Geometry is a combination of your front and rear ride height settings along with your suspension sag numbers that allow the bike to steer effectively. This is in conjunction with your personal riding style, rider weight, bike weight, wheelbase even tire sizes all affect the final numbers that need to be adjusted.

For years the conventional set-up for geometry on a sportbike (such as the RC51) was to take the bike the way it was delivered from the factory and basically raise the rear end of the bike and lower the front. The only catch was not getting the already front heavy bike so biased that the front tucked too easily.

Things have changed greatly in the last decade with much higher horsepower bikes requiring much better chassis' to keep them stable enough to avoid liability issues from consumers we see a lot of things in chassis design that used to be only available in Race Kit parts. Along with those things we are also seeing a trend of longer swingarms and lots of compromise of the rake & trail numbers on the front ends.

Raising the front end of the bike increases trail and raises the CoG. This is very common practice on many newer sportbikes to improve the handling and stop them from trying to run wide on exit. They even sell fork cap extenders for various intenral for cartrdige kits on the market to do just that. When you raise the front though the agility of the bike can suffer so many also raise the rear as well to get that quick steering back.

That's also why Offset Triple Tree mods are becoming so common on proper racebikes now as they allow massive changes of trail while other changes are minimal. Even without different clamps the offset changes to the front ride height have very little effect on other parts of the bike.

These numbers vary from bike to bike ever so slightly, but to give you a good idea of how things are affected take this into account:


6mm of taller rear ride height alters the swingarm down angle slope by .4°

That same 6mm of rear ride height alters the trail numbers by 1.5mm

(a very typical mod we do for the Ducati 848/1098/1198 are the 30mm Offset Triple clamps down from 36mm stock so that is a full 6mm of change in trail numbers and again this is done to keep the bike from running wide out of the turns period)

2mm of front ride height change adds .5mm of trail (that means to get the same results of off-setting the triple by 6mm you would have to add like 24mm of front ride height which is virtually impossible on any current bike due to the length of the forks)

That same 2mm of front ride height change is .07° of slope on the swingarm (negligible at best)

When we raise the front end up on our bikes we are basically just doing the best we can with what we have to work with. The proper race bikes all use a different offset triple clamps compared to OEM

At the bottom of all of this is personal preference involved in the geometry set-up process and a myriad of other variables as well that convolute the end result. Even orientation in minute degrees of the physical engine position in the frame & how many rpms are spinning the crank around internally cause increased amounts of gyroscopic precession to work against you etc. Sometimes just shortshifting a gear or two can significantly reduce the effort required to initiate a turn at speed.

Ultimately you want a geometry that doesn't have the bike fighting you into and out of the turns. If you are having to put pressure on the handlebars in the middle of a constant radius turn to keep the bike from either trying to fall into the turn or stand up through it then you have a geometry problem.

The second part of that issue is finding the compromise to get the bike to steer properly without running wide when you get on the gas during corner exit.

Some riders want that perfect line trailbraking into the turn and make due on the way out while most others will sacrifice some precision on the way into the turn to get the perfect drive out.