Friday, October 7, 2011

How To: Dutch Style Flat Repair

So...it finally happened.  I was riding the Kaptein one warm Indian summer evening recently when I noticed the rear end was getting noticeably squishy.  Really?  My tire was going flat?  How was that possible?  As I've recounted in earlier posts the last time I had the rear wheel off, one year ago, is when I installed  new Continental Cityride puncture resistant tires, along with plastic rim strips to ensure I would not flat unless I rolled over a land mine.  There were no land mines this day, in fact, nothing out of the ordinary that I had rolled over.  I felt disappointed, yet curious as to why my system failed.

Flashette was with me, but she had to go home to work straightaway and could not return with the car to pick me up.  I was off at the far end of the island, in fact, in front of the USS Hornet aircraft carrier museum.  I checked my bags for my repair kit...and it was not there.  I had taken it out before my last grocery run.  The pump was not present either.  I sat there in the warm orange rays of the setting sun pondering my mistakes. My biggest mistake was assuming I would never get a flat on this bike.  Just...Flashtastic.

I could have slowly walked the 3 miles home, but my sister was in town, with her SUV, so I called her for a ride.  Luckily, with the rear seats down we could stuff the whole 50+ lb machine in in one piece.  Things worked out for me to avoid that long, slow walk, but in more normal circumstances I would have been in a jam of my own recipe, as it were.

Fast forward to repair time.  As I've said, taking the rear wheel off these bikes is a bitch  headache pain in the ass challenge.  I suppose if you work in a Dutch bike shop and do this every day it is easier and faster.  It takes me about an hour to remove the wheel and re-install it.  Here's the breakdown:

1. remove screws securing upper and lower halves of chaincase.  Using screwdriver, pry the two halves    apart along the horizontal middle seam, pull halves away from chain.
2. remove 3 speed shifting chain from rear hub
3. remove rear brake cable from drum brake
4. remove rear drum brake positioning arm from frame mount
5. remove axle nuts
6. remove axle positioning stay nuts
7. remove chain from rear cog
8. shove rear wheel forward until stay bolts clear the frame
9. jerk wheel from frame.

That's the quick and easy part.  Then I fix the tire.  Getting it all back together in the proper order takes 3 times as long and the dexterity of 3 frisky cats put together.

However, I heard about an alternative rear flat repair method that does not require removal of the wheel.  In a nutshell, the tube is repaired within the frame.  This can actually be done on any bike.

Notice that Bike Bro here shows you how to remove the tube on the FRONT tire.  Even Bike Bro fears the rear wheel demonstration--- let alone the actual fix.

First, start by getting the last bit of air out of the tube.  Starting at the bottom of the wheel, use your tire levers to lift the tire bead from the rim.  Its easy on this bike as the tires are large and not tight as on a road bike.  Begin to work your way around the rim, turning the wheel as you go.  Soon, one side of the tire is lifted off the wheel.  Pull out the tube.  Note that you cannot remove the tube, it is locked in by the frame and wheel axle.

Here's the tricky part---you have to find the puncture.  Put some air in the tube, taking care not to overinflate it or have it push against any sharp parts on the bike.  You should then hear the hisssss of air escaping somewhere.  Use your stereo hearing skills or finger to locate the escaping air.  Mark the spot using a black Sharpie pen.  Make you marks horizontal and vertical, at least 3 inches long, the hole in the middle of a large "X" mark.
Next, sand the tube with the sandpaper that came with your patch kit.  The "X" will be mostly removed, but enough will remain to see the hole.  Put a good pea sized blob of glue in the middle of the X, and smear it around in a circle with your finger.  The glue circle should be slightly larger than the diameter of your patch.
Let the glue dry for 3 or 4 minutes.  The instructions state 5 minutes, but I feel that dries the glue a bit too much.  After 4 minutes, separate a patch from its backing, and taking care not to actually touch the rubber part (handle it with its plastic wrap cover) place it centered over the X.  Take the blunt end of your Sharpie and burnish (rub vigorously) all over the patch. Don't peel the clear plastic wrap off the patch.

At some point be sure to carefully inspect the tire, outside and inside.  You want to find whatever punctured the tube and remove it.  Sometimes you can't see anything, but if you run your finger on the inside of the tire you feel glass or a strand of wire poking through.  Dig it out of there using whatever you have or whatever you can find on the side of the road.

Put the tube back into the tire, and put the tire back on the rim, essentially the reverse of removal.  Make sure the tube is nicely seated within the tire and not under the bead.  Inflate with your method of choice.  Voila!  A nicely repaired  tire.

When I had my tube out I saw what went wrong with my system.  When I initially installed the tube and rim strip  I was not careful enough and a 4" long section of the polyurethane puncture strip folded over, laying up on the sidewall instead of the bed of the tire.  Sure enough, a piece of glass punctured the tube within this 4" section.  OF COURSE IT DID!!  Murphy's Law.  I am not thrilled with the Conti puncture resistance system, this piece of glass was puny but it still got through the puncture belts within the tire.  Anyway, I repaired the rim strip ( had to blast it with a heat gun to mold it back into flatness) and now the rear tire should perform as I hope it will---that is to say, no more flats.

So I learned a new flat repair method that works, is easy, and saves much time and effort.  I may just use this on my road bikes as well just for additional practice.  Of course, all of this hinges on whether or not you would even consider patching your own tubes.  Bike shops love flat repairs for the easy money.  Support your LBS!  I think tube repair is one of the fundamental skills of the true wheelman or wheelwoman;  its rewarding,  green for the planet and saves a lot of money in the long run.

Doing whatever it takes to keep riding,
Flash

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