"Tundra Tires"?

[beeryboats]

I just bought a project Mod. IV and have been bombarding these forums with questions. Thanks for all your answers! I have my own grass strip, but it's not the smoothest. My IV has spring gear but small tires. Would I be better off with larger tires? I've searched this forum for tires and came up empty. I was thinking of going to floater tires as it needs new rubber anyway.

[Av8r3400]

I'm running 21 x 800-6 tires on my IV. They are a good compromise of size versus price. Frankly, they are cheap as hell compared to the "Alaskan" tires.

Link (http://www.desser.com/store/products/21%7B47%7D800%252d6-4-PLY-AERO-CLASSIC-TL%7B47%7DTT-LSA-TUNDRA-TIRE.html)

Plenty big enough for the "off airport" work that I do.

[ackselle]

I had the small tires at first, then I upgraded to the Alaskan bushwheel 29" Airsteaks along with better brakes/wheels from Grove. The Airstreaks are phenomenal on grass/river beds/pasture... But they wear very quickly on pavement. If most of your flying is from non-pavement fields, I'd endorse the tundra tires for sure.

Cheers,
Ackselle

[Jerrytex]

http://www.teamkitfox.com/Forums/showthread.php?t=3168&highlight=Nanco


Other than being a little out of round and having to tap the brakes after take off to stop a little shake, for the money, these nancos have been a good deal. If you look around on the web, you can find them real cheap.

[deejayel]

Nanco 21" 8's are the way to go. Tires-easy.com. $30ea plus shipping makes it $100 for a pair to my door.

[beeryboats]

How did they all handle? The builder had them at one time but didn't like the way they acted. I assume he was on pavement most of the time. I also don't know his tailwheel experience. He had 200 hours on his Kitfox.

[beeryboats]

Wow! those are huge! I was thinking something like the 8.00x4.00 that my Vagabond had on the mains.

[Av8r3400]

I would say stay away from the 4" wheels. So many more option with 6" wheels. Better brakes, too.

If you already have the 8" Douglass ATV wheels setup on your plane stay with that if you like it. I hated mine. The brakes were terrible. I've been much happier since the conversion to Grove wheels and brakes. I can actually stop my plane if I want, now. I couldn't with the original Matco-Douglas setup.

[beeryboats]

I have no idea what tires are on it now, but I think it has Grove wheels and brakes. The former owner/builder said the brakes sucked. I'm still in the planning stages on this rebuild, but I need to put good tires under her so I can keep it rolling. The right tire keeps going flat. To be honest, the tires on it now look like golf cart tires.

[Av8r3400]

Look at your tires and tell us the size. That should allow us to figure out what you have there.

[Slyfox]

I agree. mine work great. I never had problems with how they stop. I guess you just need to make sure you have the little brass inserts at end of the line. If it's the see through line. The reason you need to insert is when you tighten the line it will pinch off.

The way mine work, if I had more, I would have to worry about the plane flipping over from to much brake. I can hold mine for a static check no problems. I only did one brake job on my 4. that was over 1800hrs ago. I just did an inspection on my brakes and they still have lots of pad. I generally never use my brakes anyway, what's the big deal :rolleyes:

Now the tires. I have nanco. years ago I had the king fox tires, liked those. then I had to go to nanco, that first set was great, second set of nanco's, I think they are junk, but better than anything else at this point. they get memory. and the left wheel always bounces if it gets much more that 30mph on it. I might just buy a new set and try again.

[jiott]

I put on the Desser 21x8.00x6 Tundra tires. Seem to be very good quality-no problems with out-of-round or flat spotting. They are not as cheap as Nanco but still quite inexpensive-a little over $100 each. Paul Leadabrand at Stick & Rudder uses them on his plane when they don't need the big AK Bushwheels at $1100 a pop.

Jim

[dynomike]

I second the Desser aero classics 21" .I didn't even balance mine and their vibration free and look great too

[JohnB]

I got a set of the 21x8.00-6 Aero Classics for my project and weighed them today. Thought others might be interested in the comparison to stock.

The AirTrac 6.00-6 two tires and two tubes that came with my kit weighed 18 lbs. total.

The Aero Classic 21x8.00-6 two tires and two tubes weighed 27 lbs.

So looks like a weight increase of 9 lbs.

Now I wonder if I can convince my co-pilot to lose 9 lbs to compensate and live to tell the tale? Probably not.

