stephen fredette wrote:
>
> mesdames et messieurs
> o.k.; i now have a lovely pair of 28mm
> tubular tires. i'm new to this tubular
> business. were there rims made specifically
> for wider tires?
> yr obdt svt
> Stephen Fredette
> Hull, Massachusetts
My experience...
You need to find older sewup rims (older than the 1980s) to fit sewups as wide as 28mm. The issue is with the profile of the rim bed. Newer sewup rims have deeper rim beds (more concave, smaller radius) than older sewup rims which have shallower rim beds (less concave, larger radius). Obviously the larger radius of the rim bed on older rims is going to more closely match the larger radius of a 28mm tire.
The problem of using a 28mm tire on a later rim whose bed is deep (small radius) is that the center of the rim tape won't be pushing into the surface of the center of the rim bed; just the sides will contact. The rear tire will start to creep around the rim as you apply torque and the front tire will creep around the rim as you brake.
Two solutions: First, use the correct rim for the tire or second, use a Velox double sided glue strip designed to attach sewups without rim cement, but use rim cement to attach the strip to the rim bed and rim cement to glue the tire on. The strip will fill the gap between tire base tape and the rim bed and the tire won't creep.
Chuck Schmidt South Pasadena, Southern California
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