Tire Air Pressure
 

I was just wondering how everyone keeps their tires inflated. Please take the poll and explain your reasoning/logic if you would like :)

Maximum inflation probably because I qualify for the Clydesdale section depending on what I have for breakfast & lunch on that particular day...

Maximum inflation to minimize flats--for a bike I ride regularly, I top up the tires once a week.

Middle because it rides well and feels hard enough on the road, not always a smooth road.

max or nearly max--reduce contact patch, reduce flats, increase speed from very slow to slow :)
I top up once every week or two. My 1.35 Primo Comets usually drop from 100PSI to around 85 in that time. My Schwalbes I run at max 85 and they drop to around 60.

So far I have lost my tyres due to casing failure, and so far none due to being completely worn down (although the Marathon Plus was close). So I don't like to use maximum pressure any more. There is even a school of thought that likes to deflate the tyres a bit when not riding to remove the stress on the casing threads.

A little explanatory note is in order:

Tyres are supposed to flatten out a bit at the bottom as they bear weight. So a light person will need less tyre pressure than a heavier one for the "correct" amount of deformation. Sometimes tyres are spec'ed with a maximum load-bearing weight; this is simply because they can't be pumped to high enough pressure to bear more weight while not risking pinch flats when going over bumps.

Narrow tyres need higher pressure to avoid pinch flats. As such they will typically have more threads per inch (TPI) to handle the higher pressure. A tyre's maximum pressure is designed to avoid over-stressing those threads.

I use Schwalbe tubes as these asre MUCH better than anything else I tried - I inflate once a month if that.

Setting tire pressure is simple:

http://thelazyrando.wordpress.com/20...res-and-setup/

If you do any of the following you are not getting the most comfort or performance from your tires:

- inflating to max pressure
- inflating both tires to the same pressure
- randomly inflating your tires without checking anything

I hit the curb at 140 pounds...

I am running 1.35 Comet Primos on my Twenty and run them at 95 - 100 psi as even at max they have a very nice ride quality as they have a very supple casing.

Noted that even when I ran them at 80psi they still had a very fast roll out with no discernible loss of speed.

Running 1.5 Marathons at their maximum yielded a much harsher ride and the rolling resistance increases more noticeably at lower psi.

Just picked up a Crank Brothers Power Pump that fits my frame very well, will handle the 100 psi requirement, and has a built in gauge and have a shop grade floor pump as well as a number of other good frame pumps that are just too big for the folder's frame or my backpack.

Max or close to max with Conti 406, Stelvio 451, Conti Gatorskins 26" and whatever 700c race tyres I'm using.
I'm not heavy, but I don't buy the lower pressure argument.
Most of my riding is fairly rigorous and lower pressures have meant flats or unsafe high speed cornering...No thanks.

Now for touring or pootling, then a wider, lower pressure tyre would be suitable.

The goal is not to ride lower pressure - it's to ride the correct pressure. The 15% vertical deflection criteria comes from the tire makers - presumably they understand their tires. This has also been field tested by folks who are not pootling around.

I use schwalble kojaks and I pump them up to 120 of their 115psi recommended pressure. That way it stays really good all week, I'm only 150lbs so i'm not really putting any pressure on those tires at all but boy do they roll nice! by the end of the week they are around 100.

I am on the edge of clyde range...they run at maximum pressure or close to it. I actually am running lower pressures at max than what the BQ article calls for.

Aaron :)

Thanks Vik, very informative.

At 5' 8" and 70+ kg I don't consider myself a big guy. I inflate my 700c Vittoria Rubino Pro tyres to 110-115 psi and I'm happy with the ride, especially charging down a mountain or fast cornering on a crit circuit. if I go under 100 psi the ride starts to feel sloppy. Some of the guys I race with will go as high as 140-150 psi (which is way over the manufacture's specs), it produces a rock hard tyre with a rock hard ride. They claim it makes them super fast?

What about MTB tyres?
Some riders will deflate to 40 or> psi when the terrain is rocky or lots of tree roots, when I try that I get pinch flats, so I stay just over 50 psi.

Is it a case of each to his own or try it and find out?

I pump my road tires as high as I can get away with. I run minimum pressure on my MTB.
I weigh 250lbs and have older 27 x 1 1/4s and the rims are non-clincher (I think that's the right term) so I run just over the 75psi maximum "rim" pressure at 80psi. The 75lbs was printed on the original tires. So I think that is the recommended maximum pressure.
The guy at the LBS gave me a verbal beat-down when I told him I wanted the max 120lbs that was printed on the new tires!
On my MTB, I run the minimum ~35psi. Never had a pinch flat, which is cool, considering I'm a Clyde.

I just checked out the link...

OMG! I can't even use 20 - 23mm tires!









At All!

This has been carefully tested... there is no significant change in rider speed, but what does change are rider perceptions. Almost universally, riders feel faster on harder tyres. A slightly softer ride is felt as being sluggish and slow. But testing has shown these feelings to be unreliable. Take a corner on too-hard tyres will actually lose you traction as it bounces around.

MTB: I run the mud knobblies at 15 psi offroad- about 1/4 max-recommended, and the dry surface tyres at 75 per cent max. My offroad route is mostly stones in the dry and deep mud in the wet.

On the Dahon, the Marathons at as much as I can shove in with a hand pump, about 2/3rds of max. The CO2 pump when I use that gves about 60 psi, but that's too hard. I don't put more pressure in the rear than the front.

So it's a matter of perception.
It's funny, 'cos I'm so used to the pressures I run that even a few pounds less I notice.

Usually while riding in a fast group I will take corners faster than most others, (not kidding), to gain an advantage or make a breakaway, I'm not confident to try that on tyre pressures that makes the tyres squirm around... too high or too low.
Being a motorcyclist as well, this subject is quite interesting....don't want any problems here either.