Friday, August 20, 2010

Tubular Technique -or- Why do I have a raging headache?

To start I need to give credit where credit is due. I first learned about techniques for gluing tubular tires from Eddie at Cycle Mania. His method involved something about taking one shoe off to use your foot to hold the valve in place. Or something like that. It was a long time ago. I learned the method I currently use from Molly Cameron, Pro 'crosser, and Pro vegan (although that has nothing to do with this). As far as I know Molly learned from other Pros and added a healthy dose of trial-and-error. So it's time-tested and all that...

Reasons for using tubies vs. clinchers aisde, today we're just talking about sticking a tubie to the rim. This method requires lots of time, lots of glue, and lots of ventilation. I like a nice thin glue- Panaracer Pana Cement to be exact.

Here are the steps (more or less):

1. Stretch out the tire by mounting it on the rim DRY and inflating it to the recommended max. Let it hang out like this for a while. Don't skip this, you'll thank yourself later.

2. Cut off a finger from a nitrile glove and put it on your finger. Use this protected finger to begin spreading on thin layers of glue on the tire's base tape and on the rim- 4-6 layers on each. You could use a brush, I suppose, but I think it's messier. Just use your finger. It helps to inflate the tire so it holds some shape. Wait for each layer to fully dry before applying the next layer (this is where the lots of time comes in), so that the solvent from the glue can fully evaporate (this is where the lots of ventilation come in). Take time with this- you don't want to start with a mess. The glue should only be on the base tape and in the 'trough' of the rim.

2a. Did I mention that you should be in a well ventilated area? Do it for your brain.

You can use your index finger. I cut mine with a pair of IKEA scissors a couple of years ago, and it hasn't been the same since...

3. When your tire and rim are both fully layered but dry you want to do one last wet layer on the rim. It should be slightly thicker than the other layers. Keep this layer nice and neat, too.

Spread the glue around the spoke holes, try not to get glue inside the holes.

4. All of this next step needs to be done while that last layer of rim glue is still wet. Let the air out of the tire. Put the rim on the ground and support it on both sides with your feet. You should so this with shoes you don't mind getting glue on. Start by inserting the valve, and applying pressure equally with both hands, stick the base tape to the goopy rim. As you get to the opposite side it'll get tight. This is where you benefit from stretching the tire and keeping the glue job neat. Keep pushing the base tape up and over into the glue on the rim, without dragging the tire sidewall through the glue.

Those are the very same rain boots I use to wade around in the shop basement.

5. When the base tape is fully stuck to the rim, inflate the tire to not quite the max, and stick it in a truing stand to see that the tread is on straight. The base tape and tread might not line up exactly, especially if the tire is old. That slightly thicker layer of glue should still pretty wet so you can push the tire around on the rim with your hands to get the tread straight.

6. Now here's a cool little trick- after the tread is straight, deflate the tire and roll it on a broom handle. Why? This helps to push the base tape down into the lowest point in the 'trough' of the rim. If you don't do this, you'll find that sometimes the tire hasn't made contact with the center part of the rim, and you've wasted all of that glue you very carefully applied.

7. Inflate it back up and let it sit. Seriously, for 24 hours, or more, in a well ventilated place. That allows all of those nasty solvents to evaporate.

I know there's more than one way to glue up tubies. Some people like using a thicker glue, some people like tape, but this how I do it and it's served me well. If you want to know more about it, I'd be happy to geek out... er, answer questions for you.

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