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Tundra tyres.

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Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Sat May 06, 2006 11:16 am Post subject: Tundra tyres.

On May 6, 2006, at 8:10 AM, kurt schrader wrote:



 	  Quote: 	
		   Do your tires pick up flats spots from

 sitting in one place while parked in the cold?


	


Well ... not exactly, Kurt. It looks like they were deformed in place 

because moving on an edge. First, I thought they might have locked 

themselves in the wheel penetration skis when e.g. landing. But then, I 

should see wear marks on the skis and I don't. Then there is a metal 

rail to cross when I exit the hangar. The rail is used to support the 

sliding doors. But I have never seen that before, it only came this 

winter. Strange. The tyres are working fine only that you can see that 

they are not any  longer even, there are kind of hollows areas in them. 

Difficult to explain, I should take a picture.



Cheers,

Michel



do not archive

_________________
Kitfox 3 - Jabiru 2200

smokey_bear_40220(at)yaho
Guest

Posted: Sun May 07, 2006 8:39 am Post subject: Tundra tyres.

Hummm.  Some tires still show a seam where the belt

wrap joins.  Tires are not always a continuous wrap

and lower cost tires do not hide the overlap of the

tread wrap.

Basically I know of 3 choices:

Flat spots from landing tread wear.

Flat spots from cold tires taking a while to flex out

the parking flat spot.

Flat spots from tread overlap.  Look at some new ones

of the same brand and it will probably still show

there too.

Can't think of any other reasons?

Kurt S.

--- Michel Verheughe <michel(at)online.no> wrote:

 	  Quote: 	
		   On May 6, 2006, at 8:10 AM, kurt schrader wrote:

 > Do your tires pick up flats spots from

 > sitting in one place while parked in the cold?

 Well ... not exactly, Kurt. It looks like they were

 deformed in place 

 because moving on an edge. First, I thought they

 might have locked 

 themselves in the wheel penetration skis when e.g.

 landing. But then, I 

 should see wear marks on the skis and I don't. Then

 there is a metal 

 rail to cross when I exit the hangar. The rail is

 used to support the 

 sliding doors. But I have never seen that before, it

 only came this 

 winter. Strange. The tyres are working fine only

 that you can see that 

 they are not any  longer even, there are kind of

 hollows areas in them. 

 Difficult to explain, I should take a picture.

 Cheers,

 Michel

 do not archive

__________________________________________________

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Sun May 07, 2006 12:18 pm Post subject: Tundra tyres.

On May 7, 2006, at 6:38 PM, kurt schrader wrote:

 	  Quote: 	
		   Hummm.  Some tires still show a seam where the belt wrap joins.


	


This is not the case, Kurt. Please look at these photos I took today:



http://home.online.no/~michel/tmp/Tyres.jpg



On the two upper photos, you can see, in the red circle, the 

depressions in the tyres. On the lower photo, the steel rail that may 

be the cause of the depressions. It's the only thing I can think of. 

Strange, isn't it? Also note that the hangar (actually an old workshop 

for the airfield) is not wide enough to get my Kitfox in and out 

straight. When over the rail, I have to turn the plane 180 degrees to 

get one wing out at the time.



Cheers,

Michel

_________________
Kitfox 3 - Jabiru 2200

Rex Hefferan

Joined: 10 Jan 2006
Posts: 147
Location: Olney Springs, Colorado USA "NOT a Kitpig"

Posted: Sun May 07, 2006 4:27 pm Post subject: Tundra tyres.

Michel,

 I wonder if the construction of ATV tires (tyres) differs enough that 

they may more easily form these flat spots when stored in cold for a 

while. The fact that the tire is not as thick as was designed for normal 

useage (due to the treads removed), may contribute to the problem. Is 

this a recent development? You've probably already thought of this; 

perhaps you could mark the tires or note the depression in relation to 

tire lettering. Then see if it later occurs in another location on the 

tire. That would indicate an extrernal cause (the rail) verses a defect 

in the tire.

 Please keep us informed as I and others have these kind of tires.

Rex

Florida.

Michel Verheughe wrote:

 	  Quote: 	

On May 7, 2006, at 6:38 PM, kurt schrader wrote:

>Hummm.  Some tires still show a seam where the belt wrap joins.

>    

>

This is not the case, Kurt. Please look at these photos I took today:

http://home.online.no/~michel/tmp/Tyres.jpg

On the two upper photos, you can see, in the red circle, the 

depressions in the tyres. On the lower photo, the steel rail that may 

be the cause of the depressions. It's the only thing I can think of. 

Strange, isn't it? Also note that the hangar (actually an old workshop 

for the airfield) is not wide enough to get my Kitfox in and out 

straight. When over the rail, I have to turn the plane 180 degrees to 

get one wing out at the time.

