Mounting & balancing tires yourself

From Ninja250Wiki
Revision as of 17:49, 28 June 2007 by Bokonon (talk | contribs)
Jump to navigationJump to search

BrianM, making it look easy (and it is...)

I trust that anyone looking to mount and balance their own tires at home has the skills and knowledge to remove the wheels from their bike, so I'm not going into that. But once off, you will need a couple of tools. A valve stem core removal tool, 2 or 3 tire irons, some 2x4's in different lengths and a plastic milk jug (or similar) cut into pieces.

Not shown, above, is the valve core tool. I like 11" tire irons personally, as they're just long enough to forgive sloppy technique, but not long enough to give enough leverage to Easily bend a rim. Note, I do NOT use tire lube of any sort as I don't find it necessary. But, it does make the task a bit easier... so if you're going that route, buy some purpose made tire lube. Don't try to make due with something, and do NOT use dish soap and water, as that stuff can, and will, eat at the tire. It's designed to attack grease (oil), and tires are a petroleum product. I've seen a few nasty looking tires that had gooey, melty rubber from dish soap.

The first thing you want to do is remove the core from the valve stem, letting all the air out. Next, lay the rim on 2 pieces of 2x4, which acts as a cushion from the floor, and keeps the brake rotor from touching anything.

This is so we can break the bead. I'm using the 2x4 method. It's cheap, easy and works well.

As you can see, with the wheel on the ground, you use a long 2x4 to put leverage on a shorter piece, thus forcing the bead of the tire off the seat on the rim.

You're looking to see this:

Once you get the tire started off the rim, you can usually just push it off the rest of the way. Turn the rim over and repeat on the second side.

With the bead broken, it's time to start removing the tire from the rim. Use the sliced up plastic jug to protect the paint on your rim, and work one end of a tire iron between the rim and the tire.

To remove the tire, you need to push the Opposite side (still on the top, just on the other side of the tire than the one you're currently working on) of the tire into the Drop Center of the rim. This is the narrow part of the rim in the middle, before it steps up to the bead. Doing this allows the tire to shift enough for the bead to slip off with the tire iron. If you leave the opposite side up on the bead seat part of the rim it will be much harder to remove the tire, and much easier to cause damage to your wheel. Once you have the First bit over, it's just a matter of repeating the process with the other irons. Make sure you don't try to take too big of a bite, as this is where you get into trouble wanting to use extra strength, and the rim will bend.

After you make it about half-way around, you Should be able to just pull the bead off the rest of the way with your hand.

Now for the second bead. Working from the Same Side as before, with 1 tire iron, you should be able to put it all the way through...

Push down firmly...

And pull the tire off with your hand...

At this point, I like to clean up the rim, inside and out. Mine happened to have what seemed like some sort of glue on the inside. It took some strong solvents to get this stuff off. You want to make sure the seat area (which is the Flat landing just off the edge of the rim, on the inside) is clean and fairly nick/ding free. Bends, dings, nicks or junk in there can contribute to a slow leak... and who wants to deal with that? You should also check the wheel bearings by just putting a finger in them and spinning... they should rotate smoothly and easily, without any gritty feeling. If they feel gritty, it's time to replace them before riding again.

The valve stem itself is also something you should inspect. Bend it and look for cracks anywhere in the surface, but mostly right where it gets narrow to go back through the rim. It's easy to change right now, and more work if it fails when you don't need to change the tire. Replacing it is simple: just cut off the old, use the same tool for removing the core to screw onto the stem, and pull it through from the inside of the rim until it seats. Shorter are better, angled are a bad idea (need to be replaced more often) and I'm not a fan of the screw-together metal stems mostly because they can be a PITA to get to fit correctly, and to remove later when they eventually fail. I tend to just change mine every 3 or 4 sets of tires. The stem is the same standard size as those used by cars. You should be able to get one at any tire retailer. If you run anything but plastic caps, you'll likely be doing replacements a lot sooner.

I also like to check the static balance of Just the rim, as the valve stem never seems to be the heavy point anymore. I do this on the cheap, with the axle and a couple of jack stands. You can spend lots more money to do the same thing and never feel a difference. Don't spin the wheel, that'll just take more time to slow down. Instead, rotate the wheel 90* and let go. Do this a couple times, and the heavy spot will always fall. If there isn't a heavy spot, then it won't rotate from where you let go.

