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# Tire Question

Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

# Tire Question

06-15-07, 09:29 AM
#1
Raerfani
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Join Date: Jun 2007
Location: KY
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Bikes: 08 Giant OCR 1

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Tire Question

While riding, I feel like my tires aren't inflated enough, seeing as they level off on the ground a slight bit (not that much to make me sotp riding, but it is still noticeable), but when I try to pump it with my hand pump, it is quite difficult. My quesiton is should I try harder or is it safe to not have the tires filled to the brim?
06-15-07, 09:40 AM
#2
FIVE ONE SIX
SpIn SpIn SuGaR!

Join Date: Aug 2005
Location: Long Island, NY
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step 1: get a gauge, or a floor pump with a gauge...

step 2: inflate tires to approximately 100-115 psi, depending on the tires and the weight of the rider...

step 3: proceed to do cartwheels...

done!

(point of reply, don't go by feel)
06-15-07, 11:38 AM
#3
alanbikehouston
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The correct PSI for a given tire is based on the width of the tire and the weight of the rider. Tires are designed to provide their best performance at about 15% deflection of the sidewall, which means the sidewall should flex slightly and the rim "sag" slightly toward the pavement when the rider gets on the bike.

Obtaining 15% deflection requires that PSI be adjusted for the weight of the rider. So, a tire may be marked as having a maximum PSI level of 110 pounds. And, that 110 pound PSI level may be perfect for a 200 pound rider. But, a rider that weighs 120 pounds or 140 pounds will get the best performance from that same tire at a far lower PSI level, such as 75 PSI or 85 PSI.

If you run a "search" on tire PSI levels in the Forums, you will find older threads with links to tire PSI charts that list the width of the tire and the weight of the rider.

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