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Tire pressure - experiment or go with sidewall?(13 posts)

Tire pressure - experiment or go with sidewall?Fez
Jul 23, 2002 5:25 AM
New tires are Michelin Axial Pro 700x23 and pressure on sidewall said up to 110 psi. My priorities are (1) least rolling resistance, (2) comfortable ride, and (3) long wear. I weigh 150. Does anyone exceed the max pressure or is that a NO-NO? When in doubt, should I go for the max and adjust downward if too stiff?

Kind of puzzled at the relatively low max pressure on the sidewall. My old tires were IRC and they were marked 130psi max and I ran them at that 130 with no flats and completely even wear.
I been running my Michelins higher by 10 lbs over the years withPaul
Jul 23, 2002 6:04 AM
no problem. Of course, you have to make sure you have a good gage. manufacture will state that this pressure represents the optimum point for performance. I figure I lose a little air during the course of the ride, so I put a little extra in. Too much air, and you risk blowing them off the rim. Try 110 lbs, and see how they perform. Sometimes it's a mental thing when you feel sluggish, and think you should make your tires harder.
re: Tire pressure - experiment or go with sidewall?Chen2
Jul 23, 2002 6:07 AM
I've got two sets of 700 x 23 Axial Pro's on bikes right now, the newer ones are rated at a maximum of 115 psi. I run 120# in the rear and 118# in the front. I think a lot of folks run 5 or 10 pounds over the recommended maximum without problems. I think they roll better that way.
I have Axial Pros too - run them at 130cabinfever
Jul 23, 2002 7:41 AM
I weigh just under 200lbs, and run Axial Pros at 130lbs. My pump allows the tube to lose air when I remove the chuck, so I actually pump them to 140lbs first. I use velox tape on my rim, and filed any protrusions off of the inside of the rim to help reduce flats. I also check the inside of the tire every time I get a flat by running my finger or thumb around it. I've had very good luck this way and rarely get flats. As far as wear, I have found that they will develop tiny cracks if you get them wet at all.
Check again.Len J
Jul 23, 2002 8:27 AM
That air you seem to be losing "when I remove the chuck" is not air loss from the tire, it is air loss in the pump itself. In order to get your tire up to pressure, the pump tube needs to be at the same pressure. When you remove the chuck, this excess pressure in the pump is what you hear being released. If you are unsure, use a hand air guage on the tire. I would bet that (based on what you said) that your tire is closer to 140 lbs than 130lbs.

Jul 23, 2002 9:03 AM
I agree with Len. The air you hear when pulling the chuck off of the stem is from the pump and hose. I'm wondering if the tiny cracks you are experiencing in your tires is from being over-extended everytime you've gone to 140#. I don't know why water would cause cracks in the rubber. The water might make the cracks more visible.
Velo News articleJefferson
Jul 23, 2002 8:08 AM
Over a year ago there was a spot in Velo News where they had a tech tip from a Michelin race suport guru. He claimed that most of the european racers ran their Axial pros around 100 psi. I wish I could find that article. I since have settled in with 105-110 psi. I used to run these tires around 120. The article talked about how the Axial pros were deisigned to be the most efficient at 100 psi. Any body else remember this article?
Velo News articleFez
Jul 23, 2002 8:51 AM
I am not doubting that Axial Pros are most efficient at approx 100psi, but I am a little baffled that other brands like Continental and IRC were designed to go up to 130+ psi. Is tire pressure really that dependent on brand and construction?

In contrast, car tire air pressure is pretty much standardized within a given size and the model car you drive.
Go with the manufactures recommendation...shortstroke
Jul 23, 2002 7:35 PM
The "standards" may not be as standard as you think anymore.
My daughter's car had Michelins that were rated to 50psi! She replaced two with the "same" model and they were rated to 35psi! My wife just had two tires replaced on her car and they are rated to 45psi.

Anyway, I go with the manufactures recommendations as a whole, with some tweaking for ride, speed, etc. They don't make these numbers up. I have some Hutchinsons that are rated to 120psi on the tire, but also says that 100 is recommended.
I did not see it, but found that out myselfLC
Jul 23, 2002 9:09 AM
I have been experimenting with various pressures on Axial Pro/Pro Race's too. Running lower pressure does not hurt my speed, and the cornering and comfort is definitly better. I am heavier (175 lb) than a euro pro racer, so I need a little more than 100 psi, but not much more. 110-115 psi works for me. 120 psi and tire starts to bounce more than roll and my individual TT is slower, plus cornering becomes less predictable.
maybe 100 psi for a 140 lb rider...i'll stick with 120 (nm)ColnagoFE
Jul 23, 2002 9:46 AM
re: Tire pressure - experiment or go with sidewall?JimP
Jul 23, 2002 10:24 AM
I have an old chart that was printed in one of the cycling mags several years ago about tire pressure. Assuming that your bike weighs 20 lbs and you said that you weigh 150, the "optimum" pressure for 170 lbs and 23mm tire is 87 psi. You may beleive that or not! I can't remember the rationalle for the chart but I did cut it out and still use it - for me it shows 120 lbs for a 22mm tire and I add 10 to that, since I didn't really beleive the 120.
Ya can't have it all brother...Ahimsa
Jul 23, 2002 6:03 PM
You sed: "My priorities are (1) least rolling resistance, (2) comfortable ride, and (3) long wear."

Priority 1 would lean toward higher pressure

2 and 3 would require lower pressure by comparison

150lbs huh? Try 100-110 psi. You don't need to run tires harder than that for any reason, and it just defeats comfort and increases wear.