How much tire pressure?

Hello!

I've been cycling for a month now. I cycle 4-5 times a week around Central Park (btwn 18-24 miles) and try to get out with the cycling club I've just joined at least once a week for a 50-miler.

I was advised by the bike shop where I bought my bike (48cm Specialized Dolce - tires are 700 x 23c Specialized All Condition Sport) to pump my tires to 120psi (the range on my tires says 115-125) but having posted this same question on the cycling club message board and read some of the responses, this is apparently way too much :eek: and really I should be inflating 100 psi max, even less, and that the pressure should be slightly more on the rear.

Most of the answers I got were from men who are all taller and heavier than I am, so I would LOVE to hear from some ladies who are maybe of a similar frame to me - 5'3" and about 145lbs (for the time being at least . . .:)) I've seen the chart in a previous thread, but I'd just like to see some quick numbers from you.

What's your advice? What do you inflate to? What is the lowest/highest I could go before having to worry about flats?

Thanks in advance.

Go by what the tires say, not just whatever "some guy" recommends. I think the 120psi recommended by the LBS sounds about right. Running them lower will lead to uneven tire wear, and may make you more prone to flats.

+1 to whatever the tire says it should be.

Why on earth would one tire be inflated more than the other? I can't make any sense of that advice.

-- gnat!

I'm a similar size to you - I always inflate to 120.

I inflated to about 100 for a while last spring and I kept getting pinch flats every ride.

I rarely get flats now.

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Originally Posted by gnat23

+1 to whatever the tire says it should be.

Why on earth would one tire be inflated more than the other? I can't make any sense of that advice.

-- gnat!

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I read something about this recently. It's related to the fact that the weight is not distributed equally between the two tires. But the article was specific to touring, where I think the weight difference is greater due to the extra stuff the rider is carrying on the bike.

Personally I pump my Conti Gatorskins up to the max (120 psi front and back) and they've worked fine for me.

There is a lot of talk on the forums about running lower pressures. I went looking for the chart and couldn't find it. The theory that if you put too much pressure in your tires, the ride will be harsh; too little and you pinch flat; just right and you get perfect rolling resistance and comfort. Or so the theory goes.

This is also part of threads of running 23 vs. 25. The theory being, given the same tire composition and same pressure, the 25 will offer less rolling resistance than the 23.

Do I believe any of it? I've dropped the tire pressure on my bike from 115 to 105 and have not pinch flatted and it is a more comfortable ride. I'm not noticing a slowdown, but, then, I'm not exactly a speed demon either.

At 145 pounds, 120 psi probably isn't necessary. I weigh just a little less, and I normally go somewhere around 105psi, and it makes a difference in the harshness of the ride in some of the rough roads in my area.

Here's a chart from the Michelin website:

http://www.michelinbicycletire.com/m...art121405B.jpg

I always pump my tires to 10 lbs lower than the maximum stated on the tire. My DH pumps his to 15 lbs lower. We NEVER get pinch flats or uneven tire wear. The maximum recommended is just that- a maximum pressure beyond which you should not go.

I cycle on the same crappy roads that you do (and read your thread on the club board - you're a brave girl!). I weigh about 130 and I usually inflate my Conti 4000's to 100/front and 110/back. 120 is the recommended Max psi. I've been doing this for years and have never gotten a pinch flat and the tires wear evenly.

I run a lower pressure in my tires than the max psi. I also run a bit more pressure in my rear tire than in my front because more of my body weight is over my rear tire. I've never pinch flatted and have never noticed uneven wear. If I pumped mine up to the max, I'd have a harsh and bumpy ride.

I'm about 120# and I inflate my Conti 4000s to 115 psi. If I put any less air in them than that, I notice the increased rolling resistance long before I notice a softer ride. Yes they're harsh, but our roads aren't so bad that I don't think it's worth it.

I used to ride the same bike as you and weigh the same as you (when I first started biking) and I found that I got the best balance between nimbleness and comfort at 110 psi. As a comparison, my bike shop recommended 115 back then!

I actually still use the same pressure on my current bike even though I weigh more and the tires are smaller...go figure. :)

Quote:

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Originally Posted by gnat23

+1 to whatever the tire says it should be.

Why on earth would one tire be inflated more than the other? I can't make any sense of that advice.

-- gnat!

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Sometimes I will inflate my rear more than my front; but this is usually for handling purposes, i.e. on a mountain bike. Don't know why you would do this for a road bike?

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Originally Posted by spokewench

Sometimes I will inflate my rear more than my front; but this is usually for handling purposes, i.e. on a mountain bike. Don't know why you would do this for a road bike?

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I think I remember someone saying to do this because it makes the bumps a bit gentler on the hands. But I don't know the science behind two wheels with different levels of rolling friction.

My max psi on Bontrager 700x23's is 120 psi--I inflate to 110. Supposedly a less harsh ride and I haven't had a flat so far.

I've ridden those Specialized tires. I also recommend 120psi. Closer to 100 and I got pinch flats.

Even though I'm light, I like the handling of a firm road tire, and I don't notice the supposedly rougher ride. I race on my Michelins at 110psi, even in the wet.

This is what I posted in that other thread:

Tire Width=20: Pressure(psi) = 0.33 * Rider Weight in lbs + 63.33
Tire Width=23: Pressure(psi) = 0.33 * Rider Weight in lbs + 53.33
Tire Width=25: Pressure(psi) = 0.33 * Rider Weight in lbs + 43.33
Tire Width=28: Pressure(psi) = 0.33 * Rider Weight in lbs + 33.33

I always inflate the tires to the max pressure allowed, and never had a problem.
If they are underinflated you run the risk of getting way more flats.

Thank you all VERY much for your input. Your advice is much appreciated. :)

Happy cycling!

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Originally Posted by witeowl

I think I remember someone saying to do this because it makes the bumps a bit gentler on the hands. But I don't know the science behind two wheels with different levels of rolling friction.

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I keep my front wheel slightly under-inflated compared to the rear for exactly that reason. I was having a lot of issues with my hands, and this really helped for me.