[beeryboats]

I got my 21" Nancos mounted. I weighed them with wheels at 10lbs each!

[ChugiakAK]

We got to take a tour of the AirFrame and Alaskan BushWheel Factory that makes the large Tundra tires that I have on my Kitfox. The process and curing takes time, so they are only able to make around 6 tires a day, but are sold world wide. They also build frames for Cub aircraft. They are located 200 feet from my hanger, so I can just walk across the parking lot to get service!:)

[Kurt.A]

So has anyone considered going to a 12 inch ATV rim and tire? There is a pile of larger tires on the market for 12 inch rims. Some pretty fancy mags on the market for reasonable prices as well. Gotta look good!!!! I would like to put a 24 inch tire on my bird. Has 19 inch BF Goodrich Aviator with 6 inch rims on it now. Not sure what a 12 inch ATV rim and 24 inch ribbed tire would weigh in at. Would require a little adapting but doable.

[WWhunter]

Saw this ad and in the pictures it shows older ATV tires on the plane. They look heavy as heck to me.....but what do I know.
http://mykitfoxthree.vpweb.com/

[Av8r_Sed]

The ATV tires are pretty light. Any other wheels and tires would probably add weight unless you want to go for the tiny pavement only type.

[av8rps]

I've always thought we needed a tire for our Kitfoxes that was somewhere between the $200 (or less) set of 21 inch tires and the $2,000 to $3,000 set of 26-31 inch Alaskan Bushwheel tires. But it seems that no one really made such a tire.

Then one day I discovered the Goodyear 26 inch "Blimp" tires. I originally bought a set of them for my Highlander, but honestly, they looked a bit whimpy on the Highlander (marginally too small). However, when I held them up against my model IV Kitfox project in my garage, they looked just about perfect. In fact, I'd say they looked pretty horny on the Kitfox (hey, that's what the real bush pilots call that...). The size was just about perfect, whereas many times the ABW's just look too large compared to the size of the airplane (IMHO).

So here's what I have since learned about the Goodyear 26 inch tire - the good, and the bad;

- The GY's can be bought for $665, vs $1320 for 29 inch Airstreak ABW's, and $1100 for 26 inch Airstreak ABW's

- The load rating for the GY is much higher than the Airstreak 26 inch ABW, (so the GY's are PLENTY strong for even a heavy Kitfox).

- The GY's are not actually 26 inch, but more like 24.5 inch diameter (I've measured mine)

- The GY's are heavier than the 21 inch tires, but similar to the ABW's

- The GY's being much larger than the 21's will be much better in the bush than the smaller tires

- The GY's are well proven in the Alaskan bush environment, but in the real rough stuff, the ABW's reign supreme as they are much softer

- The GY's will wear like iron on pavement, while the ABW's will wear VERY fast on hard surface -even if just taxiing

- While the GY's are much harder/stiffer than the ABW's, the long term benefit is that it is difficult to actually wear out a set of them, even on pavement

- For the GY's to work well, they should be installed tubeless (install a gasket or O-ring between the wheel haves) and run at air pressures of 7-8 lbs (If tubes are used, the tire tends to slip on the wheel rim causing failure of the tube valve stems. So tire needs to be screwed to bead if tubes used).

- Overall feel of the Goodyear on your airplane will be very similar to an 8.50 aircraft tire, but the tire is much taller and wider than the 8.50

So if any of your are looking for a tire to be used in the backcountry, primarily operate from pavement, but want a bush wheel that looks cool, you might want to consider the Goodyear 26inch tire on your Kitfox.

I think it is a really good compromise for the "gentleman bush pilots" that a good share of us are likely to be. ;)

(here's a link that includes GY tire info plus discussions regarding use - including a link to GY discussion on the Matronics Kitfox forum; http://www.skygeek.com/goodyear-26-x-10-5-x-6-smooth-tundra-tire.html (http://www.skygeek.com/goodyear-26-x-10-5-x-6-smooth-tundra-tire.html) )

First Pic below; 850's vs Goodyear 26 inch. 2nd Pic; 26 GY on a Highlander 3rd pic; Goodyears look good like the ABW, just smaller

[WWhunter]

Totally agre! Have owned 8.50's, 26" Goodyear 'Blimp' tires, 26" and 29" AkBushwheel AirStreaks, and I will say the AkBushwheels are the ultimate, if, and that is a big if, you can afford them. They do wear much quicker than either the 8.50's or the GY 26" tires but they give the best in off airport safety and cusioning. Having said that, as the previous poster states, the GY are built like iron and have been used on planes as large as 206 Cessna's in the bush country. They are heavier and not as soft but they will last a lifetime.
If I didn't already have the 29" Airstreaks I would be looking at the new tire Dessers has. Definitely affordable and made just for the LSA class of planes.

