130 psi clinchers... e.g., Felt Speed AW 700 x 25
#26
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
I usually run 25mm tires at 115 lbs. on our tandem. I'm running Conti 4000s II 28mm tires, which measure 32mm on my Kinlin 279 rims at 110 lbs. Works fine, honest. 282 lb. team.
Be that as it may, 130 is a bit high for 25mm. I used to run 140 lbs. in my 23mm Tricomps back when I rode a single on competitive rides. That worked well too. A good max pressure estimate is (tire width in mm) X (tire pressure) = 3000. Never met a rim that couldn't handle that.
BTW, 130 is the sidewall pressure on those Felt tires. However they're an inexpensive 320g tire and I doubt they'd be comfortable at that pressure. High pressure is more comfortable using tires with light sidewalls.
Be that as it may, 130 is a bit high for 25mm. I used to run 140 lbs. in my 23mm Tricomps back when I rode a single on competitive rides. That worked well too. A good max pressure estimate is (tire width in mm) X (tire pressure) = 3000. Never met a rim that couldn't handle that.
BTW, 130 is the sidewall pressure on those Felt tires. However they're an inexpensive 320g tire and I doubt they'd be comfortable at that pressure. High pressure is more comfortable using tires with light sidewalls.
#28
Should Be More Popular
Join Date: Dec 2007
Location: Malvern, PA (20 miles West of Philly)
Posts: 43,051
Bikes: 1986 Alpine (steel road bike), 2009 Ti Habenero, 2013 Specialized Roubaix
Mentioned: 560 Post(s)
Tagged: 2 Thread(s)
Quoted: 22597 Post(s)
Liked 8,925 Times
in
4,158 Posts
Let’s call it a draw.
#29
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,533
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3889 Post(s)
Liked 1,938 Times
in
1,383 Posts
One of the main reasons to ride tubulars (on the road) is not so you can inflate them to stupid high pressure, it's the opposite.
Tire construction doesn't matter all that much. 110 (or whatever) psi is 110 pounds of air pressure per square inch. How the tire is made is not going to change that very much. If you think it does your feels are broken.
Tire construction doesn't matter all that much. 110 (or whatever) psi is 110 pounds of air pressure per square inch. How the tire is made is not going to change that very much. If you think it does your feels are broken.
__________________
Results matter
Results matter
#30
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
That's not my expoerience, though. The Tricomps I rode at 140 were a 227g tire. They had a smoother ride at that pressure than do the Conti 4K2s tires at 100. The sidewalls were extremely supple. Downside: also fragile, but I rode them 10s of thousands of miles on brevets, sporting rides, and events, and at that pressure. Loved 'em. When I put these modern Contis on my bike, I couldn't believe how rough they rode.
Likes For cxwrench:
#32
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,533
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3889 Post(s)
Liked 1,938 Times
in
1,383 Posts
Statics determines the length of the contact patch, the reason that narrower tires usually ride more smoothly than wider ones at the same pressure, and also the reason that lower pressure rides more smoothly with the same tire. Within that contact patch however, it seems to me that carcass stiffness makes a difference. That's what riders mean when they talk about a smooth rolling tire. All tires of the same width do not roll the same at the same pressure. Construction does matter, and my feels and the feels of my fellow riders are not broken.
__________________
Results matter
Results matter
#33
Senior Member
Join Date: Mar 2010
Posts: 1,659
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1248 Post(s)
Liked 1,323 Times
in
674 Posts
Statics determines the length of the contact patch, the reason that narrower tires usually ride more smoothly than wider ones at the same pressure, and also the reason that lower pressure rides more smoothly with the same tire. Within that contact patch however, it seems to me that carcass stiffness makes a difference. That's what riders mean when they talk about a smooth rolling tire. All tires of the same width do not roll the same at the same pressure. Construction does matter, and my feels and the feels of my fellow riders are not broken.
#34
Senior Member
#35
Senior Member
Join Date: Mar 2010
Posts: 1,659
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1248 Post(s)
Liked 1,323 Times
in
674 Posts
There are numerous high-performance tires in the 25mm size under the 227g number however my key point is if you pump a 25mm tire to 140PSI, supple sidewalls will not be a factor as that tire's deflection will be virtually non-existant. The tire you quoted has a max psi rating of 130PSI. I am an advocate for supple tires and feel it's one of the best investments someone can put on their bike to increase performance and enjoyment on a ride. But to take advantage of that suppleness appropriate pressures should be used.
#36
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
Statics determines the length of the contact patch, the reason that narrower tires usually ride more smoothly than wider ones at the same pressure, and also the reason that lower pressure rides more smoothly with the same tire. Within that contact patch however, it seems to me that carcass stiffness makes a difference. That's what riders mean when they talk about a smooth rolling tire. All tires of the same width do not roll the same at the same pressure. Construction does matter, and my feels and the feels of my fellow riders are not broken.
