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Tire Pressure(9 posts)

Tire PressureVetteRacer
Feb 8, 2002 11:49 PM
The tires I have are Continental SuperSport Ultras
They say max pressure of 120. What pressure should I set them at?

Also, what side is the label supposed to be on? Drive or non drive? Is it the same for ALL tires (mtn also)?

Thanks
Matt
ALSO...VetteRacer
Feb 8, 2002 11:51 PM
how much pressure is figured to be lost when removing the pump? Should the pressure quoted be before or after removing?

Thanks again
Matt
ALSO...xxl
Feb 9, 2002 1:43 AM
You can run those tires at 120 PSI. In fact, you can run them a little low ( say, 110 PSI) for "comfort," though my take is if you want comfort, get a wider tire. You can also run them overinflated, because "max PSI" figures are typically dampened by the manufacturer's legal department to forestall product liability claims (Check it out: several tires have two different "max PSI" figures; one on the label, and another molded into the rubber/sidewall.) Having said that, I do not recommend overinflation; the tires will ride more harshly, you could possibly blow them off the rim, and, most importantly, what does it buy you? If you overinflate for "speed," why not just run tires that were designed for higher pressures in the first place? They'll perform better, all other things being equal.

When you inflate your tires, you shouldn't be losing much air when you disconnect your pump. If you are, get a different pump; most of the newer ones have a "knock-it-off" valve, so you lose maybe a pound or two of pressure at most disconnecting. One tip: on cold mornings, when the temperature is expected to rise later in the day, run your tires a few pounds low, as the rising temperatures will cause your tires to "pick up a few pounds," as the now-warmer air in them expands a bit. Again, though, this really isn't a big issue until you start hanging out with the guys who're putting 170 PSI of helium in their silk sew-ups.

As to your label-on-which-side question: on road bikes, tread pattern, direction, etc., isn't really much of a factor as it is on mountain bikes, because of the higher PSI's and generally good traction that road riders typically encounter. So, I don't think it matters a great deal, but I always put my labels on the non-drive side. If you need to rationalize that position, here's mine: with the labels on the non-drive side, you can read them as you inflate your tires, and not get your nice new jersey next to that filthy old chain. Just be consistent, and mount both labels on the same side, whichever side you choose; it looks better, IMHO.

I've seen good bike shops that mount tires both ways. Don't know if it's a mistake on their part, or mine, but I don't think label position matters except for aesthetics.
Label usually mounts under valve on drive side (NM)Samcat
Feb 9, 2002 4:40 AM
afterCrankist
Feb 9, 2002 12:50 PM
re: Tire PressureJimP
Feb 9, 2002 12:14 PM
The optimun pressure is dependent on the cross section of the tire and the weight of the rider. There are several web sites that have different formulas to use. I weigh 185-190 and usually run 125lbs for the rear 22mm tire and 130lbs for the front 19mm.
re: Tire PressureChen2
Feb 9, 2002 3:57 PM
I think most of the air we hear rushing out when we pull the chuck off is actually coming from the hose. The valve should seal instantaneously.
re: Tire PressureWoof the dog
Feb 9, 2002 4:12 PM
it depends on the tire if you want to go over a posted pressure. With one kind of specialized tires, i could put in 10 psi extra over the limit, while with other specialized tires, I went through two tubes and scared some relatives with nice gun shots in the basement and on the road too.

sincerely

woof the blow-off dog.
re: blowing off rims.guido
Feb 9, 2002 7:04 PM
I've done that too, scaring relatives, and another time, a large group of riders at the start of the Hottern' Hell Hundred. I seem to remember it was Specialized tires in both instances, the folding kind. Anybody under 170# would be fine on pressures as low as 95 psi. I go with 100-110 on 25Cs. Any more rides rock hard, seems a bit more prone to flats, and doesn't feel any faster to me, although technically, probably is.

Tire manufacturers always print the labels on the drivetrain side of the tires, so when people are checking out the bike, they can see all the components in one view. If you mount them that way, you never have to worry if the tread is oriented correctly.