[cubtractor]

I've been using the new Desser tires and they are working great. They seem to be just the right size and weight for the Model IV.

http://www.teamkitfox.com/Forums/picture.php?albumid=273&pictureid=4769

http://www.teamkitfox.com/Forums/picture.php?albumid=273&pictureid=4770

[Paul Z]

I have the new Desser Smoothies on my recently converted 7SS. I have flow the Tundra Tires and the 8X6 on the Stick & Rudder planes. I much prefer the Desser, and the did fine at a small dirt strip 9 miles south of KBOI, called Blacks Field. Mr Blacks runway was rougher than all but one of the Idaho back country airstrips I have landed. Pelican Point was definately in worse repair. Blacks field is probably 1900 feet X 25 feet wide, dips in the middle, prairie dog, gopher holes every where. Don't run off of the runway you will be facing some large rocks. I'm flying over it on the way out from BOI. I'll get a photo from the air.

[N981MS]

I would love to see some pictures of a Series 5, 6, or 7 on some of these Dessers.

Thanks
Maxwell

[av8rps]

Can someone flying the new Desser Smoothie 8.50's verify the overall height and width of the tire mounted on the rim? Desser says 22 inches in their info, but so many times the info seems to be off in the ads.

Also, are those of you using that new Desser tire using tubes? Or are you mounting them tubeless?

And last question, what air pressures are you running?

[Av8r3400]

(I've got the 21" Dessers - with grooves - on my yellow plane. Currently running with tubes at ~12 psi.)

[cubtractor]

I'm running my 22" Desser smooth tires with tubes at 9 lbs. Any less and I'm afraid of spinning the tube. Below is a picture of the 22" Dessers vs. the 21" 8.50's grooved I took off.

http://www.teamkitfox.com/Forums/picture.php?albumid=380&pictureid=4707

[Paul Z]

Here are some pictures of the Smoothy's on my plane.
I was parked at Boisie, I had landed at Black's field the day before.

[Paul Z]

Here is a close up of the tires. The factory aired them up at 17 lbs, they roll fine, no squealing, they are very nice and very forgiving to land on, and the price is reasonable.

[N981MS]

Thanks Paul. Those look great. I am pretty sure I am going bigger next time.

[airtire]

New Desser 27 x 10-8 Tundra coming soon.

Fits Matco 8 Inch Wheel (not pictured, pictured is test rim)
Can be run Tubeless
Made in USA for Aircraft Use.
Weight 20.5 lbs.

[av8rps]

Looks great!

But too bad they are using an 8 inch wheel, as by the time you get done upgrading your 6 inch wheels to 8 inch, you might just as well buy the ABW's.

[WWhunter]

I guess I lucked out once in my life!! The project I just got has the 8 inch wheels. :)

[WWhunter]

I think you have to add the air weight. If you put 12 lbs. of air in them, them you add that weight to the tire. 20.5 lb. tire with 12 lb. air pressure will give you 32.5 lbs. Darn, that is a heavy tire!! :eek:
LOL...not April fools day yet but a guy has to have some fun. :)

[airtire]

Looks great!

But too bad they are using an 8 inch wheel, as by the time you get done upgrading your 6 inch wheels to 8 inch, you might just as well buy the ABW's.

The introductory tire price will be $395 each

If you are using the 6" Matco MH Series, all you need is the 8" Matco wheel +/- $75 each. This will bolt right on to the MH Series setup. $150 one time

Your worst case, new 8 inch Matco wheels, brakes and spacers +/- $320 per side, $640 total....one time.

After that $395 tire change.

We are also working on an FAA TSO'd version for Certified Aircraft with STC's, etc.

