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  #1  
Old 12-31-2014, 06:22 PM
Jetguy's Avatar
Jetguy Jetguy is offline
 
Join Date: Aug 2008
Location: Texas, Fort Worth
Posts: 1,237
Default Tale of two tires. New Tires for my RV-12!

I recently put on my third set of main tires at 632 hrs. I thought I would
try something new and changed from the Desser Aero Classic All Weather tire to the Desser Elite retreads. I do a lot of transition training and probably go through tires more than the average Joe! My first set of tires which came with the kit lasted 308 hrs. The second set lasted 324 hrs. On both sets of tires around 170 hours into each cycle I flipped them on their rims to have even wear on them. Also because I practice the technique of Softfield Takeoff and Landings I still have the orginal Nose wheel tire on the plane. Here are a few observations I made while mounting the new tires. Vans actually has the best price on their web store for the Aero Classic tire. Being a first time builder and not wanting to mess with a good design I stayed with the exact same tires for the second set of tires. On my third set of tires I decided it was time for a change and selected Desser Elite Retreads. The Elite tire, as a result of having more tread is definitely taller or bigger in diameter by approximately 1/2 to 3/4 inch. However it is about the same width as the Aero Classic. So you will have to trim the front and back of your wheel pans. I recommend at least 1/2 inch clearance front and 1/2 clearance in the back as seen in the pic below. The Elite should last a lot longer than the Aero Classic, I wouldn't be surprised if they lasted 100 hours longer than the Aero Classics. Your mileage may very! It cost about $20 more for the Elite. You can run up to 50PSI per there web site, but above the chart on this page http://www.desser.com/pressurechart.php there is a disclaimer that says, "Always consult with your owners manual for factory recommended pressures"! At this web site under the FAQs under the title, "What Tire Pressure Do You Recommend" they go into a little more detail about tire pressures for Vans Aircraft and in the end the POH pressure will be the best. http://www.vansaircrafttires.com/pag...B47%7DFAQ.html At the higher PSI the tire becomes very hard. I would think that on a hard landing it would send quite a shock wave up your struts into your airframe. I will be running about 25 psi per tire to soften them up a bit until I get some experience with them. Weight, the retreads are only about a pound heavier than the Aero Classic. Balancing, one tire required 3/4 ounce and the other only 1/4 ounce to balance them on the Harbor Freight Aircraft balancer. Not bad! Since we don't change tires very often you can review the procedure on EAA video link below.
http://eaavideo.org/video.aspx?v=1967222618001
Here are a few pics of the tires and process and more pics in the next post!

Worn out tire, 324 hrs!


What a New Aero Classic All Weather looks Like!


What a New Desser Elite Retread Looks Like!

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John
RV12 N1212K
Flying Since June 2010
1020 Hours as of 9/30/2017
Johnrv12@icloud.com
RV14 Wing, arrived and building at Rdog's new Hanger at 16X
S/N 140014
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  #2  
Old 12-31-2014, 06:24 PM
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scard scard is offline
 
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Send your old tires to Vlad. He'll get another 800-1000hrs out of them. I'm going to start sending him mine .
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  #3  
Old 12-31-2014, 06:28 PM
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Jetguy Jetguy is offline
 
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Location: Texas, Fort Worth
Posts: 1,237
Default Tale of two tires. New Tires for my RV12! Part 2!

The Tube!

Trimining the Wheel Pan!



Tire Diameter!
Aero Classic. Inflated.


Elite, uninflated.
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RV12 N1212K
Flying Since June 2010
1020 Hours as of 9/30/2017
Johnrv12@icloud.com
RV14 Wing, arrived and building at Rdog's new Hanger at 16X
S/N 140014
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  #4  
Old 12-31-2014, 06:37 PM
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Vlad Vlad is offline
 
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Location: Utah
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Quote:
Originally Posted by scard View Post
Send your old tires to Vlad. He'll get another 800-1000hrs out of them. I'm going to start sending him mine .
Thank you Scott and don't forget the tubes
Happy new year to 22C crew!
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  #5  
Old 12-31-2014, 06:40 PM
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Walt Walt is offline
 
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Quote:
I would think that on a hard landing it would send quite a shock wave up your struts into your airframe. I will be running about 25 psi per tire to soften them up a bit until I get some experience with them.

