Why bother to use sealant on tubular when its not so difficult to change tubular tyre ?

Everything about building wheels, glueing tubs, etc.
TobinHatesYou
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by TobinHatesYou

audioblazer wrote:
Thu Nov 29, 2018 5:33 am
Another reason not to use sealant is that it clogged up the valve core . Every now & then , I have to remove the valve core when I pumped up the tyre. PIA to me

Never inflate the tire with the valve between 5 o'clock and 7 o'clock and this shouldn't be a problem with a decent sealant like Orange Seal. Not advocating using sealant in tubs, just a tip for those that do use it.

mattr
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by mattr

Or just do what mountainbikers do. Take the valve core out every now and again and give it a clean. Or replace it. Mine usually last a couple of years (and the tyre pressure gets checked just about every ride.)

by Weenie


Etienne
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by Etienne

Calnago wrote:
Thu Nov 29, 2018 12:28 am
This past summer I took off for a ride on a set of wheels that were just sitting on a bike with new tires stretching (not glued at all, nada). I thought I had already glued them but enough time went by that I forgot I just put them on those rims as "placeholders" to be glued at a later date. Well, I did the entire ride completely unaware they weren't glued. Near the end I noticed a hop in the rear wheel and had no idea what that was from. I couldn't see a noticeable bulge so checked it out when I got home and noticed that during braking, the tire would be creeping it's way around the rim then bunching up against the valve since that part couldn't move. I felt so lucky, but amazed that something bad didn't happen. There were no crazy technnical descents but there were some downhills with speeds and curves over 40mph. And that was with no glue. Don't do that, ever.
Scary experience indeed ... a posteriori at least :shock:

I guess that's why unconsciously I always stow my tubs on bare rims ... to avoid converting a lack of attention into a crash.

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Calnago
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by Calnago

Calnago wrote:
Thu Nov 29, 2018 12:28 am
audioblazer wrote:
Wed Nov 28, 2018 5:05 pm
From my limited experience , Vittoria Pitstop not very effective . Just bought myself a bottle of effeto mariposa expresso & see whether it’s more effective . However is wondering if I use a sealant & it doesn’t work , it will be messy to change the tyre . So might as well just change the tubular & try to repair the tub after the ride
blah blah blah... I suppose there was a time where I was concerend about riding a tubular that hadn't been properly glued but no more. blah blah blah...
After having just reread what I wrote, I came upon this sentence and thought "Whoa!, that's not what I was trying to say at all, so I hope those of you who read it got it in the larger context of what i was saying. What I meant to get across was that there was a time I would have been super cautious and worried about riding a tubular with a tire that hadn't been propertly glued. The "but no more" part needs clarification. After seeing how well a preglued spare will "reglue" itself with pressure, and even how an unbeknownst to me completely non glued tire got me through a ride, I was forever after not as concerned as I was before that. That sentence I wrote taken on its own could easily be taken to mean "glue or not, just ride it, it's fine". Well, it's not fine, but you don't have to tip toe home either. A properly glued tubular is about the safest thing you can possibly ride on. I know there was a time when those darn triathlete types would ride unglued tubulars for a quick change in the event of a flat, but they were largely on straight line events with not much technical stuff involved, and very little braking, so maybe they got away with it here and there. But I think tubulars are largely a thing of the past in tri events these days, since the ride characteristics of tubulars play second fiddle to the huge aero gains you get with a clincher that closes that little gap between the tire and rim and produces more of a straight wall with the rim profile.

Anyway, just had to clarify that sentence i wrote first and foremost.
Oh, and just in case anyone didn't realize I was being a bit sarcastic about the "huge aero gains you get with a clincher that closes the little gap between the tire and rim"... well, I was being a bit sarcastic :) .
:beerchug:
Last edited by Calnago on Thu Nov 29, 2018 8:46 pm, edited 1 time in total.
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Jugi
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by Jugi


Calnago wrote:After seeing how well a preglued spare will "reglue" itself with pressure, and even how an unbeknownst to me completely non glued tire got me through a ride, I was forever after not as concerned as I was before that. That sentence I wrote taken on its own could easily be taken to mean "glue or not, just ride it, it's fine". Well, it's not fine, but you don't have to tip toe home either.
I have started to think this way as well. About 11 months ago I purchased a slightly used tubular front wheel for my TT bike from a club mate. The tire had just been installed and "properly glued" as my mate said. I had no reason to doubt him as he has a couple of decades worth of experience, and keeps his equipment in flawless condition.

A TT bike doesn't get to descend fast, but I did go through some tight corners, intersections and roundabouts during the season at race pace. I got a slow puncture during a rainy last ride of the season, after which I pulled the tire off the rim. I was quite shocked to discover there was only a hint of glue on the rim.

Although an unglued tubular pumped to 30psi is quite easy to roll off the rim by hand, I think the riding forces exerted at the tire are quite different. Tubular tape is most likely overkill for casual road riding. Based on my experience, I'd say tape is most likely needed only for criterium racing or cyclocross.

