bigjim wrote:...........
We don't seem to have progressed that far in bike design when modern Tourers are as heavy or heavier than they were twenty or thirty years ago.
...............
What has changed in the last 20 or 30 years is that people are on average taller than they were, and heavier than they were....heavier on average, and heavier for a given height. The amount of stuff people want to take with them is also much greater....how often did you see front and rear panniers and barbags 30 years ago?
A heavy rider out of the saddle is much more likely to flex a frame enough for the F. mech. to rub than a light rider.
Shimmy is much more likely with a tall rider, as their weight (on the saddle) is higher up, its generally also more likely on a loaded bike than on the same bike unloaded.
It follows that modern tourers need to be stiffer than their predecessors.
Now titanium is less dense than steel, but its also less stiff to about the same extent. So you need more titanium to achieve the same stiffness as steel. The stiffness of a tube is influenced by diameter much more than by wall gauge, so for some frame applications, working in steel you are limited in how big you can make the tube before the wall becomes unfeasibly thin**, so its possible to make small savings in bike frame weight using titanium compared to steel by careful control of tube diameter and wall gauge.
Spa's tourer is designed for people who want to go camping or bridle-pathing.....the audax bike is good for credit card touring on the road.
**or the tube unfeasibly heavy!
