Wednesday, April 15, 2009

How To - Removing A Tubular

The wheel which needs (wants?) a new glue job.

In this particular instance, the wheel is actually out of true. Since the tire has to be removed to get to the spoke nipples, I had to remove the tire. This is a significant disadvantage with wheels with hidden spoke nipples like the Reynolds, especially if you have tubular tires.

I should point out that my wheels went out of true because things like banquet tables, leaf blowers, and heavy podium crates and boxes fell onto them regularly over the course of a Bethel Spring Series. It was so bad that at one race I had to race on a spare front wheel.

A properly glued tire barely peels away from the rim, even with considerable force. The tire is deflated in this shot to illustrate that air pressure has nothing to do with a tubular tire's security on the rim.

I'll start removing the tire opposite the valve.

I pull up what I can to expose the glue-rim seam. It's virtually impossible to pull a well-glued tire off with just your hands. Therefore I use tools.

In this case I practiced my expert Ninja skills.

I walked across the room and threw a throwing star at the wheel.

Okay, I didn't. But if I could have done it, I would have done it.

Instead I did it the unromantic way - I just gently jammed a 16T cog in there. I purposely chose the 16 because that's a really good gear for steady state riding on the flats.

Okay, I really did this because my toolbox, with my slot-type screwdrivers, was in the car, outside in the cold, and I was in my PJs. Normally I'd use a screwdriver and gently, barely touching the rim, pry the tire off. It takes a while but it works.

Failing a screwdriver you can use any sort of pointy flat thing, like a 16T cog.

Or a throwing star.

In my case I didn't have a throwing star, but I did have a 10 or 15 pound box of "cogs that can't possibly be useless so I'll move it around with me and tell the missus that these cogs can't be useless to me".

I used the 16T. See? Not useless. Now about the other 150 cogs...

Back on track. Be gentle with your throwing star, cog, or screwdriver if you're reusing anything you're touching - tire or rim. Cutting up a good tire is a great way of ruining your day. Irreversibly damaging a tubular rim is a second great way to ruin a day.

Once the tire is dismounted enough that you can get something the size of a chopstick under the tire, put something the size of a chopstick under the tire.

Actually, a real bamboo chopstick (they're rounded with a rectangular type non-eating end and a pointy eating end) works excellently. When I was a kid, I'd borrow such things from the kitchen drawer.

However, nowadays we're down to two pairs of chopsticks in our household and I really like using them to each chicken wings. So I had to improvise.

I used a screwdriver.

Once I can get a screwdriver under the tire, I shove one in. Then I turn it so it rolls along the rim, peeling off the tire as it goes.

This peels the tire slowly and steadily by default, simply because it takes a lot of effort to turn the screwdriver. Be careful with the rim - the screwdriver can damage the high points of the rim (the two sides of the gluing surface). A chopstick is better because it's softer and will "give" a bit. They break regularly though so that's a disadvantage.

If the tire is really tight on the rim I'll lift the screwdriver away from the rim (holding the rim between my toes and lifting on the screwdriver while turning it), but on an older tire that is loose fitting, you can just let the screwdriver roll along the rim.

After enough of the tire is off, you can grab and peel. Note how close my thumb is to the rim. Note also how clean the rim is - this is not normally the case, but on carbon fiber rims it seems sort of common.

If you don't care about the tire's integrity (i.e. it's shredded or worn or punctured badly), just yank. If you want to be able to use the tire again, pull slowly, steadily, and within an inch or two of the rim.

See how my thumb is close to the rim in the above picture? I would peel off maybe 5 mm or a 1/4 inch of tire, reset my hand, and do it again. Do this quickly, efficiently, and your hand will travel inchworm-like around the rim.

Don't pull perpendicular to the rim, pull in the direction of the rim. This slow, steady, close peel prevents the casing from ripping. Rip a cord in the tire and you might as well have cut it in half. A damaged casing is useless as a tire and dangerous to ride. Cut up cleanly, with the label and the valve preserved, it would make a good prop to show people exactly what a tubular tire is like.

I don't have a cut up example, else I'd stick a picture of it right here.

Finish at the valve so you can pull the tire off off without ripping the valve off.

Presto, you're done.

Now for the hard part - gluing on the tire. I'll save that for the next post.

2 comments:

kendogz161 said...

Hello All,
What is your take on clean old glue off of wheels?
Does it have to be done every time or after a certain amount of glue jobs?
Thanks for the write up.

Aki said...

Believe it or not I've never cleaned the glue off of a rim. I've scraped chunks of glue off using something like a very wide flat head screw driver, the handle side of a wrench, or even a smaller box end wrench (the round circle of a 13mm box end wrench can work well, for example). If the glue isn't coming off and it's not too thick then it's fine for me.

With carbon rims it seems the glue comes off a touch easier, meaning when you peel a tire off you remove most of the glue as well.

On the other hand some people are fastidious about cleaning all the glue off. A local racer (5 time Junior national champ so a little more than "just a local") uses Contractor Solvent to clean his rims off. I can't vouch for it personally but with all of the Zipp rims they use the stuff on it seems to be fine after a few years of continuous use.

Hope this helps.