#37
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,905
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
Mentioned: 129 Post(s)
Tagged: 0 Thread(s)
Quoted: 4806 Post(s)
Liked 3,928 Times
in
2,553 Posts
Just tried my Felt 25 x 700 tires and rims on a ride. Bikes of this type mine is 58 cm are rated for 275 lb at most and I am 385 lb. You would think that would make the ride worse since the tires are all the way to 130 psi. Ride is phenomenal, More active than a passive mountain bike ride which keeps my head in the game so far. ( just getting reacquainted ) lets see how long until a blowout. still lacking some confidence obviously. Statement complete.
I'm not saying "don't do this". Just, be aware. I've done my crashes from ignorance and refusing to listen. One was life-changing and not for the better. I'm a light rider and kind to stuff. But I took chances with a fork I shouldn't have ridden. You probably should pay that same kind of attention to the rims you ride. Yes, the blown sidewall consequences are a lot lower than breaking a fork, but a ruined CF frame and the ER for stitches to a nasty jagged wound are nobody's idea of fun. (And most of all, I want you to be around here as a happy camper a long time!)
Ben
#38
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,533
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3889 Post(s)
Liked 1,938 Times
in
1,383 Posts
There are numerous high-performance tires in the 25mm size under the 227g number however my key point is if you pump a 25mm tire to 140PSI, supple sidewalls will not be a factor as that tire's deflection will be virtually non-existant. The tire you quoted has a max psi rating of 130PSI. I am an advocate for supple tires and feel it's one of the best investments someone can put on their bike to increase performance and enjoyment on a ride. But to take advantage of that suppleness appropriate pressures should be used.
The person who re-opened this thread weighs 385 and I can assure you that his Felt tires ride just fine for him at 130 lbs. In fact, that's probably not enough pressure to prevent pinch flats.
BTW, one can easily estimate the pressure of any tire on a rim by multiplying tire size by the pressure. So 25 * 130 = 3250. I note that my old Tricomp tires' max pressure is at least 170 and the product would be 3910 at that pressure. At 140 lbs. and 23mm, it's 3220. I rode those for many years with no problem.
Rim wear is a real thing in the PNW. Our tandem tires at 32mm and 110 lbs. with a product of 3520 work just fine. I replace one rim every other year, so 4000-6000 miles on rims ridden all winter in the PNW. I've been trying 95 psi this past year on the tandem, product = 3040, no pinch flats yet, but that's probably the lower limit for our team, with a weight of 283, plus the extra weight of it being a tandem of course,
__________________
Results matter
Results matter
#39
Senior Member
Yup.
#40
Senior Member
I remember the 70s 80s and 90s. Most everyone rode at 130 or 140. It did not hurt the rims. With supple tires the bike still handled well enough. Yes, supple still functions, partially, when drastically overinflated. It did overwork the pumps. The sound of a blowout was memorable. There probably were more blowouts.
One of the big reasons to not use wider tires was they would be pumped to the same 130 and the wide tires did not like that. Still happens today. People buy fatbikes and are surprised when they won’t hold 50psi. It looks like a truck tire, don’t you inflate it like a truck tire?
Inflation pressure should be physics, more often it is just fashion.
One of the big reasons to not use wider tires was they would be pumped to the same 130 and the wide tires did not like that. Still happens today. People buy fatbikes and are surprised when they won’t hold 50psi. It looks like a truck tire, don’t you inflate it like a truck tire?
Inflation pressure should be physics, more often it is just fashion.
#41
pan y agua
Join Date: Aug 2005
Location: Jacksonville
Posts: 31,302
Bikes: Willier Zero 7; Merlin Extralight; Calfee Dragonfly tandem, Calfee Adventure tandem; Cervelo P2; Motebecane Ti Fly 29er; Motebecanne Phantom Cross; Schwinn Paramount Track bike
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1447 Post(s)
Liked 725 Times
in
371 Posts
The tire pressure’s on the inside of your door are what
you should run for the fully
loaded vehicle and they are not the maximum pressure the tire and wheel can handle.
Many cars spec a lower pressure for the front tires than the back, so clearly the spec’d front
tire pressure
is below the maximum.
If you run the maximum pressure your tire can handle its highly likely you will have excessive tire wear on the center of the tread an unnecessarily harsh ride, and poor grip.
As an example the Michelin Pilot Sport Cup tires on my car have a maximum inflation rating of 50psi.
On the street I run them 36psi front, 41psi rear which is the Car’s spec(which Michelin says to follow on road driving)
on the track I run 32psi front, 36psi rear which is again Michelin spec. However to achieve that hot, I typically am running 28 psi front and 32 psi rear cold.
So the actual optimal pressure is way below the maximum.
Last edited by merlinextraligh; 12-22-20 at 08:46 AM.
Likes For merlinextraligh: