Dale et al, Please allow a voice from the dissenting school of rim glueing: "Less Is More" If any other folks have a constant 25+ years riding and changing sew-ups, they may know the value of this school of thought as well. Cheers- David Anderson Cut Bank MT
In a message dated 7/10/2002 1:56:08 PM EDT, kurtsj@mtco.com writes:
<< So I'm asking for advice and pointers
> for mounting new tubular tires on old rims. >>
I will go ahead and answer this... Normally you would want to re-use the glue if it was originally done well, but in this case I advise removing this glue as it is so old and unknown composition.. Lacquer thinner and many rags will do it, but it is a smelly and slimy job! Clean the rim afterwards with alcohol (denatured) to get rid of the residue... I have never scored or roughened the rim surface but I know this has been done by others, so it's up to you.
The tires usually need to be prestretched. Some do not, so the best way is to try them on the freshly cleaned rims before applying glue. If they are very tight, I stretch them by strongly but gently pulling and tugging them, using my hands and foot (with sock) on the carpeted floor. It is a little intuitive so just go slowly and see what you get .....After stretching they still should be a mildly snug fit on the rims....
I then put the wheel in a truing stand and apply 2 thin coats of cement. Allow a half an hour between coats. I personally like Wolber and Continental glue and dislike brown Clement, but to each his own... There are others to choose from as well. Fastack auto trim adhesive works and some folks like it, but it works maybe too well as it frequently pulls the base tape off the tires upon later removal.
I use a piece of plastic Saran wrap around my index finger and spread & even out the glue with my finger tip. Then just throw the plastic away afterwards. Be careful not to get glue in the spoke holes or to go over the outside edges of the rim. Some folks leave the section between the spokes exactly opposite the valve with no glue to aid later removal but I do not...
The tire should have one thin coat of glue applied, hopefully done in between the coats put on the rim. The trick to this is to inflate the tire just to the point that it turns inside out. Then with Saran wrap coated finger again, carefully smear on a coat not exceeding the area where the tire will contact the rim.
Mounting the tire.. (This is the place where mere Amateurs are separated from the Aces! Ha!) Start by inserting the valve firmly in its hole in the rim. IF the tire was on the loose side or well stretched, you can use the often-recommended "2 side progressive" method. In this method, you simultaneously work away from the valve putting BOTH sides on until you meet in the middle on the far side center. I rarely end up mounting a tire this way...
The easier way is to start mounting the tire on one side of the valve and, depending upon the tightness of fit, pulling the valve hard in that direction to compensate for the last pull in the other direction when you work all the way around the wheel. Pull up and away firmly as you work around the wheel back toward the valve. The last Umph should pull the valve straight.
In all cases, you should have let the glue set up long enough to not smear it all over the place and goo up the tires and rims. NOTHING is more amateur than glue slopped all over the tires sidewalls and rim! You also must pull UP and on when you place the tires on the rim, not slide them on...
Once you have the tire in place, you inflate it to maybe 50 PSI and then spin the wheel and sight along the tire from the front to see how it is positioned, if it is lumpy, twisted or off center.. If so (and it is likely) then you reduce the pressure and pull up and tug and wrestle the tire into some semblance of roundness and concentricity. Generally, good (expensive) tires go on pretty straight and true and conversely, cheap tires are always a bit lumpy and twisty!
On cheap tires, expect a little bump at the valve.. This usually squishes in after a ride or two. But if it's a bigger bump you may have to lift and pull away from the valve to stretch more tire out toward the opposite side.. Sewup tires are a bit like those "Chinese handcuffs"... those tubes that you put your fingers in and when you try to pull them apart they grab you... The tire can change it's "fatness" based upon how stretched it is at one point or another.
So if you are finally satisfied with the mounting, pump the tire up really hard, 120 PSI or so and spin it again.. If everything looks good, deflate to maybe 60 PSI and let sit until the next day before you ride it...