Gluing tubulars for cyclocross that is.
Thinking about the people who take the tire off every year and re-glue them. Then there are those who say if you don't destroy the tire taking it off the rim, it wasn't glued on well enough.
And then the whole tape vs glue or technically tape and glue vs just glue debate.
I'm a glue only guy. Glue only is means no tape to try and take off the base tape, or the rim. Only glue. Glue is easy to deal with. Tape stuck to base tape pretty much means you learn to sew or glue on base tape.
And about the base tape. Why bother with it at all, isn't it just glued on anyway? And what's wrong about using that glue to stick the tire to the rim?
So back to the tape. I got thinking about it when I saw Smithers Minneapolis posting about gluing tubulars. With the nice picture of the tufo tape and backing.
Now the "one" benefit I hear about tape is being able to line the tire up, get it centered nicely, then you carefully remove the backing. Giving you a nicely centered tire every time.
So I got thinking seeing his picture. What material is used for the backing and, well, why can't someone just run a length of that backing over the glue and pretend there is tape there but not really.
Could it be that the glue is too fluid to work that way? Certainly there has to be a silicone or similar non-stick adhesive backing that could work w/o disturbing your nice glue job on the rim.
If that backing could be sourced - i can't imagine anyone using tape on a tubular.
heddwch
G
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Sourcing release liner is easy. Get paper, not film. It won't work well unless the solvent is already evaporated though. And you always get some silicone transfer to the adhesive, not good. We always tested for "subsequent adhesion" which was the difference in peel values before and after contact/aging on the liner. Use a thermal cure silicone on a paper liner. You probably want 90LLK liner (both sides of the paper have a coex of polyethylene skin, with the silicone on top of one side. Heavy paper can take more heat then film liners, so generally you will have better cure of the silicone.
But why bother? Centering a good tire is never a problem anyway.
There are almost as many gluing experts as there are internet users these days, or so it seems. Lots of re-inventing the wheel. Did you see Zank's photo essay on tubular gluing? I don't think he could have made it more lengthy and complicated if he tried. This is not rocket science. Use enough glue. End of story.
solo -- do you even race cross on tubulars?
If you call what I do "racing" then the answer would be sometimes. At Ice Weasels the only cx tire I had that would clear the sidepull brake on the front was an ancient Vittoria Tigre. I have a bunch and never rolled one, though I don't ride them at 20 psi like some of you guys do either.
I had days on my old job when I pumped 600 pounds of adhesive an hour into the coater. 12 hours days. Cue the violins...
"why can't someone just run a length of that backing over the glue "
Solo's point that the solvent needs to be mostly evaporated is pretty much the reason from two aspects.
Wet glue will adhere to the liner, and trying to pull a tire with wet glue on a liner that is made specifically not to stick will result in the tape not only sliding around, but removing glue because, trust me - wet tire glue will stick to the liner until it dries. If you wait until the glue has cured enough not to transfer to the liner, you run the risk of not having enough solvent left in the glue to get the two surfaces to bond.
Centering a tire, as solo points out, isn't a problem with a good tire and glue that is properly applied.
The tape is an interesting idea, and there's a link on the smithers post to a bikeman tutorial where he preps the rim and tire with a thin coating of glue before he uses the tape.
I'm not so sure about that, but I don't really know enough about the chemistry of the tape. It seems to me they engineered the tape to be used on non-glued surfaces, so unless the tape mfr specifically says it _can_ be used on previously glued surfaces, I'd be worried about whatever chemical interaction may occur between the tape adhesive and the glue.
The other thing that bothers me about the bikeman article is the line "is intended for use in temps above 70F or in applications where the rims will get very hot......if the tape holds well in those conditions it will hold even better on a cross tubular in December."
Amorphous solids are funny things, If it holds really well when hot, it may get very brittle when cold.
Again, I don't know the specifics, but I don't think I'd risk such things without having some assurances from the mfr.
wow, long comment - I think I'll blog it and ask for more comments.
Long comments are fine, esp when you read the direct link to the page.
This isn't Facebook or Twitter. Everyone is allowed to be as verbose as they want. Esp when they have encyclopedic knowledge on the subject like Solobreak.
The Vittoria stuff dries pretty damn quick... with a good well made tire getting it on straight isn't too big of a deal but it isn't a relaxed experience. The White stuff G-Ride uses (hopefully it is glue and not something else) seems to stay fluid much longer (lower % of solids maybe?).
Zen. The extreme tape is generally considered not for CX use. The Belgian tape that Stu sells is supposed to be much better for cross.
But I'm with you in thinking what's the point of having an extra layer that needs to be bonded. Why bother. Except that it is tacky enough to put the tire on and then remove the strip once it is centered.
But hey. It is something to think about and maybe it will result in one less internet monkey using tape. Or not.
See some of my ideas really stink, but it is really wicked cool when people who know way more about this shit than i do tell me why it hasn't been done that way. Much appreciated. It is awesome having smart and knowledgeable friends!
OK, I could post this on my blog, but since WilliWorld is far more widely read, I will extol my wisdom here.
You hear about tubulars rolling, but I've don't see many good descriptions of what happened, which leads me to believe that most people don't understand.
In pressure-senstive adhesive land, there are 3 categories of failure:
1) peel failure. This is when your adhesive fails to adhere to one of the two bonded surfaces (i.e. the tire or the rim). Causes could be improper gluing method, improper glue, or surface contamination.
2) cohesive failure. This is "spltting" where the adhesive itself does not have the internal strength to withstand the load and it splits, leaving adhesive on both mated surfaces. This can happen, for example, if you raced the tire when the glue was still wet. It can also happen if the rim gets too hot and you are using a glue that softens when heated.
