Geometry, Suspension & Sag Information Page


One of the biggest misconceptions in the industry about suspension is that it only benefits those that are racing or super aggressive etc. The truth is better suspension helps the Novice rider with his/her first streetbike just like it aids the Expert Racer at the top of the sport. Doesn't matter if you are commuting in stop and go traffic every day or trying to set a new lap record. If the bike is more compliant, more comfortable and more responsive then it is better for anyone's needs regardless of skill level or intent of use. The suspension can be further fine tuned to your specific needs as the racer at the limit of traction aiming for a new lap record has different needs from the damping rates than the guy wanting to take his girlfriend on a ride to his favorite lunch spot, but more compliance is always a good thing whether you need a better ride on your daily commute or more grip while getting on the gas exiting Turn 5.

What you are really purchasing when you buy aftermarket quality suspension is a greater margin of safety and a larger margin of error with some extra comfort thrown in. You get to ride faster with less drama and more compliance and feedback from your own motorcycle. For your specific needs of track riding there is no better way to improve the bike. When the bike is doing what it is supposed to underneath you then that frees up your mind to focus on other issues like body position, throttle management and hitting those brake markers with confidence instead of worrying about the ripples in the braking zone or that dip at the apex of Turn 6 and how they are going to upset the chassis etc. Proper suspension makes the bike predictable in all conditions. Additionally if the bike is working with you instead of fighting you into and out of every turn then when you do make a riding mistake you stand a much better chance of the bike correcting itself and keeping you on two wheels than if the bike is working against you and protesting your inputs the entire time.

In separate categories on the main page of the 1000RR section you will find all the steps and different levels of improving the suspension I tested on the 04-07 1000RR same for the ZX-10R and RC51 if you have followed any of those links here

Now let me go on to explain a personal stance because a lot of you like to send me emails trying to justify the OTHER brand of suspension you bought and want me to tell you that you made the right decision. I sell and service Ohlins because it is the best. I am not saying that other brands are not good or they won't work or anything of the sort. I am merely stating that if you want the best products in the world then Ohlins is what you choose! The pinnacle of roadracing on this planet is MotoGP and those Factory Teams can afford to buy any brand of suspension they want and they all go with Ohlins. You don't see any of the top Factory guys at that level using WP, Mupo, Nitron etc. They want what works the best and that is Ohlins period. Most if not all of those other brands would be glad to GIVE MotoGP teams free product just to be able to say that a team at that level uses their stuff. The real truth is Ohlins doesn't sponsor any team. Even Rossi's team pays for their Ohlins products and support. They pay because it is the best and it is worth it so when you come to me asking me what I think about the brand you chose over Ohlins don't expect me to candycoat my response and tell you its just as good as Ohlins. It's not. It may be 100 times better than the OEM crap suspension you were using, but it is not Ohlins. With the Ohlins product you get top quality everything from the actual product design to the technical support. The pool of knowledge put into their products and available to the end users is immeasurable. Additionally I should point out that sometimes it doesn't even come down to how good your suspension is, but how good you think it is. The aspect of mental confidence is rarely mentioned in this ego-driven competitive sport, but for the average rider just knowing you have the best products on the planet installed on your bike is in many cases just as effective a tool for building confidence as using those parts to their full potential would be. The point is if you already know you have the best product in the world on your bike you damn sure won't be second guessing your decision and asking me what I think about it.


The question of geometry comes up quite a bit on the various forums so I decided to take some of my postings and consolidate them here to expound a bit on the subject. Allow me to preface this by saying that in my opinion while geometry is part of the suspension set-up and overlaps with the proper sag settings and correct spring rates etc on your bike, it is still a separate facet from the damping (compression & rebound) set-up of the suspension. A lot of people try to use damping adjustments to make corrections for a poor geometry and in my experience that simply does not work.

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. It is also part of the chassis design with its own inherent limitations per the engineers that created it. All of that 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 and in some cases there simply is not enough range of adjustment available to us to overcome the original design of the bike.

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 internal 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


Sag is a mathematical equation of overall stroke. Most forks have 120mm of travel so the middle 1/3 of that range is 38-40mm for Rider Sag. This gives equal amount of travel and oil on both sides of the pistons etc.

Same with the rear shock except you only have about 90mm of wheel travel so the middle 1/3 is 30mm.

There are exceptions to those numbers, but it is outside the scope of most riders and in some cases very bike specific. When we set up Pro Racers that are at or near the lap record they have a very narrowly focused window of operation with their suspension in extremely controlled conditions where we know every millimeter of travel they are going to use on every corner. Under those conditions we use different sag numbers or in some cases those numbers are completely irrelevant as they can be dictated by the riders personal requirements. We custom tune the valve, spring, preload and fork oil height to control the way the front end sets and returns to aid the geometry of the bike into and out of turn. Street riders don't get the luxury of such consistent conditions so they don't get the same type of tuning.

Lately on the message forums I see a lot more emphasis being placed on fork oil height and while I appreciate that level of attention to this facet of set-up I do have to mention that is is often over-analyzed for street riders who would be better off at OEM recommended fork oil levels. Fork oil height only really comes into play at the very end of the stroke unless there is simply too damn much oil in the forks which limits travel altogether. Either way it is a very useful tuning tool for the confines and consistency that a racetrack provides, but not so much for street riders or the commesurate street riding skillset even at a trackday

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 or hold 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.