On 01/25/2011 11:08 AM, verktyg wrote:
> I can't speak for all makes of bikes or those built after the late 70s
> but there was a tendency for European production models to all use the
> same wheelbase length within a brand.
>
> This resulted in the smallest frames having a steep seat tube and
> relaxed head tube which produced bikes that handled like a wheelbarrow.
>
> At the other extreme, the largest frame usually had the opposite, a
> relaxed seat tube angle and a steep head tube. This resulted in the
> riders weight being concentrated over the rear axle (with the seat up
> high) and either sluggish or twitchy handling if the fork rake wasn't
> adjusted to fit the frame size.
Another factor that may have contributed is the UCI regulations on "front center" (the distance between the center of the BB shell and the center of the front dropout).
We (Trek, that is) sponsored the US Women's National Team back in 1983-84, and built bikes for the team to use in competition. Among them were a number of track bikes used in the Nationals. These were designed and sized appropriately for the riders, some of whom were quite small (46-48cm frames). When the team took these bikes to the Worlds, UCI objected because the "front center" on the smaller frames was too short, so we had to scramble and build several new frames for the worlds (we had about a week's notice). IIRC, we had to use ~55cm top tubes on 48cm frames to satisfy UCI.
Perhaps now the regulations have been modified to take into account frame size and rider size. I hope so, at least.
--
-John Thompson (john@os2.dhs.org)
Appleton WI USA