Tubular fitting and puncture repair

master6
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Tubular fitting and puncture repair

Postby master6 » Wed Jul 04, 2018 7:38 pm

I have a friend who is purchasing new tubular wheels.
He also has some misplaced faith in my out of date cycle mechanical knowledge :D
The wheels that he is purchasing will come with the tubulars not fitted.

The supplier has advised him to fit the tubulars with tape.
I my long past experience with tubulars (we called them singles) we fitted them using shellac on track wheels, and a non hardening Road Glue on road wheels. Tape was available, but not permitted by the rules of racing (at least on track bikes) I have tried tape years ago, and found that the tubular grabbed the tape and would not stretch evenly around the rim, resulting in stretching in one area of the tubular only, causing a "high and low" effect as the wheel rotated.
What are people using on road tubulars today?

The other question relates to puncture repair. My friend understands the seller to have said that there is a patch to put on the outside of the tyre to repair a puncture. I find it hard to grasp this idea. I have had many punctures in tubulars (singles), and enjoyed :cry: the process of opening the casing stitching, patching the tube, then restitching. Is there some new fangled system/method that does not require unstitching and restitching :?:

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Derny Driver
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Re: Tubular fitting and puncture repair

Postby Derny Driver » Wed Jul 04, 2018 8:10 pm

haha mate you are showing your age. I probably am too because I know what you are talking about :)
I would recommend using glue for the singles cough cough tubulars. Apparently the Caden brand tape is great, easy to use and is street legal. Gluing is still preferable I think. Shellac- well my dad was an expert with the stuff and it certainly was brilliant on the track wheels, but these days no-one uses it as the glues are just as good and a whole lot less trouble.
Punctures - well repairing singles is a lost art, again I watched my dad mend hundreds, all the boys would drop their punctured tyres off and he fixed them free of charge. But no-one does it any more. A punctured tyre is tossed away.
If your friend runs Continental Competitions, he wont need to worry about punctures, they are amazing tyres and are used by many of the top Pro teams. You can get lighter tyres but there is a trade off ... I remember an overseas tour i took a team to and our New Zealand rivals who were running light tyres (Vittorias?) got about 5 or 6 punctures per stage while our boys on the Contis never got 1 all tour. And we didnt drive the pace on the front when they punctured either, that would be poor form, making them chase like maniacs just to get back on lol.
As for stick on the outside patches, forget it, I have heard of them being used to limp home on a ride, bumpety bump bump, but they are a gimmick and are no solution.
If you're going to run tubbies, run them on race wheels only and glue them on with Continental glue. The Competitions in a 25mm are my choice.

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Duck!
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Re: Tubular fitting and puncture repair

Postby Duck! » Wed Jul 04, 2018 10:05 pm

+1 to what DD said.

Glue is the way to go. There's a bit more process to it, but it gives a bit more freedom for dry-fitting tyres to pre-stretch them before gluing, and also because the glue doesn't fully harden but maintains some tackiness, you can get yourself out of a pickle if you do have a puncture, and carry a spare pre-glued tyre with you; there's enough "stick" to allow the new tyre to hang on to finish the ride, but just be wary about chucking to vigorously into corners.

For first-time use with new wheels: if the tyre bed of the rim is finished with a very glossy clearcoat, lightly sand the bonding surface to enable the glue to key into the rim - I learned this the hard way when a customer's barnd-new wheel & tyre parted company because the glue didn't stick to the gloss surface. Fortunately without major incident or injury. Satin or matt finishes are less of a problem, but it's wise to err on the side of caution and give them a scuff too. Wipe the dust off with metho or isopropyl alcohol, allow it to evaporate fully, and then apply a thin, even coat of glue to the whole tyre bed of the rim, and allow to cure for at leat 24 hours. After priming the rim, fit the tyre to it without gluing, inflate to proper pressure, and leave for at least another 24 hours to allow the tyre to stretch. This will make fitting easier when it comes to properly mounting the tyre.