Cheers,

Michel

_________________
Rex
N740GP - M2/582
Colorado

smokey_bear_40220(at)yaho
Guest

Posted: Sun May 07, 2006 11:19 pm Post subject: Tundra tyres.

Weird Michel,

No doubt an Norwegian flat spot.  

I also had to do this 180 degree dance in my old

hangar around another plane, not on a rail.  I tried

to make sure to roll the plane a little each time I

turned it, to save the tire.

Is there only one such spot per tire?

Do you spin it directly on the rail without rolling

movement for each tire in turn sometime during your

parking?  Or is only one tire turned on the rail?

Does it thump while taxiing, or is it no problem other

than the wear look?

As Rex says, mark the flat spots somehow and see when

you get a new one.  Maybe the cause can be narrowed

down from that.

To me, it looks like the spots are larger toward the

outside of the tire.  I can't see a way for this place

to be on the bottom with your bungy mounts so close to

the belly even with the plane's weight on the gear. 

They can't pull up and bring the gear in much more in

flight to cause that spot on touchdown, or can they? 

You need to lift it off the gear to see if those

outside spots are straight down in flight.  Make sure

your wheels spin freely then as well.  If these spots

are at the bottom in flight, it must have to do with

landing and not action after the gear spreads???

More data needed....

Kurt S.

--- Rex <gypsybee(at)copper.net> wrote:

 	  Quote: 	
		   Michel,

  I wonder if the construction of ATV tires (tyres)

 differs enough that 

 they may more easily form these flat spots when

 stored in cold for a 

 while. The fact that the tire is not as thick as was

 designed for normal 

 useage (due to the treads removed), may contribute

 to the problem. Is 

 this a recent development? You've probably already

 thought of this; 

 perhaps you could mark the tires or note the

 depression in relation to 

 tire lettering. Then see if it later occurs in

 another location on the 

 tire. That would indicate an extrernal cause (the

 rail) verses a defect 

 in the tire.

  Please keep us informed as I and others have these

 kind of tires.

 Rex

 Florida.

 Michel Verheughe wrote:

 	  Quote: 	
		   >On May 7, 2006, at 6:38 PM, kurt schrader wrote:

 >

 >>Hummm.  Some tires still show a seam where the

 belt wrap joins.

 >>    

 	  Quote: 	
		   >This is not the case, Kurt. Please look at these

 photos I took today:

 >

 >http://home.online.no/~michel/tmp/Tyres.jpg

 >

 >On the two upper photos, you can see, in the red

 circle, the 

 >depressions in the tyres. On the lower photo, the

 steel rail that may 

 >be the cause of the depressions. It's the only

 thing I can think of. 

 >Strange, isn't it? Also note that the hangar

 (actually an old workshop 

 >for the airfield) is not wide enough to get my

 Kitfox in and out 

 >straight. When over the rail, I have to turn the

 plane 180 degrees to 

 >get one wing out at the time.

 >

 >Cheers,

 >Michel

__________________________________________________

kerrjohna(at)comcast.net
Guest

Posted: Mon May 08, 2006 6:49 am Post subject: Tundra tyres.

Is it possible that you have a "tight" spot in the rotation of the wheels so that it comes to a stop at the same position and touches down at the same point of the tire on each landing?



John Kerr



-------------- Original message -------------- 

From: Michel Verheughe <michel(at)online.no> 



 	  Quote: 	
		   

 

 On May 7, 2006, at 6:38 PM, kurt schrader wrote: 

 > Hummm. Some tires still show a seam where the belt wrap joins. 

 

 This is not the case, Kurt. Please look at these photos I took today: 

 

 http://home.online.no/~michel/tmp/Tyres.jpg 

 

 On the two upper photos, you can see, in the red circle, the 

 depressions in the tyres. On the lower photo, the steel rail that may 

 be the cause of the depressions. It's the only thing I can think of. 

 Strange, isn't it? Also note that the hangar (actually an old workshop 

 for the airfield) is not wide enough to get my Kitfox in and out 

 straight. When over the rail, I have to turn the plane 180 degrees to 

 get one wing out at the time. 

