Slack angles on touring bikes require moving the seat forward to get the same net position relative to the crank axle. In other words, only the seat lug moves back to net a longer top tube, the saddle stays fixed relative to the bars. For example, going from 74 to 72 degrees: sine 2 degrees X 57 cm = 2 cm longer top tube.
Old track bikes might have have a 68 degree seat angle so they flipped the clamp around or used a post with a forward extension to dramatically move the seat forward.
Joe Bender-Zanoni
Great Notch NJ
> At 4:13 PM -0400 9/15/02, Stephen Barner wrote:
> >Personally, I don't see why riding position should change
> >significantly between performance
> >riding and touring. I can understand different bends in the handlebars,
> >front end geometry, chainstay length and wheelbase, but the rider's body
> >doesn't change.
>
> I can't speak for Schwinn in specific, but I can make some leaps of
> logic in reference to why they have longer TTs. First is the desire
> for a longer wheelbase without lengthening the chainstays too much, a
> little longer in both places and you get the really long wheelbase
> folks seem to like on touring bikes. Also many touring bikes has
> slacker ST angles thus making the TT and CS' longer . A bigger factor
> I think has to do with the use of shorter stems on touring bikes
> compared to racing bikes. I remember a fear of using handlebar bags
> on long stems. By making the TT 1' longer you can get the same bar
> position using a 95mm as you would on the shorter TT with a 120mm
> stem.
>
> This is just speculation, but it makes sense from what I've seen in
> touring designs. I'm sure Tony Oliver's "Touring bikes" would have
> something to say on the subject of longer TT touring bikes. Alas
> it's not one of the books I own. If anybody has a copy that they
> don't need and would like to sell or trade for a reasonable amount
> drop me a line.
> enjoy,
> Brandon"monkeyman"Ives
> SB, CA
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