JeffOYB

[Weird. I posted this. Screwed up the subjectline. Fixed it. But then it never updated in the Forum. So I'm reposting and will try to delete the old post.]

I, uh, rolled a Tufo cyclocross tire and in so doing ripped out the valve stem. Rats.

I don't know about the innards of Tufos. I pulled off a bit of the base tape near the stem and learned that there is no stitching. I googled a bit and it seems that maybe there's no inner tube! What's up? I know they recommend repairing via their sealant but my problem is worse than that. Any hope? Fingers crossed!

Has anyone kludged together such a repair for these tires?

I was thinking of poaching a section of inner tube with a valve from another even worse off tire and somehow gluing it into the Tufo, maybe splicing it into the Tufo's tube, if there is one. I see from a Velonews letter to Lennard that it's possible to splice inner tubes. Whew! I like this narrow 'cross tubie and would love to somehow rescue it. I'm willing to spend some time on it as an experiment.

simonaway427

Tufo's in fact do NOT have an innertube. The casing is the tube.

I'd just replace the tire....cost of doing business.

JeffOYB

I hear ya, but I'm willing to try something creative. Like, I wonder how they get their valves in there. Glue em? Maybe I could try that.

fietsbob

they are probably set in the mold then the airtight rubber lined tire is built around it ,
Vulcanized in place .

Good luck.. I expect you will do a better gluing job , now,
might be a good idea to re do the glue job on the other wheel , next.

JeffOYB

Yeah, the valve is probably vulcanized. Inner tube patches are also vulcanized, right? Patch glue makes it possible. So maybe I could re-vulcanize a stem back into the tire? Anyone know if that kind of thing is re-doable or if that's what happens when we patch tubes?

But how to vulcanize a valve... I don't know what happened to the torn one. Can't vulcanize to metal, can you? So it was maybe rubber-coated. Maybe a blob of shoe-goo would work. ? i suppose I can test away. But if anyone knows anything, any science, here, it's appreciated.

Yeah, about my mistake, I'll try not to make it again. Same as any, right? Didn't tighten a nut enough? Next time tighten it. These things happen.

fietsbob

No the red layer, like, on Rema patches is not,
it is such that it bonds when exposed to the solvents in the little tubes of glue.

You cure and vulcanize the rubber in the Mold, when Manufactured.. heat and pressure (+ sulphur)
maybe you can Kludge fake it somewhat with a big patch pierced by the stem.
so the stretching patch around the stem + some chemical solvents to soften the raw rubber part
will be worth a try .. entertainment on a cold weekend in the shop..

Probably best to avoid open flame or insufficient ventilation.


https://en.wikipedia.org/wiki/Vulcanization

dscheidt

You replace the valve stem by buying a new valve stem. It will come with a brand new tire already attached, saving you the frustration of trying a bunch of things that simply won't work well. You bought wheels that take silly, difficult to repair tires, and you put impossible to repair tires on them. So, I don't see why your surprised.

Metal is bonded to rubber during vulcanization, yes, there are various cements that will cross link the rubber to the cement, and the cement to the metal surface. You're not going to get that without specialized equipment.

fietsbob

yea get a new tire, you can play with various techniques for re bonding the tube,
but the new tire will work so failed 'nice try' experiments are not stressful if, unsuccessful

with a tire glued to the rim, the ring nut is probably un needed,
wire bead tires, the tube is separate, so shoving on like a Silca air chuck on a floor pump,
the ring nut gives you something to push against.

Others prefer to remove it then too, since topping off an inflated tire
the PSI already in the tube resists pushing the stem back into the tire

I noted 'purely Custom' sells an aluminum ring nut to replace the usual nickel plated brass ones.

and a color range for those and the caps in anodized colors is possible.

JeffOYB

Awkward.

Any mention of surprise in my query?

Buncha wrongheaded offtopicness there, eh.


Ah, a voice of authority. Yet not backed up by anything. Hmm, shall we heed? ...Why?

So I'm left where I was before: I'm still asking if anyone knows of a way to glue a valve into a Tufo. I'm thinking MAYBE there is a glue out there that would work. If there isn't then fine, but this 'sez so' approach seems offpoint.

JeffOYB

UPDATE: OK, I googled Tufo repairs a bit more and found an old thread here about how they have regular tubes inside and so I cut mine open at the valve hole and, sure enough, there's a tube in there minus its valve. It was kind of stuck to the interior of the casing, but not too tightly.

Hmmm, so now my challenge is in installing a fresh valve. I cut an old valve out of a dead sewup with a couple inches of tube on either side. I'm thinking I'll just try to splice the new valve in. I'll cut the old one out plus an inch of tube on either side. Then I'll use patch cement to glue in the section of tube with the valve.

OK, I cut out the old valve and glued in the new valve with 1/2" tube overlap all around, using tube-patch cement. I'll let it dry overnight then see if it holds any air.

If I get lucky enough to get this huge chunk of tube-on-tube to seal, then I have to figure out how to reseal the Tufo casing. I think I'll just sew it as if it were a sewup. I'll lay in a strip of hanky first to protect the tube from the thread, just like a real sewup. : )

UPDATE: I let the glued inner tubes dry for an hour then fiddled a bit with the patch and it easily peeled up. Rats. I've never tried gluing tube-to-tube. Does it work with patch cement? OK, I cleaned and sanded the surfaces really good and reglued it. Fingers crossed! I'll let it cure for a day now.

UPDATE 2: So far I'm not impressed with how well inner tubes patch together. After letting the patch rest overnight I notice some of the edging didn't glue down and I've smushed in fresh glue, let it dry 20 minutes and press it down again. Now I'm noticing more loose edge and have reglued it also. I'm going to try to get all the edges down good then let the whole thing dry a day before testing.

JeffOYB

At this stage, my snag is using an inner tube to patch an inner tube. It supposedly can be done. I've let the glue dry on both surfaces then I've clamped them together then waited a day then unclamped and waited a day. I just did a test inflate. Massive blowout of the patch at 10psi (just testing bare tube portion. I've now reglued, redried, reclamped. We'll see if the reglue portion holds after another day. I have time. I'm going ask about using tubes to patch tubes over in Mechanics. Google sez it works...but sheesh...

GrayJay

I've managed to splice together then cut ends of inner-tubes together couple of times to repair conventional tubulars needing replacement inner-tube. Doubled one end of the inner tube back over on itself, apply patch-kit cement to the other end and then unfold the doubled end back over the glued end so they overlap 1". Do it while the glue is still wet and then try to pinch the overlap smooth so that there are no wrinkles at the overlap to let air out. Much easier with latex inner-tubes but I have managed to splice a few thin butyl tubes too.

JeffOYB

OK, so the diff here is wet glue. If my latest test doesn't work, I'll try that.

JeffOYB

UPDATE: Repaired tire has now held air for a day. Fingers crossed. Base tape glued back on with shoegoo type stuff. Seems to be holding. Tufo casings have a rubbery finish that kind of glue seemed likely. I suppose I really should just let the massive inner tube patch cure for a month before mounting the tire and trying to ride it...

fietsbob

OK for a Spare wheel .. would not start a race on a tire that you have questions about.

but it did give the spectators something to do when the weather bites it to go riding..

good luck.

JeffOYB

I hope I didn't give the impression that I was trying to put together RACING gear by gluing sections of tube together and doing other experimental patching. That wouldn't be a smart approach.

I've heard of cobbling things together for fun but not for racing.

I'm just doing it to get a narrow tire that will hold up long enough to test 'cross wheels in a light road frame that I have that will fit them.