Tech FAQ: On plying off tubulars and re-gluing

Published January 31, 2012 06:05PM

Dear Lennard,
I have some Vittoria tubulars I had had glued on about a year ago. The edge of the front wheel tire on half of one side is coming a little unglued. Should I re-glue for the upcoming season? I paid a lot for these Open Corsa Evo tires. Will it damage them plying them off and re-gluing? Just trying to be safe.
— Craig

Dear Craig,
If it’s peeling as much along the edge as it looks in your photo, I’d peel it off and re-glue it. If you’re careful when you peel off the tire, you won’t damage it significantly, but if you’re not careful, you certainly can do so.

Push the tire off the rim in one section with your thumbs pushing up against one side. Yours is probably free enough that you can do it from just one side, but if you can’t get it up any further than the center of the rim, then work at it the same way at the same area from the other side until the entire underside is unstuck there. Avoid using tools, because if you use a tool to pry the tire away from the glue, you will tear the base tape at the least and will be more likely tear casing cords as well. The tire will always be lumpy in that area after such damage.

Peel the tire the rest of the way off of the rim by hand. If this seems impossible, you can CAREFULLY slip the shaft of a Phillips-head screwdriver under the tire where it is free of the rim. Then carefully roll it along the rim to separate the tire and rim as you go. When you’ve gone far enough that you can now get your hand under the tire and peel it the rest of the way off by hand, do that.
― Lennard

Dear Lennard,
Does old, used Belgian tape need to removed before installing a skinny road tire onto a relatively skinny rim (Mavic Cosmic Carbone Ultimate)? If it does, what is the best way to remove it, as it is stuck on there really well?
― Michael

Dear Michael,
If the tape is perfect and is stuck down perfectly, I suppose you don’t have to remove it. I always do remove it, though. My concern is that the tape may have lifted a bit in some spots when peeling the tire off and hence not be adhered well in some places anymore. I also believe that you have more rolling resistance due to hysteresis with that extra layer of tape in there. For cyclocross, it’s more important to keep the tire on than to worry about a minor difference in rolling resistance on what is usually a slow-rolling surface anyway, but tire adhesion is not such a problem with road tubulars as the high tire pressures for road riding and the better fit of the tire into the rim bed leads to vastly superior adhesion.

I’ve always managed to peel the Belgian tape off, although it often leaves chunks and sections of fibers here and there. Scrape those bits off, and if need be, use some acetone to get a smooth surface to glue to. I recommend using only glue for road tubulars and using Belgian tape and glue for cyclocross tubulars.
― Lennard

Dear Lennard,
I’m running a tubeless setup on my Ritchey Breakaway Cross and recently traveled with this tubeless set up for the first time. When I went to re-inflate the tires (you need to let the air out to get the wheels into the suitcase), the tires would not hold air because all the sealant had dried up. I had no sealant with me so I squirted water into the tire (by way of cracking the bead), and then inflated the tires. It worked! They held air as good as with sealant. The water must have diluted the latex. It turned out to be a great on-the-fly fix.
― Ted

Dear Ted,
Good trick. I have road tubeless tires on my travel bike with S&S couplers. I’m not sure if your Ritchey case is this way, but to fit it into the S&S case, the tires must be completely deflated. As long as I don’t break the bead (knock the bead off of the rim seat) during packing or travel, when I get to my destination, I can pump them easily with a mini pump, and they hold air great. I do have sealant in them (Caffelatex).

However, if I knock the bead off of the rim seat, I am in for a lot of hassle. I have only done this once on one tire in perhaps 100 flights with this bike with tubeless tires, and that was because I put a spare tire into the case atop the front wheel. When the case closed, that tire pushed the bead off of the rim on one side, and there was no way I could inflate it with a mini pump. I was at the Gran Fondo Whistler, and I put in a bit more sealant (which I travel with), and found somebody at the expo/bib pick-up with a high-volume pump that allowed me to seat my tire again.