You may get more "shock" than you bargained for if you have a hard landing and the tire bottoms out or a you get a flat. Lowering tire pressure to get a "softer" ride is not a good trade off with aircraft tube tires. Personally I think 35 psi should be a minumum for most aircraft tube tires. When you get into the 25 psi range the sidewalls start to flex excessively and will cause the tube to fail (I would guess 98% of flats are caused by underinflation).
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EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
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  #6  
Old 12-31-2014, 07:13 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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It may come as a surprise to a lot of people, but tire pressure and ply rating are a design aspect of the landing gear system.

The RV-12 is a light (structurally) airplane. The tire pressures specified are for a reason. If a tire pressure is used that doesn't get the full energy absorption expected by the designer, a major unplanned for load could get transferred through the landing gear legs to the fuselage
Example - because of low pressure the tire sidewall fully collapses under a high load which will cause a sudden spike in peak load through the landing gear. To high of a tire pressure can cause the same thing... the tire acts more like a sold wheel and transfers a majority of the load directly to the gear leg and fuselage.

In simple terms, the tires are meant to be a major part of the energy absorbing system during a less than normal landing. Staying within the recommended pressure range (when one has been published), is strongly recommended.
Because the RV-12 is a relatively light aircraft (comparably) the main tires are recommended to be 25-28 PSI.
If someone installs a tire that is a lot stiffer than the one originally supplied, those #'s may no longer apply)
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Last edited by rvbuilder2002 : 12-31-2014 at 07:15 PM.
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  #7  
Old 12-31-2014, 07:15 PM
gasman gasman is online now
 
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The ELITE looks like it might be the wrong profile for RV (scuff) type landing gear.

This is the profile you would use on landing gear like the Warrior has.

Do let us know how it works out.
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  #8  
Old 12-31-2014, 07:36 PM
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Walt Walt is offline
 
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Location: Dallas/Ft Worth, TX
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Quote:
Originally Posted by rvbuilder2002 View Post
It may come as a surprise to a lot of people, but tire pressure and ply rating are a design aspect of the landing gear system.

The RV-12 is a light (structurally) airplane. The tire pressures specified are for a reason. If a tire pressure is used that doesn't get the full energy absorption expected by the designer, a major unplanned for load could get transferred through the landing gear legs to the fuselage
Example - because of low pressure the tire sidewall fully collapses under a high load which will cause a sudden spike in peak load through the landing gear. To high of a tire pressure can cause the same thing... the tire acts more like a sold wheel and transfers a majority of the load directly to the gear leg and fuselage.

In simple terms, the tires are meant to be a major part of the energy absorbing system during a less than normal landing. Staying within the recommended pressure range (when one has been published), is strongly recommended.
Because the RV-12 is a relatively light aircraft (comparably) the main tires are recommended to be 25-28 PSI.
If someone installs a tire that is a lot stiffer than the one originally supplied, those #'s may no longer apply)
I stand corrected for the RV12, 25-28 it is!

The only problem I see with such low pressures is folks tend not to check pressures often enough, 25 psi now means 20 or less in 2 months.
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Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #9  
Old 12-31-2014, 09:27 PM
PCHunt PCHunt is offline
 
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Location: San Diego, CA
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Anyone know the difference between the Elite and the Monster Retread at Desser Tire?
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  #10  
Old 01-01-2015, 08:02 AM
todehnal todehnal is offline
 
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Location: Kentucky Lakes area in KY
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I had a set of these from Desser in size 8.00 on my Cub. They also had a 50 lb air pressure rating. I ran them 15 to 18 psi as recommended by Piper for 10 years without a problem. What a tire!! And, you are right. They never looked low.

Tom
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