Tundra Tires and Lower Door Questions

Couple questions for the more seasoned out there: :???:

1. How suitable is the Goodyear Tundra tire for occasional (50%) landings on concrete?

2. All the way cool supercubs have plexiglass on the lower door as well as the upper. Mine has fabric. Is it a different door, STC, or how does one do that?

THANKS!

sj

My experience is that the Goodyears will handle 50 % pavement for a long time. I think they are just as durable as 8:50's without the tread.

All you have to do on the door is take the fabric off and cover the inside and outside with lexan or plexiglass. Provides some extra visability. Personally I would use lexan.

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<font size=-1>[ This Message was edited by: djfraudman on 2002-03-03 11:03 ]</font>

DJ is right, just take off the fabric and put on the lexan (#6 screws work good) Non-structural piece.

I had Goodyear 26 inch tires on the Cub I just sold for 7-8 years. 85 to 90% of the landings were on tar. They still had several years worth of rubber and life in them when I sold, just as good as an 8:50.

You'll like them better than the smaller tire because they just handle and land easier plus give you a better angle of attack for shorter takeoffs and landings. Though the Bushwheel's are superior, if you're stuck on pavement, the Goodyear's will last longer. Good compromise.

Thanks for your help gents! That is just what I needed to hear.

Next question: I the only STC for those through Cub Crafters?

sj

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<font size=-1>[ This Message was edited by: steve on 2002-03-03 16:28 ]</font>

Hi Steve,

CC has the only STC for 26" Goodyears that I know of. They also now have a STC for 8.50X6 tires, which are almost as big as 26" Goodyears. Bushwheels are now also STC'ed and can be had with harder compond for occasional pavement use. The Goodyears have a lot more wearing rubber though. Bushwheels have little rubber for wear to keep them light, and flexable. 26" Bushwheels are also bigger than 26" Goodyears. I have had 26" and 29" Bushwheels and love them. If I have to land at a "real" airport, I land along side or short of the big paved runways. Even tower controlled airports will sometimes let you do this if you ask real nice, and these large government funded facilities typically keep the edges of their runways groomed better than any back country strips. Tire selection can be a heated debate amoung Cub Drivers, but I believe you either need big tires, or you don't. Most Cubs don't. Their owners just do not venture away from airports enough, and if they have them it is just for "looks", and the cheap tires are fine for them. But for anyone who wishes to land their Cub where no one has landed a plane before and explore the real limits of their machine, tires are not a place to skimp. They earn their keep when you misjudge the softness or roughness of your intended landing site and they let you roll away unscaved, hopefully a little smarter. The money saved on tires will not seem important when the Cub is on it's nose or back in the mud or snow. Consider getting real tundra tires if you intend on using them for their intended porpose, and keeping a set of small tires mounted on spare wheels for pavement use. All this said, the 8.50X6 or Goodyear 26" would be good general use tires for the occasional off airport landing if the pilot is careful. And crosswind landings on pavement are a lot more exciting the larger, and softer the tires get. It's tough to get the best of both worlds with one set of tires. Also, I recently installed a set of retreaded 8.50X6 from Dresser that were much cheaper and looked just as good as new. These are what I would use if operating from pavement alot. Just food for thought.

Mark Drath


<font size=-1>[ This Message was edited by: SuperCub MD on 2002-03-04 07:11 ]</font>

The 26 in Goodyears will last along time on pavement. I got a year out of McCreary 850s and they were shot. Been running for 2 years on 26 Goodyears and still have alot of life left. The plexiglass door is not STCd.

You don't need an STC for big tires. You will need to fill out a tundra tire work sheet and file a 337. The work sheet asks you to fly with forward and aft loadings and certify that the plane flys okay. The pilot is the responsible party for the "test flight", your mechanic fills out the 337, that's it.

Stewart..........I would recheck with your AI if you're running big tires. You either need an STC or a Field Approval from the local FSDO since big tires were never approved on the original TCDS.

