Thursday, August 12, 2010

Shaved Chest and Pasties

That's the answer to the question: What to do about nipple chafing?  The humidity has jerseys clinging to chests.  I open mine up to better ventilate, and the zipper tends to rub on my nips.  After a couple of hours, this gets uncomfortable.  On my way home, the answer came to me.  Of course, I'm not really going to try that approach, but I might try some chamois cream or bag balm.

Anyway, let's move on...

For almost a year I've been riding Hutchinson tubeless clinchers.  They're a little expensive, but I like them.  The ride well and I think their rolling resistance is less than clinchers with tubes.  These wheels have about 1500 miles on since installing the Hutchinsons.

Until today, I didn't have any sense of ever getting a puncture, or whether the No Tubes sealant was doing much.  I did top off the sealant in the spring, but I really didn't know if it was making any difference.  About 20 miles into my ride, I got leak.  Turned out to be sharp little flint embedded in the center of the rear tread.  I heard a sudden whoosh of air, which then slowed and became a series of short whooshes, and then they stopped.  As the tire turned, I could feel the jet of leaking air (at least while the whooshing was happening) on my left calf.  But, the leak stopped and while the tire was soggy, it was holding the remaining air and not bottoming out.

Judging by the initial leak (Big and sudden), the tire would have been flat before I could stop, were it not for the No Tubes.  That impressed me.

I have a little gadget that combines a small pump and a CO2 inflator.  Being my first Hutchinson flat, I wanted to see if I could continue to ride without installing a tube.  Naturally, I wanted to save my one CO2 cartridge in case I needed to use a tube.  So I gave about 150 strokes of the pump into the tire.  I didn't seem to do much.  I don't think that 300 strokes would have made much more difference.  So I set out to see how the tire would fare.

The short story is that a couple of little whoopsie bumps in the pavement burped the air out of the tire and it was time for a tube.

No problems mate!   I'm equipped for that.  Except it turns out that extracting the tire bead really can't be done with plastic/nylon/whatever irons.  At least not the one's I was using and probably not any others either.  Any time I got more than about an inch of bead up, it would spit the levers out.  And if that didn't happen, then next lever I'd try to use would bend and cause the whole bead to slip back onto the rim.  I spent about 40 exasperating minutes like this.  Fortunately, I was traveling through a forest preserve, and was able to sit on a picnic table in the shade of a shelter.

The wheels I'm using for tubeless are Easton EA70s, which have proven, so far, to be a good economical wheel.  Stan of Stan's No Tubes considers these to be a good wheel (rim) for converting to tubeless tires - which is why I'm using his system with the Hutchinsons. 

There is a special No Tubes rim tape which seals the spoke openings (makes the airtight).  Then you mount the tires, pour some sealant in (after removing the valve cores), seal things up and pump up the tires.  The mounting went just fine, and I set the beads with just a cheap floor pump.  I did use levers to get the beads over the edges of the rims (tubeless tires have tight, stretch resistant, beads), but there was no unusual effort or drama (apart from keeping the sealant in the tires until they were pumped up).

Naturally, I wasn't prepared mentally or tool-wise for the idea that normal tire levers wouldn't work.  So multiple times I carefully worked the bead into the center of the rim, all the way around, and tried to make the levers work.  No good.

Then I had a brainstorm.  There's no tube to worry about - so the risk of using "non-standard" tire levers is minimized.  I pulled out an ancient park uni-tool (a small box-end wrench with various allen/screwdriver nubs sticking out of the periphery of the box ends), and a folding allen wrench.  Using the end of the uni-tool with a straight screwdriver blade in one hand, and a 6mm allen wrench in the other hand, I successfully got that darn bead off the rim!

I shoulda taken pictures of the inside.  Some of the older sealer had coagulated in long ribbons, and there was evidence of the sealer working to make sure the rim tape was airtight, along with the remaining liquid sealer.  I cleaned the sealed latex, and checked for anything sticking through the tire, and started mounting the tube and tire back on the rim. 

Putting the first bead on went by hand.  The second wasn't hard either, although its important to push the valve back when starting to get the tirebead well established in that portion of the rim.  For the last three inches, I needed the plastic tire irons to remount the second bead - and yes they worked just fine for that.

So I'm left wondering why it was so hard to get the tire off, when remounting it (with a tube inside) went very well.  Perhaps I'll never know, but I'm going to purchase some alloy tire irons to replace the plastic ones on this bike.  If you try the Hutchinsons (and I to heartily endorse them), you should also carry alloy tire irons ATMO.

Finally, with heat and bugs limiting my shop time, I'm starting to prepare for building another frame - this one from Carbon Fiber.  I'm going to try to get the camera working to document some of the processes as I go along.  For now, the design is finalized (in BikeCad) and the drawings and specs have been printed.  It's time to Measure and mount the miter templates to the tubes, and then start cutting.

The frame is approximately a 57.5cm.  Traditional Italian design for handling.  The head-tube is a  bit longer than most modern equivalents from Italy (actually the extra space is in the form of an external headset), but this allows for the use of a deeper drop handlebar - and a bigger variety of positions.

Proportions will be all in the normal range, and the tubing is round (which is best from an engineering point of view).  The headtube will be carbon fiber tube, 41.5mm diameter, with Ti inserts which get milled for the headset cups.  The downtube is 38.2mm - strong but not huge.  The toptube is 36.3mm, big enough to assist the downtube in keeping thing stiff.  And the seat tube is 35mm, which will fit a standard front derailer and a standard 31.6mm seatpost.  The bottom bracket is a 42.26mm carbon tube with a threaded (English) Ti shell bonded inside.  The tubes are all from EDGE, while the Ti bits come from Paragon Machine Works.  Both good folks with which to work.

The rear triangle is my last Easton EC90.  To date, I've had good success with these, but it appears that they no longer make them.  So future builds will use either Dedacciai or Edge rear triangles. 

Anyhow, enough talk, its time to go start getting the tubes ready.

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