[av8rps]

This thread is certainly getting a bit off topic, but here's my favorite "Man on the street" showing just how dumb Americans have become...

https://www.youtube.com/watch?v=SRkFDcX_72c&list=PLa8S4GilqogQRwblg-wi17_-z5jhPuxVV

[av8rps]

The introductory tire price will be $395 each

If you are using the 6" Matco MH Series, all you need is the 8" Matco wheel +/- $75 each. This will bolt right on to the MH Series setup. $150 one time

Your worst case, new 8 inch Matco wheels, brakes and spacers +/- $320 per side, $640 total....one time.

After that $395 tire change.

We are also working on an FAA TSO'd version for Certified Aircraft with STC's, etc.

Ok, back on topic...

SIGN ME UP FOR A SET! I'll convert my wheels if that's all it takes :)

[Paul Z]

The Dresser Smoothies I have posted in this link are on 6 inch wheels, the tires are $200 each from McBean.

[WWhunter]

Dang, just when it was getting good....I was going to say some of those people remind me of our governemnt. ;)


Ok, back on topic..:)

I am giving it some thought also. The plane I just acquired has a new set of the 21-12x8 Nanco's already on it and they will probably be sufficient for the expected use of this Kitfox. If they get changed, the Desser's sure look like a bargain compared to the AkBushwheels. Only other comment I will mention is if a person has the 6" wheels you can usually pick up a set of used GY 26" tires for $1,000 or less. They might be a little heavier but they will last many years before requiring replacement. Since I have a spare set of 6" Matco wheels I will mount the GY's that I have on them and compare them.

I replaced the entire gear on my RANS S7, it has the older, small caliper brakes very simlar to the Kitfox wheels albiet thye are 6" wheels insstead of the 8". I was going to advertise them but I may just keep them so I can have a 'Bush tire' for whenever I may need it. :)

[Paul Z]

I've got the Dresser Smoothies with 17 lbs of air in them and it's like landing on cushy pillows very soft landing even with full stall drop in landings. I have been pleasantly surprised. I went out Friday and man even one of my crappy landings was oh so soft. Charmin Tissue would have been proud!

[av8rps]

The introductory tire price will be $395 each

If you are using the 6" Matco MH Series, all you need is the 8" Matco wheel +/- $75 each. This will bolt right on to the MH Series setup. $150 one time

Your worst case, new 8 inch Matco wheels, brakes and spacers +/- $320 per side, $640 total....one time.

After that $395 tire change.

We are also working on an FAA TSO'd version for Certified Aircraft with STC's, etc.

How will these tires compare to the ABW's regarding softness, and tire wear / longevity?

Paul

[Av8r3400]

Just as a comparison, I have the 21" Aero Classic, treaded (21x800-6), tires. I've been running them several hundred hours now and can see no wear on them at all. I operate off a paved airport, but into lots of grass destinations. They have been plenty big enough for me and I plan on the same tires on my Mangy Fox project.

If you are into gravel bars and serious bush flying they may be a little small, but for me they are perfect.


AND at $110 each they are better than perfect!

[airtire]

7909
How will these tires compare to the ABW's regarding softness, and tire wear / longevity?

Paul

These are the same compound as our 21 x 800-6 and 850 x 6 Aero Classic's.

People have commented that the wear is extremely good on the above sizes.

Here's a better picture of the tire mounted on a Matco 8 inch tubeless wheel.

[av8rps]

Man, I'm liking them more and more...:)

[Av8r3400]

But the million dollar question is still unanswered:

Why make these tires for an 8" wheel instead of the more marketable 6"?

[airtire]

But the million dollar question is still unanswered:

Why make these tires for an 8" wheel instead of the more marketable 6"?

You got a lot of questions....who are you working for? :) :)

The saying "there's more than one way to skin a cat" is appropriate here.

The largest 6" tire we can get made at this time from current available tooling is the 850-6 which is 22 inches. Not optimum but we made the best of it and came out with the ultra lightweight 850-6 4 Ply.

To get to the next level of large in 6" would cost upwards of 350K in tooling and changes in their manufacturing process. Not a big enough market for them to change their process.

We determined the next level of large that could be made in existing equipment would be 27 diameter x 10 wide on an 8" wheel. We did some homework with Matco and Grove for the 8" wheel.

We determined that for LSA, if a person has Matco setup and all you will have to pay is $75 a wheel to upgrade to a light, tubeless, $395 Tundra Tire we would get a thank you.

