Any shortening of a bikes wheelbase on most sportbikes will make the bike steer slower, contrary to what most people would think. The reason for this is the angle that the rear axle adjuster travels up the swingarm (it's not parallel to the ground like some rare bikes in the past had - for example Ducati had the adjusters level to the ground on some of it's bikes). Due to moving at this angle (as the axle moves forward) the back of the bike drops down, which in turn lessens the angle of the front forks. Steeper rake angle of the forks generally means faster turning with less top end stability, less rake angle means slower turning with more top end stability. This is the very reason that when I use to change gearing all the time I had 3 different drive chains all of different lengths, then I could mess with the wheelbase and geometry of the bike without changing sprockets or keep the same apx. gearing ratio with a different front and rear sprocket combo. Though a shorter wheelbase should supply quicker turning ability, it needs to maintain the original rake angle of the forks to do so, this can only be achieved (on bikes with angled axle adjusters) with a ride height adjuster of some type in the rear (in order to maintain the original ride height of the rear of the bike as the axle moves forward - or backwards for that matter). Some racers will mess with adjusting the triple clamp height on the forks to compensate for this, but that can change the central mass of the bike and reduce your ground clearance as well - it really isn't the correct way to compensate for a change that should be happening to the rear of the bike.
As an example of this my freind and I were racing at Barber in 2004 and he had an issue with one of his bikes not turning worth a darn. I asked him a number of questions about set-up differences between the 2 bikes and he basically said that everything between them was set the same, even the gearing. I ended up measuring the wheelbase of both bikes and found that the bike with the problems had a shorter wheelbase, which we found was from the chain being a link shorter. He cut a brand new chain he had so it would be a link longer than what was currently on the bike, reassembled, and measured the wheelbase to find it now matching the other bike - he thought for sure it wouldn't make any difference, but I assured him it probably would. After another practice session I could see the smile he had thru his visor, he said that he was instantly 3 seconds a lap faster and the bike went anywhere he wanted it to - he was blown away that such a minor thing made such a huge difference.
Many Pro race teams have triple clamps with adjustable triple clamps to change rake angle, the changes they make are often times only .5mm, 1mm, or 2mm (3mm = apx. 1/8"). Rake angle is very sensitive to any sportbikes handling, don't discount how much of a change even small amounts can make to your bikes handling!
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