Bicycle tyre pressures?

Question

What would be a typical tyre pressure for a push bike - in pound per sq inch?

Reason I ask is that I've been advised to inflate the pneumatic tyres on my wheelchair to 70 lbs per sq inch.

Seems a lot to me.

Answer 1

I had no idea things were this technical. With my bike, I inflate until I cannot make an indentation in the tyre with my thumb. I suggest you do the same with yours. I shouldn't worry too much if you're a few lbs out.

Answer 2

for a road race bike you're looking at around 100psi for a standard (clincher) tyre, tubular tyres can be inflated a lot higher. Less than 80 and you're at a higher risk of punctures.  

Answer 3

Typical for a mountain bike is 40 to 60 psi

So at a guess - I would say for your wheelchair - 70 psi would not be far off - perhaps a little lower at 55 - 60 psi depending on your weight etc etc.

Answer 4

Pressures are typically marked on the tire sidewall.  

Judging by the tires I've seen on friend's chairs, 70 psi seems reasonable for that sort of tire.   I usually put 60 in my MTB tires, and as much as 150psi in the tubular racing tires on my triathlon bike.  

Answer 5

as long as the tyre is rated to 70psi or above then 70 psi is fine

PS Why is there so many thumbs down in these answers ! !

My mountain bike has 30- 60 psi depending on the conditions and my road bike has 120 psi

Answer 6

Depends on the bike. My road bike takes 120 psi, my MTB only 60psi. See what it says on the side of your tyres. It may be hard to see, but there should be max and min pressures set out there. My mother-in-law is in a chair and I find it best to keep her tyres up to the max recommended.  

Answer 7

70 PSI is probably not unreasonable.  Smaller tires have a smaller contact area, so you want high pressure so that they don't have to squeeze out a lot.  If you weigh 200 pounds, even at 70 PSI, you'll need nearly 3 square inches of contact area to carry your weight.

Bike tires inflate anywhere from 30 PSI on the low end - typically mountain bikers on rough terrain - up to 140 PSI on the high end - racing bikes on a smooth track.

Answer 8

For my mountain bike, for general XC use, I will inflate to 45 psi.  

However, for areas where I am expecting a lot of rocks and big hits, I may go as low as 25 psi.

Road bikes are higher.  The greater the pressure, the less rolling resistance.  Also, thinner side walls require more pressure to achieve the same result, which is why the pressures are higher than many car tyres.  Consequently, road bikes tend to be at about 90 - 110 psi, although when racing the psi can be up to 130.

So 70 psi for a wheel chair is not unreasonable.

Luck

Answer 9

I think you are confusing pressure with volume. Let me explain...

An automobile tyre is usually inflated to a low pressure, say, 28 psi but requires a large volume to fill it. High volume, low pressure.

A bicycle (or wheelchair) tyre requires a very small volume of air at high pressures... High pressure, low volume.

One of the "mechanical" reasons for this is that the higher pressure is necessary to maintain the shape of the tyre. Another is to reduce rolling resistance. Automobile tyres are subject to coarser surfaces and also require more of a surface area on the road due to weight and conditions. They also a part of the automobile suspension system tailoring the ride to be more comfortable. Bicycle (or wheelchair) tyres don't usually have these requirements.