Rear Suspension Query

[Mr Bogus]

I lowered the front 3/4" and am going to raise the rear 1"... I also have 1.1 springs and the gold valve kit.. going the right way here??

The front was involuntary as the brake lines I got at the GB do not work with the riser mod... do I need to fix this differently?

 

[Charlesbusa]

I wouldn't say raising the front or the rear "hurts" the suspension. But lowering the rear or the front decreases the bike's ground clearance and generally makes it easier to bottom out the suspension. However, if you don't ride the twisties aggressively enough, it won't affect you.

Other than that, lowering or raising gains in some areas at the expense of others.

Example, by raising the rear an inch, your bike will "turn in" better(feel lighter) than the stock geometry. But you gain this at the expense of stability. But the Busa is already more stable than GSXRs, so I feel that even though you lose some stability by raising the rear an inch, the Busa is still just as stable as a GSXR. I'm basically altering the Busa's geometry to be more like a GSXR's geometry.

There's more to it than just that, ie front and rear bias, but you get the idea.

So basically changing your bike's geometry is not a bad thing. You just have to figure out what it is that you want out of your bike and know what your giving up to get what you want.

 

[Charlesbusa]

I lowered the front 3/4" and am going to raise the rear 1"...  I also have 1.1 springs and the gold valve kit..  going the right way here??  

The front was involuntary as the brake lines I got at the GB do not work with the riser mod... do I need to fix this differently?

When you lowered the front, was the 3/4" measurement on the stock springs. If it was, when you install the 1.1 springs they will raise the front end back up some.

If the front is lowered 3/4" after the 1.1 springs, you may find that raising the rear an inch may be too much, maybe not. You can try it and always go back to stock dogbones.

If you corner hard enough and are worried about ground clearance then you may want to see if you can find longer brake lines so you can raise the front back up.

Since I mostly ride at trackdays, ground clearance to me is very important and always on my mind. In my case, my front was raised some by the .95 springs(I weigh 160lbs) and I run a 55 profile rear tire which probably equlizes the front's raising. And I raised the rear an additional inch with dogbones. So my whole bike is higher than stock but I raised the rear more than the front.

I really notice my bike's height when trying to back up

 

[GSXcite]

Charles, do you run a 180X55? I ordered a 190X55 by mistake a few tires ago, and I had it on at deals gap and I really liked it. I'm thinking about going back to a 55 and raising the rear up 1" to help the turn in.

 

[Mr Bogus]

I had to lower the front after the new springs.. (I can remove the 3/4 risers to fix this)

I suppose I can skip the links and change them out at the gap after I get a day or two on them to see how it feels..

 

[Charlesbusa]

Charles, do you run a 180X55? I ordered a 190X55 by mistake a few tires ago, and I had it on at deals gap and I really liked it. I'm thinking about going back to a 55 and raising the rear up 1" to help the turn in.

The 190/55

That is the way to go for the twisty Busa

 

[Charlesbusa]

I had to lower the front after the new springs..  (I can remove the 3/4 risers to fix this)

I suppose I can skip the links and change them out at the gap after I get a day or two on them to see how it feels..

I'm not a suspension expert, but I do try to share what I know or what I think I know

If you put the 3/4 risers on to get weight off your wrists, you'll be going right back to the same riding position when you raise the rear. When you raise the rear you will notice the chnage in riding position. I had to retrain myself to hold myself up with my back rather than my wrists. Light hands are always better.

Raising the rear doesn't make the bike faster, it just makes it easier to turn allowing you to be more precise with the line you want.

With the exception of suspension travel and ground clearance(which only matters if you ride fast enough), its all just preference. I love it raised up, makes the busa feel more like my 750.

 

[Mr Bogus]

Ok so it sounds like the risers are doing the opposite of the rear struts raising the back? by removing the front risers, it is doing the same thing as raising the rear?

I was thinking that we were working with steering head geometry more than ride position..

Thanks for taking the time to share what you have learned btw... much appreciated..

 

[raydog]

Respectfully, I think this point should be made...when the bikes chassis is raised via the rear suspension, it effects the motorcycles handling irrespective/independent of rider position. That effect is because the angle relationship of the front forks with the tarmac is increased (made closer to vertical)therefore the steering is said to be quicker, toward the high performance end of the spectrum (the opposite being the extended rake of a chopper, for example). One performance exception to this, of course, would be extending the rake slightly to gain stability, like a top speed bike. When you raise the clipons (ie Heli Bars, etc.) for rider comfort, you do not change the steering head angle, you change your body's torso angle. Raydog