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Tire & Brake Wear Trends

dan

Well Known Member
http://www.rvproject.com/20051214.html

A couple of weeks ago I changed to my 4th set of tires. I've been keeping track of tire & brake wear trends, and on the web page above, I have a couple of tables of stats. Figured some of you may find this useful.

What I found interesting was that my tire wear trend has been improving, and my brake wear trend got worse. I speculate (on that web page) as to a few possible reasons.

)_( Dan
RV-7 N714D (749 hours)
http://www.rvproject.com
 
Cheap or expensive tires?

Dan,

Interesting figures. A few years ago I was a member of an aero club at a military base in Europe (very high grip/abrasive runway surface). We had a training airplane that used 500x5 tires and typically bought Airhawks, or similar, knowing they were going to take a lot of abuse. We were getting around 50 hours per set of tires. We then changed to Goodyear Flight Customs (the ones with thicker tread, don't remember the number), and got 250 to 300 hours per set.

Pete
 
160 hrs on the originals - so far

The outer tread surface of both mains are smooth but the nose tire has all of its grooves yet. These are the original tires which are not "Air Hawks" I believe they are "Aero Trainer" which Aircraft Spruce lists at $5 cheaper than the "Hawks" from McCreary. I don't do touch and goes and most of my flights are long so there are less landings per hour. I plan to change these in March during the annual condition inspection. The brakes look OK but I expect the steering with brakes requirement to result in shorter pad life.

Bob Axsom
 
Dan, did you install the McCreary AirHawks in lieu of the originally supplied finish kit tires?

The ones Bob speaks of sounds like the ones I have seen supplied to fellow builders. They have a checkerboard shoulder tread pattern. Bob, is that what you have?

I have also heard that the ones that come with the kit aren't worth the powder to blow them to Hell. Some say to delete them from the package and buy you own elsewhere.

Is there a reason you haven't tried another brand out for yourself? When it comes to tires, personal taste is very unique. What one person likes, another may find indifferent.

:rolleyes: CJ
 
finish kit

My finish kit came with exactly these...McCreary AirHawk 5.00-5 tires. I have used the same tires since moment one.

I'm considering switching to Wilkerson retreads, but need to consider a few options first.

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
Tyre wear - or lack of it!

Hi there everyone...

You're gonna hate me when I tell you that we have an RV-6 here at the local airport (that I have maintained since day one) and it's done 650 hours TSN and guess how many sets of tyres we've gone thru.... NONE!!!! It still has the ORIGINAL tyres on it... and no, we don't operate off grass very often.

At the current rate of progress my best guess is we'll get another 100 hours out of them before replacement.

I have no idea why this aircraft is not going through tyres like you guys but my "best guess" is that the builder spent many hours getting the legs set up perfectly prior to drilling the bolt holes in the engine mount. Nowdays this is done for us and I'm left wondering if the alignment at the factory isn't as good as it could be?!?! Just a thought.

Eat yer heart out!


Cheers,

Mike :)
RV-6 wannabe.
Arrowtown
Noo Zeelind
 
No checkerboard edge tread

The ones I bought but have not installed have that tread and they are the Air Hawks. My originals that are still on the plane are smooth sided with straight grooved tread. The smooth side just extends a little farther around the outer edge of the mains than originally. I'm sure there is a little camber when the mains are hanging down in flight and the outer edges wear faster as a result. I'm tempted to keep going with them now to see if I can make 600 hours (well not really but there is no cord showing which was my old SOCAL change the tire flag).

Bob Axsom
 
tire wear

Interesting. I've got 400 hrs on Aero Trainers with moderate wear(tread almost gone) on the outboard part of the tread on the mains. No wear at all on nosewheel. Mostly paved runways, occasional gravel. Planning on replacing mains soon... can't bear to think of blowing a tire on roll out.
 
Takeoffs & Landings vs. Hours

Guys,

I don't mean to burst your bubble, but "hours" on tires is a pretty useless statistic...which is why I posted number of landings as well. In my opinion, it's the number of takeoffs/landings that represent how well the tires are wearing.

