Thursday, August 22, 2013

One Done

Ready to get started,
One set of the new tubular cyclocross race wheels that is, glued and ready to go. With the new Cannondale SuperX disc bikes that we got for the Bikeway Source/Bell lap Racing team this season came the need for some new wheels as well. For us the choice was simple, we once again went to Big Al at Bikeman for the Carver c38 carbon-fiber disc compatible tubular wheelset. For the money we personally could not beat them. Cathy and I both ran those wheels all last season and despite having to replace bearings at the end of the very muddy season, which is pretty normal for all sealed bearing wheels I have owned, we had no other issues. Sold.

Unfortunately the wheels have become popular enough that they had a limited number on hand when I finally got around to ordering them. That number was one, exactly one shy of the two that we actually needed for Cathy and I. Anyhow, Al sent me the one set that he had and I have a second pair on order that will hopefully show up this week. Regardless, we should be OK for now with what we have.

Belgian tape over the coat of glue (backing on still).
In terms of the glue up, I thought I would share my current favorite technique. I'm not saying that it is the end-all be-all or anything but it has worked pretty well for us. The first thing that I want to stress in gluing tires is that you have to use a literal ton of cement on them. I'm talking gobs of the stuff such that when you mount the tires, it oozes out the edges. That translates to lots of smooth layers and then one final layer that is almost poured onto the rim surface to which you mount up the tacky tire, wet.

The way that I start the process is to clean and rough up the rim surface, especially with carbon-fiber rims. This starts with steel wool on the glue track to rough it up a little while not really abrade the rim surface. Then I hit the surface of the rims glue track with a quick swipe of lacquer thinner on a clean rag to remove any contaminants or dust. Let that evaporate or hit the surface with a clean dry rag before applying the first coat of cement. I personally prefer Mastic One but have had pretty good luck with the Continental carbon fiber specific cement as well. Either way, I use the big can of cement and a flux brush to apply it.

Half width Belgian tape with backing off.
After I coat the rims with a nice even and smooth layer, I move onto the tires for their first layer. You should make sure to coat all of the base-tape to help try and protect it from the elements, mainly mud, dirt and water. The first layer will soak in and almost completely disappear, however it will seal the tape and prepare you for a more visible second coat.

Before we move onto the second coat, lets discuss my new best friend, that being Belgian gluing tape. I personally Velox Jantex because it is easy to find. I like to use it a little differently than most though. The biggest benefit of the tape is obviously to help adhere the cement to the rim surface by giving base support and tying it all together, sort of like reinforcement mesh in concrete.

Glue, tape, glue.
There are also a couple of secondary benefits to the tape that I like. One of those is that it covers the spoke holes which gives more surface area to which to glue and for the tire to in turn adhere. It also helps build up the center channel which, for road specific narrower rims based on a 23c tire and not a 33c tire I'm putting on them, helps better match the inflated tire profile. To that extent, I also spend the time to cut the Jantex tape in half. It is a massive pain in the butt however it then uses half as much of the tape, still covers the spoke holes and only builds up the center of the rim channel.

Once the tape is set, apply it to the mostly set up initial layer of cement on the rims. When it is on the rim correctly, I like to burnish it down lightly so that it adheres to as much of the rim surface as possible. After that you can go ahead and start the process over again, adding the second even coat of cement to the rims and tires. By the time you get through all of that, depending on the conditions and how fast you are, the cement is probably tacky enough to move onto the third coat. That is usually enough for the tires assuming you put a nice thick even coat on but new rims will usually need another coat.

Finished product ready to mount up.
For the final coat I try and really lay a thick bead of cement into the center track. Smooth it out some but make sure that it is still extra thick in the center channel. Once you are done with the pair you can go ahead and mount a tire onto the first wheel that you glued up as that one will at least have started to tack up a bit. I'm not going to say anything about mounting as it is just a painful, miserable and messy job no matter how you approach it. Once the tires are on and centered correctly I roll them out on a small wooden dowel that closely matches the arc of the glue track. This helps bed the tire to the rim. I then throw a little air in them, spin them to make sure they are centered correctly and round and leave them to dry for a few days.

Sweet, a box just arrived from the wilds of Maine with the new second pair of new Carver wheels from Bikeman. Thanks Al!

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