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]

(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.


(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.

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.

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.

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

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

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]

(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.

[fourflys]

I think most people run pressures that are way too high... I used to be that way as well... on a 25mm tire, I used to run no more than 90 in the back... I weigh around 190-200, depending on the season...

now with running nothing smaller than a 28, I can go down at least 10 in either end and be safe... if you can fit them, I suggest going bigger on your next set of tires!

[mtechnica]

I feel like most cyclists tend to run too high pressure, at 150-160lbs there's no reason to exceed 95-100psi on any tire IMHO and 75-80 can be totally acceptable for some people with 25-28c

[FastforaSlowGuy]

I have exactly that setup. I run 80/80. Works great as an all around pressure. I'll drop some out for wet stuff. With 23s, I run 100/105.


(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!

[xeladragon]

I don't remember the last time I pumped a tire up to 100 PSI.

Less body weight = lower PSI
Wider rims = lower PSI
Wider tires = lower PSI
Tubeless = lower PSI

Currently running:

Pacent SL23 (18mm ID) + 700x27 Vittoria Pave = 70/75 PSI F/R
Velocity Aileron (20mm ID) + 700x28 Schwalbe One Tubeless = 60/65 PSI F/R

I'm about 155lbs. For 700x25 tires, I'd probably do 85/90 PSI.

[carpediemracing]

Late to the party but some thoughts:

- lowest I saw was when I got to a ride late and didn't pump up the tires. I'd pumped them up 2? days prior? I forget. Anyway I did the ride. After I put the pump to the tubes and saw about 55 psi. Keep in mind that some air came out of the tires to pressurize the hose and whatever gizmo stuff near the gauge. However I'm guessing it couldn't be more than 10 psi worth of air.

Weight at the time was 155-160, 700x23c tires (Bontrager crappy tires that I bought because they came in orange trim), 23mm rims (HED).

I almost washed out on two turns. I was uncertain in one, in another I felt like I was going to hit the curb. Made a clip of the ride (https://www.youtube.com/watch?v=0SwxsCQ4fj4). The turns are the two lefts, both on descents/downhills.

- I pump up my 23c tires to 95/100 or 100/105 psi in the dry. I don't ride much in the wet so I basically ask someone nearby what they put in their tires and do the same. Sort of. I have a hard left at the bottom of a descent at the beginning of the ride and trying less pressure (I've experimented down to 65-70 psi) scared me in the turn. Around 90 psi the tire suddenly feels much better.

- When not cornering hard, when not doing hard out of saddle efforts (sprints/jumps) 65-70 psi is fine. I'd want wider tires to run those pressure consistently. Like my mtb with 2.1" tires, they're at 65 psi for road riding.

[thwart]

I don't remember the last time I pumped a tire up to 100 PSI.

Less body weight = lower PSI
Wider rims = lower PSI
Wider tires = lower PSI
Tubeless = lower PSI



You forgot:

Tubular tires = lower PSI