Air Pressure: 8.00x6 Tires

[SkySteve]

Today I replaced my 6.00x6 tires with 8.00x6 on the mains. The tire mfg recommends 35 psi for the 800's. Well that's not going to happen! You guys running 8.00x6's. What air pressure do you use? I'm mostly off airport stuff: dirt & gravel backcountry type strips, cow trails and ranch roads.
http://i237.photobucket.com/albums/ff12/KitfoxSteve/8C39A08C-60DB-4159-8860-ECBE05152CB0.jpg (http://s237.photobucket.com/user/KitfoxSteve/media/8C39A08C-60DB-4159-8860-ECBE05152CB0.jpg.html)

http://i237.photobucket.com/albums/ff12/KitfoxSteve/70A4A981-50A6-489F-A1AF-32AFC1801B43.jpg (http://s237.photobucket.com/user/KitfoxSteve/media/70A4A981-50A6-489F-A1AF-32AFC1801B43.jpg.html)

[beeryboats]

Hi Steve, I have no idea on pressures, but I love the paint job! I'm a proud new owner of a mod IV that's been setting for 10 years. My first purchase was large smooth tundra style tires for my grass strip. If those are Goodyear "big plane" tires they are plenty tough. Maybe you could see how they behave by starting at 25psi and do a few touch and gos. Then drop 5psi and do it again until you get where you want to be? I wouldn't get too crazy low and blow a tire off the bead on landing though.
Jay

[SkySteve]

Jay,
Thanks for the kind remark regarding the old girl's paint. Dan Denny painted her in 1986 when she was the Kitfix factory demo. To fine tune the air pressure in her new tires I will be doing exactly as you recommend. But I'm hoping to get a head start by taping into the large pool of experience we have here at TeamKitfox.

[Av8r3400]

Are those the 12x8.00-6 Aero Classic tires? If they are that is the same as what I run.

Depending on the season, I run 10-20 psi. 10-12 psi in the summer and 20 in the winter with my wheel-skis to give a little more clearance under the skins.

I am currently running them with tubes on my yellow plane, therefore I won't go below 10 psi to keep from slipping on the rims and shearing the valve stem.

[SkySteve]

Naw Av8r3400, they're Air Trac's. They are quite a bit wider than the 6.00x6 Air Hawks I took off. They do have tubes. I was guess 15-20 psi. You are running with 10 and haven't slipped the tubes?

[airlina]

Naw Av8r3400, they're Air Trac's. They are quite a bit wider than the 6.00x6 Air Hawks I took off. They do have tubes. I was guess 15-20 psi. You are running with 10 and haven't slipped the tubes?

Steve , i have airtracs 8.00x6 and fill them to 20 psi. , works great lasts a long time. Bruce

[SkySteve]

Thanks, Bruce.

[cubtractor]

I run 8 to 10 lbs. More than that it bounces like crazy.

[SkySteve]

Thanks Cubtractor. Sounds like a lot of 10 pounders out there.

[jiott]

I am running 15 psi on the Aero Classics with tubes. Don't notice any excessive bounce if I do a normal decent landing.

[PapuaPilot]

Is anybody using 8.50 x 6.00 tires? That is what came with my plane. What pressure do our use in them?

[airlina]

Phil, I started out with 8.50s on my Outback but didn't like them for a couple reasons. They sure looked cool but they weighed alot (as I recall I saved 14 lbs-7 per side ) just by going down one size to 8.00x6. With the IO-240 up front, weight savings anywhere you can get it is helpful. And they sure didn't like pavement-because they weighed so much it takes a bit to spin(that inertia thing) them up on landing so you get some directional control excursions on touchdown that always had me sitting up a bit taller on hard surface landings. Going down to 8's hasn't affected where I can land , (mostly grass) and they handle much better on pavement. Sold my 8.50's on Barnstormeres and they went quick. Theres another guy on this site who had a similar opinion on his experience with 8.50's and he sized down to 6.00 as i recall. (you out there Jeff?) I used 20 lbs on the 8.50's when I had them. Bruce

[Av8r3400]

You guys probably already figured this out, but I meant 21x8.00-6 tires... :o

I have a set of tubeless Grove wheels for my Mangy project and I'm planning to run the same tires there. I don't think I'll go less than 10 psi with that setup, either.

[n85ae]

That would be me Bruce. I'd highly recommend 8.50's to anybody who flies
off pavement a lot, and a has a desire to really fine tune their rudder pedal
skills .... In fact that's where "Whoa Baby!", and "Phew!" became part of
my regular vocabulary

I have 6.00's which I use most of the time for pavement now, sold the 8.50's,
and have a set of 8.00's in the hanger ready to try out this summer.