You might have 500 hours on a set of tires but only 200 landings. That's no better than having 100 hours on a set of tires with 200 landings. Know whaddamean?

The cost per landing is what I'm interested in.

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
Whew - OK

122 landings. 120 pavement, 2 grass. Tread grooves on outer edge of main landing gear tires are gone - smooth rubber surface remains in this area and the grooves across the rest of the tires and still there but worn. The nose gear tire looks like it came out of the box - no noticable wear. As much of my flying now is on trips I expect the wear per flight hour to go down - which only means something if you are paying the bills.

Bob Axsom
 
Good point

dan said:
Guys,

I don't mean to burst your bubble, but "hours" on tires is a pretty useless statistic...which is why I posted number of landings as well. In my opinion, it's the number of takeoffs/landings that represent how well the tires are wearing.

You might have 500 hours on a set of tires but only 200 landings. That's no better than having 100 hours on a set of tires with 200 landings. Know whaddamean?

The cost per landing is what I'm interested in.

)_( Dan
RV-7 N714D
http://www.rvproject.com
Cost per landing is an interesting perspective. Lots of people calculate cost per hour of flight, figuring in fuel/oil/etc but not taking into account tires. So, in order for us to help you determine which is the least expensive tire(labor not included), we need to give you the number of landings along with the type of tire. Maybe you could set up a poll to collect data?
 
redbeardmark said:
Cost per landing is an interesting perspective. Lots of people calculate cost per hour of flight, figuring in fuel/oil/etc but not taking into account tires. So, in order for us to help you determine which is the least expensive tire(labor not included), we need to give you the number of landings along with the type of tire. Maybe you could set up a poll to collect data?

Yeah, it's kind of fuzzy comparing one guy's wear trends to another. Different airplanes, possibly slightly different toe-in, different types of use, different airplane weights, etc.

I don't mean to imply that I really want everybody to send me their data. I was posting mine as sort of a public data point. You hear a lot of "oh, yeah, the tires I use are way better than the ones you use" type of comments, but I think the only way to quantify that is to try to get a sense of # of landings for a given configuration.

Then there's also the factor of...when do tires need to be rotated or replaced? It's very subjective. I'm sure some people do it later than others. This whole thing is not exactly the most controlled experiment! I guess all I can say is that we can monitor trends on our own planes, do our best to compare apples with oranges, and share our data for other builders & pilots to see. Any conclusions anybody draws is their own doing.

)_( Dan
RV-7 N714D (751 hours)
http://www.rvproject.com
 
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When should the tires be replaced, I have been told when the cord shows. I have 435 Hrs on the tires on my 7A now and I don't have a clue how many landings. I baught a new set from Avery a year ago in so I would be ready. Sure hate to waste any ware.
 
Tires

Mr. Dan,
May have missed it but I didn't see mention of tire pressures. If using 25# and less tire wear will be high. We use Aero Trainers with excellent results. The results are that they last a tad longer but at lower cost. Still pressures rarely below 28. Normally 30 to 32.
Another lesson I personally learned the hard way (in the pocket book) is working more on my landing techniques. It increased tire life as well as brake life. I used to land fast and brake hard.
Tail draggers have a tendency to wear on side faster that the other. We have both a TD and a tri gear. The TD uses the right side more than the left largely due to crosswind landing and touching one wheel first. The tri gear has little effect but favors the right tire. I believe that the location of the field, whenever doing one wheelers in cross winds seem, to favor the right more. Still the TD shows up more so than the tri gear.
We use Rapco linings exclusively, and found them to be superior to the Clevelands. Cleves are woven linings (old technology) while Rapcos are newer longer lasting composites. We also "do not " practice the abominable method of breaking in linings used in aviation, by "burning" them in.
We install linings and "dress" out the high spots, should the assembled wheel not spin fairly freely. Once dressed, taxi normally and brake normally 5 to 10 times or so and the pads are worn in without over heating the pads or the rest of the brake.
The "burning" method is destructive to the pads, calipers, and the rotors. This method is only found in aviation, is bizzare to the rest of the industries using similar braking systems.
Hope you get better results.
T88
RV10
 
