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Discussion Starter · #1 ·
I was checking my competition tubulars before Jefferson Cup and noticed with the tire deflated, that while in most spots on one tire, the rim/tire adhesion was great, but in others, the tire could be easily separated from the basetape. I was really irritated(didn't race on them) and put them aside to get another wheelset ready.


This morning I went to investigate more and sure enough, long sections of the base tape had separated from the tire. The tape meanwhile was incredibly well attached and a bear to get off.

I have kept this wheelset in a dark humidity controlled basement when not in use, and it only gets used for races or 'A' rides. Also, I've reglued it, not because it necessarily needed it, but just to be safe(I reglue all my tires each year).

So, the question is, is this an expected failure? The front tire is fine and no signs of the tape coming off. Should I try and get Continental to warranty the tire, or send it to TireAlert to get another basetape put on? They still have many many miles on them and I would hate to simply throw them away. Right now, I'm a bit dissapointed with Continental--I've run lots of tubulars from Challenge(cross and road), Vittoria(road) and have yet to have such a severe separation. What gives?
 

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Could be a faulty tire, but incompatable glue will do the same thing. Fast tack with Conti tires was an awful combination for base tape seperation. I've gotten away with using Vittoria Mastik one, but I use very thin base coats on the tire and take care not to saturate the base tape.

YMMV.
 

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We looked at what caused base tape separation and found a host of potential causes. Rarely is it actually a manufacturer's problem, though we might wish for better adhesion on their part.

Here's what we found: First, the reason they use latex (or a synthetic equivalent) instead of an organic-based solvent is because they don't want it affecting either the inner tube or the tread adhesion. It doesn't help to stick your base tape on better if your tread wants to peel off. This has been a problem with some of the handmade tires such as Dugasts in recent years. Tufos do better on base tape retention because with their sealed tubular design and the nature of their vulcanizing, they can use a stronger base tape adhesive with impunity.

Second, any latex adhesive is still somewhat sensitive to the solvents in rim cement. Too much glue on a tire in any one coating and you weaken the latex. We applied pre-measured amounts of rim cement per coat to tires and found that the number of coats doesn't matter but the amount applied per coat definitely does. The first coat provides a bit of insulation for the base tape from subsequent coats of rim cement; similarly, Vittoria tires with a lot of latex on them do better than any standard tubular without latex (such as Contis).

Third, rim cement composition is important. There was a time when rim cements were fully organic based and pretty hard on base tape adhesion, and when base tape latexes were pretty weak. Both had to be improved, the rim cements because in Europe the organic fumes were prohibited and the base tapes because of all the bad press. Now, as far as we can tell, there's no difference in base tape reliability between Conti and Mastik One rim cements. There is still a meaningful difference in strength for Mastik One over Conti, which is accentuated with carbon rims. (We're currently trying out the so-called Carbon Rim Cement from Conti; so far we can say that it smells different but doesn't glue any better but we're working on it.)

Next we get into the observation that the base tapes don't peel off immediately, but only after use. Well, here are a few somewhat anecdotal observations that we're trying to quantify. First, if you stretch your tire unevenly in mounting it, you are more likely to pull a base tape loose (no surprise). This may explain much of why some people have base tape problems, others don't.

Second, strength of gluing makes a difference, but not what you'd expect -- if you glue your tires on really tight, the base tape is less likely to separate. This seemed odd at first but may reflect the fact that if your tire gets to rock back and forth more, it'll gradually work the base tape loose. Remember that the latex adhesion is one that (unlike rim cement) once it separates, it's gone for good. It doesn't heal itself.

Third, if you let your tires deflate entirely (whether sitting on the floor or hanging), you increase the risk of base tape separation. Keep them inflated 50-80 psi.

Fourth, water exposure increases base tape separation. Duh. Latex isn't completely waterproof and the water interferes with the bonding (as it does with rim cements these days too, by the way). Race in the rain, let everything dry out quickly and carefully. And avoid powerwashing when you wash your bike off. Likewise, soaps increase base tape separation. Again, duh.

We also saw plenty of unexplained base tape separations on all the wheels we've been examining, but what we've included here is just what we've been able to see a pattern in so far. To the OP, short version is that you probably did something at some point to promote base tape separation (even though they simply shouldn't separate, period). Old Contis used to have a big problem with base tape separation with old stye rim cements, but that problem is pretty much gone. In the end my advice is akin to my advice on considering tubulars in the first place (if you tend to puncture clinchers a lot, think twice) -- if you have problems with Contis, just chalk it up to your personal learning curve and stick with some of the other tires. There are lots of good alternatives available these days, thank god. Pick one that works for you.
 

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1) Only use Conti glue with Conti tires.

2) Buy some "Barge Cement" at your local hardware store and reglue the tape to the tire. (google "barge cement" to check it out.
 

