Flat tire again

[Bevan]

Originally Posted by BobTurner

The talc is to encourage the tube to slide easily during the early stages of inflation, to prevent folds and pinches in the tube.
On touchdown all of the rotational forces should be transferred from the tire bead to the wheel rim, none thru the tube. If the tube does move relative to the wheel you will shear off the stem.

What I meant to say is will the talc on the edge of the rim promote slippage of the tire on the rim? And if so, could this cause a stem leak?

Bevan

[FORANE]

Using no talc for the last 800 hours or so in my Lancair I have never had a stem sheared off, nor heard of that failure from others on the Lancair forum. I may be mistaken but I believe these flat tires are more common on the 2 seat Lancair variants (235,320, 360) than in the RV's. This may be due to less shock absorption in the gear of the Lancairs or possibly because all 3 tires on those Lancairs are the same size as the nose wheel on our RV-9A. I believe the smaller tire is more prone to flats. Anecdotally, we have never experienced a flat on our RV with about 200 hours in it now.

It is a frequent enough failure that at least one of the Lancair transition instructors will carry a spare wheel / inflated tire assembly with him when going to give transition training.

I believe that it is easy for the tire pressure to creep down and go unnoticed. Unless we check air pressure every time we fly, which I do not do and doubt many of us do, we are possibly flying with lower air pressure that we realize. On the Lancair forum it is widely agreed that the common factor in flat tires is low air pressure. The common finding is scuffing / pinching along a lateral margin of the tube. As a result of numerous flats (to the point that I accurately predicted when it would occur but flew anyway to beat a rapidly approaching low overcast with ice only to land and get a flat upon landing) I am convinced increased air pressure is key to preventing it, and in fact have never experienced a flat with higher air pressure. Because I do not check every time, I will typically fill to the high side (as high as 60 psi) and plan to refill when it gets as low as 45 psi (which can be estimated by visually inspecting the curvature of the side of the tire in contact with the ground).

[texdog]

Before, 3 flats, pressure to low. I have been using 50+ PSI with no flats for 400 hrs. RV6A. Lots of talc.

[Walt]

I've probably said it a million times, but might as well say it one more time -
I guarantee to following is true:

LOW PRESSURE = TIRE FAILURE

My recommendation, use 45-50 psi all around (if possible), check and re-inflate every 45-60 days, flats will be a thing of the past.
35-40 psi should be an absolute minimum.

[mr.sun]

Any idea what the maximum pressure rating for the mains is?

[Paul 5r4]

I use 40 in the mains. Initially was using less but the wear was too excessive. I don't know what the max would be. Isn't it on the side of the tire/tube?

[zilik]

An old thread reopened.

The max pressure of the tire is stamped on the sidewalls.

I run all three tires on my 6A at 50 psi.

[JohnInReno]

If you use wheel chocks that are a "U" shape, a low tire will make itself known by how easy the chock goes around the wheel.

I made wheel chocks from PVC and 2 elbows and 2 endcaps that just fit around the tire. If I have to force or wiggle them to get around the tire, then I have an early indication of low pressure.

Not a perfect tire pressure gauge but useful.

[Tbone]

On initial tube & tire install I have always used talc. Nothing excessive. I inflate tire without the scrader valve in and inflate and deflate several times. It seems to "relax" the tube and position the tube in the correct position. Install valve and inflate to preferred psi....

[AlexPeterson]

Originally Posted by Walt

I've probably said it a million times, but might as well say it one more time -
I guarantee to following is true:

LOW PRESSURE = TIRE FAILURE

My recommendation, use 45-50 psi all around (if possible), check and re-inflate every 45-60 days, flats will be a thing of the past.
35-40 psi should be an absolute minimum.

Another guarantee is that high pressure = less vibration damping. One needs to find the balance for your airframe. I would like my mains to be at 50 (for easier pushing), but I get a nasty resonance at that pressure. I have to keep the mains between 35-40. No main flats in 1500 hours. Several nosewheel flats in the first couple hundred hours before using a lot of talc. None since.