Tire Wear

Dan, You might try what I have found to work. Years ago when I flew fast landing fighters F100C (183kts on final) and the F102 (170kts on final) we were not allowed to do touch and goes. Only low approach and full stop landings were authorized. I have adopted this policy for my RV4 and guess what? Tire and Break wear are no problem. Roger Moore [email protected]
dan said:
http://www.rvproject.com/20051214.html

A couple of weeks ago I changed to my 4th set of tires. I've been keeping track of tire & brake wear trends, and on the web page above, I have a couple of tables of stats. Figured some of you may find this useful.

What I found interesting was that my tire wear trend has been improving, and my brake wear trend got worse. I speculate (on that web page) as to a few possible reasons.

)_( Dan
RV-7 N714D (749 hours)
http://www.rvproject.com
 
Roger Moore said:
Dan, You might try what I have found to work. Years ago when I flew fast landing fighters F100C (183kts on final) and the F102 (170kts on final) we were not allowed to do touch and goes. Only low approach and full stop landings were authorized. I have adopted this policy for my RV4 and guess what? Tire and Break wear are no problem. Roger Moore [email protected]

Roger,

Thanks for the advice. I'm not sure why people think I'm claiming to have a "problem." My cost per landing is LOW compared to other builders I've spoken with about this. I'm just reporting my data points, not complaining!

)_( Dan
RV-7 N714D (751 hours)
http://www.rvproject.com
 
Get my Drift.

I wonder if perstistent drift at touchdown or lack of might be effecting tyre, sorry, tire wear.
Pete.
 
check alignment. I had replaced both gear legs and the moter mount on my rv4 and wore out a new set of tires in about the first 20 or 25 landings. I clamped a pair of 4 foot levels, turned sideways, to the wheels and found over 3.5 inches of toeout. after aligning and installing tapered pins in the top of the gear i went some 18 months (many,many landings) before having to replace the tires again.........DRC
 
I got 382 landings out of the original kit tires. All the wear was on the outside. I could have probably rotated them but they were pretty bald and those cheap tubes had to be aired-up about every two weeks.

I replaced them last year with Aero Classic "Vintage" 500-5 6 ply with new leak guard tubes (Desser was running a special). They have the diamond shoulder pattern that someone asked about. I put 190 landings on them this year and just rotated them. Judging from the tread left, I think they're wearing at about the same rate, but I'll get more life out of them because I rotated them before I wore out the side tread. The tubes are great -- I think I added air once last year.

I also replaced the brake linings last year. The new linings look like they're wearing about the same as the old ones did, but it's hard to be sure. They're wearing evenly and look fine, but ever since I replaced them my brakes have squeaked when taxiing. Not sure what the deal is there. I had a real hard time with the rivets -- they kept splitting when I set them, even though I was using a special brake rivet tool. I checked with a local A&P on the field and he said those hollow brass rivets always do that and not to worry about it. I guess he was right -- they never came loose and they looked the same a year later. But I've always wondered if that's why they squeak.
 
Tire Brand

I have purchased an RV-6A quickbuild kit from another builder that Van's shipped in the year 2000. The mains have Aero Trainer tires already mounted, but the unmounted nose gear tire & tube is made by Cheng Shin and is labeled 11 x 4. The nose wheel matches Van's plans and is labeled Matco NW501.25. I can't find the tire size in the book nor on the plans.

Question: Which is the correct size for the nose gear tire, 4" or 5" ?

Mike Stephenson
 
Brake pads

DON'T LET YOUR PADS GET TOO THIN!

If you do maintenance and think, uhaaa, I think I might get by with another X hours (sorry Dan) without replacing them, REPLACE THEM. Look they are cheap, easy to replace and there are drawbacks to letting them getting too thin. Whats the draw back?