In fact, there is a handbook addendum to the FAA ASI Guidebook (HBAW 97-01)
telling them to no longer do field approvals for these installations:

http://www.safetydata.com/tundra.htm

An STC is required.

sj

Kase, when you say the plex door is not STC'd is it considered a "minor" modification not requiring a 337?

sj

The tundra tire worksheet is from the Anchorage FSDO, it is used to help the field approval process along, but a field approval is still required. Now that Bushwheels, Goodyears, and 850's are STC'ed, field approvals will only be needed for Airstreaks, car tires, or anything else someone might want to use. Some FSDO's will still do the approval, some won't. I never had any trouble with the locals here.

Most would consider glass on the bottom door minor, and could even be installed by the owner.

Mark Drath

Although sj is correct about an directive not to field approve tundra tires it can still be done. I got a field approval for 30" Airstreaks on a J-3. Para. 3.362 of CAM 3 states: A landing gear whell may be equipped with any make or type of tire provided that the tire is a proper fit on the rim and that the approved tire rating is not exceeded.
IMPORTANT NOTE: Ya gotta find a FAA type that has some horse sense.

Steve,

Our FSDO requires a field approval to remove the fabric off the door. My airplane also has a field app to remove the fabric off the landing gear.

Two comments:

1) I try to touch down prior to the runway in the grass to start the wheels spinning... then hop onto the runway for a "landing"
This spins the tires (no scrubbing during spinup) and takes the lurch out of the touchdown, especially if the inflation is low.

2) Lexan is stronger than plexiglass, but it scratches very easily. And while you do the work, make a spare.... much easier to replace later if ready to fit

Landing is not the only wear a tire encounters on pavement. Just taxiing on pavement can cause plenty of wear. If you have big tires(streaks, bush wheels or gar aero) with low air pressure(4-6lbs) the tire will cup as the plane taxis. The heavier the plane the more the plane will oscillate up and down causing the cupping. This will wear on the tire. Hot pavement will also cause wear. Running a large tire with higher air pressure defeats the purpose of the large tire.pak

I have been wearing big tires on my cubs for over 15 years, since the price has gone out of site! I just plain don't go where I have to land on pavement! You are right on PAK about the wear, landing, taxiing all cause wear! Landing short is the best option, I have had some difficulty "getting permission to use the Govt-grass, at tower strips, I usually ask for a low pass/ or midfield crossing to assess the possibilities, talk to the tower,(ask questions and see what their mood is?) I have found the "contract tower" guys are pretty cool! If I ask and they refuse to: "allow landing at pilots own risk", then if I really got to pee, I will make a normal landing and "touch down" a couple feet short of the gooey black stuff,and hop onto it (as light/slow)as possible! Non tower strips, I just land where I see fit (it is the pilots responsibility to insure the safety of the place of intended landing)

My two cents worth! (it would save a lot of tax payers money if they would just tear up the pavement and let the grass/gravel grow! More "environmentally correct" anyway for those concerned!

Tim

No kiddin' Tim.........we had an excellent grass strip here in YKN until a couple of the weekend fliers decided they would like to do their crosswinds on asphalt also. There is nothing like the feel of a good,smooth grass landing.....even in "other airplanes"

Steve,

Get the glass door, you will love the visibility. As you can tell from the pics of my plane, I have as much glass as possible, I can even see my buddy flying behind me at 6 o'clock!
As all have said, asphalt wears big tires, esp. tires w/o tread on low pressure. But the most wear obviously comes from touchdown, when the tire is not rotating and suddendly screeches onto the sandpaper. That is the big one.
Cheers!
Andy

I would not put plexi on the lower door, but if you must, I would reccommend Lucite SR II plexiglass in .100 if you can find it, or .125 if you can't. SR stands for "scratch resistant. Lexan scratches too easy and gas fogs it, if splashed.

delete

STC's 337's and all that **&^%%((*&^

Non of this crap makes the plane fly any better. It has been said when the weight of the log books is equal to the empty weight than you are at gross weight!

I know one sad fact is that most FISDO's don't have anyone that knows anything about cubs, big tires or anything else that isn't on a king air!

Bill Dunkin: (800) 442-8473 with AK bush wheels is a great guy to work with and the $100 for the Tundra tire STC is Cheap compared to the hassle I had to go through! If you try to get an field Approval at your local FISDO and they won't approve it then they have a problem with you going to another one to try again!!