 

 Cheers, 

 Michel 

 

 

 

 

 

 

 

 

 

 

 

 

 

<html><body>
	


<DIV>Is it possible that you have a "tight" spot in the rotation of the wheels so that it comes to a stop at the same position and touches down at the same point of the tire on each landing?</DIV>

<DIV>&nbsp;</DIV>

<DIV>John Kerr</DIV>

<DIV>&nbsp;</DIV>

<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message -------------- <BR>From: Michel Verheughe &lt;michel(at)online.no&gt; <BR><BR>&gt; --&gt; Kitfox-List message posted by: Michel Verheughe <MICHEL(at)ONLINE.NO><BR>&gt; <BR>&gt; On May 7, 2006, at 6:38 PM, kurt schrader wrote: <BR>&gt; &gt; Hummm. Some tires still show a seam where the belt wrap joins. <BR>&gt; <BR>&gt; This is not the case, Kurt. Please look at these photos I took today: <BR>&gt; <BR>&gt; http://home.online.no/~michel/tmp/Tyres.jpg <BR>&gt; <BR>&gt; On the two upper photos, you can see, in the red circle, the <BR>&gt; depressions in the tyres. On the lower photo, the steel rail that may <BR>&gt; be the cause of the depressions. It's the only thing I can think of. <BR>&gt; Strange, isn't it? Also note that the hangar (actually an old workshop <BR>&gt; for the airfield) is not wide enough to get my Kitfox in and out <BR>&gt; straight. When over the 

 rail, 

 us sup

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Mon May 08, 2006 11:25 am Post subject: Tundra tyres.

Thank you for your answers, Kurt, Rex and John.



On May 8, 2006, at 7:45 PM, kurt schrader wrote:



 	  Quote: 	
		   Do the flat spots disappear and leave just scrub marks when the tire 

 gets warm?


	


I was hoping they would, but they are still there and the OAT has been 

up to 20 C this week-end. But there are no scrub marks, no little cuts, 

nothing, just depressions on the surface of the tyre. Really weird!



Now, if it is not the rail, it must be the skis. But then, I have made 

them with some clearance, of course. Ice could build up but it was too 

cold when I flew to have ice, only dry snow. It could be that the tyre 

changes shape as it rotates, getting wider in the middle with speed. 

But if that happens, when is it most likely to happen? Under landing, I 

would think, right? But then, if the tyre was expanding and locked 

itself on the edge of the skis, I would feel it like a dangerous 

braking and nose down, wouldn't I? I didn't notice anything when 

landing. Could it be that it happens when taking off, when the trust of 

the engine is such as a brake effect won't be felt?



In any case, I don't like it much and I will change the tyres. I could 

take them to a shop and ask what they think it is, but in any case, the 

answer will be: Change your tyres! Which I will, when I find what I 

want. Maybe more ply. Maybe with grooves. But I have problems to find 

the right dimensions because any other dimensions would mean that I'll 

have to modify the skis too. Hum, I need a cold beer right now! 



Thanks for your help, guys!



Cheers,

Michel

_________________
Kitfox 3 - Jabiru 2200

smokey_bear_40220(at)yaho
Guest

Posted: Mon May 08, 2006 5:23 pm Post subject: Tundra tyres.

Been trying not to go there Michel, but....



Have you seen any crop circles lately?  



Actually, people don't realize how much a tire flexes

in use.  If you look at how much it squashes down when

the plane is loaded, well it has to bounce back from

that flex as the tire rotates and the tire elongates a

bit.  Many people with wheelpants experience damage to

the pants from tires hitting them as the tires flex on

landing, either the sides or tread.  The clearance may

look fine, but tires do bounce.



Again you need to look closely at the flat parts to

see if you can detect damage.  Otherwise don't install

the new tires until you have the skis off for the

summer.  Then see if the pattern shows up again only

after the skis are added.



Looking inside as was already suggested, is a good

idea too.  I had a tire on my van where the tread

looked fine, but seperated internally and got a big

flat spot.  It made the van wobble like a drunk!



Sounds like this is not a dangerous thing but a tire

wear economic problem for now.  Wierd or not, it is

nice to have these kind of problems to enjoy solving

instead of the other kind.



Kurt S.  S-5./NSI turbo



__________________________________________________

skyflyte(at)comcast.net
Guest

Posted: Tue May 09, 2006 5:23 am Post subject: Tundra tyres.

I have lumpy looking tires like that too!  Mine are caused by the inner tube, which can fold over on itself due to the low inflation pressure.  After I found out the cause, I quit worrying about it.



-------------- Original message -------------- 

From: Michel Verheughe <michel(at)online.no> 



 	  Quote: 	
		   

 

 On May 7, 2006, at 6:38 PM, kurt schrader wrote: 

 > Hummm. Some tires still show a seam where the belt wrap joins. 

 

 This is not the case, Kurt. Please look at these photos I took today: 

 

 http://home.online.no/~michel/tmp/Tyres.jpg 

 

 On the two upper photos, you can see, in the red circle, the 

 depressions in the tyres. On the lower photo, the steel rail that may 

 be the cause of the depressions. It's the only thing I can think of. 