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Discussion Starter · #5 ·
Thanks for the info 11.4 I'll stop by the shop and see if they think it's worth having conti send me a new one(worth a chance) otherwise I'll just mail it down to TireAlert. Didn't realize a new base tape was only a few dollars.

I stretch my tires before gluing(Can you over stretch them?) Use Mastik 1(although I used to use conti, can't remember which I used for this set originally), and always keep them inflated when not in use--these hold air for a really long time too. If it happen to both then I wouldn't be surpised it was user error, but I've glued 10 or so sets of wheels, and since the first set of cross wheels, havent had a failure since.

What I thought was interesting, and I didnt notice it when I bought the tires, was the tape isnt sewn onto the casing, but simply glued on. I would think that this would be another possible area to fail/roll a tire.
 

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cantdog said:
Thanks for the info 11.4 I'll stop by the shop and see if they think it's worth having conti send me a new one(worth a chance) otherwise I'll just mail it down to TireAlert. Didn't realize a new base tape was only a few dollars.

I stretch my tires before gluing(Can you over stretch them?) Use Mastik 1(although I used to use conti, can't remember which I used for this set originally), and always keep them inflated when not in use--these hold air for a really long time too. If it happen to both then I wouldn't be surpised it was user error, but I've glued 10 or so sets of wheels, and since the first set of cross wheels, havent had a failure since.

What I thought was interesting, and I didnt notice it when I bought the tires, was the tape isnt sewn onto the casing, but simply glued on. I would think that this would be another possible area to fail/roll a tire.
Note that since your base tape came off, the remaining latex on the casing is probably bad. Just gluing a new base tape on doesn't work as well as the original. We've seen lots of base tapes reglued and they rarely work as well. To the comment above, Barge Cement does a pretty good job of reattaching base tapes before a failure (i.e., when fixing a flat) but after the base tape has separated it hasn't worked as well. The solvents in Barge Cement aren't that good for the other latex components in the tire, however. To do the best job possible, just be sure to apply a THIN coat to each side, let it mostly dry, then reattach the base tape, mount the tire on a rim, and pump up hard overnight. Barge Cement is what's often used to glue hiking boot soles back onto hiking boots with, and felt soles onto flyfishing wading shoes, and the like. It sticks most anything quite well, but the solvents aren't the best around tires; just plan to use it carefully and with some discretion.

As for the base tape not being sewn on, the only time I have EVER seen a sewn-on base tape was on some Belgian steyr tires for motorpaced track racing. And those guys, after gluing the tire on to a fare-thee-well, then wrap tire and rim with strips of silk and coat it in shellac -- they want to be absolutely certain nothing comes off. I don't know of any commercially made or even custom made tubulars available today with stitching on the base tape. Don't know how they'd do it either, since they no longer have access inside the tubular at the point the tape is attached.
 

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Discussion Starter · #7 ·
I just took a peak at some challenge cross tires I have unmounted in the basement and they have a small stitch running down the center all the way down the tire. Do you know what that's for?
 

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cantdog said:
I was checking my competition tubulars before Jefferson Cup and noticed with the tire deflated, that while in most spots on one tire, the rim/tire adhesion was great, but in others, the tire could be easily separated from the basetape. I was really irritated(didn't race on them) and put them aside to get another wheelset ready.


This morning I went to investigate more and sure enough, long sections of the base tape had separated from the tire. The tape meanwhile was incredibly well attached and a bear to get off.

I have kept this wheelset in a dark humidity controlled basement when not in use, and it only gets used for races or 'A' rides. Also, I've reglued it, not because it necessarily needed it, but just to be safe(I reglue all my tires each year).

So, the question is, is this an expected failure? The front tire is fine and no signs of the tape coming off. Should I try and get Continental to warranty the tire, or send it to TireAlert to get another basetape put on? They still have many many miles on them and I would hate to simply throw them away. Right now, I'm a bit dissapointed with Continental--I've run lots of tubulars from Challenge(cross and road), Vittoria(road) and have yet to have such a severe separation. What gives?
I had the same issues on some Conti Comps I bought a couple of months ago. I had these tires mounted in a rim to stretch and noticed the base tape separating.So, no glue had even been applied to them.Happened in those and also a couple of my teammates have had it happen(albeit on already glued and mounted wheels) on both Conti Comps and Sprinters.
 

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cantdog said:
I just took a peak at some challenge cross tires I have unmounted in the basement and they have a small stitch running down the center all the way down the tire. Do you know what that's for?
That positions the base tape so it's automatically centered when they glue it down. They sew it simultaneously with the protective fabric tape inside the stitching. But don't count on the stitching to hold the tire on. Or to hold the sides of the tape to the tire.
 
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