‘Gluing’ cyclocross tubulars with Carogna
A month ago, I installed new Clement PDX ’cross tires to Bontrager Aeolus 5 rims (27 mm external width) using the Carogna tape M. I had used a different roll of the same width tape to secure a road tire to these rims, and I raced on them all summer.
When I removed that road tire to get the wheels ready for ’cross, the old tape pulled off the carbon rim and left only a slight sheen of residue behind. When I installed the ’cross tires, after pushing the tape down into the rim channel, the edges of the Carogna seemed flush with the very top of the internal edges of the rim channel.
In horrible mud at Jingle ’Cross, the rear tire rolled off the rim on an off-camber section of the course. The Carogna stayed affixed to the rim; the cotton base-tape stayed on the tire and simply detached from the Carogna.
I’d like to keep using this new tire, so I’ll peel the Carogna tape off the rim and reapply a new roll, but do you have any tips to keep this occurrence from happening again? There was very little tape residue sticking out between the glued tire and the rim, but should I align the tape flush with one side of the rim and cut off the tiny excess on the other side? Should I clean the base tape on the tire or otherwise prepare it for re-installation somehow?
FWIW, I weigh about 200 pounds, and I was running 32 psi in the rear tire.
This is right up my alley, as I have exclusively mounted ’cross tubulars with Carogna the past couple of years. After so many years of gluing them with a combination of Vittoria Mastik One and Belgian Tape, I have relished a much quicker, cleaner method that also will peel away from the tire so that the tire can be reused after removal. Achieving similar results with Carogna, especially in muddy conditions, requires extra steps.
Cyclocross tubulars present a unique gluing challenge due to:
1. The rim bed generally has a 12mm (or so) radius of curvature to mate to a 23mm (or so) tire, meaning that a 33mm cyclocross tubular will be touching only the edges of the rim bed, leaving a gap under the center.
2. Low tire pressure does little to hold it on. Pumping a road tubular to 130psi holds it onto the rim so well that a poor gluing job will still be sufficient to keep it from rolling off, but that is not true with the weak inward pressure provided by a cyclocross tubular at 30psi.
3. The leverage the ground applies on a 33mm-tall cyclocross tire when cornering is much higher than on a low, 23mm road tubular.
Your 27mm-wide rim is ideal; the deeper, wider rim bed provides more security for the tire. And with that wide rim, I assume you have disc brakes, which, unlike rim brakes, do not constantly push mud into the tire/rim interface. But you have to do more for muddy races.
I do believe that there is no more secure way to attach cyclocross tubulars than with the Mastik-One-and-Belgian-Tape method. I think it is because the tape’s woven fabric acts like the rebar in reinforced concrete, holding all of the cement together, and it also wrinkles and creeps toward the center, filling the space that is the mismatch between the rim curvature and the tire curvature. However, it is extremely time-consuming and messy to do (both upon installation and removal), and it can damage tires and rims upon removal.
And while one’s time is expensive, a higher cost of this method can be during tire removal, which generally results in ruining the tire and can also ruin the rim. The tire can’t be reused because torn chunks of tape will be left so firmly bonded to it that they essentially will not come off without using a solvent that could then compromise the adhesion of the base tape to the tire. As for the rim, on many occasions, I have torn patches of carbon fibers off of the rim bed of expensive carbon wheels when pulling off a tire that I had glued on with Mastik One and Belgian Tape. Since the carbon fibers tend to break off at the top edges of the rim, only the rim bed may be damaged, but sometimes a chunk of carbon gets torn off of the brake track, and this definitely affects performance with rim brakes. Also, even if you peel off any other fibers that seem loose, after sections of fibers have lifted off of the rim bed, there still may be some that are partially detached from underlying layers, so the next tire could roll off due to chunks of the rim tearing off.
Once the tire is off, Carogna Remover makes light work of cleaning the rim. After letting it stand overnight on the rim, you can easily scrape the chunks of Belgian tape off. After another coat, you can wipe any glue off with a rag. It has no fumes, unlike the pounding the lungs get cleaning rims with acetone or VM & P Naphtha.
The beauty of Carogna (though it means “carrion” in Italian) tape is that it is quick and easy and clean to apply, and the tire and rim can both be easily reused after removal. In dry conditions (which is all we’ve had in Boulder races this season other than on November 19), my tires are held on super well to 27mm-wide Zipp rims and 26mm-wide ENVE rims. Our tech editor, Dan Cavallari, was amazed at how hard it was to peel a worn-out Challenge Chicane off of one of them when I challenged him to try.
