correct tire pressure

[skydreamer]

Correct inflation for 8.00x6 tires. Thanking you for response in advance.

[Bruce Fenstermacher]

To the best of my knowledge, I've never seen a Cessna document with tire pressure for 8:00 x 6 tires. I used in the neighborhood of 24 lbs. when I ran them. It was convenient to remember because that is what Cessna calls out for the 6:00 x 6.

[GAHorn]

Be aware that our 170 Aircraft were intended to utilize 4-ply tires. Even tho' you might be running 6-ply rated tires, you should still use 4-ply inflation pressures.

The recommended tire pressures for aircraft are related to aircraft operating weight, runway type, and tire size and tire carrying-capacity. If you don't know the aircraft mfr'r recommendation, then a good reference is to use the tire's weight-capacity recommended inflation. Different sized tires are listed by Desser here: http://www.desser.com/content/pressure_chart.asp

As you will note, Bruce is right-on-the-money.... 800X6, 4ply tires should be run at 23 psi.

[Bruce Fenstermacher]

As much as I like to be right on the money, and the chart from Desser might be good, it recommends a tire pressure of 29lb unloaded on a 6:00 x 4 while Cessna states 24 lbs. Anyone running 6:00 x 6 6 ply with 42lb?

From Desser's chart

Code: Select all

Size     Ply Rating   Max. Load (per tire)	  Unloaded Inflation (psi)
6.00-6	4	             1150	                          29
6.00-6	6	             1750	                          42
7.00-6	6	             1900	                          38
8.00-6	4	             1350	                          23
8.00-6	6	             2050	                          35

[juredd1]

I only run about 10lbs on grass and I rarely land on pavement so before heading to the convention I had to dig for some air pressure numbers and I found the chart that Bruce listed. I thought there's no way I'm running 42lbs in that tire. Also i don't think I even noticed the ply rating so I we just put air in until they looked like they would work. 27lbs is what we ended up with. It seemed a bit still on taxi but glad to know we were not to far off.

Tail wheel pressure?

Justin

[Bruce Fenstermacher]

Justin, 10 lb is a wee bit low for a normal tire. That is even low for my Cub.

You don't want to spin the tires on the wheel and rip the tire stem out with a resulting instant flat. I'd be airing those tires up a bit more. Even in grass.

[Bruce Fenstermacher]

Got to thinking about the Dresser chart compared to Cessna recommendation.

The Dresser chart is for tire pressure at the max loading for the tire. In all cases higher than the 1100lb per tire our Cessna 170 should be at max. So I figured out what air pressure per pound Dresser was calling out and adjusted that to 1100lb. We only know what Cessna calls out for a 6:00 x 6 4ply tire which is 24lb. I adjusted all the numbers using that adjustment. Pretty interesting.

Tire pressure chart.jpg

I have run 8:00 x 6, 6 ply tires and used in the neighborhood of 24lb. I probably operated down to the adjusted 16 lb at one time or another but probably thought the tire was a bit low on air. I've been running 7:00 x 6, 6 ply for the past several years and use the same 24 lbs and probably air up when it gets down about 16 lbs I think.

I may let air out of my tires Sunday and see at what pressure I thought my tires where low.

[juredd1]

Thanks for the input Bruce, much appreciated. When i get a chance to fly again I'll play with it a bit and see feels good for for me on grass.

Justin

[sfarringer]

Bruce, I agree that looks like a reasonable normalization approach.

For what little it may be worth, I usually run my 8.00 x 6 at about 20 psi for general flying around home. When near gross weight when traveling, I usually run them up to 24 psi.

[170C]

Bet you could get a good bounce with 42# psi

[GAHorn]

As much as I like to be right on the money, and the chart from Desser might be good, it recommends a tire pressure of 29lb unloaded on a 6:00 x 4 while Cessna states 24 lbs. Anyone running 6:00 x 6 6 ply with 42lb?

From Desser's chart

Code: Select all

Size     Ply Rating   Max. Load (per tire)	  Unloaded Inflation (psi)
6.00-6	4	             1150	                          29
6.00-6	6	             1750	                          42
7.00-6	6	             1900	                          38
8.00-6	4	             1350	                          23
8.00-6	6	             2050	                          35

Just to re-emphasize what may have been missed:

Be aware that our 170 Aircraft were intended to utilize 4-ply tires. Even tho' you might be running 6-ply rated tires, you should still use 4-ply inflation pressures.

The recommended tire pressures for aircraft are related to aircraft operating weight, runway type, and tire size and tire carrying-capacity. If you don't know the aircraft mfr'r recommendation, then a good reference is to use the tire's weight-capacity recommended inflation. Different sized tires are listed by Desser here: http://www.desser.com/content/pressure_chart.asp

As you will note, Bruce is right-on-the-money.... 800X6, 4ply tires should be run at 23 psi.

[ghostflyer]

I run Michelin 8.00-6. 6 ply tires at 35 psi all the time regardless of what surface I am landing on. This pressure was on a label that came with the tires. My wear pattern is flat across the tire . And my tail wheel tire is at 45 psi. Again no issues but my tail wheel tire comes from aero Habour freight [again I think they are 6 ply] . I do wear out tail wheels due to the landing strip surfaces. 99% of my landings are wheel landings but the tail wheel gets a bashing due to its size . I have found taxi-ing at large airports and some of the very long taxiways at these airports with a high cross wind put a lot of wear and stress on the tail wheels .PS. Never blown a aero Habour freight tire while the other brand many times.

[GAHorn]

I run Michelin 8.00-6. 6 ply tires at 35 psi all the time regardless of what surface I am landing on. This pressure was on a label that came with the tires. My wear pattern is flat across the tire . And my tail wheel tire is at 45 psi. Again no issues but my tail wheel tire comes from aero Habour freight [again I think they are 6 ply] . I do wear out tail wheels due to the landing strip surfaces. 99% of my landings are wheel landings but the tail wheel gets a bashing due to its size . I have found taxi-ing at large airports and some of the very long taxiways at these airports with a high cross wind put a lot of wear and stress on the tail wheels .PS. Never blown a aero Habour freight tire while the other brand many times.

You're tires may last longer because they are fresher....you're closer to the factory.