 Strange, isn't it? Also note that the hangar (actually an old workshop 

 for the airfield) is not wide enough to get my Kitfox in and out 

 straight. When over the rail, I have to turn the plane 180 degrees to 

 get one wing out at the time. 

 

 Cheers, 

 Michel 

 

 

 

 

 

 

 

 

 

 

 

 

 

<html><body>
	


<DIV>I have lumpy looking tires like that too!&nbsp; Mine are caused by the inner tube, which can fold over on itself due to the low inflation pressure.&nbsp; After I found out the cause, I quit worrying about it.</DIV>

<DIV>&nbsp;</DIV>

<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message -------------- <BR>From: Michel Verheughe &lt;michel(at)online.no&gt; <BR><BR>&gt; --&gt; Kitfox-List message posted by: Michel Verheughe <MICHEL(at)ONLINE.NO><BR>&gt; <BR>&gt; On May 7, 2006, at 6:38 PM, kurt schrader wrote: <BR>&gt; &gt; Hummm. Some tires still show a seam where the belt wrap joins. <BR>&gt; <BR>&gt; This is not the case, Kurt. Please look at these photos I took today: <BR>&gt; <BR>&gt; http://home.online.no/~michel/tmp/Tyres.jpg <BR>&gt; <BR>&gt; On the two upper photos, you can see, in the red circle, the <BR>&gt; depressions in the tyres. On the lower photo, the steel rail that may <BR>&gt; be the cause of the depressions. It's the only thing I can think of. <BR>&gt; Strange, isn't it? Also note that the hangar (actually an old workshop <BR>&gt; for the airfield) is not wide enough to get my Kitfox in and out <BR>&gt; straight. When over the 

 rail, 

 us sup

Rex Hefferan

Joined: 10 Jan 2006
Posts: 147
Location: Olney Springs, Colorado USA "NOT a Kitpig"

Posted: Tue May 09, 2006 7:48 am Post subject: Tundra tyres.

Michel, As "skyflyte" suggests, if a tube fold is determined to be the 

cause of the flat spots, I believe the fold can be relieved with talcum 

powder during assembly and careful inflation technique. I know that 

inflating a tubed tire with the valve core out and letting it deflate at 

least once is a good practice to allow the tube to align itself inside 

the assembled rim and tire. Talcum powder (or the like) is required as 

an aid. This also can reduce valve stem stress if a tire were to rotate 

on the rim from the sudden rotational forces seen at landings.  

(especially if  brakes are inadvertently applied during touchdown).



 I did a little Googling and here are some links of interest:

http://www.aeroinstock.com/pdf/SpecMountTire.pdf

http://www.planeandpilotmag.com/content/2004/sept/just_tires.html

http://www.desser.com/tech/tiremount.html

http://www.sheldonbrown.com/brandt/talcum.html

 I have never changed an aircraft or ATV tire, but have lots of 

experience with automobile, motorcycle and bicycle tires and tubes. It 

is common to see tires rotate and cause valve stem stress on dirt bikes 

and bicyces where low air pressures are used. Also be aware that extreme 

valve stem stress could result in an air leak. Talcum powder can prevent 

the tube from sticking to the tire if it were to rotate on the rim.

Rex

Florida



skyflyte(at)comcast.net wrote:



 	  Quote: 	
		  



I have lumpy looking tires like that too!  Mine are caused by the inner tube, which can fold over on itself due to the low inflation pressure.  After I found out the cause, I quit worrying about it.

_________________
Rex
N740GP - M2/582
Colorado

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Wed May 10, 2006 12:18 pm Post subject: Tundra tyres.

Thank you for your help, guys.



Skyflyte, how long have you had those bumps in your tyres? Have you 

tried to inflate them hard, as Kurt suggests it? Rex, thanks for the 

"googling" I read all of the links.



I will eventually remove the tyres and find out what is the problem. 

But right now, I have difficulties to understand how a fold in the 

inner tube can produce what I see. But I am still a very young pilot 

and I have much to learn.



Of course, I'll let everyone informed of my findings, once the tyre are 

removed and inspected.



Cheers,

Michel



do not archive

_________________
Kitfox 3 - Jabiru 2200

KITFOXPILOT(at)msn.com
Guest

Posted: Wed May 10, 2006 4:30 pm Post subject: Tundra tyres.

I wanted to add my thoughts on the tire issue!  I searched high and low =

for similar tires like the old slick tires sold by Denney years ago,  I =

have used turf glide on the old style ATV wheel and on my Matco 6" split =

wheel!  I decided to go to Air Tacs on my split wheels, and I am glad I =

did so much better.  Here is my set up:  Matco 6" split wheel with 600x6 =

air trac tires.  Still using the original Matco brakes.



Ray

Model IV 1200, 912ULS

  ---

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