If you need to fork over $640 now for new wheels and brakes to be able to use our $395 Tundra Tire, we will probably get a grunt now, but my math shows me that $1430 for a complete setup is cheaper than the least expensive option out there for a tundra type tire.

The ABW tire is the best option for a lot of operators. It's a proven, well made product.

We are just exploring a different side of the market from a different angle.

and that's all I got to say about that :)

[WWhunter]

I know my opinion on here is worth less than what you pay for it but I think you guys made a very good business decision and they way it was thought out with the end product saving the end user a bunch of money... SMART!! I'm going to guess you will end up with a very marketable product. Might even want to get a bulk buy on some Grove or Matco 8" wheels and sell them as a set with the tires. Someone there deserves a big bonus. Better yet, just send me a free pair for saying nice things. ;)

[dynomike]

I second that .just the fact that they wear like the 21" classics that I have on now is worth the price of a wheel. 200 hours and there still new .what size tubes will we need?

[N981MS]

I might not mind having an extra set of wheels to ease swapping out between tires. Does anyone know if the 8" wheels work with my cleaveland brakes?

[kitfoxnick]

Pardon me if this has already been answered. Can you use the 8" Douglas wheels? How low of an air pressure can you run these at?

[av8rps]

I commend you for doing what you are. I think it is a great business strategy and will be looking forward to getting a set for my next project.



You got a lot of questions....who are you working for? :) :)

The saying "there's more than one way to skin a cat" is appropriate here.

(Snip, snip...)
We are just exploring a different side of the market from a different angle.

and that's all I got to say about that :)

[Av8r3400]

Pardon me if this has already been answered. Can you use the 8" Douglas wheels? How low of an air pressure can you run these at?


Yes, the Douglass wheels would work perfectly, but the Matco brakes on that setup are woefully inadequate with the 20" ATV tires. I doubt you could even hold the plane to run up the engine with 26" tires.

[av8rps]

I'm guessing that if using the Matcos with the big tires you may have to use double calipers like the Highlander guys are doing? My Highlander with Matco brakes will not hold on runup with just 850's and single calipers.

(Although recently I've learned that if I used smaller brake lines they will hold better?)

[kitfoxnick]

I ran Nancos for a couple of years until I found a deal on a set of 26" Airstreaks with double caliper Matco brakes and wheels. Never had a problem with the original calipers (I could lock my Nancos up), but I knew of a few who did. I have a friend who is running Nancos and looking for somthing more. Would it be possible to install two of the original matco calipers.
I'm curious as to how low a psi these can be run at. To me size is one thing but the performance of a bush tire is based on the cushioning effect. I used to run my nancos at 4-5 psi. I run my Airstreaks at 2.5 to 3 psi.

[WWhunter]

Nick,
Funny you mention using double calipers as I have a spare set I took off my RANS S7 when I replaced the entire landing gear. I noticed they are identical to the older style calipers on this Kitfox I just purchased. I know they were barely adequate when on the RANS and it had 6-6.00 tires. I am going to try and make a dual caliper set-up with this 'take-off' set I have. It should be fairly straight forward, just have to get a different backing plate made.

Also, Matco sells an 'intensifier' that is a sleeve and new piston to go inside the stock sized master cylinder. I spoke indepth with Goerge of Matco this summer at Oshkosh and he recommended that I should try it before other options since it is the least expensive upgrade. I think the cost was $17.00.
Unfortunately I have Cleveland master cylinders and he was not sure at the time if the kit would fit since it is designed for the Matco cylinders.

[rdooley79]

What would be the best route if you have a grove setup of 6" wheels and matching brake rotors.
Could you keep the Grove brakes and rotors and switch to a different Matco rim and Desser 27" tire?
That would be awesome to be able to swap between them.

My KF4-1200 and many others run that setup. Grove brakes are nice and strong and can hold the Desser 22" smoothies no problem.
I'm very happy with them but I'd be very interested in a 27" for sure!

[kitfoxnick]

Anyone try the 27" yet?

[dynomike]

their not shipping till march 2015.im also anticipating

[kitfoxnick]

Oh, so I guess no ones tried them ;)

[dynomike]

desser shipped my 27" yesterday .looking forward to trying them.id like to hear others experience with them as well.

[JorgeEC-YUQ]

Hi there,

After considering many options, I am finally looking foward for the 27" from desser.
My problem is that I have the 8" Douglas ATV and I am not sure if they will fit in this rim ...

