Fork Trail (Fork Offset)
The product of the head tube angle and the fork rake is the ‘trail’. This is the measurement that gives us the best indication of how fast a bike will steer. It’s a measurement not often provided by bike manufacturers despite being the most important steering speed information for the handling of the front end.
Less trail equates to faster steering. Making a bike feel more nimble like it’s steered ‘with your hands’.
More trail equates to slower steering. Making a bike feel more stable like it’s steered ‘with your hips’ (leaning).
Touring bikes have a lot of ‘trail’ to slow steering response and keep heavy loads stable on fast descents. On the other hand, high trail bikes experience more ‘wheel flop’ making it harder to keep a straight line at slower speeds (although front panniers tend to dampen this feeling).
In an ideal world, a bike designed to use a wide handlebar (flat, riser, alt bars) will benefit from more ‘trail’ than a bike using road handlebars. This is because wide bars provide greater steering leverage and therefore require less steering input when turning.
Trail Comparison for 57cm Bikes:
Touring bikes 55-70mm trail
Road bikes 50-60mm trail
CX 55-65mm trail
Steering Summary
A touring bike’s geometry is optimised so that it’s stable carrying front and rear loads. This is evident through the slacker head angles and higher ‘trail’ than both road and cyclocross bikes.
Road bike steering is tuned to be fast with its low trail geometry. This makes sense in a racing situation where you may need to change direction in a split second. On the other hand, cyclocross bike geometry tends to fall somewhere between that of a road and touring bike.
Some randonneur, bikepacking or light touring bikes are designed with less trail than even a road race bike (sub-40mm). The idea is that a quicker steering speed is offset by the heavier steering input of a front load. On a bike with road handlebars using a sub-10kg (22lbs) front load, I tend to really like this design approach. However, I’ve found that low trail bikes ride a bit strange without any front load. They can also be a little harder to handle with heavy front panniers at higher speeds too.