What effect does ride height adjustment have?
Ride height adjustment is usually only found on top-of-the-range sports bikes, nakeds and the occasional sports-tourer, It raises or lowers the height of the rear shock, lifting or lowering the entire rear of the bike accordingly.
Raise the ride height and you jack up the rear. This makes the front tyre work harder and allows the bike to turn quicker.
The trade-off is a loss of stability. Lower the ride height and you do the opposite dropping the rear of the bike and reducing the load on the front tyre.
The bike becomes more stable, but with slower steering. Ride height adjustment is usually made by a pair of open-ended spanners one used to loosen a locknut, the other to turn a nut screwed on to the main ride height adjuster shaft.