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Top Document: Rec.Bicycles Frequently Asked Questions Posting Part 3/5 Previous Document: 8b.20 Gluing Sew-up Tires Next Document: 8b.22 Folding a Tubular Tire See reader questions & answers on this topic! - Help others by sharing your knowledge Date: Wed, 06 May 1998 21:49:53 CDT I have been racing for 6 years now and have tried multiple tire/rim combinations. I have come to the conclusion that good tubular tires on a pair of good carbon fiber rims provide the ultimate ride. But many people dislike tubular tires because of the gluing process and the possibility of rolling the tire during fast cornering. I decided to write this article because of the three to four racers who rolled a tire at the recent Baylor/Mirage sponsored criterium. Rolling a tire at anytime during race can be catastrophic. Everyone has their "best" way of gluing a tire. I can assure you, this is by far the best and SAFEST way to glue a tire to prevent it from rolling during any type of cornering at any speed. I took this process out of Cycling USA last year and now follow it religiously when gluing my own tires. This gluing process was far superior to the manufacturers recommended process in regards to bond strength at tire/rim interface. We will briefly discuss the following; 1) The glue 2) Mounting tubulars to new rims 3) Mounting tubulars to used rims. Not all glues are the same. Especially in Texas! The temperature outside may be 90 to 100 degrees, but the surface you are racing on may be 150 to 160 degrees. You definitely want a glue that sets up hard in hot weather. If not, as the temperature increases the glue/bond gets softer/weaker and chances of roll off and serious injury increase. The article listed seven glues in this order of strongest to weakest tire/rim bond; Vittoria Mastik' One, Continental, Wolbar, SM Fast Track, Vittoria Gutta, Pana Cement and Clement. I prefer clear glues. That way if you screw up its very difficult to tell. With colored glues, if you screw up everyone knows. Also for your information I use Pana Cement. It does not provide the strongest bond, but it sets up perfectly in all extremes of hot weather and it takes one hell of a finger bleeding effort to get the tire off the rim. Gluing tubulars to new rims properly should take about 84 hours. Here's the process. Test mount the tubular to a dry rim, inflate to 100 psi and allow to sit 24 hours. This stretches the tire which will make mounting easier and also allow you to inspect the tube and tire for defects (most "good" tubulars are hand made). After 24 hours remove the tire. Clean the rim with acetone, lacquer thinner or alcohol only. Other types of cleaners may leave a film on the rim that cannot be seen by the eye and will decrease tire/rim bond strength. Composite rim owners should contact the manufacturer for recommended solvents. Roughing the rim surface will not improve the bond strength. Gently scrap the base tape on the tire with a straight edge to remove any latex. If you scrap a one inch section and the appearance of the base tape does not change, then you probably have no latex on the base tape and can stop scrapping. But be sure to visually inspect the entire base tape just to be sure. Inflate your tire off the rim until the base tape rolls outward. Apply a uniform layer of glue over the entire base tape area. It is best to do several tires at this time. You can store those tires not used and anticipate that the adhesive bond will remain strong as long as the tire surface is kept clean. Apply a uniform layer of glue across the entire width of the tire rim gluing surface. The principle bond is at the rim edge; therefore, it is critical for performance to ensure that the glue reaches the edges of the rim. Allow both to dry for 24 hours. Apply an additional coat after that 24 hour period and allow that 2nd coat to dry for 12 hours. Apply a third coat. This is the mounting coat. With Pana Cement, once the third coat is applied to the tire and rim mount the tire immediately. (One tip I would suggest here is before putting glue on the rim is to put black electrical tape on the entire outside edge and breaking surfaces. This makes for very easy cleaning after the tire is put on. Just peal the tape away and all excess glue comes with it and leaves behind a nice, clean breaking surface). Place the rim vertically on a clean, smooth surface with the valve hole at the top of the rim. Place the valve stem through the hole and ensure that it is properly aligned-straight through the hole (Another tip…For those with deep dish rims requiring valve extenders, place a small amount of loctite on the tube valve stem threads and then screw the valve extender on. This will prevent any leaking at that junction once the tire is glued on). Grab the tire 8" away from the valve stem in both directions, pull outward with a mighty heave and place the section of tire between your hands on the rim. Slide your hands down another few inches down the tire, pull and install this section. Once a full 180 degree section of the tire has been mounted, turn the wheel over and place the valve stem section down vertically on the ground. This is the point where I have my wife hold the section of tire I had just put on the rim with two hands at 0 and 180 degrees. I then grab the tire at the top and turn it so the base tape is facing up. At this point I pull up on the tire and roll it onto the top of the rim. It's actually very easy with two people. Once the tire is on the rim, it must be aligned. Inflate the tire to about 50 psi so it can be easily "turned" to align. You can either align the tire by the tread or by the base tape. Here, I prefer to align my tires by the base tape. Higher quality tubulars treads will align properly. Lower quality tires were not necessarily made straight, so perfect alignment may not be possible. Once aligned, inflate the tire to 100 psi and allow to dry for preferably for 24 hours. When gluing tubulars to used rims, do not remove the old tire until you are ready to begin the gluing process as the old tire keeps the rim surface clear of debris which would weaken the new tire joint. You must find a weak point in the joint and begin removing the old tire. On my Zipp 440's, I use a tire lever so I do not damage the rim surface. On aluminum rims you can use a flat head screw driver to make it easier. You may glue a new tire over the old glue on the rim unless it is not contaminated or old, if there is too much glue on the rim or if the remaining glue covers the rim only in spots. If one of these conditions applies to your rim, remove the old glue with heavy duty furniture stripper. Apply the stripper according to the manufactures recommendations. I always put the stripper on and let it sit for 30 to 45 minutes and the old glue then wipes away like butter. DO NOT wipe the glue along the rim. This causes the old glue and stripper to be pushed down into the nipple holes. Wipe across the rim in small sections. Once the rim is free of glue, begin the process as described above in the article. If you leave the old glue on the rim, apply at least one additional coat before installing the tire. To the tire, apply at least one coat and let it dry for 24 hours before putting on the mounting coat. In concluding, let me state once again everyone has their "best" way to mount tubulars. I can honestly say I have mounted and raced on tubulars put on in 24 hours. Those instances are far and few between though. I always make a 100% effort to follow the procedure written above if all possible. 84 hours seems like a long time to wait just to mount a stupid tire. It all comes down to how much you value safety. When it comes to the safety of the other riders, not to mention the consequences of roll off to my wife and my job, I want to be damn sure I'm as safe as I can possibly be because I took the time to do things right! User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: Rec.Bicycles Frequently Asked Questions Posting Part 3/5 Previous Document: 8b.20 Gluing Sew-up Tires Next Document: 8b.22 Folding a Tubular Tire Part1 - Part2 - Part3 - Part4 - Part5 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: iglesias@draco.acs.uci.edu (Mike Iglesias)
Last Update August 08 2012 @ 06:18 AM
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