Anyone has tried them on the Douglas or maybe someone knows the widht of this rim?

Thanks!
Jorge

[Av8r3400]

The Douglas wheels are 8", they should fit just fine.

[ackselle]

Here's mine with the 29" ABWs. One of the best additions to my Kitfox...absolutely!

[Paul Z]

desser shipped my 27" yesterday .looking forward to trying them.id like to hear others experience with them as well.

The 27” are for 8” Rims, correct? Proportionally they look like exactly the correct size for the size of plane.

[airtire]

Are the Douglas wheels meant to be used "Tubeless?"

[dynomike]

mine are tubeless . the dessers are tubed or tubeless tires

[Jono]

Are the Douglas wheels meant to be used "Tubeless?"

I've got tubes (since day 1)

[JorgeEC-YUQ]

Does anybody know the internal width of the Douglas wheels?

Thanks!

[tomec]

6" wide 8" da. is what mine are

[dynomike]

Got the tires today and mounted on the douglas rims . They are really soft and pliable .and they are huge! Awesome shape like the airstreaks .mounted tubeless.cant wait to try em.here's some pictures

[Slyfox]

boy, I've been really he haw'n about putting those tires on my 4. If I do, I plan on updating the rear spring and put on the matco to raise that up a little so I can keep the same ground level. I generally like to drag the tail on landing in case the tail wheel is unlocked, seems my major slips could unlock it, so I do that. also it's fun. :D

[Flybyjim]

Tires look cool, but how's that angle of attack on windy days on the flair?

[Peteohms]

So where does one buy Nancos formerly sold by Highwing's?

[B767]

Hey guys,
I just got my Dresser 21x6x8 tires today, mounted them on my 6 inch rims and am little disappointed in the height. They are about 19.5 inches tall overall.
My 7.00 series I had on before were about 18 tall......does the 21" number not refer to the height of the tire?
It's on,y an inch and a half, no biggy.....again just curious.

Wade

[Av8r3400]

What pressure do you have them at? I have the Desser 21x800-6 tires mounted on both of my Kitfoxes (on 6x6 Grove wheels) and at 15 psi they are at about 20 1/2".

Aired up to 25 psi for winter (wheel-through skis) they are over 22" tall.

http://www.teamkitfox.com/Forums/showthread.php?t=6601

[Paul Z]

I air mine up to 17 lbs., they measure 20 inches.

[Nu2me]

Pete
Tires Easy.com. Just received 2 this week

[B767]

I originally had the pressure right up to 25psi.
The pressure published on the sidewall. I measured the tire at that and it was around 19.5 inches. I deflated them down to around 15 and the measurement was about the same.
It is a very cool day today..... So maybe in the scorching heat with 25 psi they might tickle the 21 inch height...... Who knows!

[Paul Z]

I know, I was just admitting my ignorance to the older models. I had gotten away from flying for 15 years and got back in to it about 6 years ago. I can finally afford it. The early Avids, and Kitfoxes are hard for me to tell apart. I really like your plane, and the tires look great on it.

[B767]

So with a few responses with regards to the height of the Dresser 21x8x6, from what I see no ones tires are 21'' tall.
Am I wrong to assume that the 21 in the numbering is the height of the tire?
If so why isn't mine and several other posters tires 21 inches tall?

[Paul Z]

There are several things that play into the tire diameter.
First, 21" is the tire diameter, not the "Tire Height".

I would bet if you went and measured the molds the tires are made in at room temperature they are 21". When they form the tire the mold is hot, the bias ply belts are hot, and the rubber is hot. As they cooled down there is shrinkage. I've never worked with the molding of rubber, but I have with both plastics and aluminum. The are all effected by the coefficient of thermal expansion (CTE) as thing heat up they expand, and as they cool down they contract.


Also if you measured the diameter of the tired after installing it on the rim, air them up when they are mounted to the wheels, and sitting on the flat on the floor and measure the diameter of the tire, without any weight on the tires. I would bet the tires would measure about 20 3/4" up to 20 7/8".

With the 300+ lbs on each of the tires the weight of the aircraft the aircraft it flattens the tire. Mine measure 20" with the planes weight on the tires, with 15 PSI air pressure.

With less pressure the tires get flatter, if you measure the tire with 15 PSI from the floor to the top of the tire you will get a different measurement than if you put in 18 PSI.

