My two cents:
Seems to me, even with older, better-made tires (I'm thinking mostly the italian tires like Clement, Vittoria, Gommitalia; Hutchinsons seem to be extremely well-made and if well-glued, make few problems until the casings fail or the treads wear out), the problem with well-used tires that have been on rims for years does not seem to be that the glue holding them to the rim will fail, but that the base tape will fail. Over time, that latex adhesive dries out pretty badly. The recent Taiwan/indonesian Clements are terrible in this respect, but otherwise well-made.
I just test older tires by shoving them around with my thumbs very thoroughly to see if the base-tape or the rim/glue joint is failing. I won't discuss casing failures. Usually those are obvious before a tire blows up, or so has been my experience. I did pop a Clement silk many years ago, in the rain-storm, but I deserved it: riding silks in the rain is transcendentally stupid... ;>
I haven't rolled a tire yet, for whatever that's worth, and I've ridden tubies for nearly 30 years now. Either dumb luck, or the method works.
Your mileage will vary, of course.
Charles Andrews
nippy So. Cal.
> -----Original Message-----
> From: Larry Strung [mailto:strungl@pathcom.com]
> Sent: Tuesday, October 31, 2000 7:09 PM
> To: classicrendezvous@bikelist.org
> Subject: [Classicrendezvous] Tubular Tire Question
>
>
> Hi Gang,
>
> Here is one for the group to debate, as I'm sure opinions
> would be varied.
>
> How does one judge the safety of a tubular tire? I am
> thinking in terms of bikes we own that may be ridden only on
> occasion that have old tubulars on them. When does the glue
> dry out and the tires become a danger to rider (or followers)
> by potentially rolling off the rim? Some of my bikes only
> get exercise on special sunny days. Tubulars on such bikes
> may have been mounted 2 or 3 years ago. The tires are
> otherwise in fine shape, but what is the risk?
>
> It certainly would take away the spontaneity if the safe
> routine would be to re-glue the tires on these machines 24
> hours prior to riding. Then there is the additional problem
> (I've experienced with the Clement Paris-Roubaix tires made
> in the far east in particular) where the base tape can
> separate from the tire when removing it from the rim.
> Presumably that indicates that the tire was still adequately
> adhered to the rim, but by then it is too late.
>
> I have a vested interest in this discussion, as last summer I
> was taken down in a track bike race when the rider whose
> wheel I was following rolled a tub of his rear wheel. The
> resulting crash left me with a fractured hip. You may
> imagine that I am a little gun-shy regarding tubulars at the
> moment. I dearly love the ride of tubulars, and even like
> the ritual of mounting them. However, with the winter
> maintenance season upon us, my thoughts are towards
> converting some bikes from tubs to clinchers. Advice from
> the experts on our list would be appreciated.
>
> Best regards,
>
> Larry Strung