Another reason that Experimental makes sense for "Non commercial operations"

Tim

FYI on Tundra Tires

Just pulled the skis off and put the 30" Air Streaks back on the PA-18. Just for the heck of it I weighed them to compare with a new set of 29" Alaskan Bushwheels I just purchased for my PA-14. I also measured them side by side with a level and ruler. The owner of Bushwheel is always dissing the Air Streaks when he's here for the Airmans Show. Says they are really only 25" instead of 30" and poorly built etc. etc.. I am here to tell you he is full of beans. The 29" Bushwheel on a 6" Cleveland 6 bolt wheel with disk weighs 38.5 lbs. each. The 30" Air Streak with same set up, weighs 37.25 lbs. I have been told the 31" Bushwheel weighs 6 lbs each more then an Air Streak. The big difference is side by side the Air Streak is guess what... 30" tall the 29" Bushwheel is only 28" tall the big part is the Air Streak is 2" wider!!! I went Hmmm, and rolled the Air Streak down the strip and put it next to a 31" Bushwheel on a PA-18. The Air Streak, even allowing for squat, measured 1" taller and 1 1/2" wider. It is just a much bigger tire when you put them side by side. So there, just to set the record straight. I was lucky and bought one of the last sets of Air Streaks made, they still look new after five seasons out in the Bush. My new Bushwheels have mold divots here and there and are poorer quality them the Airstreaks. The Bushwheels also seem a lot less flexable. I run over 6" rocks with the Streaks and they just suck em up. Crash

tire comparison

Crash, I have had both over the years and I can tell you this, the Airstreaks were great tires, unfortunately the compounds used to build them were horribly un predictable and the molds were not very accurate. They were often way out of balance do to the fact that evidently the rubber did not flow evenly in the molds? I can tell you this Bill Dunkin that now owns AK bush wheels is a swell guy and is working very hard to manufacture a stable product that will keep the Feds off our back! I have had his (new 29's on my 12 for 250 hours now and they show no sign of wear. They are the mid hardness rubber "60" and they have never skidded on pavement! Another atta boy for bill is he spent the money, did the work and has an STC for all his tires to cover all the cubs, last I heard near completing the approval for the 180-5!

I do think some of the "good Airstreaks" were a little more flexible and perhaps some were lighter. I can tell you I weighed a set I had 12 years ago and one was 32lb and the other 36!! Crap I had to lean out the door to fly straight and level!!

Thanks for the test!

Have fun this summer!

Tim

What's the recommended air pressure for 26" Goodyears, used some on pavement, some on grass?

For asphalt/grass runway combo I like to use 10#. For off airport I drop it back to 7-8.

Who has the best price on the 26" Goodyears? Has anyone tried the Air Hawk Tubeless Tundra Tire (26 x 10.5 x 6.00) that Wag-Aero sells for $347.50 each?

The goodyears' are about that price also from Wag Aero...

Don't know that the Air Hawk has the STC,...

26" Goodyears

Todd

The 26" tires that Wag-Aero sells are Goodyears or at least they use to be but I don't believe you get an STC. If you have an STC or they are going on an experimental no problem. Give them a call to find out for sure.

Si

I bought the the Goodyear 26x10.50x6 6ply from Wag (~$700)
and
the STC from CC ($150).

Total ~$850 as compared to $1190 from CC

Don't forget the tubes (~$37) from Wag (I already had a pair)

Ok, I have been searching left and right and nothing specific.

My soon to home cub has the 4" drum wheels. Understanding that I need the Cleveland 6" wheels and disks breaks. (I have seen both offers from CC and AircraftSpruce) all I would need is to get the Cleveland Mod and then go either 8.50x6 or GoodYear 26" on my cub provided I buy the STC from CC??

I am a bit confused since I have been trying to get this bought and I can´t seem to get any answers from CC.

If I buy from AS, it claims that I need some sort of modification to the break lines, but there is no doc on what I need. Also, does the STC require anything else to go to 8.50X6 or 26" GY?

From this thread looks like I´m best to go to 8.50x6 since I will be doing alot of airport landings here is Spain with some grass and dirt touch downs when possible.

Could some if possible tell me what I would need get the Cleveland 6" on? And what else I would need aside form the STC to get the 8.50x6? I want to make my purchase ASAP since I want to get it installed once the Cub lands in it´s new home and goes in for it second annual in a week (don´t ask, Spanish, EU laws).... :evil:

TIA