If I lower... do I lower?

[Anonymous]

I plan on (over the upcoming winter) mounting a GSXR front end and a GS Extended rear swing arm. My question is, the GSXR front will drop the nose about 2 inches. The swingarm is just a stock swingarm extended from 7"to 13". Do I need to find a lowering kit for the rear and where can I get one? Also, ground clearance is quickly becoming an issue with this project if I build my exhaust. Is there a better way to tighten the corners with out lowering the front? I'd kinda like to use the GSXR wheels though.

Final thought, How is an extended swingarm gonna treat my cornering, and how much is too much. (and don't say any is too much because I'm gonna do it and I don't need sarcasm, just help)

[Anonymous]

handling

If you drop the nose but not the tail, it will turn in quicker, making it longer will make it turn slower. As for lowering it, you can either get shorter rear shocks, or move the mounting point on the frame, dont cant the shocks forward when you do this, as this makes the geometry to one of falling rate, and that is exactly what you want to avoid. I think how you like the results is going to depend exactly on what sort of handling you like from your bike, and how it behaves under you is a matter of preference. My fav handling bike before the gs was a gpx600r, and theyre not exactly well loved because of the speed of the steering due to the 16" front wheel and ultra short wheelbase.
Going to the gsx-r wheels is going to make the most changes to the handling I think, one of the charecteristics of the ol gs is the stable but slow steering front wheel, caused mostly by having the 19" wheel up front acting as some sort of huge gyro. But of course good rubber in a 19" size is a sod to get hold of, but you can order a dual compound bridgestone battlax in the correct fitment to suit a gs. Theyre pretty good too.
As for ground clearance, well, a stock gs doesnt come with enough anyway, with modern tyres on you'll soon have the ends of the rests worn away, great for feeling a hero, but only until the centre stand digs in. Ive kept every one of mine on the wall of the workshop, with pins i can just push in when i need a centre stand for maintenance. With your extra length, your going to have more of a clearance problem, its no coincidence that you only see drag swingarms on drag bikes and those designed for not going round corners.
What are you aiming for? a fast straightliner that you can ride occasionally on the street for a bit of traffic light grand prix, or something to scare people in the twisties?
Having both is a problem. Its suck it and see teritory with frame mods this radical im afraid...
Ive personally got 8" longer usd's up
front but keeping the 19" wheel in a attempt to not quicken the steering up too much, with 10" or so longer swingarm at the rear, with a monoshock set up to jack the rear up to suit, ive been off the edge of my front tyres on quite a few occasions but it does have a tendancy to spin out at the rear in the damp, and having something that long wag its tail on the power is serious brown trouser material...
I used to run 8" over gs forks (used motorcross stancions) but they had a tendancy to flex when on the brakes banked over, despite a monster fork brace, steel front guard etc...
Ive also got more MrFluffy bits on it than suzuki too, so you cant really use my setup as a baseline for anything, sorry!
Have fun
de Phil

http://fluffycentral.com/photos/GS850DB-pic2.jpg

:twisted:

[Jethro]

Holy crap. I should have paid more attention in geometry class. I have always wondered why people wish to extend the rear swingarm. Due to the drag bikes I have seen, I am assuming it is to slow the handleing down and increase high speed stability. Am I interperting this correct Fluff-R-Nutter?

[Anonymous]

long arms

Holy crap. I should have paid more attention in geometry class. I have always wondered why people wish to extend the rear swingarm. Due to the drag bikes I have seen, I am assuming it is to slow the handleing down and increase high speed stability. Am I interperting this correct Fluff-R-Nutter?

It helps loads with avoiding wheelies, longer wheelbase means the front end weight is leveraged against the back wheel with more length, thus it takes more torque/power to lift it up from simple force x distance theory, but having a longer swingarm does slow the steering down and help straight line stability, at the expense of cornering and a turning circle bigger than a large lorry. Long bikes are definatly more stable in a straight line, but mid corner when youve messed up the line, or your steering to miss something, stability may not be the most desirable thing, you want a short circuit racebike to react as quick as possible but still be useable, and you want any direction change to be yours and not the product of chassis flex and the like. Having a long bike causes the steering to be dampened, One of my other bikes is a bimota, and that has a ultra short quick steering chassis but with incredible torsional strength, it needs that strength to try to avoid twitching. It makes it a bloody awful bike for drag racing, but brilliant in twisty backroads.
Ive heard people say that a long swingarm helps quarter times more than having a pair of wheelie bars, and I think its the effect on the handling that causes this.
The last place I lived I couldnt get the gs out the garage without shuffling back and to because of a bend entering the workshop, and u turning in the road isnt exactly easy either. Long swingarms arent that practical on the street...
If you really want to get technical about chassis etc, tony foale's book is the bible...

http://www.tonyfoale.com/index.html

But im n
owhere near that level, im just a tinkerer with a few homebrew frames and suspension swops under my belt.

[Anonymous]

what I really want is the stability of a long swing arm ( I am building a lot of power into the engine and HATE the front wheel come up) but I also want somewhat of faster steering... I figure if I get it right, the length of the swingarm will add stability and the Gixxer front end will counterbalance the loss of handling. It really is gonna be a streetlight racer in the end, occasionally used for touring.