Bad advice about tire pressure in the ride listings

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12 replies [Last post]
MSilver's picture
MSilver
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"Pump up tires to the pressure specified on the sidewall."

Sorry, but this is very bad advice. The pressure specified on the sidewall is arbitrary and isn't the ideal pressure for any given person. I always run my tires below the recommended pressure, with no risk of pinch-flats.

Please change it to "make sure your tires are properly inflated," or something to that effect.

nycc_oldtimer's picture
nycc_oldtimer
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Joined: Nov 10 2010
My Vredestein Fortezza

My Vredestein Fortezza TriComp tires show "12 bar MAX" while the documentation shows 8.0-12.0 bar permissible range.

I don't think there is any problem with inflating tires to the MAX rating on the sidewall. On the other hand, if the tire doesn't show the minimum recommended pressure, I would stay as close to the MAX rating as possible. I'd rather have a slightly harsher ride and know I'm going to get home, than go too low and risk snake bite punctures.

It would be great if the tire vendors could post MIN and MAX pressure on the side of their tires. I'm not sure all of them do.

NYC Oldtimer

MSilver's picture
MSilver
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Yes, there are problems with overinflating...

Harsh ride, bad traction when cornering, and greater liabilty to punctures by sharp objects are penalties of overinflation.

The advice in the ride listings is for newbies, not experienced cyclists. Experienced cyclists (I hope) have already experimented with tire pressure and found what works best for them. I've known newbies who pumped up their tires before every ride to 150 PSI, because that was the number on the sidewall. They don't know any better, but to encourage this kind of ignorant thinking is wrong.

Most tires aren't specified to be used for front or rear. Obviously, the rear tire should be at a higher PSI (5-10 higher than the front tire), because there's usually much more weight on it. So should the recommended pressure on the sidewall be used for the front or rear, or should it be an average between the two?

Should a 250-lb rider and a 110-lb rider both pump their tires to the pressure recommended on the sidewall? Obviously, the lighter cyclist should be using less pressure.

Panaracer advises on the sidewall of my Pasela 700x28 tires, "Inflate to 105 PSI."; I inflate the rear to 85-90, and the front to 75-80, and don't get pinch flats. My Vredestein Fortezza 700x25 (which run somewhat narrow) have a maximum recommended inflation of 130 PSI. I usually inflate the front to 90, the rear to 100. Again, no pinch flats. For reference, I weigh 170 lbs.

Please read Sheldon Brown's excellent article on tire pressure:

http://www.sheldonbrown.com/tires.html#pressure

"Most tires have a "maximum" pressure, or a recommended pressure range marked on the side of the tire. These pressure ratings are established by the tire manufacturers after consultation with the legal and marketing departments.

"The lawyers want the number kept conservatively low, in case the tire gets mounted on a defective or otherwise loose fitting rim. They commonly shoot for half of the real blow-off pressure.

"The marketing department wants the number high, because many tire purchasers make the (unreliable) assumption that the higher the pressure rating, the better the quality of the tire.

"Newbies often take these arbitrary ratings as if they had some scientific basis. While you'll rarely get in trouble with this rote approach, you will usually not be getting the best possible performance.

"Savvy cyclists experiment with different pressures, and often even vary the pressure for different surface conditions.

"Optimal pressure for any given tire will depend on the load it is being asked to support. Thus, a heavier rider needs a higher pressure than a lighter rider, for identical tires."

Anon2's picture
Anon2
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Joined: Nov 9 2010
Please...

There are many cyclists in the NYCC with far more riding experience and education than Sheldon Brown. Quoting Sheldon on Tire pressure is, in my opinion, just plain silly.

Personally, I'll take for a fact that bicycle tire manufacturers have superior knowledge in understanding the proper inflation for their tires and I will continue to abide by their recommendations and ensure that my tires are inflated to the manufacturers recommended pressure before each ride.

nycc_oldtimer's picture
nycc_oldtimer
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There are many cyclists in

There are many cyclists in the NYCC with far more riding experience and education than Sheldon Brown. Quoting Sheldon on Tire pressure is, in my opinion, just plain silly.
Personally, I'll take for a fact that bicycle tire manufacturers have superior knowledge in understanding the proper inflation for their tires and I will continue to abide by their recommendations and ensure that my tires are inflated to the manufacturers recommended pressure before each ride.

I have to agree with Anon2. I will take the manufacturer's advice over anyone else's. The manufacturer spends a lot of money on research and development, and so are in the best position to make recommendation on tire pressure for their products.

I think Sheldon Brown has a great site, clearly he had the time and motivation to create it. That doesn't make him an expert on subject matter. Of course Sheldon passed a few years ago, my condolences to his family and friends.

NYCC Oldtimer

alan west's picture
alan west
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Everyone has an opinion

When it comes to safety. How can following the manufacturers recommendations be less safe and bad information?

I'm sure the various manufacturers of tires go through many US safety tests and procedures. If the advise was that bad they would be open to liability.

