I removed road tubulars and installed tubular cyclocross tires on my cross bike this weekend and I wanted to take the opportunity to document my process - maybe it will help others who are new to tubulars. The process is the same for both road and cross tires.
Gluing tubular tires is an art and not an exact science but understanding how the tire stays on the rim will go a long way in helping you to safely and efficiently mount tires. The majority of the holding power comes from adhesion on the outer edge of the rim. In addition, an inflated tire will shrink inward towards the hub so proper inflation is critical to ensure you do not roll the tire off the rim.
First the tire must be stretched for ease of mounting. Start with your feet around the valve stem and work your way around the entire circumference. Don't pull too hard but some force is required. If you hear snapping, then you've gone much too far.
A clean, well ventilated environment is critical. If there is dirt and dust around, it will get on the rim or tire. Tubular glue is a contact cement and the solvent will evaporate and kill brain cells and get you high in a bad way.
Use latex gloves. Use only plastic tire levers on carbon rims. Flathead screwdriver are suggested by some for alloy rims, but I only use plastic levers because tires are expensive and I want to be able to preserve the base tape when removing a used tire.
Inflate the new tire tire to 7 psi to give it shape and hold in the following manner. Apply glue in thin strips working on one section at a time. It's better to do few thin layers than one fat layer. Similarly, it better to do one section at a time so the glue will be easier to spread. I use 1/2 a tube of Vittoria Mastik per tire.
Use an old toothbrush to spread the glue evenly on the basetape. Make sure it's consistent and not too thick. This will take time to do it properly. Avoid getting the glue on the sidewall. If you do, don't try to get it off. It's better to let it dry into place.
Here is a comparison of a glued and unglued basetape. The glued one shown will receive another thin layer once it dries in about 30 minutes. If you layer too thickly, it will take hours to dry. Some glues like Panaracer dries over 24 hours. Vittoria Mastik, which I used, dries 30 minutes or so. Continental glue dries somewhere in between the two. Vittoria Mastik is the hardest setting glue with the fastest drying time - this is great if you've had practice but it it difficult to work with because it requires precision and speed.
While the newly glued tires are drying, remove the old tires. Use a tire lever to pry a small hole between the rim and basetape and slowly work your way until you expose about 12" of tire. This will take substantial elbow grease if you've done a good job of gluing the first time.
Once you get a about 12" of exposed basetape, use your hands to pull the tire off the side. Be careful to keep the basetape attached to the tire.
The rim should have a thin coat of glue from the prior application. Do not remove this unless you used too much glue the last time and you ended up with big globs. The old glue will still be sticky.
Here is how the removed tire should look. Note that glue was applied the outer edge of the basetape. This is ideal.
Repeat the process of gluing for the rim. Spread thinly (I do 3 thin coats) and focus on applying glue to the outer most edge of the rim. This is of paramount importance. I use 1/2 tube of glue per rim. Again I used 1/2 tube of glue per tire, so this works out to 2 tubes per bike.
Once both the rims and tires are dry - the duration of drying will depend on the type of glue you use, humidity and temperature and thickness of coats - you are ready to mount the tire.
Insert the valve and grab each side around the valve. Pull down hard and work your way to the final few inches on the opposing side of the valve. If you skip this step it will be very difficult, if not impossible, to get the final few inches of the tire over the rim due to the tire's tendency to shrink in.
Once you are ready to pop the final few inches over the rim, tuck the valve side into your gut and use your thumbs to force the tire over the rim lip. This will be difficult and require force.
Quickly align and center the tire on the rim using the basetape as a reference point. It should be a consistent width throughout the tire. It's very important to work quickly here because tubular glue is a contact cement and it will get progressively more difficult to move the tire once mounted.
Then, inflate to a low psi - say, 30 psi - and realign and check again by spinning the wheel while holding the skewers. The first alignment is a major alignment; the alignment while inflated should be fine tuning. Some cheap tubular tires aren't necessarily round or aligned laterally to start with so take note and buy decent tires. Pump to max psi and roll the tire on the ground with all your weight to set the adhesive bond. Let the tire dry on the rim for at least a few hours before riding.
I think this a fantastic set of instructions, and the pictures help a lot!
I also think the pre-stretching step should be approached carefully, if done at all. I have stressed older tires when stretching them. When I don't stretch a tire, I can get it on the rim if I "stretch down" tightly when installing the glued tire.
The only thing I would add is I prefer to stretch new tires by putting on the rims unglued, inflating them to full pressure and leaving like that for a day or two. It streches the tires well without accidently tearing the casing.
I thought disc brakes were illegal for cyclocross races...or do they not really enforce that?
Forbidden in UCI-sanctioned races. Unless your racing calendar includes the pro division at one of these events, you are fine using disc brakes.
There is a similar UCI rule which requires drop (i.e. road) handlebars. As far as I can tell, the only reason for these rules is to preserve the "look and feel" of traditional cyclocross. It has nothing to do with safety or any other rational reason.
shortly after the tire has been mounted you should uninflate it and then roll the wheel over a round broom handle to ensure ultimate contact.
you focus a lot on gluing the edge of the rim which is very very important but its also worth noting that you need to build up the center channel of the rim with glue so that the tire will hold well on the entire rim. If this isnt done well and just a tiny bit of glue on the edge breaks down water can start creeping in and compromise the entire job.
My first time gluing tubulars I used WAY too much glue.
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i just finished putting the first coat on a cross tubular a few minutes before posting that. I am about to run out the hardware store for some other stuff to finish the job.
Another tip is to use some masking tape on the rim braking surface to make clean up A LOT easier. I also buy the can of mastik 1 and apply the glue using acid brushes.
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last night i had to remove a really well glued tire i had only mounted a little over a month ago. It took forever to get a bit of the tire pried up. I eventually got a long thin screw driver and pried up just enough to slide the screw driver all the way through. Once I got that far I just rocked and rolled the screwdriver back and forth along the entire rim, removing the tire.
My blog (Newest entry: 5.18.10 "Who's responsible for your online privacy?") "When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works." ΛΧΑ ΔΞ179 - 15% off your first Hammer Nutrition order!
shortly after the tire has been mounted you should uninflate it and then roll the wheel over a round broom handle to ensure ultimate contact.
you focus a lot on gluing the edge of the rim which is very very important but its also worth noting that you need to build up the center channel of the rim with glue so that the tire will hold well on the entire rim. If this isnt done well and just a tiny bit of glue on the edge breaks down water can start creeping in and compromise the entire job.
Interesting, I have not heard of that method. I'll have to try that but since this DIY was intended to be a primer, I wanted to especially emphasize the importance of gluing the edge since the vast majority of the adhesion comes from this area.
Originally Posted by bdcheung
I used painters tape on the braking surface
I use to do this. If the tire is properly stretched (without glue, I also mount fully inflated tires for a week on spare wheels in addition to stretching) and the glue is sufficiently dried, then you should not need to do this. The glue should be dry to the touch and only slightly sticky so if it is smearing on the rim, it isn't dry enough.
Originally Posted by flargle
That's too nice a sweater to be wearing while mounting tires.
I would have agreed with you on my first glue job. It's definitely something that becomes cleaner and cleaner with practice.
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Originally Posted by eb314