As the pad gets thinner, the piston needs to extend further. If you look at the overlap between the piston and bore is not that great considering the diameter of the piston. The piston can get skew and stick in an extended portion. If the piston sticks, it does not allow the pad to float back easily, which increases brake drag, playing havoc with heat and even takeoff distance. Be conservative and replace them sooner than later. George
 
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Flight Custom

Embery Riddle Flight Academy recently did a comparison between the Goodyear Flight Customs and another tire (don't recall which). The main purpose of this evaluation was that Goodyear had just introduced a nitlile butyl intertube material has holds air about 10 time longer (natural rubber is porus like a sponge on a microscopic level). The results from this evaluation were greaty increased wear life, and less frequent maintenance and need for re-inflation.
The McCreary tires are pretty crummy. They don't wear well and they also tend to be out of balance.
 
Resurrecting an old Thread!

No use starting a whole new thread when I remembered that Dan had started this a year ago....this way, newbies can read all the older posts! :)

Looks like tomorrow is gong to bring yet another foggy morning in Houston...and Sunday as well....so I might just install new tires. Here are my numbers:

Installed current tires (Desser re-treads) and brand new Michelin Air Stop tubes in February. Put 140 hours on them until the two outside ribs were worn almost smooth. Swapped the tires around on the wheels to wear the other side - got another 110 hours out of them. Now there's just a hint of tread grooves left, which is my signal for a change.

Total landings on the tires = 490 in 250 flight hours. I'm going to re-use the tubes - I've only been adding about 3 psi every two months - love those Michelins! I'm sticking with the Desser re-treads - have used them for many years with good results.

Oh - time for brake pads as well - first replacement set since the airplane was new - 338 hours.

Almost all landings (probably all but about ten or twenty) have been on pavement.

Paul
 
Its not all landings

something I do not see that may cause more wear on tires. How far do you taxi to get to the runway. If you are on a large airstrip you might be putting several miles on the tires every time you go for a flight. My plane is in a group hanger about 500 feet from the departure end of the runway, very little wear in about 150 - 200 landings and I know my toe in is greater then factory says it should be as I used the wrong shims during constuction and did not catch it until it was too late. Have had no problems. I know the tires scrub a little as when I back the plane over a slick surface (Hanger floor is epoxy coated) you can hear them.
 
yarddart said:
What is the correct tire pressure RV8/


I have no idea what the "correct" pressure would be - I've never found a place that it is documented. I've heard people use everything from 25 to 50 psi. I'm using 35, and it works for me - started out at 30, and felt it needed a little more. I was worried about squishing and cutting a tire on the wheel pant (again!)...

Tire and brake pad change - with wheel bearing cleaning and packing - took about 2.5 hours this afternoon. I probably could have gotten another 50 - 75 hours out of the pads, but I decided to be conservative and change them out.

Good thoughts on taxi distance. I'm hangared at one end of a 5,000' runway, so generally have a mile of taxiing half the time....new smooth concrete though - I have no idea how to factor that in.

Paul
 
We recently sold our 7 which had 274 hours & 313 landings on the original tires. They still had some tread.
Doug Preston
BHM
 
Tire design vs service life

500 x 5 tires come in two basic designs-a 'rounded' shape vs a 'squared' shape. Our local flight school mechanic who has changed many more tires than I have said that aircraft with the rounded style tires which wear on the edges (like my 6A) do much better with the square style because there is more rubber on the 'corners.' He also suggested to opt for more plies for added edgewall stiffness. I've seen both styles sent out with Van's kits.

Anyone tested the two designs against each other? Results?

FYI:Having Aircraft Spruce next door allowed me to compare tires in their showroom. I noted that among various brands they carry that at least two lines manufactured by Michelin are in stock. The labels,paperwork, and all features appear identical between their Michelin brand and their off brand. Both certificates show manufacture was in the Michelin Tire factory in Thailand.The only difference was the word Michelin and the price.
 
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