Did Sheldon go through the same testing procedures? I like his site and many of his opinions but on this I think we need to follow the makers suggestions.

I believe the information on the ride listings is good. I used it when I started and found my rides were less tiring on my legs and by using the advise my bike had less drag and actually performed better but that's just my humble opinion.

LValte's picture
LValte
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Joined: Nov 4 2010
Disagree with bad advice statement

I definitely agree with the recommendation. I think it does prevent flats as long as it falls between the range given on the tire sidewall. "Make sure you tires are properly inflated" is too general of a statement, especially if individuals don't know what proper tire pressure is.

prestonjb's picture
prestonjb
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Joined: Nov 17 2010
max tire pressure can blow your rim tape

Telling someone to go to max pressure IMHO is just as bad as "proper pressure"

i believe the "proper pressure" statement is more valid than attempt blanket statement...

i know several ppl told to use max pressure only to get a blowout either hitting something hard or just their rim tape doesnt matck/good for that pressure...

not to mention lower quality rims may actually have issues with spokes too...

DDeLuna's picture
DDeLuna
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Joined: Nov 4 2010
Tire Pressure

An inidcator on the sidewall giving a maximum pressure or a pressure range is not a specific recommendation for a tire pressure.

So if it says max. 115 psi, what do I inflate tire to?

If is says 80 - 120 psi, what do I inflate tire to?

The manufacturers parameter gives some helpful information, but still does not answer the ulitmate question.

Anon2's picture
Anon2
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Joined: Nov 9 2010
What if the tire pressure recommendation is unclear on the tire?

Contact the manufacturer and obtain the proper pressure or range. If you don't have the time or patience for that, contact the LBS that sold the tire to you and have them contact the manufacturer. If there is a range - make sure you stay within the range.

DDeLuna's picture
DDeLuna
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Tire Pressure

Sheldon Brown and the manufacturers ranges are not really an "either/or". Confronted with say an 80 - 120 psi manufacturers range, you could still go to Sheldon Brown's site (or other sources) for some guidance as to where in that (pretty wide) range might be likely to work better for you.

MLoftis's picture
MLoftis
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Tire Pressure

I'm with Mordecai (and Sheldon Brown) on this one. For one thing, inflating to the pressure indicated on the sidewall suggests that I should use different tires for the front and rear wheel since the pressure in the rear tire should be higher than the pressure in the front tire as it's carrying more of the load. Inflating to the pressure indicated on the sidewall also assumes that a petite rider, let's say someone weighing 110 lbs, should ride inflate his or her tires to the same pressure as someone weighing 210 lbs. This is ludicrous and potentially very dangerous on a technical descents.
A few years ago I believe someone posted a link on this message board to a study that discussed rolling resistance, tire pressure, and body weight. I can't find this study right now but are many other sources that support Mordecai and Sheldon's position on this. Here are a few:

For those who want a recommendation from a manufacturer, the following link will provide you with a tire pressure recommendation based on your weight.
http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpr...

Here's a link to an article in Bicycle Quarterly that also provides tire pressure recommendations based on weight.
http://www.bikequarterly.com/images/TireDrop.pdf

Roadbiker.com sells an eArticle about tire pressure. Here's the blurb from their website:

All About Tire Inflation by Frank Berto

$3.99 How full should you fill your tires for greater comfort, better cornering and lower rolling resistance? (Hint: It's probably not what's listed on the tire label.) The author uses extensive testing to clear up the confusion. His exclusive charts show you the ideal pressure for your weight and tire size. Off-road tires are included. 6 pages. [PDF file size: 456 KB] Tips for printing an eArticle. See delivery schedule & refund policy.

I haven't read the eArticle but my guess is that it's the same article in the following link:
http://www.bccclub.org/documents/Tireinflation.pdf

And here's a quote from last week's Roadbiker.com newsletter:
"If tire pressure is too high, the tire loses contact with the ground and energy is wasted. This holds true not only for cyclocross but also for road tires. Too much pressure actually increases rolling resistance on the road." -- Nick Legan, VeloNews tech editor and former ProTour mechanic.

[There are many other factors besides weight that one may take into consideration when inflating your tires including the condition of the road (smooth or rough, wet or dry), the terrain (flat or hilly), the temperature, and riding style.]

RShay's picture
RShay
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Joined: Nov 4 2010
Tire pressure

I'm with the manufacturer on this topic.

Manufacturers are in a much better position to research, test, design, and develop tires and inflation recommendations. Stay within the manufacturers recommended inflation. When in doubt, ask the manufacturer. Mark posted some good information from one manufacturer on how to inflate your tires based on the recommended inflation rate range and your weight. Absolutely no reason to use different tires for front and back wheels.

Marks link to one manufacturers recommendations within the inflation range:

http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpr...

If you consider yourself a "pro" rider and believe you have special inflation needs I suggest shopping around for the manufacturer that makes tires to meet your needs.

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