Ok here goes
Mark at MH, yes top man he has done some Ohlins work for me. His name was known to me back in the days when i was attending MX races. I used to attend regularly with Billy Aldridge who was the Ohlins GP tech for about 2 years or so and i'm sure his name was mentioned then.
Right the Aprilia claim for your RSV is 50/50 weight distribution.
Most manufacturer claims will be an engineering target based on an average of all the variables.
Eg. Wheelbase alters with load and configuration which will alter the COG. You can see from the Ducati example the alteration in wheelbase from what they claim to what was found and where it ended up and the difference variation can make to the COG. The wheelbase is not a constant between laden and unladen machine.
The Ducati figures were interpreted with the aid of Dan Kyle who is a big Ohlins Tuner and Ducati specialist using DOS tools
dunno) which apparantly are very accurate so i have no reason to doubt them.
In an ideal world the COG would be at the same height as the axles, then the COG would alter in a straight line back to front but obviously that doesn't happen in the real world.
The Higher the COG above the axles the greater affect it has on weight distribution.
The closer the COG to the rear wheel then the greater the variation in it's movement to the front in relation to a change in ride height at the rear.
On my Ducati a 3mm alteration at the linkage equats to a 15/16mm alteration at the back.
In relation to your reason for finding all this out which was where to best put your weight fore/aft in a corner that's tuffy. I'm no racer so i can't speak from experience and i guess experience counts for as much a theory if not more.
On a road bike i have always believed the weight should be biased towards the front. I think that has more to do with grip levels that anything to do with the physics of getting around a corner though.
The key to a good corner seems to be the height of the COG and how far you are inside it.
The lower the COG the more stable the bike but the less force it applies to the overal mass in a turn.
Because the lean angle is basically gravity against the gyroscopic forces of the wheels the lower your mass the more you have to lean the bike.
The key obviously is to lean off and move your mass inside the COG of the bike to counteract the lower overall height of the COG. YOu then get a stable bike due to the low height but a reduced lean angle because your inside the the COG of the bike. The weight transfer front to rear seems to have little affect on this other than determining the grip of the tyres. As the front tyre has a much smaller contact patch it stands to reason it would need a greater load to achieve the same grip as the rear all things being equal (tyre compound etc)
I went to a talk with Lester Harris a while back and he went into weight transfer in his talk. he made a point that if you look at the top racers like MotoGP etc they obviously sit up under braking and corner entry. Various reasons why such as stronger arm position against braking force, wind braking against your body etc but also the fact it raises the COG which means their weight has a greater affect on the forward transfer of weight distibution.
If you look at them you also notice they stay as low as poss as soon as they get on the gas, sometimes actaully getting lower towards the end of a turn than start to mid corner. The point being that the closer the COG to the axles the less affect it has on weight transfer so as they get on the gas from mid corner they reduce the affect of power on the weight transfer as much as poss to maintain front wheel traction.
I think that's why some peeps have embraced the electronic motorcycle racing age better than others. The antispin etc has allowed riders to use their weight differently than before. Now they can maintain more front wheel weight bias allowing braking further into a turn, faster corner speeds etc knowing that they have the gadgets to control the spin at the rear.
Had they not had those devices they would have had to use more weight transfer to the rear as soon as any power came in just to prevent highsides and wheelspin which ultimately would reduce front grip most of the time.
that's just my own observation.
So after all that i guess my answer re your weight in general is to have a front end bias if poss and vary your hang off to allow you to keep your weight as low as poss for stability but still have a sensible lean angle for the corner.
The faster the corner the the more important the height of the COG and vice versa.
Out of interest i thought i would see what the makers claims for current bikes are at the moment re Balance of weight out of the box.
R1 - 52.4/47.6
Rsv4 - 50/50 (adjustable)
1098 - 49/51
GSXR 600 - 51.7/48.3
Kawasaki i couldn't find. General trend ssems to be to a front end bias though.
Can of mworms ain't it.
None of this has anything to do with the sag qustion that started the thread though so might move it to another thread later.