Regards,
Jeff


Phil, I started out with 8.50s on my Outback but didn't like them for a couple reasons. They sure looked cool but they weighed alot (as I recall I saved 14 lbs-7 per side ) just by going down one size to 8.00x6. With the IO-240 up front, weight savings anywhere you can get it is helpful. And they sure didn't like pavement-because they weighed so much it takes a bit to spin(that inertia thing) them up on landing so you get some directional control excursions on touchdown that always had me sitting up a bit taller on hard surface landings. Going down to 8's hasn't affected where I can land , (mostly grass) and they handle much better on pavement. Sold my 8.50's on Barnstormeres and they went quick. Theres another guy on this site who had a similar opinion on his experience with 8.50's and he sized down to 6.00 as i recall. (you out there Jeff?) I used 20 lbs on the 8.50's when I had them. Bruce

[beeryboats]

Sounds like my educated guess of starting at 25psi wasn't too far off. What do you guys think I should run with my 21" Nanco smoothies? 10psi?
Jay

[Slyfox]

yes, I've used that for years

[Timberwolf]

You guys probably already figured this out, but I meant 21x8.00-6 tires... :o

I have a set of tubeless Grove wheels for my Mangy project and I'm planning to run the same tires there. I don't think I'll go less than 10 psi with that setup, either.

Are these the same tires you are talking about?
http://www.desser.com/store/products/21%7B47%7D800%252d6-4-PLY-AERO-CLASSIC-TL%7B47%7DTT-LSA-TUNDRA-TIRE.html

If so I'd be interested to hear actual height and how they perform?

[Av8r3400]

Yup. Those are what I run. I like them very much.

They are plenty large for the strips I fly into yet they have enough carcass to handle pavement. Plus they cost a fraction of what the "big" tires cost and will last me many times as long.

The diameter of these was nearly exactly the same as my 21x12-8 ATV tires were. I can inflate them to 25 psi for about 22" diameter or at 10 psi for about 20" working diameter (factoring in the "squish" at the bottom).

[Timberwolf]

Awesome. Thanks. Been trying to find information as these are essentially the same size as 8.5's without the price tag.

Seems like most people are running anywhere from 10-25psi in tires around this range without any issues. But the few I've seen that try to run the single digits typically end up with sheared valve stems and a bad day

[Av8r3400]

These are far, far lighter than 8.50s, too!

As a rule I keep to 12 psi with tubes on my current plane. I have the tubeless wheels for my project and may experiment with a bit less on those.

[n85ae]

My experience with tires after ten years flying N85AE (Series 5, IO-240B):

8.50's are too big/heavy - Scary landings on pavement. (One year flying with them)
they are heavy which doesn't affect the flying part much, but the gyro
precession stuff, and the rotational mass is noticeable when landing and
they really yank the plane around a lot (and not in a "be gentle" way).

6.00's are too small - Great on pavement, Terrible in the rough. (Nine years on them)

I'm going to try a normal size 8.00 next per Bruce Lina's advice. Seem like
a good compromise size.

I think the tall Desser 8.00's would likely be scary handling on pavement like
the 8.50's ...

Attached is a pic when I weighed my 8.50's they were 11 lb's heavier (26 lb.s
mounted) than the 6.00's (15.5 lb.s mounted). Adding 11 lb.s rotational
mass is very noticeable at touchdown and with the rubber footprint on the
pavement as well they do not like to change direction easily.

Jeff

[SkyPirate]

I second that Jeff ..on asphalt my 5 didn't like the larger mass either , I have the 6:00's on now..with pants and so far I like it

[Av8r3400]

You need to look at the stats for the 21x8.00-6 tires before making recommendations against them. They only weigh 11 pounds apiece.





Product Description
21/800-6 4 PLY TUBE TYPE or TUBELESS LIGHT SPORT TUNDRA AIRCRAFT TIRE

Brand New Oversize 800-6 to replace 800-6 for Light Sports and Experimentals. (Not FAA approved) Made in the USA.

Compared to a standard 800-6.

4 inches Taller

Same width

Can be used with tube (Recommended tubes are below) or Tubeless (Tubeless rated wheel required)

Lightweight, only 11 lbs.

SKU: 21/800-6 4 PLY


On pavement (what I fly off from my airport) they handle very nicely. Much, much better than the ATV tires I had before. I've been flying these for about 200 hours now.

[n85ae]

You need to speak up favorably sooner supporting them, to prevent people
speaking out against them :)


You need to look at the stats for the 21x8.00-6 tires before making recommendations against them. They only weigh 11 pounds apiece.

[Av8r3400]

You need to speak up favorably sooner supporting them, to prevent people speaking out against them :)

See post #18 and #20, this thread. :):)

[DAT]

I was told when I got the 21x8.00x6 (with tubes) that a good rule of thumb was 1 psi for every 100 lbs of gross weight. Gross of 1320 = 13.2 psi. My plane grosses at 1500 and I run 15 psi and it's easy to handle on both grass and pavement. I did run 24 psi when I first got them but that was a little to much. Better ride at the lower pressure.

[n85ae]

Oops, you're right! Well it's good to know that they work better than the 8.50's
which I never did like the feel of.

Thanks,
Jeff


See post #18 and #20, this thread. :):)

[Slyfox]

message 15 says, nanco smoothies. that's what I have. nice tire, would not use anything else. what are you guys talking about for the big tire size. 21x8.00x6

[Timberwolf]

You ever have issues with nanco's due to the smooth flat tread all the way across? Heard of people having issues on pavement with them being a bit squirelly

[Slyfox]

yes they can be a little more. but if you stall land, there is no problem.

[SkySteve]

I did some testing today landing on both asphalt and dirt. I settled for 12# air pressure. It just felt right.