With a cyclocross tire, there is no way to fit it into the S&S case without pushing the bead off of the rim and sometimes even removing the tire completely, since the case is just barely big enough to fit a rim with a deflated road tire on it. Removing the tire completely is definitely required to fit a 29er mountain bike wheel into an S&S case; the rim diameter is the same 700C as on road bikes, but the tire is way too thick to fit into the case while on the rim. So my recommendation is to use inner tubes instead when traveling with a compact case and a collapsible ’cross bike or 29er.
― Lennard

Dear Lennard,
I have a Kestrel Talon with a seatpost that keeps slipping. Carbon paste, even shimming haven’t solved the problem. The seller and manufacturer have not been helpful. (That’s what I get for buying online.)

I figure my only resort is gluing the post in. I can’t sell the frame in good conscience, and my position and contact points are sorted out.

What kind of glue, preferably non-water-soluble would hold the post still?
― John

Dear John,
I have never tried anything of the sort. I suppose I would try J-B Weld epoxy. I would give shimming it another go first, though…
― Lennard

Regarding the post last week about adaptors for press-in bottom brackets in carbon frames as well as my article on this subject in the 2012 Velo Buyers Guide, here are two letters, the second of which is a compilation of several letters from back-and-forth correspondence over a period of months with a single reader on that subject:

Dear Lennard,
From someone who has used Campy cranks on a newer Giant, the BB is 86.5 mm. The cups will creak as you pointed out, because the frame shell is aluminum inside. I found that a medium strength Loctite for press fit applications solved the problem, though it did stain the paint slightly where it dripped. The cups are removable still, but they won’t creak.
― Mike

Dear Lennard,
In June, I purchased a new 2011 Cervelo R3 built with Campy Record 11. I was a bit leery about the press fit bottom bracket, but everything I’d read about the bike was positive and a test ride sold me.

The bike has been a joy to ride. Three weeks ago I noticed a gap between the drive side cup and the BB shell. The mechanic at the shop I bought the bike from thought that the cups had not been completely pressed in as they do not work loose from peddling forces. They removed and reset the cups and away I went. Last Saturday, during a ride, the chain would no longer shift to the big ring. I looked down at the crank and there again was a gap between the drive side BB cup and the BB shell. I returned to the shop and they called Cervelo. The service manager at the shop said that Cervelo told him they recommend a “mounting compound,” essentially a semi-permanent Loctite-like material that “fills the voids (tiny pockets air seen in bare carbon BB shells),” when installing press fit BB cups in bare carbon BB shells.

My question to him was, if this is what Cervelo recommends, why didn’t they include this compound with the frameset? I did not get a clear answer there. In any event, they had to order the compound and we’ll see how it goes. I told them I’m willing to try this, but if it does not work, the frame must be replaced. The service manager at the shop said “They almost certainly will replace it.” The “almost” worries me a bit. The shop has been great and I believe they will do what’s right. They have been very accommodating.

The shop installed the cups using mounting compound and I let the bike sit for a week before riding it. The BB cup for the drive side still moved out after about 30 miles. It was a small amount, maybe only 2 mm, but a gap was clearly visible in the front part of the BB as viewed from above, but the rear portion stayed in, so only the front portion moved. The shop called Cervelo and they are replacing the frame and will install the Campy BB cups at the factory (well, not at the factory as that’s in China).

I suppose the adhesive issues doesn’t bother me as much as the sad truth that there is no agreed upon “standard” for bottom bracket specs for these newer frames. Seems as though it’s pretty common to hear of adhesives used in carbon construction. As to tolerances, I’m surprised that the BB shell can’t be prepped in a way similar to facing and chasing (yes, I know they are not metal and not threaded). As you state, manufacturers apparently don’t want to be bothered with this.

I finally received my replacement R3 (now a 2012 model) from Cervelo, complete with “factory” pre-installed Campy BBRight adaptor cups. So far, so good, nothing has moved. No creaks that I can discern, but there is sort of a funny drivetrain noise after I’ve ridden for a couple of hours. As a precaution, I replaced the chain and cassette after the new frame was built up. But, all in all, I really like the bike and hope that’s the end of the problem.
― David
Follow Lennard on Twitter

Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.