I would venture to say the tire diameter is measured in the Free State, with no weight on the tire, laying on its side, and aired up to a engineering specific PSI Air Pressure. I have no clue what pressure they may have specified on the engineering design specification. Also, per the ASME Dimensioning and Tolerancing Standards it states measurements apply in the Free State, unless otherwise specified on the engineering drawing, or specification.

[B767]

Good explanation Paul, thank you.
Thought as much. Still, my diameter of about 19.5 inches is off the mark more then casting or moulding errors and tolerances would allow.....you would think.
For what it's worth, my tires are mounted on the rims, OFF the airplane, pumped up to 30 psi and sitting in the hot sun......thermal surface temp of tires at 4pm was over 100 degrees..........yup still 19.5 diameter..
Again, don't get me wrong. These tires have a great rep, and I'm sure I will be satisfied. I was just looking for a min diameter of 21 inches, which would have made the difference from my old 7.00 tires to these new ones more worthwhile.
I'm sure they will be fine.

[Kurt.A]

Excellent explanation Paul. Just one thing to add is that rim width also affects tire diameter. The wider the rim the shorter the tire becomes once mounted and inflated.

[SkySteve]

Here ya go, Paul. Just for you:
http://i237.photobucket.com/albums/ff12/KitfoxSteve/85DD/1952B88B-F4F2-42C1-882B-8D1988DBA355-1579-0000014C2D8B5153.jpg (http://s237.photobucket.com/user/KitfoxSteve/media/85DD/1952B88B-F4F2-42C1-882B-8D1988DBA355-1579-0000014C2D8B5153.jpg.html)

[Foxfan2]

I have been running the 22" Desser smooth Tundra tires for a year now on my Kitfox 5. Over 100 landings, mostly on Willamette River gravel bars, some pavement as well. I love them. They show no wear so far. I have them on Cleveland wheels, therefore, I have tubes. I'll take some heat for this but here goes. I'm running a 6 psi. I started with 18 psi and kept reducing till I stopped at 6. I did several landings on pavement with heavy braking to see if they were going to slip on the rim and shear the stem. I couldn't detect any slippage. I'm not saying I recommend it but they sure are soft. Still easy to taxi too. It helps to have a 650 lb. airplane. Now I want the 27".

[Esser]

650lbs Model 5 with tundras? Tell us your secrets...what equipment and powerplant/prop do you have.

[Foxfan2]

Well, I bought, didn't build. No options on the airplane that I'm aware of, including a trim indicator. I took all the steam gages out and installed the small Danon EFIS. Rotax 912UL, so only 80hp with an IVO ultra light proop. It may not be the lightest one around, but it's got to be pretty close. Does a nice job off airport.

[SkyPirate]

my model 5 registered LSA weighs 750 empty 912 UL but with 3 blade tapered tip warp

[Jerrytex]

My Nancos are giving it up. I guess the pavement is too hard on them. I was running about 10 pounds, any higher and the bouncing started. Basically where the sidewall meets where the "tread" starts, they are paper soft and now the cords are starting to show. I am grounded until I get new tires. Also while inspecting them, I noticed they are only rated for 365 pounds. I think I'll look around for some different tires with a little higher weight rating and better wear on pavement. I put 75 hours on these. While cheap enough, Its a hassle to to have to change tires every 75 hours. I see the aero classics and the dressers are pretty popular. Anyone find any other tire "deals" here lately. I have the 8" Douglas wheels.

[Av8r3400]

If you are still running the 8" wheels. The new Desser 27" (http://www.desser.com/aircraft-tires-and-tubes/2710-8.asp) tires are an option for you.

http://www.desser.com/images/27-10tundra_med.jpg

The Matco "internal" brakes used on the Douglass setup may not be up to the task, unless you do something to improve them...

[JorgeEC-YUQ]

My Kitfox III with the Desser 27" tyres and Matco 8" wide tailwheel. Didn't fly it yet, still working on the installation of the double caliper ...

[Monocock]

That's a great looking Kitfox!

Out of interest, have you got the single arm Matco tail wheel or the double arm one?

[Slyfox]

how much did they slow the airplane down

[dynomike]

What a transformation.looks great! !

