kfl@hoxna.UUCP (Kenton Lee) (10/22/84)
xxx
In his "Bicycle Maintenance Manual", Eugune Sloan, a Bicycling
magazine editor, recommends that sport clinchers be pumped up to
100-115 psi. Most clinchers have recommended pressures of 90-95
psi. Is there any danger associated with higher pressures? Is
the reduced rolling resistance really noticable?
--
Kenton Lee, Bell Labs - WB 1D302, x7178
{ihnp4 or allegra or cbosg}!hoxna!kflwagner@uw-june (David B. Wagner) (10/26/84)
Regarding exceeding the rated pressure on clincher tires: Relax! The rated pressures have such a large safety margin built in that you can safely pump good quality clinchers up to 125% or more of their rated pressure. I always run my 95 psi tires at 110 psi. And yes, you will notice reduced rolling resistance (although, that has a great deal to do with how much you weigh. In my case, at 210 pounds, the tire shape is distinctly flattened out when I run my tires at only 95 psi.) Happy cycling! Dave Wagner wagner@uw-june
dsn@umcp-cs.UUCP (Dana S. Nau) (10/30/84)
> From: kfl@hoxna.UUCP (Kenton Lee) > > In his "Bicycle Maintenance Manual", Eugune Sloan, a Bicycling > magazine editor, recommends that sport clinchers be pumped up to > 100-115 psi. Most clinchers have recommended pressures of 90-95 > psi. Is there any danger associated with higher pressures? Is > the reduced rolling resistance really noticable? There sure is--you're likely to get flat tires that way. Several times when riding in hot weather I've gotten flat tires simply because the tires got so hot that the air pressure got too high. -- Dana S. Nau CSNet: dsn@umcp-cs ARPA: dsn@maryland UUCP: {seismo,allegra,brl-bmd}!umcp-cs!dsn
pws@faron.UUCP (Phillip W. Servita) (11/02/84)
In article <umcp-cs.512> dsn@umcp-cs.UUCP (Dana S. Nau) writes: >> From: kfl@hoxna.UUCP (Kenton Lee) >> >> In his "Bicycle Maintenance Manual", Eugune Sloan, a Bicycling >> magazine editor, recommends that sport clinchers be pumped up to >> 100-115 psi. Most clinchers have recommended pressures of 90-95 >> psi. Is there any danger associated with higher pressures? Is >> the reduced rolling resistance really noticable? > >There sure is--you're likely to get flat tires that way. Several >times when riding in hot weather I've gotten flat tires simply because >the tires got so hot that the air pressure got too high. >-- >Dana S. Nau >CSNet: dsn@umcp-cs ARPA: dsn@maryland >UUCP: {seismo,allegra,brl-bmd}!umcp-cs!dsn Not Quite. if anyone out there remembers his high school chemistry, the pressure difference caused by a change in temperature as extreme as 30 degrees F to 100 degrees F is pretty trivial once converted to the Kelvin scale. (it produces about a 12 percent increase in tire pressure) so if your clinchers are pumped to 100psi at 30 deg F, 100 degrees will only increase the pressure to 112psi. FAR below the safety factor of any reasonable clincher out on the market. as for a noticeable difference in rolling friction, most definitely. but i find that unless i am racing, it is not worth the extra bumps. -the venn buddhist
craig@hp-pcd.UUCP (craig) (11/07/84)
I've always run my tires @ 120psi (clinchers or otherwise). I now use Turbo S's and latex tubes (can't get a better ride than this without sewups), used to be various Specialized tires w/ butyl tubes. It is my subjective opinion that higher pressure reduces rolling resistance, flats (from pinched tubes) and glass cuts (don't ask me why I think this, but I seem to have less trouble). Craig Durland ...!hp-pcd!craig
jans@mako.UUCP (Jan Steinman) (11/07/84)
In article <faron.158> pws@faron.UUCP (Phillip W. Servita) writes, quotes: >In article <umcp-cs.512> dsn@umcp-cs.UUCP (Dana S. Nau) writes: >>> From: kfl@hoxna.UUCP (Kenton Lee) >>> >>> ...recommends that sport clinchers be pumped up to >>> 100-115 psi. Most clinchers have recommended pressures of 90-95 >>> psi. Is there any danger associated with higher pressures? >> >> ...--you're likely to get flat tires that way. Several times when >> riding in hot weather I've gotten flat tires simply because >> the tires got so hot that the air pressure got too high. > >Not Quite. if anyone out there remembers his high school chemistry, >the pressure difference caused by a change in temperature as extreme >as 30 degrees F to 100 degrees F is pretty trivial once converted >to the Kelvin scale. (it produces about a 12 percent increase in tire >pressure) so if your clinchers are pumped to 100psi at 30 deg F, >100 degrees will only increase the pressure to 112psi. FAR below the >safety factor of any reasonable clincher out on the market. > Ah, but what happens when you come down a long, winding hill, using considerable braking? Although I don't carry a thermometer around in my cycling clothes, I've had rims too hot to touch (even when pumping the brakes) after a hill. We're no talking Mt. Evans, either. A steep drop of 400 feet is enough to almost make the rims sizzle, depending on rider's weight and riding (braking) style. Flippant remarks about "high school chemistry" aside, I have seen tires blow during and after hard or long braking descents. Most tires have a large safety margin, but use good sense, especially if you have hills like Upper Bucks County, PA! -- :::::: Jan Steinman Box 1000, MS 61-161 (w)503/685-2843 :::::: :::::: tektronix!tekecs!jans Wilsonville, OR 97070 (h)503/657-7703 ::::::