What's a good Tire Pressure for a Road Bike for sport riding?
#126
Senior Member
Join Date: Jul 2009
Posts: 5,945
Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 3948 Post(s)
Liked 7,291 Times
in
2,945 Posts
Likes For tomato coupe:
#127
Senior Member
Join Date: May 2021
Posts: 8,399
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4393 Post(s)
Liked 4,837 Times
in
2,991 Posts
#128
Grupetto Bob
Join Date: Sep 2020
Location: Seattle-ish
Posts: 6,208
Bikes: Bikey McBike Face
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 2577 Post(s)
Liked 5,632 Times
in
2,918 Posts
Now on my tubeless 28s its 68-70lbs and on my tubed 700/25 its 82/85lbs. Certainly is a lot more comfortable and am able to maintain within 1 mph my average speeds when I was in my 40s riding 5000 miles/year - but I do that same amount now too.
I could care less if people use a tire calculator (I use the Silca one) or not. What they want to do or not do, or maintain or whatever, has no bearing on me and my enjoyment. I just like to minimize effort so I can either ride further or faster or both. As has been made painfully clear on BF, that is not many peoples objective, and so be it.
__________________
Road 🚴🏾♂️ & Mountain 🚵🏾♂️
Road 🚴🏾♂️ & Mountain 🚵🏾♂️
Likes For rsbob:
#129
Senior Member
Join Date: Mar 2021
Posts: 1,995
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 2700 Post(s)
Liked 486 Times
in
351 Posts
The issue is that to truly make an online calculator you need to add stat weights that depend on the changing conditions. For instance, if its horribly rainy or if it is icy, almost every online calculator will overestimate the pressure very badly. Its easier to "misuse" an online calculator than one might initially suspect. When I used to have to ride in the sleet, id take my mtb tires that I normally pump to like 60-80 and take most of the air out, probably run like 20 if that. These numbers are estimates because as has been pointed out in this thread gauges can be deceiving, a ballpark of +-15% of your target is almost always adequate and easily detectible by hand. I'm not taking out air and then rechecking the pressure with a gauge lol, nobody did that.Trying to put that in an equation is difficult.
Last edited by LarrySellerz; 03-22-23 at 01:58 PM.
#130
Senior Member
Join Date: Jul 2009
Posts: 5,945
Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 3948 Post(s)
Liked 7,291 Times
in
2,945 Posts
The issue is that to truly make an online calculator you need to add stat weights that depend on the changing conditions. For instance, if its horribly rainy or if it is icy, almost every online calculator will overestimate the pressure very badly. Its easier to "misuse" an online calculator than one might initially suspect. When I used to have to ride in the sleet, id take my mtb tires that I normally pump to like 60-80 and take most of the air out, probably run like 20 if that. These numbers are estimates because as has been pointed out in this thread gauges can be deceiving, a ballpark of +-15% of your target is almost always adequate and easily detectible by hand. I'm not taking out air and then rechecking the pressure with a gauge lol, nobody did that.Trying to put that in an equation is difficult.
#131
Banned
Best to check the tire charts as the PSI depends on the weight of the rider and the volume of the tires. A 240 lb rider needs a higher PSI than a 140 lb rider. A 1.95 x 29 clincher tire can run at half the PSI of a 19mm tubular tire with the same rider weight.
My wife and I ride road bikes, road e-bikes, and mountain bikes and so I have 6 different PSI that I use. I made a chart and taped it to my high and low pressure bike hand pumps for fast reference.
My wife and I ride road bikes, road e-bikes, and mountain bikes and so I have 6 different PSI that I use. I made a chart and taped it to my high and low pressure bike hand pumps for fast reference.
#132
Senior Member
Join Date: May 2021
Posts: 8,399
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4393 Post(s)
Liked 4,837 Times
in
2,991 Posts
#133
Senior Member
Join Date: Mar 2021
Posts: 1,995
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 2700 Post(s)
Liked 486 Times
in
351 Posts
Don't get hung up on the numbers, divide by 3 would be better, but my point is that very wet conditions require enormously lower PSI, to the point in which trying to rely on an equation for all conditions is impossible. Using a calculator allows for more user error; any talk of calculators for OP is missing the forrest for the trees because he mentioned he rides in terrible conditions in his first post.
