Main Gear tire change

[Big Flapper]

Hi All

Tomorrow I will begin changing tires on my "new" CTLS. I have been checking this forum for hints & tips but have not found much.

The FD MM is pretty good about removing wheels but I was just wondering if any of you might have any helpful tips for me before I jump into this project.

Thanks in advance

Tom

[BravoFoxtrot]

Hi Tom, do you know if you have Marc wheels (gold color) or Matco wheels (natural aluminum color)? There are different procedures for each. There are a number of discussions on tire changes. If you just enter tire in the search box, you will get 35 pages to sort through. By going a little more specific and entering "tire change" you should get 24 items. Some good tips in that group. Look them over and feel free to ask questions.

[Big Flapper]

Thanks for the update.

Did one wheel today, pretty much straightforward, next one tomorrow. Sure is great to know that we have such a great bunch of talent to help us do our maintenance jobs.

So far I'm really happy with my CTLS. 

[FlyingMonkey]

The big question is "standard or tundra tires?"  Tundra tires are significantly harder and take more work.  If you have the standard tires I have a few suggestions. 

[Big Flapper]

Hi Andy

I have standard tires and am open to any suggestions you have.

Tom 

[FlyingMonkey]

2 hours ago, Big Flapper said:

Hi Andy

I have standard tires and am open to any suggestions you have.

Tom 

A few things:

1) Go to Harbor Freight and get the set of plastic automotive trim tools (I use the blue ones).  You can use them to break the bead of the tire to the wheel and get the wheels to release the old tire easier.  It makes things MUCH easier.  The tool won't hurt the wheel or tire (who cares about the tire, you're changing it!), so feel free to put some muscle on it.  The tool will flex, but I've never broken one.

2) Before mounting the tire, put the tube into the tire (use tire talc) and then inflate the tube just enough to take shape.  That will help avoid pinched tubes.  If you use too much air the wheel halves won't go together -- use just enough air to make the tube take its shape.

3) Before mating the wheel halves together, set the valve stem so that the tube is as far from the wheel as possible while still going through the stem hole.  Then run a finger wound the wheel half and get the tube as far from the wheel as possible all the way around.  It will only be a few millimeters.  Then carefully set the other half of the wheel on and bolt it together, trying not to shift things around too much.  This is not super easy, the bolts often don't want to go through enough to get the nuts on.  You might have to use a fair amount of elbow grease.

4) Don't worry too much about the bead of the tire setting on the wheel.  If you can get the halves together enough to start the bolt, then tighten them, you'll be fine.  Once the wheel is together fill the tire to 35psi and it will set itself on the wheel bead.

5) Bounce tire on the ground several times as if the wheel is landing, hard.  If the tube is pinched, you want to find out before you mount it so you don't have to do everything again.  Listen all around the wheel for the sound of any hissing air, even faint.  If you hear air you might have a pinched tube.

6) Remount the wheel and set the airplane's weight on it, and check the pressure.  Roll the airplane back and forth a couple of feet, then let the airplane sit at least a half hour, an hour or more is better.  Re-check the psi.  You will lose a tiny amount of air every time you check the tire, they don't have much volume.  But if the two measurements are more than 2psi apart you probably pinched a tube (or let a lot of air out when checking them).  Refill to 35psi and check them again in another half hour if they were down a lot.

7) If the tires are holding air well, go fly.  I'd make a few landings locally on them at first.  Watch while taxiing for poor taxi speed, excessive throttle needed to taxi, or the airplane turning strongly in one direction or the other -- those are signs of a tire losing air.  If the tire goes really flat the airplane will not taxi at even full throttle.  I had to change a tire beside a taxiway last year, it's not a fun time!

As you can see, pinching a tube is the biggest danger here; other than that it's straight forward.  The trim pry tools will make your life a little easier...I keep one and a spare tube in the airplane in case I need to change a tire away from home.

Good luck!

[Tom Baker]

I will add a couple things to what Andy's said.

On number 2 remove the valve core when you add air to the tube. The tube will keep its shape inside the tire, but it will not hinder assembly. This will also aid with #3. Pinching the tube is a major concern with the Matco wheels, not so much with the older Marc wheels.

On #4 I like to inflate, let it deflate with the valve core removed. This will set everything in place. Now install the valve core and inflate to 35.

As far as pinching tubes with the Matco wheels it may happen, and it has happened. It happened to me. The heavier Airstop tube is less prone to pinching than the cheaper light weight tube. Also you may not know they are pinched with what Andy suggest to do. The tubes I pinched I found a year later when either changing or rotating a tire. I checked the tire on the other side of the airplane, and it was pinched too. These were light weight tubes, and also may have been previously installed on Marc wheels, because it was after a switch to Matco wheels and brakes. I learned my lesson.

Lastly, always use a new tube when changing tires, let me repeat, ALWAYS USE A NEW TUBE WHEN CHANGING TIRES! 

[Big Flapper]

Thanks for all the suggestions, really great to have expert input on all these procedures.

[FlyingMonkey]

1 hour ago, Tom Baker said:

I will add a couple things to what Andy's said.

Pinching the tube is a major concern with the Matco wheels, not so much with the older Marc wheels.

 

This made me think a bit.  The Marc wheels are stamped, whereas the Matco wheels are machined.  As a result, the seam between the wheel halves is tight and sharp on the Matcos, and a gentle curve on Marc wheels.  I wonder if one could round/chamfer the squared edges of the Matco wheels to make a gentle curve down to the contact between halves, leading to much lower possibility of tube pinching.

Just a thought.