Tyre Pressure

The other day i changed to a moutain bike tyre on my 24, and i pumped it back up with a normal bike hand-pump. Then i rode it to a garage(\filling station\ petrol station) and pumped it up with their high-power car tyre pump.

Really big difference. With a really hard tyre there’s so much less grip on the road, so i end up riding in much more of a squiggly line than usual, as well as lurching into the middle of the road when freemounting, before i got it under control. Also, the chunky tyre was a lot more “jittery”. . Another thing, at the club one guy has a pretty thick tyre on his 20 that was really flat - bunny-hopping almost made the rim touch the floor - and i found it to be much, much easier to bunny-hop on than mine.

My question is, how hard do you inflate your tire (and psi values etc. mean nothing to me :o) do you use a hand pump or a car tire pump?

(sjoe, that was long…)

Re: Tyre Pressure

My father used to be part owner of a bike shop and I worked there part time
myself.
I’m not a bike or tire expert, but we always told people not to use a gas
station car
tire inflator. They can pump too much air into the tire too quickly and
bust your tire.
I always use a bicycle pump. I have an old Schwinn model which works fine.
It has
a gauge and inflates my tire back up to the pressure I like in less than 20
pumps.
They do make better bicycle pumps with dual air chambers if you are looking
for
more speed.

KG

> My question is, how hard do you inflate your tire (and psi values etc.
> mean nothing to me :o) do you use a hand pump or a car tire pump?
>
> (sjoe, that was long…)
>
>
> –
> e7h3r - It’s pudding time.
> ------------------------------------------------------------------------
> e7h3r’s Profile: http://www.unicyclist.com/profile/2102
> View this thread: http://www.unicyclist.com/thread/25749
>

There is no scientific answer to how much tyre pressure you should have.

Too soft = damage to rims, or sluggish riding.

Too hard = uncomfortable ride, feel every bump.

Knobbly tyres need lower pressures. If too hard, the knobbles can fold over making it steer badly.

Too low a pressure can cause a uni to swerve all over the place when riding down or across a slope.

So just pump it up until it gives firm resistance when pinched firmly between thumb and forefinger. Then if it seems too soft, put a bit more in; and if it feels a bit firm, let a bit out.

Pumping preference

For years I have always visited the service station to fill my tire from their free air pump. It is quick and easy, but the drawback is that it’s a couple of blocks away from home, and sometimes you have to wait for a car or bus to fill their tires first (occasionally they can be generous and allow you to go first seeing that you only have one tire to fill). If my tire has a puncture, it is annoying walking to the service station instead of riding. Recently after blowing thousands of dollars on a new Unicycle I decided that my 24x3" tire deserves a decent pump just in case it ever needs air. I quite like riding hard tires on the road, so I keep a medium amount of air in mine to get the best of both worlds for on/off road and hopping. I scored myself a Topeak JoeBlow pump just in case I ever get a puncture. It is not something I would want to lug with me on rides, but it would be ok in a car for trips away. Afterwards I saw an Air compressor for a quarter of the price at an Auto-parts store (hunting Anti-seize which is only sold in huge quantities). They also had pressure guages for way less than the price of JoeBlow. At least if there is a power cut I will still have an air supply instead of relying on an air compressor. I like the double-sided head for both Presta and Schraeder valves.

joeblow.jpg

You want tire pressure info but don’t want it in PSI or other numbers? Where does that leave us? With how hard you squeeze it between thumb and forefinger? To be useful, that would have to be turned into a number as well.

But before you get disgusted with me, there’s more. Ever since unicycling started branching out into fatter tires, the old rules of tire pressure no longer apply. Rider weight and tire size make a huge difference in how much air you need, not to mention the type of riding you’re doing.

So here are some basic guidelines for tire pressure:

  1. Keep the rim off the ground!
    This is the main rule. Whatever it is you’re doing, if your rim is hitting the ground you’re eventually going to have a flat. Hopping, Trials, and riding on rough stuff put your tire at greater jeopardy of this. But how much air you need depends on those factors above. Just make sure you know you’re not bottoming out. That’s half the battle.

  2. Low pressure for grip and bounce.
    On trails, you get better traction by not having too much air in the tire. Just keep this balanced with the need to keep the rim off the ground. It’s okay if the rim touches down every once in a while, as long as you’re in control when you do it. But if it’s happening a lot, you need more air.

  3. Low pressure for learning to ride.
    When learning, high pressure makes the unicycle rotate to the sides too easily. Let some air out and it will be easier for that beginner rider to get the basics figured out. Put the pressure back up before the student starts riding without support though.

  4. High pressure for speed.
    When we race, we want as much air as possible. This reduces friction, which increases speed. It’s especially important when racing on a soft surface, such as a rubber track. It also helps a lot if you have to ride on carpet. More air can also give you better bounce if you’re using a skinny tire, and better spinning ability, if that’s what you’re trying to do.

Any other suggestions for basic tire pressure rules?

Re: Tyre Pressure

On Mon, 16 Jun 2003 17:25:27 -0500, johnfoss
<johnfoss.p50sn@timelimit.unicyclist.com> wrote:

>More air can also give you better bounce if you’re using a
>skinny tire
Not sure about that one. A skinny doesn’t give much bounce anyway.

>Any other suggestions for basic tire pressure rules?
The fatter the tyre, the lower pressure it can tolerate.

Klaas Bil - Newsgroup Addict

Marilyn Monroe had six toes.