#134
Klaatu..Verata..Necktie?
Join Date: May 2007
Location: SF Bay Area
Posts: 17,952
Bikes: Litespeed Ultimate, Ultegra; Canyon Endurace, 105; Battaglin MAX, Chorus; Bianchi 928 Veloce; Ritchey Road Logic, Dura Ace; Cannondale R500 RX100; Schwinn Circuit, Sante; Lotus Supreme, Dura Ace
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 10420 Post(s)
Liked 11,881 Times
in
6,087 Posts
Likes For genejockey:
#135
Senior Member
Join Date: Jul 2009
Posts: 5,945
Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 3948 Post(s)
Liked 7,291 Times
in
2,945 Posts
Likes For tomato coupe:
#136
Senior Member
Join Date: May 2021
Posts: 8,399
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4393 Post(s)
Liked 4,837 Times
in
2,991 Posts
Don't get hung up on the numbers, divide by 3 would be better, but my point is that very wet conditions require enormously lower PSI, to the point in which trying to rely on an equation for all conditions is impossible. Using a calculator allows for more user error; any talk of calculators for OP is missing the forrest for the trees because he mentioned he rides in terrible conditions in his first post.
#137
Senior Member
Join Date: Dec 2020
Location: Wake Forest, NC
Posts: 5,783
Bikes: 1989 Cinelli Supercorsa
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 3504 Post(s)
Liked 2,922 Times
in
1,774 Posts
#138
Happy With My Bikes
Join Date: Sep 2020
Location: Oklahoma
Posts: 2,186
Bikes: Hi-Ten bike boomers, a Trek Domane and some projects
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 884 Post(s)
Liked 2,307 Times
in
1,117 Posts
#139
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,975
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4941 Post(s)
Liked 8,081 Times
in
3,822 Posts
They do? I haven't found that to be the case. Also, enormously lower pressures increase the chance of pinch-flatting, burping (if tubeless), and/or rim damage, and having to fix a flat in the rain is not something I really want to increase the odds of happening. Having to walk because of a busted rim - no thanks. I prefer to keep my tires at the same pressure, and just be a little more cautious when I need to be. All that said, I don't like riding in the rain, and try to avoid it.
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
Likes For Eric F:
#140
Klaatu..Verata..Necktie?
Join Date: May 2007
Location: SF Bay Area
Posts: 17,952
Bikes: Litespeed Ultimate, Ultegra; Canyon Endurace, 105; Battaglin MAX, Chorus; Bianchi 928 Veloce; Ritchey Road Logic, Dura Ace; Cannondale R500 RX100; Schwinn Circuit, Sante; Lotus Supreme, Dura Ace
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 10420 Post(s)
Liked 11,881 Times
in
6,087 Posts
Again, you can ride what you like, but I remember you saying you prefer to FEEL fast like you do on 140 psi to actually BEING fast at lower pressures. To me, this means your mind misinterprets the sensations you feel through the bike, so that when you hit a bump or rough pavement, feeling each little bump is interpreted as your rock-hard tires trading comfort for efficiency, when the reality is you're giving up both. Obviously, there's a point in the rolling resistance vs. tire pressure curve where decreasing pressure increases rolling resistance, but the same is true for INCREASING pressure. The curve is a V, not a simple negative correlation.
EDIT: the optimum pressure for lowest rolling resistance varies with how rough the road surface is, which is why 1) drum testing doesn't reveal this, and 2) track riders still ride really high pressures.
__________________
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
Likes For genejockey:
#141
Senior Member
Join Date: Mar 2021
Posts: 1,995
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 2700 Post(s)
Liked 486 Times
in
351 Posts
I was talking about literally sleet and snow/wet ice on the roads, which i was assuming is what OP faces in the PNW winter. I should have clarified that because the psi needed for that and just "very wet" rainy days is dramatically different. My bad
#142
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,975
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4941 Post(s)
Liked 8,081 Times
in
3,822 Posts
In my understanding, this is accurate. Rolling resistance is only one factor in the story of how efficiently a tire gets down the road. Aerodynamics play a part (in conjunction with the rim). Hysteresis loss plays a part. Vibration and vertical deflection losses play a part. The best tire and pressure choice finds the balance that minimizes all of them as much as possible. When you get outside that balance point, minimizing one factor increases another, and the overall result is diminished.
