Tire Pressure

[Michelle T]

I'm 4'10" and weigh about 100 pounds. I'm going to buy a bike with tires that will take 120 psi. I've heard that lighter riders don't need and can be uncomfortable with the maximum tire pressure. How do I know what tire pressure is right for me?

[indysteel]

Just experiment. I'm 120 and ride at 100 psi on tires that can hold up to 120. I'd start with 90 psi if I were you and see how that feels.

[Xrayted]

Never go to max pressure on a tire, bike, car or otherwise. That is the upper limit. I would go, in your case, about 20lbs less than max to start. Get on it, see how it feels and how it LOOKS. Have someone look for you from the side as you go by. If it is compressing too much, put a little in. If it seems hard and you're feeling the road too much, taking into account what kind of frame/seat you have, then take a bit out. The biggest thing is to find a pressure that isn't harder than needed, so soft it won't give you a pinch flat and check the pressure at least twice a week depending on how much/how far you ride normally. If you only ride on weekends, then absolutely, check it everytime you ride. If you ride to work everyday, then every other day give it a quick check.

I just hate seeing someone riding around on 1/2 the air needed, almost on the rim. The rest of the air must be lodged between their ears.

[Dogmama]

I'm 118 pounds & I've always run on 120 pounds of pressure (20 years of cycling.) I use Continental tires. I notice more rolling resistance at less PSI.

[indysteel]

On the often rough roads we have in Indiana, I'm willing to have some extra rolling resistance if it makes for a more comfortable ride.

[Catrin]

On the often rough roads we have in Indiana, I'm willing to have some extra rolling resistance if it makes for a more comfortable ride.

Hmmm, I am 138 pounds and have kept my Trek's psi at 110. I am wondering if I should drop that to 100 and see if the ride is a little more comfy on my country roads? With my weight would 90 pounds be too low?

[Chicken Little]

I keep them maxed for wear and flat protection.

[artifactos]

My tires have an optimum range of 100-120 psi and I keep mine right in the middle of that.

[OakLeaf]

I'm 122# and I keep my Conti GP4000s at 110 front and rear. I definitely notice the increased rolling resistance if I go lower. There is a tradeoff in efficiency when the roads are so rough that your drive wheel is losing contact with the road surface - but those are also the times that a pinch flat is most likely. So just experiment.

Also, I air my road bike tires every ride. High-pressure road tires and tubes lose almost as much pressure just sitting around as they do being ridden. On the fat-tire commuter, once a week is plenty.

Out of curiosity, does anyone run their tires at different pressures front to rear? If so, how do you like it?

[indysteel]

I run the same pressure front and rear. I'd note that I've never (knock on wood) had a flat.

[OakLeaf]

Whoa, whoa, whoa, do you mean you've never had a pinch flat (neither have I, that I can recall - I think they're pretty rare when you're under 150 lbs)? Or you've never had a puncture, a leaky valve, any kind of flat????

[Dogmama]

Whoa, whoa, whoa, do you mean you've never had a pinch flat (neither have I, that I can recall - I think they're pretty rare when you're under 150 lbs)? Or you've never had a puncture, a leaky valve, any kind of flat????

Oh man. Never say never. The Flat Gods will visit you frequently. I've had one pinch flat & honestly - it had been two weeks since I'd aired up my tires & I was probably running about 80 pounds (I'm 118 pounds.)

[indysteel]

I have never had a flat of any kind. I guess I've been lucky thus far.

To the OP, there was a thread last year that gave a formula for determining psi, along with a link to a Sheldon Brown article. I'd provide a link to the thread, but I'm on my Blackberry and can't. It's from May of 2009, and was titled "tire inflation and rider weight" if you want to do a search.

The bottom line I took from it is that you should just experiment with psi to see what you prefer.

Sheldon Brown's article indicates that you should run the rear tire at a higher psi (by about 10 percent).

[redrhodie]

Indy, you are lucky! Maybe I should run lower pressure (I usually go to 118, and I weigh 123). Although, that probably wouldn't have helped when I ran over the wood screw.

Drift--I patched a flat a couple of weeks ago, and it (the patch) failed this week. What did I do wrong? I used a self stick patch, and sanded the tube lightly, as per the instructions. The hole was on a seam, which is where the air ended up escaping from under the patch. Should I have sanded more, or used another kind of patch?

[OakLeaf]

Patching over a seam is tough. It's possible that it just wasn't going to happen... but things I do are sand the seam extra to try to bring it closer to the level of the rest of the tube ... and be extra careful that there isn't a glob of wet glue up against the seam when I apply the patch.


ETA - I missed that you used a self-stick patch. I don't have a lot of experience with those, but I've heard they're not as reliable. I carry them for on-the-road repairs, but if I have the luxury of mounting a spare tube and patching the hole at home, I use the kind with the separate rubber cement.