so who would like to setup my suspension?

[Old Lemon]

So after my last track day I've been very interested in suspension. I've looked through a few threads about it and noticed that I have no Idea what is going on. Got like .75 kg or .90 kg springs or something, got different oil like 15w or 20w. I have no idea of the differences they make to the bike or ride and I would like some suggestions on how I should upgrade my suspension.

Some info about my self: 120 pounds before gear and starting to get into intermediate group pace.

So I do not have the know how to do this work my self. So what I would like to do now is get some ideas from you guys and buy all the parts and figure out exactly what I want so I can tell a shop I reasonably trust to do exactly what I ask them to do.

I'm looking for front suspension stuff at the moment since the rear shock is just a swap to a Gsxr. So, please send me some suggestions

[CC Cowboy]

Originally Posted by Old Lemon

So after my last track day I've been very interested in suspension. I've looked through a few threads about it and noticed that I have no Idea what is going on. Got like .75 kg or .90 kg springs or something, got different oil like 15w or 20w. I have no idea of the differences they make to the bike or ride and I would like some suggestions on how I should upgrade my suspension.

Some info about my self: 120 pounds before gear and starting to get into intermediate group pace.

So I do not have the know how to do this work my self. So what I would like to do now is get some ideas from you guys and buy all the parts and figure out exactly what I want so I can tell a shop I reasonably trust to do exactly what I ask them to do.

I'm looking for front suspension stuff at the moment since the rear shock is just a swap to a Gsxr. So, please send me some suggestions

I'm not sure if this guy knows his stuff but he sounds good.

http://www.youtube.com/watch?v=bBlqVx4mWUw

[subxero]

Originally Posted by Old Lemon

So after my last track day I've been very interested in suspension. I've looked through a few threads about it and noticed that I have no Idea what is going on. Got like .75 kg or .90 kg springs or something, got different oil like 15w or 20w. I have no idea of the differences they make to the bike or ride and I would like some suggestions on how I should upgrade my suspension.

Some info about my self: 120 pounds before gear and starting to get into intermediate group pace.

So I do not have the know how to do this work my self. So what I would like to do now is get some ideas from you guys and buy all the parts and figure out exactly what I want so I can tell a shop I reasonably trust to do exactly what I ask them to do.

I'm looking for front suspension stuff at the moment since the rear shock is just a swap to a Gsxr. So, please send me some suggestions

Read Rojo's race suspension set up thread several times until you understand it. Get the correct springs for your weight, some emulators and some fork oil and you are good to go.

If you weight 120lbs and you plan on doing GSXR swap, YOU MUST buy a new spring for that shock. It will be way... way... WAY to stiff and harsh for your weight

I have GSXR shock, with the 9.4kg/mm stock gsxr spring and i weight 190-195lbs with gear and the shock feels stiff to me. I am still dialing in my dampening so hopefully i can get it sorted out with the spring i have. Other wise i will have to buy a new spring as well.

[quarterliter]

Seems like your springs will be too stiff

[quarterliter]

Seems like your springs will be too stiff if you weigh 120

[cbinker]

http://racetech.com/ProductSearch/2/...20250R/2008-12

.70 is the closest rate to your weight.

[Old Lemon]

I see. But I thought stiff was good for track riding? I really don't know how my suspension is suppose to feel whether it is good or bad right now, that's why I'm confused when I try to read up on things but it's just stiff or soft. Also, say the fork oil I have now is 20w, what differences would I see if I switched to 15w?

[choneofakind]

It can't just be stiff, it has to be the correct type of stiff.

[alex.s]

Originally Posted by Old Lemon

I see. But I thought stiff was good for track riding? I really don't know how my suspension is suppose to feel whether it is good or bad right now, that's why I'm confused when I try to read up on things but it's just stiff or soft. Also, say the fork oil I have now is 20w, what differences would I see if I switched to 15w?

there are basically 4 parameters to your suspension

two have to do with the spring, and the other two have to do with oil and valves.

the spring:
you have around 4 inches of travel in your suspension. you want to use as much of it as you can without using too much. if you use too much you "bottom out" or "top out" and the suspension stops going any more and things get harsh real fast. the main concern for your spring is the "spring rate" which is defined as kg per mm. example above is that 0.70kg/mm. this means the resistance applied from the spring increases by .7kg per mm of deflection. it is hard to choose a right spring rate because it is entirely dependent on how hard you push the bike. harder braking, cornering and accelerating put more force onto the suspension. so for track riding for example you need stiffer springs since you are putting much more force into the bike. but for street, since you aren't pushing the bike as hard, you can use looser springs. tbh you want as loose of springs as you can get without going so loose that you bottom out.

once you figure out what spring rate you need, setting the correct "sags" is important. in order to be able to soak up all the bumps and not "top out", you need some buffer room at the top of the suspension travel. typically for street 30mm is the general guideline. you set your sags by adjusting preload. the spring itself is however many kg/mm, but your bike and body weigh a certain amount, so in order to maximize the available travel in your suspension, you add preload (extra compression) to the springs, since you wont ever be under a certain weight (unless you are cresting a hill or jumping something for example) so in order to not waste that travel, the preload is added to get correct sags.


so now you have a correct spring and preload setup. the other big side is damping. springs have very little damping and will bounce back and forth for a long time. this is bad for traction. so they add oil into the forks to give it a constant "friction" against bouncing. the lower the friction, the easier it is for the forks to move up and down. thicker the oil, more friction, more resistance to the motion, less bouncing. refer to the docs i sent you for tuning this.

[InvisiBill]

You need the proper rate spring to match the weight it's supporting. If it's too soft, the bike will wallow (too much squishing up and down). If it's too stiff, the spring won't compress for bumps and the tire will skip. Generally you can get away with a stiffer setup on the track because you don't need to plan for the big bumps you'd encounter out on public roads, and you're probably willing to deal with a bit of discomfort to go faster. But as mentioned before, too stiff can be just as bad as too soft - both result in the wheel not following the road surface well.

Once you've got the proper spring rate to allow the bike to bounce in the right range, then you can adjust the damping to control that bouncing (if your springs are too soft, the damping has to work harder to control the excessive bouncing too). On the little Ninjas, the damping is a simple system of fork oil weight vs. holes in the damper rod. The size of the hole and the density of the oil determine the rate of flow. On a certain size bump, that rate will be ideal. On anything smaller, the flow will be too much and the forks will feel soft. On anything bigger, the flow will be too slow and the forks will feel harsh. Emulators and Intiminators are a way to add more adjustability to the damping rate, so it works better over a range of road conditions.

[cbinker]

Originally Posted by choneofakind

It can't just be stiff, it has to be the correct type of stiff.

thats what she said.

[Old Lemon]

Wow Alex and bill, thanks a lot. That is very useful info on how suspension works and imo you guys should combine those 2 posts into a new thread and get a sticky

[simook]

I'd be interested in those docs you sent Alex.

[alex.s]

sorry they are top secret. straight from erik buell himself