If "twitchiness" is important to you, the best indicator is the amount of trail.



Trail - the horizontal distance between the tire's contact patch and where the steering axis contacts the ground. Photo: road.cc

Trail takes some effort to calculate, and manufacturers usually don't report it directly, but these statements are true:

• Lower head tube angle = more trail
• More fork rake = more trail
• Larger wheel diameter = more trail
• Wider tire = (slightly) more trail

Some other things influence the steering, but they tend to be less significant than the trail.