If you were passed on gravel roads, you were passed on the straights or you were riding well below a TW's, and the other bikes', limits of traction.
"Conventional" wisdom on dirt tires is tall and skinny. This actually works quite well for competition bikes.
From a weight perspective, skinny tires are lighter. Lighter tires reduce unsprung weight, which makes controlling suspension movement much easier and allows faster acceleration. Therefore, to enjoy the benefits of skinny tires, treads and riding styles must be optimized. Such optimizations work well in competition, where maximum acceleration, braking, and cornering must be a balanced set of compromises in order to provide the best overall performance. For instance, a rider would be willing to give up a half second per lap of acceleration in order to gain one second per lap in braking, the net being lap times reduced by a half second.
On the other hand, most dualsport riders would give up acceleration and braking for comfort, something about which competition riders care not a wit. The entire balances of performance parameters of most trail riders and competition riders are very, very different. This simple fact is what most people don't understand. A great former *insert type of racing here* racer does not necessarily make a good trail riding buddy. Former racers tend to show up for trail rides with bikes prepped like race bikes with lights, and tend to ride like they are in a race. Consequently, former racers' bikes are not prepped for pleasant trail riding and pretty much suck at it, and the competition riding style often results in competition crashing style. Far from trackside EMTs, ambulances, and trailers to drag the wounded bike home. Not good.
Front tread patterns on competition tires are pretty much evenly spaced knobs laterally and longitudinally to provide a balanced potential for steering and braking.Usually, the cross-section profile of front tires is rounded to allow sufficient traction at all angles of lean. During acceleration, front tires really amount to nothing because in competition, the rear tire is chosen to provide sufficient traction to loft the front tire for maximum weight transfer to the rear for maximum rear traction for maximum acceleration.
Excess rear tire traction bogs the engine. Insufficient traction allows the engine to over-rev. Maximim thrust on most unpaved surfaces, especially the loamy soils generally used for racing, occurs with the tire turning 8-12 times faster than the actual speed. That is why a properly set up motocrosser is so quick out of the hole. Rear tires are designed with rows of knobs stretching the width of the tire, usually in a 4-5-4-5-4-5 pattern, to provide maximum straight-line traction for acceleration and braking with minimum weight. Ususally, the knobs along the edges are built up to provide a nearly flat tread surface for improved straight-line traction, not so they dig in on corners as commonly believed. In fact, the built up edges lift the major portion of the tread from the surface and function to reduce traction, making it easier to slide.
All this nuttiness actually works pretty well on race tracks because within just a few laps of the first practice session the spinning rear tires dig ruts through the corners and pile up slung soil on the outside of the ruts, creating what are called "berms." Berms are then used to steer the bike--approach at speed, intentionally lowside the bike at the prerfect location that it slides sideways into the berm, which compresses the suspension and forces the bike to a new direction. Skilled riders will often use the heavily loaded rear suspension to accelerate sufficiently to "pop a wheelie", which, with bike layed down practically flat, results in the bike aimed at the inside of the corner, a handy manuever when attempting to pass on the inside. There are dozens of such "tricks" that take advantage of the traction characterisitcs of tires with specific traction vectors.
Generally, there are no berms on gravel roads. Road graders wipe them out. Of course, there are often ruts that can be used as berms, if they aren't too deep, too narrow, and/or aim in the wrong direction. Most of the time, no ruts. Still, competition style suspensions and tires can make good time, by powersliding like a dirt track bike. Lots of fun, if you can do it. Consistently. Most riders think they are powersliding when what they are really doing is throttling up a little wheelspin for gits and shiggles by kicking the rear wheel out a little in a corner, but they are not powersliding through a corner crossed up like a dirttracker. Such riders are merely fooling themselves about the limits of their abilities, and there are lots of them. Such riders have a bad habit of ruining your ride by requiring you to assume responsibility for their emergency medical needs when (not usually if) they crash, as well for recovering their motorcycles.
Summary: Skinny tires have a place and serve a purpose--if your goal is speed and nothing else matters. Next question is, "What about trials bikes?" They do have skinny tires. Trials tire sizes are limited by rules. So are tread designs allowed in competitions sanctioned by major organizations. 2.75-21 front, 4.00-18 rear, pretty much across the board in every adult class. Fat-tired bikes can be ridden just as precisely as skinny-tired bikes, though more effort is required of the rider due to increased inertia. How much more effort? Not much, really. Fact is, if one isn't strong enough to manhandle any tire one probably should limit one's offroad excursions to riding a powered wheelchair. Thousands of Rokon and BW riders prove the notion that big tires make riding difficult every day.
So, why does the TW excel at tight, twisty gravel roads? Easy answer is it doesn't. Big tires provide big traction and TWs really are lighter than the bigger bikes, with a lower center of gravity, factors which combine to require less traction to maintain a desired line. TWs aren't really that great, other bikes pretty much suck worse under such conditions when ridden at anything less than racing speeds. No berms and riders lacking the skill to crossup every corner makes for slippery going.
