37c Paselas on the Kelly Knobby X.
Really, except on uber smooth surfaces, there's no up side to running high pressure.

[Kirk Pacenti]

Originally Posted by exapkib

(Not a thread on local politics--I promise!)

Question on tire pressure:

On the tail end of my ride this morning (and what a ride it was--nothing like fall in the mountains), I notice that my bike was riding exceptionally smooth. Almost too smooth, if you know what I mean.

When I got home, I checked the pressure in my tires--I was surprised to find that it was 80psi in the back and 70psi in the front.

I generally run 100psi in the back and 90psi in the front. I'm running Veloflex master (25) on Pacenti SL23 rims. I weigh between 150 and 155.

What is the collective wisdom on tire pressure? Was the 80/70 way too low? I rode 30 miles in the hills (including some significant stretches of rough road) without incident this morning--does that mean this is an acceptable tire pressure for me, or that I tempted fate and got away with it (this time)?

Thanks!

Nothing wrong with those pressures at all. The SL23 increases the tire volume quite a bit, so it is actually a good idea (if not a necessity) to reduce the pressure.

Cheers,
KP

[pakora]

I'm about the same as Lewis - ran 80/90 in Pro4s at 210ish when not racing, and in Grand Bois 32s I run 55/60.

(I learned the hard way that running pressure too low racing is something you don't do)

Jan Heine has a long article on measuring tire deflection to figure out your optimal pressure for comfort and rolling resistance at a given width, but heh I never tried it because it would take like an hour and involve another person to learn that what I've settled on by experience is close to ideal.

[KidWok]

Shouldn't be any harm in riding at those pressures...especially at your weight. I'm 190 and don't do more than 80/90 on my 25's.

Tai

[ctbiker]

Jan Heine, editor of Bicycle Quarterly, has done much testing on "best" psi (see http://www.bikequarterly.com/images/BQTireDrop.pdf). Essentially he agrees with Frank Berto that a 15% drop is optimum for rolling resistance/comfort and that fatter tires many times equal or surpass skinnier tires' performance.

I'm amazed when I see cyclists pumping both tires to the sidewall pressure. Your findings seem to verify that lower (to a point) is better.

[Gern]

I am all for comfort, but I have noted that if I go much below 90 in the front with 23, 25 or 28mm tires I get a very "mushy" feeling from the front end. The feeling is particularly present out of the saddle and seems to affect steering accuracy. It is consistent with my Serotta and my TIME (different wheels, etc). I have seen this with Michelin, Conti and Mavic tires. So, in summary, I can't go below 90 psi. I have never tried tires wider than 28mm on a road bike, so no data there.

[shovelhd]

27mm/56mm carbon clinchers
GP4000s 23mm
Butyl tubes
150 lbs
95/90 psi

[vqdriver]

i think at your weight, 100/90 is actually too hi.

Originally Posted by exapkib

(Not a thread on local politics--I promise!)

Question on tire pressure:

On the tail end of my ride this morning (and what a ride it was--nothing like fall in the mountains), I notice that my bike was riding exceptionally smooth. Almost too smooth, if you know what I mean.

When I got home, I checked the pressure in my tires--I was surprised to find that it was 80psi in the back and 70psi in the front.

I generally run 100psi in the back and 90psi in the front. I'm running Veloflex master (25) on Pacenti SL23 rims. I weigh between 150 and 155.

What is the collective wisdom on tire pressure? Was the 80/70 way too low? I rode 30 miles in the hills (including some significant stretches of rough road) without incident this morning--does that mean this is an acceptable tire pressure for me, or that I tempted fate and got away with it (this time)?

Thanks!

[bicycletricycle]

I like to runmy tires down super low, like dangerous low, just for variety.
700x28 panaracer t servs down to 45 or 50. Just got to corner slower and watch for the potholes.

Also, when I air them back up it makes me feel super fast.

[exapkib]

I love learning things. I don't know why I had a line drawn in my head at 90psi. Thank goodness I was running late this morning and forgot to top off the tires! Already looking forward to the next ride.

Originally Posted by Matt-H

It was a great morning for a Fall ride here, too.

I am currently riding Veloflex Corsa 25's on Fulcrum 1's (20 mm wide). I am running 80-85 p.s.i. front and rear and, at about 145 lbs. really like the feel. Definitely smooths out the stiff Fulcrums (I love 'em) but the ride doesn't feel squirmy at all cornering at speed. I say if it feels good, go for it- unless you start pinch flatting the rear.

Originally Posted by Lewis Moon

On Michelin Pro4 25s I run 75/80 and I weigh 180. I need to watch the pressure because that's about as low as I can go w/o pinch flatting on bad bridge joints, etc. I run 55/60 in my Panaracer 37c Paselas on the Kelly Knobby X.
Really, except on uber smooth surfaces, there's no up side to running high pressure.

Originally Posted by Kirk Pacenti

Nothing wrong with those pressures at all. The SL23 increases the tire volume quite a bit, so it is actually a good idea (if not a necessity) to reduce the pressure.

Cheers,
KP

Originally Posted by KidWok

Shouldn't be any harm in riding at those pressures...especially at your weight. I'm 190 and don't do more than 80/90 on my 25's.

Tai

Originally Posted by vqdriver

i think at your weight, 100/90 is actually too hi.

[Admiral Ackbar]

I'm the same weight as you and i run my 25s around 70-80.

i am on 28s right now and loving it. 50psi or less on the road and no problems. I've ridden them down to <35psi for gravel shenanigans and they ride amazing ... gotta watch out for stuff in the road tho.

[oldpotatoe]

Originally Posted by exapkib

(Not a thread on local politics--I promise!)

Question on tire pressure:

On the tail end of my ride this morning (and what a ride it was--nothing like fall in the mountains), I notice that my bike was riding exceptionally smooth. Almost too smooth, if you know what I mean.

When I got home, I checked the pressure in my tires--I was surprised to find that it was 80psi in the back and 70psi in the front.

I generally run 100psi in the back and 90psi in the front. I'm running Veloflex master (25) on Pacenti SL23 rims. I weigh between 150 and 155.

What is the collective wisdom on tire pressure? Was the 80/70 way too low? I rode 30 miles in the hills (including some significant stretches of rough road) without incident this morning--does that mean this is an acceptable tire pressure for me, or that I tempted fate and got away with it (this time)?

Thanks!

I outweigh you by 50 pounds and I use 90 front and back, Vittoria Open Pave clinchers/25 or Vittoria Corsa Elite/25 tubulars. ..I think 80-85 or so would be fine. Don't need 100 psi.