Bicycle Mechanics - Promising Tufo Repair Method

http://www.tufo.com/img/nakres_plast.jpg

Here's what I've tried on two Tufo tires, both with cuts that won't seal (they contain sealant in them):

1 - Super Glue - attempted to simply close the hole, but the carrier in the sealant in conjunction with the inflation pressure (sometimes as low as 40 psi) re-opened the leak.

2 - Super Glued Inner Tube Patch - inflation pressure caused the inner tube material to bubble, then the entire repair gave way as the carrier in the sealant corrupted the bond.

3 - Soft Rubber patch (Elmer's Rubber Cement rolled off of tire after some set-up time) glued in place with inner tube repair cement, and then coated with Super Glue - inflation pressure reached about 90-100 psi, then the Super Glue fractured from the pressure.

Grrrrrr!

I decided to replace my second rear tire with a new one (third)--both first and second rear tires suffering from the same type of cut.

Next, I sacrificed the oldest damaged tire. I cut it open with a pair of scissors and found that the inner tube (F) is NOT bonded to the carcass (E). This is what you would find for a 'normal' tubular tire.

I tried a few different methods to cut the carcass in hopes of reaching the inner tube, but most resulted in a slashed inner tube.

Then, I attempted to cut through the middle of the fabric bound to the base of the bead profile [3]--about three inches. Voila! I was able to, with much care, gain access to the inner tube without inflicting more damage. With a lot of difficulty, I pulled the inner tube completely away from the carcass and twist it so that I could get to the puncture. If I hadn't cut the tire into pieces, I would have been able to patch the hole using an inner tube patch kit.

I pushed the inner tube back into place within the carcass. I made the assumption that I would need to "boot" (insulate) the inner tube from the cut that I made in the bead profile. So I made a boot and placed it in between the inner tube and the bead profile. (I used paper, but may use a cotton strip instead.)

My ideas for sealing were:

- Sew it up. Then, glue some cotton fabric back over the cut I made into the middle of the bead profile. I thought the best glue to use would be something similar to what is used for reconstruction of regular tubular tires--latex emulsion (I think that is what Jobst Brandt recommended in a USENET group)

-OR-

Just glue the cotton fabric and forget about sewing the carcass.

As soon as I get some fresh blades for my Exacto knife and some latex emulsion, I'll try this process on a tire that I actually want to save.

Opinions?

I'm assuming that the superglue is used because it sets up so quickly? That is a great attribute of the stuff, but since it dries brittle rather than pliable its usefulness is very limited.

I wonder if a butyl caulk would stick to a tire that is prepped correctly? A soft patch held with an adhesive that remains pliable might give the sealant a fair chance.

Information on fixing these tires doesn't seem to be easily available. Anything you can share would be welcome.

Information on fixing these tires doesn't seem to be easily available. Anything you can share would be welcome.

I plan on repairing the next tire after getting my tools in order. If I can successfully repair the next tire AND it passes all tests (i.e., inflation at high pressure, boot protection of the inner tube, bead stays in place on the rim after being damaged by the repair), I'll update this thread with the results.

If it fails, I'll post that too. Hopefully, if it fails, it won't be that the tire rolled off the rim while I was making a turn during a high-speed decent. :(

Here's a link to Jobst Brandt's "Tubular Tire Repair" article:

http://sheldonbrown.com/brandt/tubular-repair.html

Ok... I tried to repair two tires--one 2 days ago and the other last night. Score = TUFO 2 / NoRacer 0.

The first failure was caused by unsteady hands ('cuz my GF does not appreciate my need for peace and quiet while performing such a delicate operation). I poked a huge hole into the inner tube. Trash.

Last night, the second tire went better. I managed to patch it (in two places because -again- I went too far and hadn't managed to push the tube far enough out of the way, poking a small hole in the bottom of the tube.)

Next, I placed a paper boot between the inner tube and the clinch profile. Then, I used a piece of waterproof tape to keep the cut in the clinch profile closed while I applied cyanoacrylic glue (super glue) to the area--no, I haven't acquired latex emulsion, yet. I covered the glue with cotton cloth tape. Everything looked good--on the surface. I pumped the tire (unmounted) to about 100 psi. Everything was holding up well, until I started to walk to another room to fetch my rim, then... BANG! LOL! @$?&!

Apparently, the boot that I used was not sufficient (too soft) and the edges of the cut in the clinch profile pushed through causing a rupture. This new gash was too long to fix. Trash.

So..., that's my update for now.