With the rim primed and the tyre stretched, we come to gluing. Partially inflate the tyre so it inverts and makes the base tape more accessible, and apply a generous layer of glue to the base tape, because it will soak in. Some tyres - particularly Vittoria - have a factory-primed base tape, so you can be a bit lighter with the glue on those. Apply a layer of glue to the rim, but leave a section between two spoke holes opposite the valve hole unglued - this will make it easier to get a tyre lever under to get started when it is time to replace the tyre later on. Leave the wheel and tyre to dry for 20 minutes or so (time may vary depending on temperature and humidity), until the glued surfaces are tacky and almost dry to touch. Run a final thin bead of glue around the centre of the rim, deflate the tyre, and starting from the valve work around in much the same way as fitting a clincher, using your thumbs to push the last bit of tyre onto the rim. If the glue on the tyre has been allowed to tack off properly, this will be a pretty clean process; not so clean of the glue is still very sticky. The final layer of glue on the rim helps you move the tyre around to centre it; push the tyre around so there's an even strip of base tape showing on each side - depending on rim & tyre combo it should be 1-2mm of base tape visible each side. Inflate the tyre, clean off any excess glue with turps, and leave for 24 hours before riding.
I had a thought, but it got run over as it crossed my mind.

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Thoglette
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Re: Tubular fitting and puncture repair

Postby Thoglette » Wed Jul 04, 2018 10:48 pm

Duck! wrote:+1 to what DD said..

What they said

Duck! wrote: Leave the wheel and tyre to dry for 20 minutes or so (time may vary depending on temperature and humidity), .

The only caveat I have is that glues vary: Vittoria mastic (and similar Conti, IRRC) dries hard & quickly (looks like hot caramel when wet) and seems to behave like contact cement, achieving decent strength the moment the tires are pumped up. Whereas Velox Tubasti (like sticky PVA) is still quite wet when you put the tyre on and takes a lot longer to set (it really does need the 12 hours).

I'd also add that you need to check your glued tubs every year: eventually the Vittoria/Conti turn to dust. Literally. I tend to keep the brush I used lying around as "the canary in the coal mine". Don't panic - I've ridden safely with dead glue (the first symptom is thump-thump-thump as the tub moves under braking but the valve doesn't :oops:

I've only used Velox recently so I'm not so sure how that ages. However every old wheel I have shows the same age-related failure mode. This is not a problem if you're wearing out the tyres but is if you're only using the tyres/bike once or twice a year.

But I;m guessing you know all this already

ps - beware of tubulars that aren't actually sewn up with base tape. In my experience (mostly at the cheaper end) these suck, being un-supple compared to traditional tubulars. And they are completely impossible to repair.
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Jmuzz
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Re: Tubular fitting and puncture repair

Postby Jmuzz » Thu Jul 05, 2018 11:13 am

Can tubeless slime be used to patch a pinprick leak in a tubular?

Abby
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Re: Tubular fitting and puncture repair

Postby Abby » Thu Jul 05, 2018 11:36 am

I can highly recommend the new Carogna Tape from Effeto Mariposa (which I probably just spelt wrong). I used it to mount my tubulars, and it was ridiculously easy with a super-secure bond.

I also use some Caffelatex sealant in the tubular tyres to help with any punctures, and its worked very effectively so far.
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Re: Tubular fitting and puncture repair

Postby Thoglette » Thu Jul 05, 2018 11:39 am

Jmuzz wrote:Can tubeless slime be used to patch a pinprick leak in a tubular?

Yes. I carry a bottle of Stan's for that reason. (Around here there's no point in pre-loading the tyre) Sometimes you get a little lump forming as the Stan's sets (it's not as flexible as a good tubbie) but it's easier than swapping tyres.
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Re: Tubular fitting and puncture repair

Postby ironhanglider » Thu Jul 05, 2018 11:53 pm

I can offer some bits and pieces of information and possibly folklore.

I've used tubulars back when they were known as singles and have repaired a good few of them too. I never really found a glue to stick the backing tape on that worked to my satisfaction, whilst I've never had a tyre roll off as a result of poor adhesion I have often found the edges of the backing tape peeling off. I'd also be more reluctant to patch butyl tubes now because the newer butyl tubes don't seem to patch as effectively as they used to, and I'd really hate to have to go through the whole process again because a patch failed. "Outside tyre" patches are at best a bodge to be used to get you home but are no better than that.

I did use tape for a while when I thought it was easier and cleaner. There were two methods proposed for dealing with the premature sticking issue you described. One was to wet the tape with water, making it less sticky so that the tyre could be easily lifted off and centred on the rim. Once the water dried off, the tape resumed its stickiness. The other was to leave the backing tape on and only remove 10cm or so on either side of the valve with the extra poking out the side. Then once the tyre was on and centred the idea was to pull the backing tape out from underneath. I used carpet tape for a while and it was fantastically sticky. I punctured in a crit once, never mind getting a lap out for a mechanical, it nearly broke my thumbs and took three laps before I even got the tyre off. However I stopped using tape 25 years ago and I'm not confident that the same methods would apply now. I'm not sure about the 'rules' for attaching tyres, I suspect that they never actually restricted the method, just that they specified the tyre should be attached securely. However I have no doubt that interpretation of the rule has varied at times and places.