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
#143
Klaatu..Verata..Necktie?
Join Date: May 2007
Location: SF Bay Area
Posts: 17,952
Bikes: Litespeed Ultimate, Ultegra; Canyon Endurace, 105; Battaglin MAX, Chorus; Bianchi 928 Veloce; Ritchey Road Logic, Dura Ace; Cannondale R500 RX100; Schwinn Circuit, Sante; Lotus Supreme, Dura Ace
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 10420 Post(s)
Liked 11,881 Times
in
6,087 Posts
In my understanding, this is accurate. Rolling resistance is only one factor in the story of how efficiently a tire gets down the road. Aerodynamics play a part (in conjunction with the rim). Hysteresis loss plays a part. Vibration and vertical deflection losses play a part. The best tire and pressure choice finds the balance that minimizes all of them as much as possible. When you get outside that balance point, minimizing one factor increases another, and the overall result is diminished.
__________________
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
#144
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,975
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4941 Post(s)
Liked 8,081 Times
in
3,822 Posts
Valid. Mentioning hysteresis separately was probably unnecessarily redundant in my comment. However, vibration and vertical deflection losses due to irregular surfaces don't show up on drum tests (as far as I'm aware). It seems to me that this is an area that tends to be ignored by the "harder is faster" folks, but plays role in picking the right tire and pressure, and is significant in why softer tires may be faster in many real-world conditions.
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
#145
Klaatu..Verata..Necktie?
Join Date: May 2007
Location: SF Bay Area
Posts: 17,952
Bikes: Litespeed Ultimate, Ultegra; Canyon Endurace, 105; Battaglin MAX, Chorus; Bianchi 928 Veloce; Ritchey Road Logic, Dura Ace; Cannondale R500 RX100; Schwinn Circuit, Sante; Lotus Supreme, Dura Ace
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 10420 Post(s)
Liked 11,881 Times
in
6,087 Posts
Valid. Mentioning hysteresis separately was probably unnecessarily redundant in my comment. However, vibration and vertical deflection losses due to irregular surfaces don't show up on drum tests (as far as I'm aware). It seems to me that this is an area that tends to be ignored by the "harder is faster" folks, but plays role in picking the right tire and pressure, and is significant in why softer tires may be faster in many real-world conditions.
__________________
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
Likes For genejockey:
#146
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,526
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3661 Post(s)
Liked 5,408 Times
in
2,747 Posts
Bizarre tangent
FWIW, OP isn't asking about snow, sleet or ice. Says he rides trails when the roads are worse than rainy. For rain, conventional wisdom is to reduce pressure 10%-20% but I don't know that there is actual evidence that it matters.
#147
Senior Member
Join Date: May 2021
Posts: 8,399
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4393 Post(s)
Liked 4,837 Times
in
2,991 Posts
FWIW Pirelli advise simply reducing by 5 psi for wet conditions. Zipp calculator suggests similar (6 psi for my weight). They don't advise for snow/ice. If I was riding regularly in those conditions I would change to some more appropriate tyres anyway.
Likes For PeteHski:
#148
Senior Member
Join Date: Jan 2010
Posts: 39,232
Mentioned: 211 Post(s)
Tagged: 1 Thread(s)
Quoted: 18409 Post(s)
Liked 15,525 Times
in
7,325 Posts
#149
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,526
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3661 Post(s)
Liked 5,408 Times
in
2,747 Posts
Yes, just trying to redirect from the tangent The Larry went off on after his "enormously" reduce pressure in the wet silliness.
Last edited by shelbyfv; 03-23-23 at 06:10 AM.
Likes For shelbyfv:
#150
Senior Member
Join Date: Dec 2020
Location: Wake Forest, NC
Posts: 5,783
Bikes: 1989 Cinelli Supercorsa
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 3504 Post(s)
Liked 2,922 Times
in
1,774 Posts