What is the correct air pressure on the main tires?

[juasiel123]

I know,, I know,, dumm question.

But still want to know what you think...

how much PSI is the correct pressure for the main's and how much PSI on the tail gear tire?

Just wanna have it right.

Any feedback will be appreciate.

Juasiel

[pojawis]

Just aired up the other day. My a/c has a sticker inside the glove box door that indicates 24 mains (6.00X6) and 32 tailwheel (Scott 3200).

[mrpibb]

My poh states 24 psi max, If I have no data I'll figure 1 psi per 100 pounds of the gross weight for a ballpark get em flying figure. This works for light planes only, different math for a B777.

[doug8082a]

24 in the mains, 30 in the tail.

[N2255D]

CESSNA SERVICE LETTER SLN-56

DATE: 08-03-48

The amount of air in the tires also has a good deal of bearing on the rate of tire wear. Too much air in the tires results in no give in the tire with a resultant scuffing that greatly increases tire wear. The following list shows the correct tire pressures which will result in smoothest operation of the landing gear with maximum of tire life.

190-195 Main Wheels 32#
Tail Wheel 45#
170 Main Wheels 24#
140 Main Wheels 16#

Sure sounds like a lot of pressure for the tail. I've always put 24 mains/32 tail.

[Paul-WI]

So, what about 8.50 tires (those that are running them). I had to run 35psi for the skis (as per the STC) but am wondering if I should drop them down for the summer?

[GAHorn]

Per the Owners Manual: 24 psi -Mains, 34 psi tail.

Regarding other tire sizes, See:
http://www.cessna170.org/phpBB2/viewtopic.php?t=3181

[Paul-WI]

Thanks for the link.

[1SeventyZ]

I couldn't find a spec for tailwheel tire pressure in my POH. Where did you guys find that?

It makes mention of a solid rubber tire for the tailwheel. Is that right or am I downwind of the meth lab?

[cessna170bdriver]

The volume of tailwheel is so small that it is difficult (for me at least) to hit an exact number. I usually just air it up 'till it's round.

Miles

[GAHorn]

I couldn't find a spec for tailwheel tire pressure in my POH. Where did you guys find that?

It makes mention of a solid rubber tire for the tailwheel. Is that right or am I downwind of the meth lab?

The pressure offered (of 34psi) is for the Scott 3200 tailwheel and tire. Scott also provides a graph which is depicted in the SRAM which offers various conditions for that tire/wheel versus weight to be carried....but that graph is applicable for industial useage of the that tailwheel....not necessarily specific to aircraft use. The 170 Owner's Manual specifies 34 psi for the Scott 3200.

[4stripes]

Air is cheap, why not use a little more?

[GAHorn]

Because it causes excessive tire wear and reduces the tire's ability to survive bruises/cuts.

[n2582d]

Here's a case from Pierce Aero for higher air pressure in your tailwheel:

You should carry sufficient air pressure in your tail wheel to keep the tire firmly attached to the rim when it hits the pavement on landing. Due to the small diameter of the tail wheel, it accelerates very rapidly on contact. If you have insufficient pressure in the tire it will slip on the rim and cut the valve stem. You now have a flat tail wheel tire. I know- it’s happened to me twice. I now carry a minimum of 45 pounds of pressure in my Scott tail wheel. The same thing can happen to your main tires but with more surface contact area around the rim it is less likely to happen unless your plane lands at very high speeds.

[blueldr]

1SeventyZ,

The stock tail wheel for the C-170 was a smaller Scott tail wheel with a solid rubber tire the same as was used on the C-120 and C-140. The Scott 3200 was an optional item.