I am a confirmed glue person (3 thin layers on tyre and rim and one more on rim to mount). I prefer the security of having the spare stick to the glue remaining on the rim when the tyre is removed. Fortunately I've not had to take a tyre off in a hurry for a while, but it is difficult, I always need to use a tyre lever to pry a tyre off.

As for sealants, there are mixed reports. I suspect that tubes being thin and flexible are more difficult to seal than a tyre. For me I mainly use tubulars as race tyres, and the roads that I race don't seem to cause many punctures. I wouldn't be putting sealant in a tyre until I actually got a puncture. On a related topic Tufo tubulars are also tubeless, so a sealant would work better with them. I'm sure Tufo tyres have other good qualities, but I can't think of any. It may be a consideration if you are in a puncture-prone area.

Cheers,

Cameron
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foo on patrol
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Re: Tubular fitting and puncture repair

Postby foo on patrol » Fri Jul 06, 2018 5:06 pm

I run tuffo tape on my road wheels and you just put the tape on, then throw ya strip on, put about 20-30psi in and then pull the tape out from under the strip, once you have centred it of course. :wink:

Just so ya know, the wheels were called singles and the rubber was strips back in my day and oh how I loved the Clement 3s. :mrgreen:

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Re: Tubular fitting and puncture repair

Postby ValleyForge » Mon Jul 09, 2018 10:20 pm

Abby wrote:I also use some Caffelatex sealant in the tubular tyres to help with any punctures, and its worked very effectively so far.


+1 for Caffelatex. And Conti glue.
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Re: Tubular fitting and puncture repair

Postby Paul B » Mon Jul 16, 2018 12:02 pm

Good insights for the “Tubular Novice..... me :shock: So just picked up my first set of tubs. Scored some new Enve 3.4s at a crazy low price. Can’t wait to get these on the Canyon :D
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Re: Tubular fitting and puncture repair

Postby Paul B » Mon Jul 16, 2018 2:46 pm

Based on the above advice I have purchased the Effretto Mariposa tape and the Caffelatex sealant. Thanks Jeff for starting the conversation.
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Re: Tubular fitting and puncture repair

Postby ValleyForge » Mon Jul 16, 2018 8:14 pm

Paul B wrote:Based on the above advice I have purchased the Effretto Mariposa tape and the Caffelatex sealant.

If you can take the valve cores out - all the better - but it's not necessary. Fill with the stem at the 4 o'clock or 8 o'clock positions and inflate always at 12 o'clock. Otherwise you will end up wearing it or picking it out of the pumphead for a few days.

Got Carbon-specific pads?
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Re: Tubular fitting and puncture repair

Postby Duck! » Mon Jul 16, 2018 8:26 pm

If pre-loading with sealant (as opposed to using it once you have a flat), be careful to not let the tyres deflate too much (all tyres naturally lose air over time), or the sealant can stick the tube together, which can then tear the tube apart when reinflated.
I had a thought, but it got run over as it crossed my mind.

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Re: Tubular fitting and puncture repair

Postby ValleyForge » Mon Jul 16, 2018 9:23 pm

Duck! wrote:...or the sealant can stick the tube together, which can then tear the tube apart when reinflated.

I can admit here, amongst friends, that I am terribly guilty of this, yet never had an issue. I have three classic bikes with tubulars and Cafelatex and I let the tyres go flat for months at a time. Perhaps they are saved as they hang rather than rest on the tyres.
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Re: Tubular fitting and puncture repair

Postby Paul B » Mon Jul 16, 2018 9:37 pm

All very interesting.... and yea... the Enve’s come with brake pads designed specifically for their brake tracks. Great tips BTW.
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Re: Tubular fitting and puncture repair

Postby Duck! » Mon Jul 16, 2018 10:12 pm

Hanging may be your saviour. I've only seen one failure that could be attributed to a stuck-together tube, so it's probably uncommon, but possible nonetheless. Before it let go, when the tyre was inflated there was a weird "flabby" section of the tyre where the tube obviously wasn't inflating to support it.`
I had a thought, but it got run over as it crossed my mind.

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