[Foxfan2]

They look really nice. I just got my 27" Aero Classics installed with Matco wheels and brakes. I love the tires but I'm disappointed with the single puck brakes. You made the right choice with double puck. I might have to go that way. I started with 10 psi but I'm now at 7 and think I'll keep coming down. They don't look deflected at all with 7 psi and it's easy to push around. Might have to carry a step stool to get in. By the way, I measured them on my bench with 10 psi and they are exactly 27 inches.

[dynomike]

I have about a hundred pavement landings on mine now and the little molding strip in the center is still there. I think there going to last a long time

[Jerrytex]

Wow. Nice looking tire. Yeah I am curious too, how much they slowed you down.

I searched for options but I ended up going back with Nanco 21". I did get almost 300 landings out of them all on pavement with no problems. I am going to run a little higher pressure from now on, and the new ones seem to be less "out of round", so I don't get the bad vibration on take off. We'll see how it goes.

The Dresser 27" were way, way out of my price range but they sure look cool.

[jrevens]

I got a set of the Aero Classic 8.50-6 22” tundra tires and tubes for my bird. I’m thinking that perhaps it would be a good idea to forego using talcum powder inside the tires when installing the tubes since they are a low-pressure tire. My thinking is that it might make it less likely that the tubes could shift in the tires. Any thoughts?

[Esser]

Seems like good reasoning to me John. One other direction of thinking:

I do think that a lot of the stem shear is from the tire rotating and dragging the tube with it which pulls on the stem. Maybe copious amounts of talc would be better so the tire can move with out pulling the tube with it? I have heard of people using short small screws to hold the bead stationary to the rim? Also, maybe you would regret this, but maybe you could use windshield urethane to hold the tire in place?

[jiott]

I think that is an excellent idea John. On initial installation of tubes into the tires maybe do several extra inflation/deflation cycles to help the tube slide around and seat itself without any wrinkles.

[jiott]

Here's some other ideas: the source of the problem is the tire bead slipping on the rim. Most off road motorcycles have rim locks to prevent this very thing; as Josh said, and old motorcycle trick (before rim locks were standard equipment) was to use short screws thru the rim and into the tire bead. This probably could be done on an aircraft wheel if you don't mind drilling your wheel rims. But I also noticed on my Honda XR500 dirt bike that the inside of the rim where it contacts the tire bead was somewhat serrated to provide a rough surface to prevent slipping under torque. Maybe this could be done to an aircraft rim with a Dremel or something.

On second thought John, I don't think your idea of eliminating the talc would help much, since it would only ensure the tube moves with the tire, which is NOT what you want. You want the tube with its valve stem to stay put exactly where the valve stem hole is in the rim. The only way to do this is to prevent the tire from slipping on the rim. I doubt very much that the small valve stem has enough strength without tearing the rubber to hold itself in place if the tire slips, even if you put massive amounts of talc inside as Josh was wondering.

Bottom line for me would be: no talc or rubber lube on the bead/rim area, roughen up the rim bead area on the wheel, and be reasonable in lowering the inflation pressure too much. As part of my preflight, I always look at the tire valve stems to see if they are starting to tip sideways.

[airlina]

I recently switched to the Desser 850 Tundras and I am very happy with them. I too was worried about the $ 90 tube valve stem shearing , so I started out with 18 PSI in them but have since come down to 14 PSI and will probably stay there. I also marked the stem location on the tire and rim and make it part of every preflight to check for any slippage. So far no slippage is evident. These tires handle well on grass or blacktop and I have noticed quite a difference from my old treaded 8.00's. Plus they look cool-apparently size does matter! Bruce N199CL

[jrevens]

Thanks to all of you guys. I clearly wasn't analyzing the issue very well... think I'll start with 14 or 15 psi, and mark & monitor the tire/rim position. I'm gonna' stay away from adding screws or doing any machining on my magnesium wheels for now! :)

[Av8r3400]

John, you are on the right track. If the tire (and tube) are properly inflated they will not turn on the rim. This only is possible if they are under inflated.

If you need your tires so soft that they must be under inflated, I would suggest doing what I did and run them tubeless. I ran mine 8-12 psi for several years this way. This does not allow you to run them at 5 psi, like a bushwheel however. Aircraft wheels do not have a safety bead like an ATV or automotive wheel. THey need some pressure to hold them in place.

[airlina]

also very important to keep a tire gauge at the hangar and check pressure with temperature changes (especially decreasing temp) Bruce N199CL