3) Interfacial failure. You don't hear much about this one, but I suspect it's quite common in CX tubular failures. Think about gluing a piece of corrugated cardboard to something and then peeling it up. Half the cardboard is in your hand and half of it is still stuck to the other surface. The base tape coming off would be an extreme example. Also possible is the base tape failing in such a way that a thin layer of it's fibres are left on the adhesive. I have seen cx tubulars that got very wet fail in this manner due to rotting of the base tape. If the tire comes off and it has not glue stuck to it, but all the glue left on the rim does not feel tacky at all, then you probably just experienced I.F.
Clear as mud?
And zen, in general retained solvents will weaken an adhesive bond. However, in the case of tires, I think having the glue wet allows it to mechanically work deeper into the base tape. Think about it. You are gluing to a piece of friggin' cloth. It's not a strong chemical bond, and in fact the mechanical component of having the glue worked into the fibers is quite important to the security of the glue joint.
But who is going to listen to me? And Ge, does this mean you actually bought some tubulars?
Solo,
Yes actually. I have tubulars. Been racing them since NoHo last year. Got some funky FMB RR custom not so straight tubies, ripped a hole in the rear sidewall on lap one (surely you remember), and put a Fango on.
Only after a week and the base tape ripped off in a handful of places it was so well glued (f#cking bitch to get off).
Now i've got RR front and Fango Rear.
So yes. I bought tubulars. I just haven't bought any other wheels besides the Grammos which actually have been really good to me - haven't had to true them or touch them.
Oh yeah, I forgot about you getting those wheels. Do they sell them separately, or just in pairs? I have plenty of fronts but I could use few new rears, huh-huh.
just pair it looks like $220 for the set right now... pretty cheap
Blogger solobreak said..."in general retained solvents will weaken an adhesive bond."
Of course, I thought it was implied that the solvents would evaporate even if the glue was fresh when the tire was installed - it just takes longer to cure - and the less viscous glue can absorb into the fibers of the base tape and form a better.
great info on the types of failure, btw!
Blogger gewilli said..."The extreme tape is generally considered not for CX use".
That casts even more doubt on the bikeman article, they're mounting a CX tire and assuming the glue will behave normally in cold temperatures:
http://www.bikeman.com/content/view/92/132/1/0/
Correct, it will evaporate eventually, because the base tape is porous. There is always some degree of retained solvent however. Even if you didn't put the tire on "skin" forms on the surface, trapping solvent below. With heat and/or passage of time, most, but not all of it will eventually find its way out.
Putting glue directly on the base tape is of course the best way to work it in. Then you are pretty much mating glue to glue when you mount the tire. From what I gather, base tapes are adhered to the casing with "liquid latex" which is the white aqueous rubber-based stuff. I'm not sure that is true. The bonds there are certainly not always that great and reliable. Whether or not various glues solvents soak through and attack that bond is an open question. For CX I'm more concerned with water attacking the tape and/or the bond on either side of it, so the sealers that have been gaining popularity are probably a very good idea. Personally I will confine my use of tubulars to dry courses. I don't like mud to begin with, and in the deep slop I don't think I'd even notice the difference between a $125 FMB and a Michelin Mud clincher. And I'll be at least 5 minutes down on the winner with either.
You know, that's a good reason to let the glue dry for a few days before applying the AquaSeal. Otherwise the solvent could be trapped.
Just let this guy teach you:
http://euphoriabeforetotalimplosion.blogspot.com/2009/09/wanna-learn-how-to-glue-tubulars-ill.html
Solo: I am impressed by your knowledge of adhesives and thoughts on tubular tires in cyclocross conditions. I believe though the definitive studies on the quality of glues and the proper process for gluing was done by a chemical engineering professor and bike racer at my alma mater (go Jayhawks!) Dr. Colin Howat. His worked impressed the folks at Park Tool enough that they use one of his articles on their website. The short version of his work is always use Vittoria Mastik, and proper gluing process/curing time is key to a good bond. Follow Stu Thornes process with tape, or add an extra layer of glue on the rim with/out tape. After 3 roll offs in 3 seasons with the best white glue, I am a Mastik only guy now.
ringcycles - I've seen at least one of his papers where he got high peel numbers with Mastik. All well and good. IIRC all the others tested were acceptable too, even though they used the same gluing procedure for all products. That is not always appropriate. Fasttack, for instance, will produce much higher peel if you use it correctly. It doesn't take nearly as long to setup as Mastik, and if you wait the same amount of time as in the Howat tests, you won't get the best results with it.
It would be nice if they would analyze the products and publish exactly what they are. I am sure they have that capability. The MSDS will reveal a little bit if you can get one. They could also test to see what is holding on the base tapes, which was Gewilli's original question. Maybe they have and I've just never seen it.
But back to where we started, it seems that everyone who has a gluing method that works believes their way is the best and only way. I've never used Tubasti and don't know what it is, but I've used Wolber, Vittoria, Conti, and Fasttack and never rolled a tubular, and only had one come off easier than I thought it should.
Gluing tubulars is alot like transmission electron microscope sample preparation. Every where i've worked people did it differently. I've been fighting this kind of thing my whole life. People doing things because that's what they were taught. Not because it made sense. Not because it was based on science and the physical properties of what they were using, but because that is what they were taught and was the end all be all way to do it.
I've managed to convince people with painstaking evidence, but with electron microscope preps it is [relatively] easy to demonstrate success. With tubulars you are really only measuring it by lack of failure.
And lack of failure does not equal success. And there in lies your problem.
Hell fucking Gorilla Glue might be the bees knees for tubular adhesive, but has anyone tried it?
NO people are using a glue formula that is as old as fucking Eddy Merckx.... Certainly the adhesive science has advance beyond natural rubber solids dissolved in Hexane and other solvents.
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