Make note, or mark on the inside of the wheel, where the heavy spot is located. As you can see above, my valve stem is off to the right, and very much Not the heavy spot.

It's important to note that tires are Directional due to how they're constructed. The arrow is plainly shown on the side of the tire, like this (to the left)

Also notice the DOT code. It's a 4 digit code that lists the week and the year the tire was made. Mine is 3205, so the 32nd week of 2005. More than 3~4 years old, and tires start to go 'off', get hard and aren't Any fun to ride on (worse than the stock Dunrocks on the 250!) You should Also look for a round dot, about the size of a dime, on the tire. This is an indicator of the lightest spot on the tire from the manufaturer, though not all brands have this (my Avon did not)... you'll want to line this up with the Heaviest spot on the rim that you noted earlier.

When it comes time to put the new tire on, you should be able to just walk the first bead over the rim without any tools other than your bodyweight. Though, if needed, you can use a rim protector and tire iron to help, as I needed here:

Then push the top bead into the center of the rim, and slowly work the tire on with your irons... There are no pictures of this process, as it's impossible to stop without having the tire work its way off the rim. Here's Leon to give you a good idea of how it works. Keep your knees on the part that's already on the rim, work your way around with your tire irons, and it should only be difficult the last little bit.

With the tire on the rim, it's time to seat the bead with an air compressor. Those cheaper units that just provide an on-demand supply (often in blue boxes at gas stations), do NOT have enough umph to do the job. You need a good source of air, but that's usually easy to get ahold of at any sort of shop doing any sort of work, or (my favorite), the old time gas station/garage. They always have good air. Fill the tire up without the valve stem core in the valve stem and listen for 2 "pops". Front tires are usually Very quick and easy with this; rears can be more difficult. But just lay the tire on the ground, as it was when you were changing it, and use your spare hand and knees to bump and lift the tire where air seems to be escaping from. It Will seat with some patience and work. You'll then want to look for an even ring all the way around the rim, on the tire (there's usually some rings moulded into the tire to make this task simple). If it's not even all the way around, the bead is not fully seated. Now, put the core back in the valve stem and fill the tire up. I usually go over what I normally run until I get it back on the bike. Always easier to let some out than to add some back.

And it's time for a final static balance, the same way as before:

You'll most likely need some weight to balance everything up. There are 2 main kinds of weights: clamp on and stick on:

I like, and use, stick ons myself. They're cheap, easy to come by and do the job well. You'll want to put your weights as close to the centerline of the wheel as possible. After you hold the wheel up and let it go, it will settle with the heaviest point at the bottom, just like before. You then want to put the weights on the top, at the lightest point. I like to tape mine on with something that's easily removed (painters, masking, electrical, scotch, whatever) and check again before affixing for good.

Static balancing is good enough for professional roadracers, so it's certainly good enough for the average street rider. If you feel better having your wheels dynamically balanced by a machine, you can take it in to a shop and pay for that peace of mind. The primary advantage of the balancing machines seems to be that they're faster -- static balancing can take a while (5-20 minutes per tire) to do correctly.

And with that, you're done mounting and balancing. Time to just put the tire back on the bike and go for a ride.

Here are 2 videos demonstrating the techniques.

http://video.google.com/videoplay?docid=-7546109776315225781&q=tire+change

NOTE: This one is on a Tubed Tire, it's Slightly different. Also, he obviously doesn't care what his rims look like... heh.

http://video.google.com/videoplay?docid=-8635543758286799977&q=tire+change


One final thing I want to mention, in relation to tires, is the Tread Wear Indicator (T.W.I.) It's how you know that it's time to replace your tires, as running them till they're slick is a Bad idea. The indicators are always listed on the side of the tire, usually in a few different spots, with the letters TWI or a small triangle. Here, I have the letters TWI:

Then, if you look across the tread, in the grooves, you'll find little blocks of rubber that stand up.

When these become flush with the rest of the tread, it's time to put new tires on the bike (or car).

Hope this helps some folks who are interested in saving the rather stiff prices charged for mounting tires. You can Easily buy all the tools needed for less than what it'll cost to have a shop do the tires for you.