Duragrouch

"Doctor, heal thy self." I've said in the past of my liking the Park sticky patches, good luck with them, others have said they are more temporary patches. Went to ride today, not quite flat but really soft, rear of course. Last rode on Friday so could be a very slow leak. Pumped up tire, soapy water, looked on tire for leak, nothing. Pulled off wheel, tire, tube, pumped up, into water bath. Nothing. Looked over tube, two Park sticky patches, didn't seem to leak under low pressure of only tube inflated, but both patches were bubbled to edge. I think both had been on a year. Pretty good, but yes, not permanent. I replaced tube. I had very poor luck in past with rubber patches, but was doing it wrong, not waiting until glue dried, need to do that, use like contact cement. I'll buy one of those kits, but also look for a small jar of cement, which will last better than the tiny tube of cement which, once opened, dries out fairly quickly.

I have some rubber tube material, and some contact cement that I've used in place of (not having) rubber cement, for dipping rubberized rope car tire plug and inserting while wet, has worked fine, I wonder if that will work on bike tube, in intended fashion of letting both halves dry and then press together?

I will say, that I found a number of tiny shards of glass in tire tread, most not penetrated but did find one small cut through, I think I recall removing a shard or staple from the outside and having no flat, I think my trick of putting a deflated tube sans stem between inflated tube and tire, I think does help there, not tough enough to stop anything, but just an increase in thickness such that a small shard or other may not make it through right away.

squirtdad

why bother with tube pieces and glue, they will not work as well as a real vulcanizing patch

just get the Rema TipTop patch kit and use it the small kits are like 5 bucks, so get a couple

Steve B.

I am reasonably certain that had I run the tube thru a bucket of water with no apparent leaking bubbles, I will have tossed the tube and spent the awful amount of $7 for a new one,

Duragrouch

I just don't have any rubber patch kits. I still have the boxes, holds presta-schrader adaptor (I haven't needed in a couple decades but I help others who do) plus a ball-needle inflator. I'll look on amazon.

I'll have to look up what vulcanizing cement actually does.

noglider 

So far, of the theories presented here, I like (1) abrasion from the inside of the tire and (2) loose valve core. I have suffered from both. Recently, a bike shop owner says he has seen a lot of loose valve cores coming in new tubes. Now I carry a valve core tool with me, and I hope to build a habit of making sure my valve cores are tight.

Spraying with soapy water, as has been suggested, sometimes finds a leak better than immersion in water.

grumpus

I've always assumed it breaks sulphur bonds in the rubber molecules on the surface of the tube, and the surface of the patch also has unvulcanised rubber and sulphur in some form. Slap them together with some secret chemistry juju and molecular bonds form between the patch and the tube.

noglider 

Yes, it causes some kind of interlocking on a molecular level. Or something like that. My chemistry is very weak. @cyccommute is a chemist and has explained how it works. His explanation convinced me I should use vulcanizing fluid rather than rubber cement, even though rubber cement often works.

grumpus

I used cyanoacrylate and a bit of plastic bag once, it got me home. But a good Rema Tip Top repair lasts the life of the tube, and I enjoy mending things that other people would throw away.

ScottCommutes

Many good idea given!

This would be the bane of a bike shop environment. They don't want customers coming back.

For comparison to another slow leak, I just set up our kiddie pool for the third season. It's about 30" deep by 17' across and it has a prick-sized leak in the side. A piece of Gorilla tape cut the leak 90%, but it still leaks continuously. Still, the leak is insignificant compared to the amount of water that gets rained into and splashed out of the pool.

squirtdad

it is the combination of the cement and patches designed to work with the cement that is the magic....there is a reason for the red part of the patch that you expose by peeling the cover off......

of course if you go way back, when cars used tubes (and getting real inner tubes to float rivers in was easier) gas stations used a type patch that you set the glue on fire bringing vulcan the fire god into the party https://www.bikeforums.net/bicycle-m...atch-kits.html

unterhausen

I had a slow leak that I never could find on the ride. It was on my road wheels for my gravel bike, and I switched back to my road bike after the ride with the slow leak incident. A couple of years later, I wanted to use the road wheels again, and immediately found a wire sticking through the tire. No idea why I couldn't find it before. It's pretty common for this to happen, I think. Just never happened to me before this. Slivers of wire are pretty good at hiding. It's things like this that have induced me to switch to tubeless.

Duragrouch

All good info! I wondered about the red part on those patches (which I haven't seen in 20 years).

I recall from the late 60s or early 70s, a goodyear tire shop I would pass had as part of their sign, "VULCANIZING". To this day I didn't know what it meant.

Today's find: 20" x 1.75-2.25" tubes at goodwill, new and in shrink-wrap, which may prolong their shelf life, $1.99 each. Don't say 406 but 99% chance there are, saying "BMX". Schrader. They had 9, I bought 9. I usually run 1.75" and use tubes 1.75-2.00 range, less stretch than 1.5-1.75". But I recently acquired a couple 1.95 or 2.00 used tires like new at the LBS for cheap, these tubes will be dandy when I mount those, I'm pretty sure I have cleance for those on my Dahon Speed. Pic:

grumpus

ISTR the old school tyre shops used a heated press to get a raw rubber repair patch to fuse with the tyre, not sure what else was involved.
I'm all for saving money, but tyres are one thing I'll spend a bit more to get better performance where the rubber meets the road. Not super high performance, or super puncture resistant, but something that will grip and roll well enough, that cheap tyres tend not to do so well.

Duragrouch

Tires: I agree. But my experience has been a (rubber) tube is a tube, get best price available.

grumpus

I agree that for the most part a tube is a tube, unless you're talking thick thorn-resistant, extra-light skinny 700C, latex or TPU. But it was the used tyres I was commenting on.

Duragrouch

Oh, yes. One set of tires I looked at, seemed fine, but then I pinched them, and could see the age of the rubber in fine cracks, I passed. And rubber can age well before that in terms of traction. These looked good in that regard, barely mold flash off the tread, and were a really good price for the tire, like 1/4 new, I won't overspend on used rubber. Some still had the mold flash, clearly take-offs for someone upgrading from the stock tires immediately. I've had good luck there. Between that, and using up the tires off every other same size wheel bike I have in storage before they are useless, I haven't had to buy "new" tires in decades. Eventually if I get those bikes on the road or sold, I'll do a bulk buy to tire them. I only used to buy new tires, Nashbar had such raging deals in late fall and winter.

cyclomath

Couple of years ago I had a tube that would stay inflated for a full week when left on the bike stand (just the tube) and showed no leak when submerged in water and no (obvious) problems with the (Presta) valve, but would go almost completely flat in less than a day once installed. It drove me mad for some time, and then I decided that the tube shouldn't mess with me so much so often, remembered that I was the boss in our relationship, so I cut the valve off and used the tube as repair material. I lived happily ever after.

shelbyfv

Wonder how this was resolved by OP?

drlogik 

All of the above but also inspect the inside of the tire. You could have a shard of metal tire cord in your tire and they sometimes aren't easy to located. Gently wipe the inside of the tire slowly with a cotton ball, or better yet a swatch of an old Nylon-Lycra bike shorts (that works really well). If nothing, switch directions and do it again. The cotton ball will snag on the wire.

If nothing and you've done everything above, by a different brand of tube and install. If it keeps air it may be a bad batch of tubes. I've only had that happen once in my years of riding but it was really irritating trying to find the cause for a leak.