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Calnago
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by Calnago

audioblazer wrote:
Wed Nov 28, 2018 5:05 pm
From my limited experience , Vittoria Pitstop not very effective . Just bought myself a bottle of effeto mariposa expresso & see whether it’s more effective . However is wondering if I use a sealant & it doesn’t work , it will be messy to change the tyre . So might as well just change the tubular & try to repair the tub after the ride
For most sealants you would remove the valve core (easy peasy) when you add sealant such as Orange Seal, Stans, etc. On the other hand, with Vittoria Pitstop you insert it right through the presta valve from its pressurized cannister and if you're lucky, some of the sealant gets in the tube. If you're extra lucky, that sealant that made it's way into the tube will actually seal the puncture. And if you're super super lucky, enough compressed air will have made it into the tire to give you at best a pretty poorly inflated, but sealed tire to get home on. At least that was my experience with it.

So, with the likes of Orange Seal, or other liquid sealant, you do remove the valve core and I usually add about 15ml or so when I get a flat and rotate the tire so that it flows to the area of the puncture. Then replace the valve core and pump it up with a regular pump that I carry (Lezyne Road Drive). I can quite easily get full pressure back. Ok, so while I never seem to get clogged valves (I never add loads of sealant in there and I make sure the valve is located somewhere in the top of half of wheel when I infalte), I have come across some tires that air would just not go into. In fact, I knew one guy who threw away a perfectly good tire because of that. So, one fine day I decided to do an autopsy on a valve that you could not get air "into" the tire to see exactly how the sealant was clogging things up. What follows is my story (which I've posted elsewhere before, but seems appropriate here too)... actual names have been omitted to protect the guilty... :)

I never use sealant as a "preventative" measure in my tubulars, as it can potentially stick your latex tubes together if they are allowed to go flat, and it also means you would never be able to use that tire as a spare once changed out for a newer tire. But I do use sealant to fix punctures, rare as they seem these days, while on the road. And occasionally, the sealant will ultimately clog a presta valve in a way that prevents you from pumping up your tire. Even though you unscrew the top of the presta valve, it is impossible to pump air into the tire. So, out of curiosity what it was that was actually clogging, I did an autopsy on a presta valve that would not allow any air into the tire.

What happens is the sealant gets in the valve, and for whatever reason, perhaps you didn't quite screw the top back down all the way for example, as I think happened here, the sealant pools and forms a nice little o-ring so perfect that you might think it actually is an o-ring intended to be there....
Image
As it is above, that "o-ring" on top will quickly act just as the valve on the inside of the presta valve acts to prevent air escaping... it immediately blocks the passage of air throught the valve into the tube.

Simple solution... dig that sealant based latex o-ring out of the valve and prest-o... your valve core is free again and good as new. Oh, if you don't see the sealant formed 0-ring as in the picture, that just means it must be dug out of the cavity, as I had to do in this example with a small pick or a needle.
Image
Last edited by Calnago on Thu Nov 29, 2018 9:33 pm, edited 1 time in total.
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audioblazer
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by audioblazer

Was thinking if sealant can’t work , it will be very messy to remove the tubular & store the wet tub. Might as well just change the tub & sort out the punctured tyre after the ride

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Calnago
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by Calnago

I don’t follow you there. Are you sure you’re not confusing tubular with tubeless? In a tubular there is no mess due to sealant if you have to remove it and put on a spare, other than road grime of course if you’re riding on a wintry wet day. All the sealant is contained in the tubular, well, except for where a small amount might escape from the actual puncture area but it would be very minimal when deflated, unless it was a rare huge gash.
If sealant or plugs etc didn’t work in a tubeless setup, then yes, there is a helluva mess as you would have to insert a spare innertube, if you have one, but you would likely be using the same tire. Then you’d have to deal with it all over again when you got home to remove the now gummed up tube and either repair or replace the tire.
Either way, I think the key is to just learn how to effectively deal with a flat with whatever system you like. For tubulars, I like to just add a bit of sealant when I get the first flat, but hope that I never need to add sealant in the first place so that I can use that worn tire eventually as a spare, so long as it is still ok and not threadbare. It’s really not a big deal at all.
Last edited by Calnago on Fri Nov 30, 2018 3:14 pm, edited 1 time in total.
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audioblazer
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by audioblazer

I have not ride tubular for very long . However, I do observed sealant dripping off when I deflated the tyre . So when I have to fold it tight to keep it in my jersey back pocket or saddle bag , I m sure some sealant will have to be removed when deflating the tyre. I m not as clueless as not to know the difference between tubeless & tubular . Anyway, I agree with you that the key is to learn how to effectively deal with a flat

bm0p700f
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by bm0p700f

For me it's carry a spare tube and simply swap it. I'll leave sealant for my tubeless tyres where I don't carry a spare tyre.

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