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within 06-28-07 08:26 AM

Help tubular tire repair
 
I'm looking for some feedback on repairing a tubular tire. I am interested if anyone has used Tirealert. See link below:

http://www.tirealert.com/


I'm also interested in DIY, but would like a detailed description of someones experience and maybe some pointers, etc...I've searched sheldon's site and Park Tools. The tires are Vittoria and Conti's. Thanks.

carpediemracing 06-28-07 01:24 PM

I might have used Tire Alert in the pre-internet days. They take the whole tube out, put in a new tube, resew. A teammate and I did about 8-10 tires which we flatted when virtually new. One tire came back crooked (they misaligned the threadholes - like misbuttoning your shirt) but the others were fine.

DIY - when I was a poor racer I patched a few tires - only if they were new (I flatted one at a race after going about 100 yards in a parking lot), had good casing, no cuts.

First, I don't know how to patch latex tubes. I only patched tires with butyl tubes.

Basic steps:
1. Get a tubular repair kit and a good tube patch kit.
2. Find the hole. Air comes out by the valve so ignore that - find the "other" spot from which the air escapes.
3. Remove base tape from the area where you suspect the tube is punctured. You can remove a lot, you just need to glue it back on.
4. Verify the tube really is flatted in that area. If you have the base tape off the air bubbles out a bit easier.
5. Mark reference points using markers so you know which holes line up with which holes. I do this every inch or so.
6. Cut the threads for about 8-10 inches. Every thread you cut is another you have to sew so be judicious. I would fold the tire so the threads were at the "top" and then slice them with an Xacto knife.
7. Pull out all the thread bits from the thread holes in the casing.
8. Hopefully the tube is punctured there.
9. Patch the tube (you can pull it out a bit), do a low pressure test to make sure it's holding, and put tube back in.
10. Sew the tire back up. Line up your reference points - if you don't your casing will twist and the tire will be unusable. Use a thimble or three. Your fingers will be killing you if you don't. I might have used pliers to hold the needle, I forget, I just remember the threading was the hardest part of the whole thing. Use the specific thread that came with the tubular kit. Don't make the thread too tight - the edges of the casing should be flush with each other, not squished together. I never replicated the actual pattern, did something similar though.
11. Do another pressure test. I'd dry mount the tire and let it sit over night on a rim. If you didn't patch it well you'll know right away. Then you have to repatch. If you were unlucky there might be a second puncture to fix on a different part of the tire.
12. If it's good, glue the base tape on (I always used tubular tire glue even though they say not to), glue the tire back on, and you're good to go.

I think I'd spend about 2-3 hours per tire. I did this in the winter with flat tires saved from the summer. The patched tires became my training tires unless the casing and pressure retention was perfect - in that case, they could be race tires.

There is a tool that holds the tire so you can sew the casing together. You throw out the old tube and use a new tube. The tool thing holds the tube down and the casing up so you can thread the big needle through the casing without flatting your new tube. Apparently it works well but I rarely flat a tire worth fixing nowadays so I don't patch my tubulars anymore.

hope this helps,
cdr

within 06-28-07 03:05 PM

Just what I was looking for! Thanks much!

San Rensho 06-28-07 04:31 PM

Not to discourage you, but I tried repairing flats several times and I could never get it right. I invariably re-sewed the casing too loose or too tight and always had a blip in the tire. It was never close to being raceable and I only used them as spares to get me home.

For me, it was like doing abdominal surgery on a snake and the patient always died.

foofoosmoo 06-28-07 07:17 PM

I used to repair my own tubulars when I was 15--piece o' cake

Sheldon Brown 06-28-07 08:56 PM


Originally Posted by carpediemracing
I might have used Tire Alert in the pre-internet days. They take the whole tube out, put in a new tube, resew. A teammate and I did about 8-10 tires which we flatted when virtually new. One tire came back crooked (they misaligned the threadholes - like misbuttoning your shirt) but the others were fine.

DIY - when I was a poor racer I patched a few tires - only if they were new (I flatted one at a race after going about 100 yards in a parking lot), had good casing, no cuts.

First, I don't know how to patch latex tubes. I only patched tires with butyl tubes.

Basic steps:
1. Get a tubular repair kit and a good tube patch kit.
2. Find the hole. Air comes out by the valve so ignore that - find the "other" spot from which the air escapes.
3. Remove base tape from the area where you suspect the tube is punctured. You can remove a lot, you just need to glue it back on.
4. Verify the tube really is flatted in that area. If you have the base tape off the air bubbles out a bit easier.
5. Mark reference points using markers so you know which holes line up with which holes. I do this every inch or so.
6. Cut the threads for about 8-10 inches. Every thread you cut is another you have to sew so be judicious. I would fold the tire so the threads were at the "top" and then slice them with an Xacto knife.
7. Pull out all the thread bits from the thread holes in the casing.
8. Hopefully the tube is punctured there.
9. Patch the tube (you can pull it out a bit), do a low pressure test to make sure it's holding, and put tube back in.
10. Sew the tire back up. Line up your reference points - if you don't your casing will twist and the tire will be unusable. Use a thimble or three. Your fingers will be killing you if you don't. I might have used pliers to hold the needle, I forget, I just remember the threading was the hardest part of the whole thing. Use the specific thread that came with the tubular kit. Don't make the thread too tight - the edges of the casing should be flush with each other, not squished together. I never replicated the actual pattern, did something similar though.
11. Do another pressure test. I'd dry mount the tire and let it sit over night on a rim. If you didn't patch it well you'll know right away. Then you have to repatch. If you were unlucky there might be a second puncture to fix on a different part of the tire.
12. If it's good, glue the base tape on (I always used tubular tire glue even though they say not to), glue the tire back on, and you're good to go.

I think I'd spend about 2-3 hours per tire. I did this in the winter with flat tires saved from the summer. The patched tires became my training tires unless the casing and pressure retention was perfect - in that case, they could be race tires.

I haven't patched a tubular for at least 30 years, but one thing I remember is that it's a BIG help to have a "sewing awl."

I got mine at Tandy Leather, but I'm sure there are other sources. This is a tool that looks sort of like an ice pick. The business end is a chuck that holds a _sewing_machine_ needle. The handle is hollow and holds a small bobbin of thread.

This is not only MUCH easier on your fingers, it also allows you to duplicate the original two-thread stitch.

Sheldon "Not Worth The Trouble" Brown


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