Oh God He is Thinking Again.. (bout suspension)
- Thread starter theskaz
- Start date
AJAY
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You will raise your center of gravity 2 inches, slowing your roll rate, while simultaneously reducing stability and control.
Seriously, why would you want to raise both ends of the chassis when you already have enough clearance to ride to the edges of the tires?
Raising the rear only will also raise the center of gravity, but not as much as raising both ends, while reducing the rake of the fork and reducing the trail of the contact patch. This will quicken steering while also reducing stability a little bit. Raising the rear 1/2 to 1 inch would be acceptable.
Alternatively, you could lower the front by the same amount and get the same geometry (rake/trail) changes while lowering the center of gravity, increasing roll rate, but giving up some ground clearance to do it. Or you could split the difference, raising the rear half an inch while lowering the front half an inch, with virtually no change in CG, perhaps only tiny loss of ground clearance, and steepening the steering.
But my first recommendation would be to not mess with geometry at all and FIRST set your bike up properly (preload, compression, and damping) for your weight and riding style. Then fool with geometry.
Seriously, why would you want to raise both ends of the chassis when you already have enough clearance to ride to the edges of the tires?
Raising the rear only will also raise the center of gravity, but not as much as raising both ends, while reducing the rake of the fork and reducing the trail of the contact patch. This will quicken steering while also reducing stability a little bit. Raising the rear 1/2 to 1 inch would be acceptable.
Alternatively, you could lower the front by the same amount and get the same geometry (rake/trail) changes while lowering the center of gravity, increasing roll rate, but giving up some ground clearance to do it. Or you could split the difference, raising the rear half an inch while lowering the front half an inch, with virtually no change in CG, perhaps only tiny loss of ground clearance, and steepening the steering.
But my first recommendation would be to not mess with geometry at all and FIRST set your bike up properly (preload, compression, and damping) for your weight and riding style. Then fool with geometry.
This was just a theory type of thought. I have no intentions on doing such.
Note, my suspension is tuned to my weight and riding style. But on the track, i still have scraped my fairings a tad at the out limit of the lean angle. That is what sparked the idea.
Note, my suspension is tuned to my weight and riding style. But on the track, i still have scraped my fairings a tad at the out limit of the lean angle. That is what sparked the idea.
fastblackblur
Registered
My knowledge of suspension is only basic... but I can tell you that some bikes need to be raised at both ends for racing. Both my '03 GSXR 1000 and my '11 GSXR 600 are raised at both ends. When I asked why they do this I was told because it increases stability and helps the bike complete the turn. I have no idea why.
I would not do anything on a Hayabusa that reduces ground clearance if going around corners is a priority.
Be safe and get some profesional advice before making such a big change in geometry.
I would not do anything on a Hayabusa that reduces ground clearance if going around corners is a priority.
Be safe and get some profesional advice before making such a big change in geometry.
It's not all geometry. Raising the back of the Busa 1" increases both turn in and straight line stability. The reason for this is that it moves the weight bias forward which in this case makes the handling noticeably better. Not sure I would go up 2" on both ends though, seems like that would really be potentially destabilizing.
As for rubbing the fairings, I would say don't worry about it. The real reason the busa rubs the ground is because of it's width at the crank more than anything. If the suspension isn't bottoming out then I would just get a set of clean side panels for when she needs to get all dressed up to go out on the town.
As for rubbing the fairings, I would say don't worry about it. The real reason the busa rubs the ground is because of it's width at the crank more than anything. If the suspension isn't bottoming out then I would just get a set of clean side panels for when she needs to get all dressed up to go out on the town.
fastblackblur
Registered
Consistantly dragging hard parts on the ground is not a good idea. You could eventually lift one of your wheels off the ground.
If you are correct, why does every professional racer sit upright at the tip in point raising the center of gravity?
Raising the rear or lowering the front increases tip in due to a reduced trail AT THE EXPENSE of stability! There are no free rides. When you gain in one area you loose something in another area.
Raising the rear one inch does transfer some weight forward "About four pounds". Hardly enough to be noticeable. Move your bum a quarter inch forward and you'll transfer 4 pounds to the front.
Watch Ben Spies, he is all over the bike from as far rearward as he can possibly reach to out over the tank. A masterful display of control.
AJAY
Registered
I was speaking only of roll dynamic of the motorcycle itself. Neglecting fore/aft weight shifts for braking/accel, the motorcycle itself can only roll and raising the bike moves the center of mass away from the tire contact patches. The rider shifts weight as part of the vehicle dynamic and can change the combined center of mass of the rider and motorcycle when viewed as a system. As they heel the bike over, they shift the combined center of mass back towards the contact patches, reducing the angle of the center of mass to the contact patches, effectively reducing side loading on the tires.
But I am certainly not the expert rider here and defer to your positions on these subjects.
Are you planning on putting on a set of twenty twos afterward.
Maybe even a Double Deuce badge on the side?
Maybe even a Double Deuce badge on the side?
AJAY
Registered
Didn't see that one, but it sure is common in the movies. It adds an extra bit of fun for us motorcyclists to look for the dirtbikes dressed in different clothing.All I keep thinking about is the movie Torque. Remember when they were riding in the desert and the bikes magically turned into dirtbikes with sportbike plastics?They were like 5 feet high. Tried to find pics online to no avail... :down:
Go rent it today. It's a must see. It could possibly be the WORST motorcycle movie in the history of mankind. Although Biker Boyz is a close second. You owe it to yourself to watch it...
uke:
All I keep thinking about is the movie Torque. Remember when they were riding in the desert and the bikes magically turned into dirtbikes with sportbike plastics?
That was also when they were riding on top of the train.
I've done that.
Skaz has seen lamb on Miramar rd many a times
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I am here: http://maps.google.com/maps?ll=33.319387,-117.150522
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I am here: http://maps.google.com/maps?ll=33.319387,-117.150522
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