Off airport with 8.00x6s?

[Grantmac]

Since I'm away from my plane right now I've got lots of time for musing.

It got me thinking:
How rough of a field can you use with 8.00x6 tires?
I'm working on the paperwork to go larger but I wonder if its really going to be necessary.

My Clipper is quite a bit lighter than a Super Cub or Pacer if that makes a difference.

Thanks,
Grant

[Troy Hamon]

The experts will be along shortly...but in the meantime...I'll summarize the answer...

It depends.

There that was easy.

[Student Pilot]

We have 800's on ours and they do everything we want. Most of our work is or tarmac with strips as short as 300 metres.

[Steve Pierce]

Depends. Besides more prop clearance a 26" Goodyear is only going to give you more flotation with a larger foot print. Great on sand etc. but no real advantage on rough terrain in my opinion because the sidewall is so stiff. Alaskan Bushwheels are soft and very low pressure to absorb the rough stuff. It all depends on you landing zone. I bent my Clipper gear on a pretty smooth gravel bar on 700x6 tires. Been in there lots of times but rolled over over a small hump and collapsed the rear tube which took out the front strut, lower cowl, nose bowl and prop. Luckily a few friends and I were able to hike in several miles with a prop, landing gear and strut.

[SuperPacer]

Grant, As advised above, It depends on the enviroment you are flying to. Our "experience" with 7:00x6; 8:00x6 & 8:50x6 on Tri-Pacer & Pacers here in Utah / Idaho & Nevada backcountry strips has been very satisfactory, with really little difference in performance, once you take out the "cool factor" that the bigger tires give "the look" of our planes. All of us would like some 29" ABW's for Christmas (mine must have gotten delivered to the wrong address again!!) I land in the same jeep trails and dirt roads & mud flats that I did with the 7:00's ten years ago, just now with 8:50's, and a bit lower air pressure. While it now feels better, it would probably be difficult to quantify the difference. The better prop clearance you get from larger tires is a REAL benifit, that helps with prop errosion from gravel etc found on the back country strips, as well as the improved wing incidence for short field take off performance (again, probably not a real big player till you get to the 26" or 29" tire combinations). Continue with the "Paper Work" and enjoy your tires when you get them,

john

[nicka]

Another pilot friend, that has been flying in Alaska for a long time, told me " Every off airport landing that you make is experimental".

[Stephen]

I ran 8.00's for years on my Pacer and I've now had my GY 26" for about 3 years. I'm happy with them...but all measurements of improvement are subjective. I think I get off sooner, I think I stop sooner, I think I can work on rougher surfaces. My only landing gear collapse happened with the 8.00's so I must be right....really.

[pistoncan]

I can't add anything in fact, but In theroy, The larger the diameter of the wheel, the proportionally eaiser if will roll over ruts, rocks, etc. (which is why horse drawn wagons had such large wheels). The roads were awful.
Laying aside the angle of attact, cushion effect, etc, it should take less power to move forward over rough terrain with a larger dameter, with less of a tendancy to nose over or bend a gear leg.
I hope to be able to use hay fields, which around here are fairly rough (not by alaska standards) Having to balance cost, drag, rough field preformance, I am hopeing 800x6's will be enough.

[Grantmac]

Thanks for the well thought out answers guys.

I've got 6.00x6s right now and they got me through the smoother Idaho strips over the summer, but definitely not comfortably.

I'd really like to be able to start using beaches, gravel bars and some of the more interesting back country strips this summer.

Flotation is something I've been thinking of as well, I suppose that really depends more on the width of the tire though or am I totally off base.

Thanks,
Grant

[nicka]

The 26" goodyears will really provide good floatation over mud and sand, so will the bushwheels, I have heard others complain that the Ak Bushwheels are too soft and that when you are landing sideways on a beach that the airplane feels like it wants to tip over, but it is purely a subjective opinion. I will tell you that a Cessna 170 w/ 26" Goodyears fully loaded, and I mean fully loaded, will leave about about an 1/8 inch or so footprint in very soft mud w/ a little water standing on it, significantly less than on 8.50's. The wet parts it just hydroplanes right across it pretty well. If you use the Goodyears you will want to run them a liitle low on pressure, not too low or the tire will spin on the wheel, but a little soft. Either way there is a fair amount of technique involved in different types of ground, like rocking the wings, like a float plane, to pick up one wheel and break the ground contact etc. This is the subject of much debate and I don't think that there is really one good all around solution it really depends on the type of places you are going. It gets complicated, such as, are the bigger tires w/ more weight better or would you just be better off going into places light. Figuring it out is all part of the fun.

[pistoncan]

Thanks for the well thought out answers guys.

Flotation is something I've been thinking of as well, I suppose that really depends more on the width of the tire though or am I totally off base.

Thanks,
Grant

As I understand it, floatation is a function of both diameter and width. (total displacement)