on my 93 f2 cuz im a big guy i need to harden my front and rear suspension. how is this done?
i have the back figured out, but what about the front fork how are they done? thanks

 

you can always go for a heavier oil in the forks. and up grade the spring too..

 

http://www.racetech.com/SubMenu.asp?...howPage=street

Check that site out. They've got a "calculator" of sorts to find the right springs for your weight.

 

http://www.kgrant.co.uk/Per_Handling2.htm this should help too...

 

Start by turning your preload all the way in. This is done with the "*****" on the top of the fork by the triple tree. Then do the rear spring with the hawkbill shaped tool in the tool kit. It fits on to the shock and you pull the shock through its different detents. This stiffens the stock springs. Most of us are probably heavy enough to run the preload all the way in first thing. The bike comes set up for about 160lbs rider, and 180lbs at full stiff.

 

Turning the preload adjuster does not stiffen the rear spring. All it does is changes your sag (aka how much the suspension compresses from topped out when you sit on it). The spring rate is linear and stays the same now matter how much preload you add. If you really want to tune the bike for a heavier weight you need a spring with a higher spring rate. Apparently I have one on my F2 (don't know who changed it) and I need a lighter weight spring.

 

Uh, spring isn't linear...

In a way your right and not.

When you push the spring some it takes a force to push that spring that distance (dx), now if your preload to dx guess what it will take more force (not the same force but more) to move 2*dx.

I have adjusted my preload (wish I had compression adjustment but I don't) and it helps a lot, I use to drag peg a lot and now I don't. Although I'm running about 5 in the back and two lines up in the front I might tighten in the future.

Also get some better tiers the new quali's will make you faster with out even trying (in the twisties anyway).

Also figure out your style of riding and setup for pre-sag as someone else stated. I think its like 30mm in the front and back, but that is for like racing maybe... I don't remember off the top of my head. My buddy weighs 240-260 and he had his **** at 2 (I don’t know why) and we put it at 6 now he feels a lot better on his bike. (Get a manual - it will give you directions for setup)

 

So are you saying f2's springs aren't linear rate springs?? As far as I knew they were.. Never seen one spec'd as progressive rate.

I own a '93 f2 and according to race tech the stock spring rate in the rear is 13.3 kg/mm. Now this translates to a different wheel rate because of the installation ratio. The installation ratio can also create a rising or falling rate, but unless you can convince me you understand that and then explain to me how the f2 kinematics produce such a rate I'm telling you the rate is linear.


I can't quite follow your terminology, but you're dead wrong. Preload is technically a misnomer and does nothing but change ride height. A spring only cares about displacement and only reacts with a force equal to its spring rate times its displacement. I.E. force at the spring = displacement at the spring * spring rate.

Let's say your spring rate is 200 lbs/in. Now lets say you crank your preload adjuster so the spring is compressed 1". Now let's say you weigh 200 lbs. and sit on the spring. When you sit on this spring it will not compress one bit from it's "preloaded" state. Now if you add an additional 200 lbs. on top of you the spring will compress one more inch therefore compressing 2" from it's free height overall. It doesn't take more force to move the spring because it's preloaded.. Your spring will compress to the same height on your bike no matter what preload u put on it unless you preload it so much the installed spring height is more than your weight would compress it.

Again, adding preload does not change your spring rate one bit. It only changes ride height (technically sag).

 

Ok your right, about linear.

What I'm saying though is if you set the presage you well have to have more weight to make the spring compress.

So now that you have gone one inch you need 200+lbs to go beyond that one inch. So I guess I don't see why you’re adding more weight, what’s your point? I now understand what you mean by linear, I was thinking to move two inches it doesn't matter 200 lbs would do it, but obviously I wasn't thinking on the same lines as you guys.

So what I'm kind of saying is once you set the sag right, he will be a lot better off then just going with a new spring (he should upgrade to an f3 suspension before messing with a spring in my opinion).

Summary; when he set presage for 200lbs, he will be able to hit bumps his bike isn't going to bottom out like it would if the presage was set for a 150lb kid. Because the bike is going to sink tell it hits for 200lbs killing a lot of the geometry and spring distance for bottoming out (just when he sits on the bike).

Also if you crank that sag up it would make the bike harder to compress with just the riders weight, in less you’re planning on putting weights on your bike. (I agree, this isn't the right way to do this but it is a cheap way to fix this problem or make it less of a problem.) So I guess I disagree with the word stiffen, the spring has a constant stiffness but you can make the spring stiffer by compressing the spring.

 

I think you're still missing the idea. It still doesn't take more weight to compress the spring.

I just used 200 lbs. as an arbitrary number. I added weight as an attempt to explain how the preload works. If you do set preload to a point where you sit on the bike and the sring doesn't compress then you are riding with the suspension topped out and that is not a good thing.


But without the correct rate spring to begin with you might not even be able to set sag correctly (this will happen when you run out of adjustment room because your weight compresses the spring too little or too much). For the rear if you do get sag correct and your spring rate is wrong for your weight then your suspension will not react on the road like it should. Correct rate needs to be found before you can worry about sag. Granted most stock springs are close enough for the average rider.

I'm a little confused again with what you're saying.. But again it's a combination of correct rate and sag setting...

No, it does not make the bike harder to compress with just the rider's weight. The spring itself will always compress to the same height when you sit on the bike no matter the preload.. Again, adding preload does NOT make the spring stiffer. I promise. Your wheel rate does not change. If you agree that the spring has a constant stiffness then you're also agreeing that compressing the spring does not make it stiffer.

Think of it like this. Sit on your bike. For simplicty sake say your spring actually compresses one inch. Now imagine you could crank the preload adjuster in the direction you would to "add preload" while you still sit on the bike. What happens?? Does the spring compress more? The answer is no. What happens is the shock extends and raises the rear of your bike. This is how "preload" is adjusting sag so your suspension rests at the right point throughout its travel with you on the bike. Make sense now?