Tire Pressure

[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.

[Skierchickie]

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

Wow! I want your tires! What are you using?

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?

A few years ago the owner of my LBS sold me some of those self-stick patches, saying they were fantastic. Most people around here, including him, are primarily mountain bikers. I used one on my road bike, and it failed. Tried a few times, and they always failed the same way. The sticky part isn't strong enough, and the air (at road bike tire pressures) forces a path out to the edge. It just creeps along, following the path of least resistance. I don't think you did anything wrong - and it chose the seam to travel along, as the easiest path, but I'm pretty sure it still would have failed.

I haven't used them in 10 years, so maybe they've been improved, but those things really should be labeled with a maximum suggested pressure, in my opinion. Give me the old kind (with the glue that sometimes evaporates out of the sealed tube ) any day! I think I have the self-stick kind in my mtb seat bag, but never again on the roadie.

[makbike]

Does the "never inflate to max" apply to tubeless tires too?

[maillotpois]

Does the "never inflate to max" apply to tubeless tires too?

even more so, I believe. and they run at much lower pressures. I was a 115 - 120 psi on tube tires and 90 - 95 on tubeless.

[OakLeaf]

Give me the old kind (with the glue that sometimes evaporates out of the sealed tube )

drifting...

You raise an interesting point. With the rubber cement, it's immediately obvious when it's gotten so old that it's dried up. With the self-stick patches, you don't know until you go to use one. Or you wind up discarding them just because a certain amount of time has passed and they could be stale.

Yeah... I guess if my second spare tube has failed, either my riding buddies have already left or they'll be willing to wait an extra 90 seconds or so for the glue to dry, even though it does seem like fer-frickin'-EVER even when you're doing it at home with no time pressure.

[indysteel]

Wow! I want your tires! What are you using?

I use Vittoria Rubino Pros.

[ny biker]

I have a friend who sent me a bunch or articles showing that lower psi is better than high psi. There is no measurable increase in rolling resistance but your ride is smoother and more comfortable. In fact lower pressure is better for when you hit bumps, because your tires roll over them more easily so your momentum keeps going forward instead of being interrupted by the bump. If I can find them I'll post the articles here, but I have to warn everyone that they will make your eyes glaze over -- it's very dry reading.

Anyway, I used to keep my tires at 120 psi. I agreed to experiment with lower pressure and I'm averaging the same speed at 110 psi. One of these days I will drop it to 100 psi and I won't be surprised if it makes no difference in speed. I also mentioned the experiment to the mechanic at the LBS and he said he wouldn't go above 100.

[OakLeaf]

I'd think you'd need a power meter and laboratory conditions to really know the difference. Most everyone I know says they can feel the difference in rolling resistance - myself included - but of course that's subjective, even for individuals using a power meter outside.

But it's well known that higher tire pressure always increases fuel efficiency in cars. There's just a tradeoff in traction on imperfect roads, that becomes more apparent the worse the road gets.

I would think that the theory is no different for general road riding than it is for racing or mountain bike riding - the smoother the road surface and the better the traction, the higher the pressure should be for best efficiency. There's never any "one size fits all" for tire pressure. It's just that paved roads are more uniform than unpaved trails.

[ny biker]

I'd think you'd need a power meter and laboratory conditions to really know the difference. Most everyone I know says they can feel the difference in rolling resistance - myself included - but of course that's subjective, even for individuals using a power meter outside.

But it's well known that higher tire pressure always increases fuel efficiency in cars. There's just a tradeoff in traction on imperfect roads, that becomes more apparent the worse the road gets.

I would think that the theory is no different for general road riding than it is for racing or mountain bike riding - the smoother the road surface and the better the traction, the higher the pressure should be for best efficiency. There's never any "one size fits all" for tire pressure. It's just that paved roads are more uniform than unpaved trails.

Yes I thought the same thing but my friend is a persistent statistician. And really, I've actually tried it and am riding the same speed without working harder.

[redrhodie]

So, I ran lower pressure today, 108 instead of 118, and I felt like my brake was rubbing. I actually stopped and checked to see if my brake was rubbing, then I remembered it was the tires.

Hard to say if I was any slower. I don't use a computer, and although my time was a little off, I did get a few more red lights than usual. Maybe that was because I was slower. Eh, I'm going back to 118. I didn't like how it felt.