The standard steps to ensure good adhesion between Carogna and cyclocross tires are here. I recommend taking particular care to:
1. Clean the rim and the tire’s base tape with isopropyl alcohol. The rim should be completely clean and smooth; use Carogna remover to get any old glue off.
2. Don’t sand the rim. Although adhesion on the rim-side is normally not an issue, the rim side of Carogna tape requires maximal surface area of contact.
3. Use the correct width of Carogna tape (your M-25mm is correct for your 27mm-wide rims), or trim the excess width with a sharp knife before installing the tire. Exposed tape attracts dirt.
4. Make sure the rim and tire and tape are warm. Effetto Mariposa says that the ideal thermal range for Carogna application is 21°C to 38°C (70 to 100°F), allowing eight hours to reach 80% of the adhesive strength. I keep wheels with newly-taped tires warm for a week in front of the heater or out in the sun on warm days. If it’s too cold, the glue can’t develop the permanent bonds it’s supposed to. Once adhered, you can ride it at low temperatures (Effetto Mariposa says down to -40°C [= -40°F] is not a problem); I’ve ridden tires down to -5°F that are still solidly attached to the rims.
5. Inflate the tire to 60psi to cure. The 2mm-thick glue on the tire side of Carogna is pressure-activated. With sufficient heat and pressure, it will not only bond but will also flow to fill in gaps. Once adhered, riding pressure can be low (I’ve ridden mine as low as 15psi), but it’s important to keep CX tubulars inflated at their max pressure (in a warm place) for a couple of days after installation.
The parameter most difficult to control is the “readiness” of the tubular base tape to accept adhesion. Different base tapes, different coatings, traces of lube, and grease from your fingers all affect the glue bond. Effetto Mariposa suggests cleaning the base tape with isopropyl alcohol or mineral spirits, solvents which leave no dry residue and are effective at removing oils but are not aggressive enough to dissolve the glue holding the base tape onto the tire. My method of scraping any coated base tape works as well with Carogna as it does with Mastik.
While climate change is likely to result in generally drier American cyclocross racing conditions, Boulder scientists yesterday indicated that we could see occasional conditions far muddier than we’re used to. It’s not hard to keep a ’cross tire on with Carogna in dry conditions, but it is a real challenge in wet conditions. I believe this is due to mud getting in between the Carogna tape and the tire’s base tape, and due to the cotton base tape absorbing water and disrupting its bond to the Carogna tape. I’m experimenting with applying a coat of Mastik One on the base tape and letting it dry overnight before taping it to the rim with Carogna. This weekend’s Colorado state CX championships seem to promise mud, and I’m gluing two sets of all-cotton Challenge Limus Team Edition tubulars to 20mm-wide rims for rim-brake bikes. I’m taping one set without and the other with Mastik on the base tape first. The Mastik One coat is a better bonding surface than bare cotton, and it seals water from seeping through the base tape to the Carogna. To that end, in January Effetto Mariposa will introduce a primer called “Eau de Carogna” for application on the tubular base tape before Carogna taping.
I recommend checking the tire’s bond before racing on it. Near the valve stem (to least affect overall tire adhesion), try to peel up the edge of the fully deflated tire. It should be very hard to get the edge to release. If the adhesion doesn’t seem good enough, try restoring 60psi in the tubular and keeping it in a warm environment for a longer time. That can fix it; Carogna requires heat and pressure to flow and stick.
On a tactical note, you didn’t say what you did after rolling your tire, but most people run the entire way back to the pit. As long as you stop when it pops off before you tear the valve stem off, you can push the tire back on and ride on it (with care on the turns) to the pit a lot faster than you could run there. In experimenting with lots of methods to hold ‘cross tires on a decade ago, I have a bunch of experience with rolling tires in races! I tried many varieties of glue alone and rolled some tires. I tried Mastik One combined with either Tufo tape or combined with Velox Jantex tape, and I rolled tires off of both. Despite what Jensen says here about using Jantex tape in tandem with tubular glue, I highly recommend against using either of these tapes with glue. I describe what happens with the glue and Tufo tape far down the page here — BTW, I no longer recommend sealant in tubulars unless you are riding in thorn-prone areas, or re-gluing a ’cross tire at the beginning of the following season (if it is held on well, just replace it when the sidewall is shot; the sidewalls on top-tier cyclocross tires raced at low pressure, especially in the mud, will last a disappointingly short time!).